In situ electrochemical hydrogenation of dibenzyl toluene as liquid organic hydrogen carriers

In situ electrochemical hydrogenation of dibenzyl toluene as liquid organic hydrogen carriers | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article In situ electrochemical hydrogenation of dibenzyl toluene as liquid organic hydrogen carriers Haiyan Huang, Song Zheng, Zhifang Cheng, Keng H. Chung This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7003084/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 14 Jan, 2026 Read the published version in Journal of Applied Electrochemistry → Version 1 posted 9 You are reading this latest preprint version Abstract Liquid organic hydrogen carriers (LOHC) are an important development direction for diversified hydrogen storage and transportation technologies. Electrochemical in-situ hydrogenation of liquid organic compounds can effectively couple hydrogen production and storage processes, which has important research significance and potential application prospects. This paper uses dibenzyl toluene (H0-DBT) as an electrochemical liquid organic in-situ hydrogen storage material, which is a new attempt and provides new ideas for the selection of future electrochemical liquid organic hydrogen storage materials. The research results indicate that in situ electrochemical hydrogenation of H0-DBT is feasible. Through the analysis of cyclic voltammetry and electrochemical impedance spectroscopy, the hydrogenation reduction of DBT on the Ru-Ti-Ir electrode surface is carried out in multiple steps controlled by diffusion. With the increase of temperature, proton donor concentration and H0-DBT concentration, the hydrogenation current density of H0-DBT increases. The hydrogenation products of H0-DBT are incomplete hydrogenation product H12-DBT and complete hydrogenation product H18-DBT. The process of hydrogenation from H0-DBT to H12-DBT is faster, while the process of hydrogenation from H12-DBT to H18-DBT is slower. Liquid Organic Hydrogen Carriers (LOHC) Electrochemical hydrogen storage Hydrogenation Dibenzyltoluene(H0-DBT) Electrodes Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction Green hydrogen is directly produced through renewable energy sources such as solar and wind power, and does not produce greenhouse gases during the production process. With high energy density, it is an environmentally friendly form of energy. The storage and transportation of hydrogen has always been a key and important step in the hydrogen application chain. Liquid Organic Hydrogen carriers (LOHC) technology is based on the hydrogenation of unsaturated liquid organics (mainly aromatic hydrocarbons, such as toluene and benzene) under the action of a catalyst to generate stable compounds, and then dehydrogenation reaction is carried out when hydrogen is needed. The reaction of liquid organic hydrogen storage is reversible, the hydrogen storage density is high, and the storage and transportation of hydrogen carriers is safe and convenient, which is suitable for long-distance transportation. It can also use infrastructure such as gasoline transmission pipelines and gas stations. Therefore, LOHC technology is one of the most promising hydrogen storage methods and has received extensive attention. LOHC technology [ 1 – 3 ] is mainly divided into thermal catalytic hydrogenation and electrocatalytic hydrogenation. There have been relevant demonstration projects for thermal catalytic hydrogenation in Europe, but its reaction conditions are relatively harsh, requiring high temperature and high pressure. [ 4 – 5 ] Electrocatalytic hydrogenation can complete the reaction under mild conditions (normal temperature and pressure), so it has gradually attracted the attention of researchers. Most studies focus on the electrochemical hydrogenation of organic compounds benzene and toluene. The hydrogen storage rate of toluene is 6.2wt%, and the general temperature for hydrogen release is greater than 300 o C. Yuta Inami [ 6 – 8 ] attempted to load Ru and Ir onto carbon materials to obtain higher electrocatalyst activity. Researchers Toyoki Imada et al. [ 9 , 10 ] and Matsuoka et al. [ 11 ] used Rh, Au, Pd and Ir to modify Pt electrodes for improving the conversion of toluene. Kensaku Nagasawa [ 12 ] and Atsushi Fukazawa [ 13 ] studied the effects of noble metal catalyst materials on the selectivity of the hydrogenation of toluene in PEM reactors. The hydrogen storage capacity of benzene is higher than that of toluene, which is 7.2wt%, but the hydrogenation reaction is more difficult. F. Montilla [ 14 ] and Yao J L [ 15 ] studied the electrochemical behavior of benzene on Pt electrodes (polycrystalline and single crystal electrodes) in acidic and alkaline solutions. It was found that benzene can be completely converted to cyclohexane in acidic solutions, but no reduction reaction can occur in alkaline solutions. N. Itoh et al. [ 16 ] prepared an Rh/Pt electrode on a polymer electrolyte (Nafion 117) by impregnation reduction method, and conducted a coupled electrochemical hydrogenation reaction of benzene reduction and water electrolysis at 25 ~ 70 o C and atmospheric pressure. Sung Mook Choi [ 17 ] studied the hydrogenation activity of benzene using PtRhM/C (M = W, Pd, or Mo) metal alloy electrodes. Ying Yu et al. [ 18 , 19 ] used 0.2 wt% polyethylene glycol 6000 to modify the Pt/C electrode to increase the solubility of benzene in water, which effectively reduced the mass transfer resistance of the organic phase and increased the hydrogenation reaction rate. And the preparation method of Au/Nafion/Pt composite electrode was proposed for electrochemical hydrogenation of benzene. For other organic hydrogen storage materials, Dafeng Zhang [ 20 ] reported the possibility of using acetonitrile/ethylamine as a hydrogen storage medium, with a hydrogen storage efficiency of 8.9wt% higher than the hydrogen storage capacity of aromatic/cycloalkanes. Ryo Kato [ 21 ] found that poly (vinyl fluorenol) can quantitatively generate hydrogen at 100 ℃ using Ir as a catalyst. Although the theoretical hydrogen storage density of this material is only 1wt%, its dehydrogenation temperature is significantly lower than that of traditional benzene or toluene, which has far-reaching significance for the industrialization of existing organic hydrogen storage. Due to the high volatility and toxicity of benzene and toluene, researchers are also actively searching for some new organic hydrogen storage materials. Dibenzyltoluene (DBT) has a high boiling point and a low melting point. It is inexpensive, nonvolatile, non-toxic and liquid at normal temperature and pressure. Its hydrogen storage efficiency (6.2wt%) is the same as that of toluene. Research on DBT thermochemistry hydrogenation has been reported. [ 22 – 25 ] The hydrogen evolution temperature of DBT after hydrogen storage is lower than that of benzene and toluene, generally less than 300 o C. In this paper, dibenzyl toluene (DBT) will be proposed for the first time as an electrochemical hydrogen storage organic compound. The reaction of electrochemical hydrogenation of dibenzyl toluene in an electrolytic cell is as follows: Anode: 9H 2 O → 18H + + 9/2O 2 + 18e − (1) Cathode: H0-DBT(C 21 H 20 ) + 18H + + 18e − → H18-DBT(C 21 H 38 ) (2) 2H + +2e − →H 2 (side reaction) (3) During the electrolysis process, the hydrogen evolution of electrolyzed water is combined with the hydrogenation of organic compounds to achieve in-situ hydrogenation of liquid hydride, as shown in Fig. 1 . In the paper, the possibility of hydrogen storage and its hydrogenation characteristics will be discussed. The electrochemical behavior and electrochemical hydrogen storage mechanism of DBT were analyzed. This study provides new ideas and ideas for hydrogen storage in liquid organic compounds with potential application prospects. Experimental Materials Nafion® 324 membranes were obtained from DuPont Company. The membrane was treated with solution of H 2 O 2 and 0.5 mol/L H 2 SO 4 in the same way as previously reported. [ 18 ] Analytical grade DBT and sulfuric acid were obtained from the Beijing Chemical Plant. Electrolysis and performance indicator The Ru-Ti-Ir mesh electrode was used as the working electrode with a saturated calomel electrode (SCE) as a reference electrode and Pt was the counter electrode. The anode and cathode were separated by Nafion® 324 membrane. The anode electrolyte is 0.5 mol/L sulfuric acid. And the reduction reaction of dibenzyl toluene (DBT) hydrogenation was on the cathode. Protons produced in the anode by electrolysis of water, are transmitted into the cathode through the membrane. Due to the poor conductivity of organic DBT, the mesh electrode and the membrane should be as close as possible. In the experiment, the mesh electrode and the membrane were thermally pressed at 1.5 MPa for 100s at 170 o C to form the composite electrode with reduced resistance and space between the electrodes. The cell was held at a constant temperature in a water bath. A CHI660 electrochemistry test station was used to measure alternating current impedance (AC impedance). The data of electrochemical impedance spectroscopy (EIS) were analyzed and fitted using the Zview software. The cyclic voltammograms and the current of the process with the bulk electrolysis coulometry (BEC) curve were measured by an electrochemistry test station. In-situ cyclic voltammetry was conducted by cycling the potential at various scanning rates (300, 250, 200, 150, 100, 80, 50 and 30mV/s) between − 0.7V and 1.6 V. Hydrogenation products of DBT were analyzed by Agilent 7890 gas chromatography (GC-SCD) and an Agilent 7890A 5975C gas chromatography mass spectrometry (GC-MS) Results and discussion As shown in Fig. 2 (a), when the scanning range is -0.6 ~ 1.6V, reduction peaks A and B, and oxidation peaks C and D appear. When the scanning range is reduced to 0.2 ~ 1.6V, the B reduction peak corresponds to the D oxidation peak; When the scanning range is -0.7 ~ 0.8V, the A reduction peak corresponds to the C oxidation peak. The results indicate that the reduction process of H0-DBT is carried out in multiple steps, with the more obvious reduction peak being A and the corresponding oxidation peak being C. The change in scanning rate in the CV diagram causes changes in the position and size of the reduction and oxidation peaks in the electrochemical reaction. As shown in Fig. 2 (b), as the scanning rate gradually increases, the potential corresponding to the A and B reduction peaks decreases and the current density increases, while the potential corresponding to the C and D oxidation peaks increases and the current density increases. The main reason is that as the scanning rate increases, the electron transfer rate continues to accelerate. When there is no significant change in the diffusion rate, the peak current will lag due to the concentration of the substance diffusing to the electrode not being replenished in a timely manner, resulting in each peak potential gradually moving away from the equilibrium potential. The oxidation peak moves toward the positive direction, the reduction peak moves toward a more negative direction, and the peak current continuously increases. This indicates that the electrode process is controlled by diffusion. At the same time, the I P / \(\:\sqrt{\text{v}}\) values of reduction peak A and oxidation peak C are independent of changes in scanning rate, [ 26 ] indicating that a simple charge transfer reaction \(\:\text{O+n}{\text{e}}^{\text{-}}\text{⇌}\text{R}\) (on the electrode) is performed first, and the product R gradually diffuses from the electrode surface to the solution as the subsequent chemical reaction occurs. Therefore, the CV curve of this electrochemical reaction process has the characteristic of a larger oxidation current peak, so the ratio of peak current to C oxidation peak and A reduction peak is greater than 1. Combining electrochemical impedance spectroscopy data, use the equivalent circuit method to calculate solution resistance, reaction resistance, and other data. As shown in Fig. 3 , the diffusion process on the electrode surface and the multi-step hydrogenation process of organic matter is reflected by fitting circuit R(Q(R(CR)) (Q(R(CR))). R 1 refers to the solution resistance, and the two trapezoidal circuits in series represent each hydrogenation reaction process. The actual reaction resistance and diffusion adsorption resistance are separated in the trapezoidal circuit, where R 2 represents the actual reaction resistance and R 3 represents the diffusion resistance on the electrode surface, Q is a constant phase angle element (CPE) used to characterize the dispersion effect and increase the accuracy of the equivalent circuit. According to the equivalent circuit shown in Fig. 3 , the electrochemical impedance spectroscopy is fitted. The Nyqiust plot of the fitted circuit are highly coincident with the real Nyqiust diagram, which proves the accuracy of the equivalent circuit. EIS data fitting results show that its error rate is extremely small because χ 2 is only 4.736×10 − 4 . R 3 and R 5 , representing diffusion resistance, respectively, which are particularly large, indicating that the H0-DBT electrochemical hydrogen storage reaction is controlled by the diffusion process. Figure 4(a) shows that the current density of H0-DBT reduction increases continuously with increasing temperature. The increase in temperature leads to an increase in the diffusion coefficient of the reactant, a decrease in the viscosity of the liquid, an increase in the conductivity of the solution, and a decrease in the resistance, all of which are beneficial for improving the rate of electrochemical hydrogenation reaction. The relationship between current density and temperature is based on the Arrhenius equation [27] . The apparent activation energy of the reaction is about 6.66kJ/mol, and the activation energy of the H0-DBT electrochemical hydrogen storage reaction is less than 15kJ, which further indicates that the H0-DBT electrochemical hydrogen storage reaction process is controlled by the diffusion step. Figure 5(b) shows that as the concentration of proton donor (H 2 SO 4 solution) increases, the current density of H0-DBT reduction also continuously increases. From Figure 5(c), it can be seen that when the concentration is low, the current density increases sharply with the gradual increase of H0-DBT concentration. As the concentration gradually increases, the increase in current density also tends to be gradual, but the overall trend of current density gradually increases. Under appropriate conditions for the electrochemical hydrogenation reaction of H0-DBT, Plate and Frame Electrolyzer was used for the hydrogenation reaction. By analyzing the intermediate products during the hydrogenation process of H0-DBT, the hydrogenation efficiency and hydrogenation mechanism of H0-DBT were studied. The chromatograms before and after electrolytic hydrogenation are shown in Figure 5, Figure 6 and Figure 7 are the mass spectra of the reactants and products after hydrogenation. Chromatography-mass spectrometry analysis revealed that the hydrogenation products of H0-DBT included incomplete hydrogenation products H12-DBT and complete hydrogenation products H18-DBT, but no hydrogenation products H6-DBT were detected. The mass fraction of incomplete hydrogenation product H12-DBT is 1.99% wt, and the mass fraction of complete hydrogenation product H18-DBT is 0.22% wt, resulting in an H0-DBT hydrogenation current efficiency of 33.70% and a hydrogenation rate of 2.155×10 -4 mol/h. The products of electrochemical hydrogen storage of H0-DBT in SPE electrolytic cells are more H12-DBT and a small amount of H18-DBT. It can be inferred that the lower the saturation of H0-DBT, the faster the electrochemical hydrogen storage rate. As the electrochemical hydrogen storage reaction progresses, the higher the saturation, resulting in a slower electrochemical hydrogen storage rate. Therefore, the process of hydrogenation from H0-DBT to H12-DBT is faster, while the process of hydrogenation from H12-DBT to H18-DBT is slower. H0-DBT is a polycyclic aromatic compound with three benzene rings in its structural formula. When ignoring its partial hydrogenation ring and regional isomers during the hydrogen storage reaction, there are six DBT derivatives in the hydrogenation process from H0-DBT to H18-DBT. From the intermediate products, it can be inferred that there are two possibilities for the hydrogenation process of H0-DBT. One is that the middle ring and one side ring are first hydrogenated, followed by the other side ring. The second hydrogenation process involves the hydrogenation of the two sides rings first, followed by the hydrogenation of the intermediate ring. This hydrogenation path is also the H0-DBT thermochemistry hydrogenation path on Ru catalyst. [28] The first step of each possible hydrogenation process reacts quickly due to the high degree of unsaturation of reactants, and the next step reacts slowly. Taking 3,5-dibenzyl toluene as an example, the process may be shown in Figure 8. Conclusions H0-DBT is completely feasible as an electrochemical liquid organic hydrogen carrier, providing new ideas and directions for the selection of future electrochemical liquid organic hydrogen carriers. The study by Cyclic voltammetry and EIS shows that the hydrogenation of H0-DBT on the surface of the cathode Ru-Ti-Ir composite electrode is carried out step by step, and the diffusion resistance is far greater than the reaction resistance. The electrochemical hydrogen storage reaction is a process controlled by the diffusion process. The effect of H0-DBT on the hydrogen storage reaction on the electrode surface increases with the increase in temperature, proton donor (H 2 SO 4 solution) concentration, and H0-DBT concentration. Chromatography-mass spectrometry analysis results showed that the hydrogenation products of H0-DBT were incomplete hydrogenation product H12-DBT and complete hydrogenation product H18-DBT. The current efficiency of H0-DBT hydrogenation was 33.70%, and the hydrogenation rate was 2.155×10 − 4 mol/h. The current efficiency and hydrogenation rate are relatively low and can be further improved by improving mass transfer and modifying electrodes in the future. The lower the saturation of H0-DBT, the faster the electrochemical hydrogen storage rate. The process of hydrogenation from H0-DBT to H12-DBT is faster, while the process of hydrogenation from H12-DBT to H18-DBT is slower. Declarations Author Contribution H. Huang and S. Zheng designed and conceived the experiments. S. Zheng and Z. Cheng carried out the experiments and data processing. H. Huang wrote the main manuscript text and S. Zheng prepared figures. All authors reviewed the manuscript. Acknowledgements This work was supported by State Key Laboratory of Heavy Oil Processing of Project 1158, SKLHOP2023115802. References Li L, Yang M, Dong Y, et al. Hydrogen storage and release from a new promising Liquid Organic Hydrogen Storage Carrier (LOHC): 2-methylindole[J]. International Journal of Hydrogen Energy, 2016,41(36):16129-16134. Modisha P M, Ouma C N M, Garidzirai R, et al. The Prospect of Hydrogen Storage Using Liquid Organic Hydrogen Carriers[J]. Energy & Fuels, 2019,33(4):2778-2796. Cacciola G, Giordano N, Restuccia G. Cyclohexane as a liquid phase carrier in hydrogen storage and transport[J]. International Journal of Hydrogen Energy, 1984,9(5): 411-419. Orimo S I, Nakamori Y, Eliseo J R, et al. 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Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 14 Jan, 2026 Read the published version in Journal of Applied Electrochemistry → Version 1 posted Editorial decision: Revision requested 09 Nov, 2025 Reviews received at journal 03 Nov, 2025 Reviewers agreed at journal 18 Oct, 2025 Reviews received at journal 07 Sep, 2025 Reviewers agreed at journal 18 Aug, 2025 Reviewers invited by journal 14 Aug, 2025 Editor assigned by journal 04 Jul, 2025 Submission checks completed at journal 01 Jul, 2025 First submitted to journal 29 Jun, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7003084","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":501701077,"identity":"002a7402-6a4b-40af-8ad5-b7a31e0c2356","order_by":0,"name":"Haiyan Huang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAoUlEQVRIiWNgGAWjYBACAwkGxgcQZgLxWpgNSNbCJkGaFnPpHrOKn213GPjZcwwYfu4gQovlnDNmN3vbnjFI9rwxYOw9Q4zDbuSY3WZsOwxiGDAzthGppRikxZ4kLcxgWySI15JWLNlz7hmPxJlnBQd7idOSvPHDj7I7cvztyRsf/CRGCwMDBygmD/CAmAeI0sDAwP6ABMWjYBSMglEwIgEABHc2e3MfJA8AAAAASUVORK5CYII=","orcid":"","institution":"China University of Petroleum","correspondingAuthor":true,"prefix":"","firstName":"Haiyan","middleName":"","lastName":"Huang","suffix":""},{"id":501701078,"identity":"64f52999-b5f2-4b35-b5f0-36e9ca349095","order_by":1,"name":"Song Zheng","email":"","orcid":"","institution":"China University of Petroleum","correspondingAuthor":false,"prefix":"","firstName":"Song","middleName":"","lastName":"Zheng","suffix":""},{"id":501701079,"identity":"1bb5878d-2b48-4d92-b2da-316f96dbe769","order_by":2,"name":"Zhifang Cheng","email":"","orcid":"","institution":"China University of Petroleum","correspondingAuthor":false,"prefix":"","firstName":"Zhifang","middleName":"","lastName":"Cheng","suffix":""},{"id":501701080,"identity":"33f92864-4a91-4b2d-899c-72a09c1d4097","order_by":3,"name":"Keng H. Chung","email":"","orcid":"","institution":"Shandong Institute of Petroleum and Chemical Technology","correspondingAuthor":false,"prefix":"","firstName":"Keng","middleName":"H.","lastName":"Chung","suffix":""}],"badges":[],"createdAt":"2025-06-29 13:53:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7003084/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7003084/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10800-025-02397-9","type":"published","date":"2026-01-14T16:30:32+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":89576140,"identity":"90772abf-e267-43d5-9a35-a1e33048bd02","added_by":"auto","created_at":"2025-08-21 13:06:58","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":205709,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of in situ electrochemical hydrogenation process of H0-DBT on the electrode (a working electrode, b proton exchange membrane, c counter electrode)\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/cd36a3f2017b0abae4bebcfa.png"},{"id":89577580,"identity":"210c9cc2-8bbd-4c74-a9f3-c34d15b1aa1a","added_by":"auto","created_at":"2025-08-21 13:22:58","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":129407,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Cyclic voltammogram of H0-DBT on Ru-Ti-Ir electrode at a scan rate of 80 mV/s at different scanning ranges; (b) Cyclic voltammogram of H0-DBT on Ru-Ti-Ir electrode at different scanning rates.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/f5f2a3f15a52bc46dd088e62.png"},{"id":89576148,"identity":"77476ce0-1d35-4d88-a0d7-eaeab33a6945","added_by":"auto","created_at":"2025-08-21 13:06:58","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":151175,"visible":true,"origin":"","legend":"\u003cp\u003eNyqiust plot of H0-DBT hydrogenation at -0.3 V\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/12b96ecfbf5f1ccd79dca77d.png"},{"id":89577107,"identity":"425a73d9-bd90-4210-89bb-1dc9e25b81f7","added_by":"auto","created_at":"2025-08-21 13:14:58","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":164968,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Relationship between H0-DBT reduction temperature and reduction current density; (b) Relationship between proton donor concentration (H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4 \u003c/sub\u003eaq) and reduction current density; (c) Relationship between H0-DBT concentration and reduction current density.\u0026nbsp;\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/c1a308d0f791aae0b29761e4.png"},{"id":89576145,"identity":"59bef076-278c-4e12-8591-8fdeaa73bc85","added_by":"auto","created_at":"2025-08-21 13:06:58","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":57644,"visible":true,"origin":"","legend":"\u003cp\u003eChromatogram of reactants(a) and products(b) of electrochemical hydrogen storage\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/b39226d743134ed5862a702a.png"},{"id":89576143,"identity":"dc28015c-1d8d-48f4-8bce-a3ffb0bed2e0","added_by":"auto","created_at":"2025-08-21 13:06:58","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":125281,"visible":true,"origin":"","legend":"\u003cp\u003eGC-MS spectra of H0-DBT before electrolysis\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/0c5cb7a7f5804e69f822655a.png"},{"id":89577110,"identity":"8077f289-b567-46fd-9160-b6a1e0f2dc55","added_by":"auto","created_at":"2025-08-21 13:14:58","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":328127,"visible":true,"origin":"","legend":"\u003cp\u003e(a)Mass spectra of hydrogenation products H12-DBT; (b) Mass spectra of hydrogenation products H18-DBT\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/ced0247fe920d55c06e0ec3a.png"},{"id":89577116,"identity":"1a0bf6d0-d1d9-4f39-95c1-51b441980049","added_by":"auto","created_at":"2025-08-21 13:14:59","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":64031,"visible":true,"origin":"","legend":"\u003cp\u003eH0-DBT electrochemical hydrogen storage process\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/87b3b434aad9508ebac229a3.png"},{"id":100616224,"identity":"d768fbf2-a8c8-488a-b016-b396b55248d4","added_by":"auto","created_at":"2026-01-19 17:41:39","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1521460,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7003084/v1/7650c664-1303-4147-85f9-9828f84a2a62.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"In situ electrochemical hydrogenation of dibenzyl toluene as liquid organic hydrogen carriers","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGreen hydrogen is directly produced through renewable energy sources such as solar and wind power, and does not produce greenhouse gases during the production process. With high energy density, it is an environmentally friendly form of energy. The storage and transportation of hydrogen has always been a key and important step in the hydrogen application chain. Liquid Organic Hydrogen carriers (LOHC) technology is based on the hydrogenation of unsaturated liquid organics (mainly aromatic hydrocarbons, such as toluene and benzene) under the action of a catalyst to generate stable compounds, and then dehydrogenation reaction is carried out when hydrogen is needed. The reaction of liquid organic hydrogen storage is reversible, the hydrogen storage density is high, and the storage and transportation of hydrogen carriers is safe and convenient, which is suitable for long-distance transportation. It can also use infrastructure such as gasoline transmission pipelines and gas stations. Therefore, LOHC technology is one of the most promising hydrogen storage methods and has received extensive attention. LOHC technology \u003csup\u003e[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e is mainly divided into thermal catalytic hydrogenation and electrocatalytic hydrogenation. There have been relevant demonstration projects for thermal catalytic hydrogenation in Europe, but its reaction conditions are relatively harsh, requiring high temperature and high pressure. \u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e Electrocatalytic hydrogenation can complete the reaction under mild conditions (normal temperature and pressure), so it has gradually attracted the attention of researchers.\u003c/p\u003e\u003cp\u003eMost studies focus on the electrochemical hydrogenation of organic compounds benzene and toluene. The hydrogen storage rate of toluene is 6.2wt%, and the general temperature for hydrogen release is greater than 300 \u003csup\u003eo\u003c/sup\u003eC. Yuta Inami\u003csup\u003e[\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e attempted to load Ru and Ir onto carbon materials to obtain higher electrocatalyst activity. Researchers Toyoki Imada et al.\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e and Matsuoka et al.\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e used Rh, Au, Pd and Ir to modify Pt electrodes for improving the conversion of toluene. Kensaku Nagasawa\u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e and Atsushi Fukazawa\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e studied the effects of noble metal catalyst materials on the selectivity of the hydrogenation of toluene in PEM reactors.\u003c/p\u003e\u003cp\u003eThe hydrogen storage capacity of benzene is higher than that of toluene, which is 7.2wt%, but the hydrogenation reaction is more difficult. F. Montilla \u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e and Yao J L \u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e studied the electrochemical behavior of benzene on Pt electrodes (polycrystalline and single crystal electrodes) in acidic and alkaline solutions. It was found that benzene can be completely converted to cyclohexane in acidic solutions, but no reduction reaction can occur in alkaline solutions. N. Itoh et al. \u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e prepared an Rh/Pt electrode on a polymer electrolyte (Nafion 117) by impregnation reduction method, and conducted a coupled electrochemical hydrogenation reaction of benzene reduction and water electrolysis at 25\u0026thinsp;~\u0026thinsp;70 \u003csup\u003eo\u003c/sup\u003eC and atmospheric pressure. Sung Mook Choi \u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e studied the hydrogenation activity of benzene using PtRhM/C (M\u0026thinsp;=\u0026thinsp;W, Pd, or Mo) metal alloy electrodes. Ying Yu et al. \u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e used 0.2 wt% polyethylene glycol 6000 to modify the Pt/C electrode to increase the solubility of benzene in water, which effectively reduced the mass transfer resistance of the organic phase and increased the hydrogenation reaction rate. And the preparation method of Au/Nafion/Pt composite electrode was proposed for electrochemical hydrogenation of benzene.\u003c/p\u003e\u003cp\u003eFor other organic hydrogen storage materials, Dafeng Zhang \u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e reported the possibility of using acetonitrile/ethylamine as a hydrogen storage medium, with a hydrogen storage efficiency of 8.9wt% higher than the hydrogen storage capacity of aromatic/cycloalkanes. Ryo Kato \u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e found that poly (vinyl fluorenol) can quantitatively generate hydrogen at 100 ℃ using Ir as a catalyst. Although the theoretical hydrogen storage density of this material is only 1wt%, its dehydrogenation temperature is significantly lower than that of traditional benzene or toluene, which has far-reaching significance for the industrialization of existing organic hydrogen storage.\u003c/p\u003e\u003cp\u003eDue to the high volatility and toxicity of benzene and toluene, researchers are also actively searching for some new organic hydrogen storage materials. Dibenzyltoluene (DBT) has a high boiling point and a low melting point. It is inexpensive, nonvolatile, non-toxic and liquid at normal temperature and pressure. Its hydrogen storage efficiency (6.2wt%) is the same as that of toluene. Research on DBT thermochemistry hydrogenation has been reported. \u003csup\u003e[\u003cspan additionalcitationids=\"CR23 CR24\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/sup\u003e The hydrogen evolution temperature of DBT after hydrogen storage is lower than that of benzene and toluene, generally less than 300 \u003csup\u003eo\u003c/sup\u003eC.\u003c/p\u003e\u003cp\u003eIn this paper, dibenzyl toluene (DBT) will be proposed for the first time as an electrochemical hydrogen storage organic compound. The reaction of electrochemical hydrogenation of dibenzyl toluene in an electrolytic cell is as follows:\u003c/p\u003e\u003cp\u003eAnode: 9H\u003csub\u003e2\u003c/sub\u003eO \u0026rarr; 18H\u003csup\u003e+\u003c/sup\u003e+ 9/2O\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;18e\u003csup\u003e\u0026minus;\u003c/sup\u003e (1)\u003c/p\u003e\u003cp\u003eCathode: H0-DBT(C\u003csub\u003e21\u003c/sub\u003eH\u003csub\u003e20\u003c/sub\u003e )\u0026thinsp;+\u0026thinsp;18H\u003csup\u003e+\u003c/sup\u003e + 18e\u003csup\u003e\u0026minus;\u003c/sup\u003e \u0026rarr; H18-DBT(C\u003csub\u003e21\u003c/sub\u003eH\u003csub\u003e38\u003c/sub\u003e) (2)\u003c/p\u003e\u003cp\u003e2H\u003csup\u003e+\u003c/sup\u003e +2e\u003csup\u003e\u0026minus;\u003c/sup\u003e \u0026rarr;H\u003csub\u003e2\u003c/sub\u003e (side reaction) (3)\u003c/p\u003e\u003cp\u003eDuring the electrolysis process, the hydrogen evolution of electrolyzed water is combined with the hydrogenation of organic compounds to achieve in-situ hydrogenation of liquid hydride, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eIn the paper, the possibility of hydrogen storage and its hydrogenation characteristics will be discussed. The electrochemical behavior and electrochemical hydrogen storage mechanism of DBT were analyzed. This study provides new ideas and ideas for hydrogen storage in liquid organic compounds with potential application prospects.\u003c/p\u003e"},{"header":"Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eMaterials\u003c/h2\u003e\u003cp\u003eNafion\u0026reg; 324 membranes were obtained from DuPont Company. The membrane was treated with solution of H\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e2\u003c/sub\u003e and 0.5 mol/L H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e in the same way as previously reported.\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e Analytical grade DBT and sulfuric acid were obtained from the Beijing Chemical Plant.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eElectrolysis and performance indicator\u003c/h3\u003e\n\u003cp\u003eThe Ru-Ti-Ir mesh electrode was used as the working electrode with a saturated calomel electrode (SCE) as a reference electrode and Pt was the counter electrode. The anode and cathode were separated by Nafion\u0026reg; 324 membrane. The anode electrolyte is 0.5 mol/L sulfuric acid. And the reduction reaction of dibenzyl toluene (DBT) hydrogenation was on the cathode. Protons produced in the anode by electrolysis of water, are transmitted into the cathode through the membrane. Due to the poor conductivity of organic DBT, the mesh electrode and the membrane should be as close as possible. In the experiment, the mesh electrode and the membrane were thermally pressed at 1.5 MPa for 100s at 170 \u003csup\u003eo\u003c/sup\u003eC to form the composite electrode with reduced resistance and space between the electrodes. The cell was held at a constant temperature in a water bath.\u003c/p\u003e\u003cp\u003eA CHI660 electrochemistry test station was used to measure alternating current impedance (AC impedance). The data of electrochemical impedance spectroscopy (EIS) were analyzed and fitted using the Zview software. The cyclic voltammograms and the current of the process with the bulk electrolysis coulometry (BEC) curve were measured by an electrochemistry test station. In-situ cyclic voltammetry was conducted by cycling the potential at various scanning rates (300, 250, 200, 150, 100, 80, 50 and 30mV/s) between \u0026minus;\u0026thinsp;0.7V and 1.6 V.\u003c/p\u003e\u003cp\u003eHydrogenation products of DBT were analyzed by Agilent 7890 gas chromatography (GC-SCD) and an Agilent 7890A 5975C gas chromatography mass spectrometry (GC-MS)\u003c/p\u003e"},{"header":"Results and discussion","content":"\u003cp\u003e\u003c/p\u003e\u003cp\u003eAs shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a), when the scanning range is -0.6\u0026thinsp;~\u0026thinsp;1.6V, reduction peaks A and B, and oxidation peaks C and D appear. When the scanning range is reduced to 0.2\u0026thinsp;~\u0026thinsp;1.6V, the B reduction peak corresponds to the D oxidation peak; When the scanning range is -0.7\u0026thinsp;~\u0026thinsp;0.8V, the A reduction peak corresponds to the C oxidation peak. The results indicate that the reduction process of H0-DBT is carried out in multiple steps, with the more obvious reduction peak being A and the corresponding oxidation peak being C.\u003c/p\u003e\u003cp\u003eThe change in scanning rate in the CV diagram causes changes in the position and size of the reduction and oxidation peaks in the electrochemical reaction. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(b), as the scanning rate gradually increases, the potential corresponding to the A and B reduction peaks decreases and the current density increases, while the potential corresponding to the C and D oxidation peaks increases and the current density increases. The main reason is that as the scanning rate increases, the electron transfer rate continues to accelerate. When there is no significant change in the diffusion rate, the peak current will lag due to the concentration of the substance diffusing to the electrode not being replenished in a timely manner, resulting in each peak potential gradually moving away from the equilibrium potential. The oxidation peak moves toward the positive direction, the reduction peak moves toward a more negative direction, and the peak current continuously increases. This indicates that the electrode process is controlled by diffusion.\u003c/p\u003e\u003cp\u003eAt the same time, the \u003cem\u003eI\u003c/em\u003e\u003csub\u003eP\u003c/sub\u003e/\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\sqrt{\\text{v}}\\)\u003c/span\u003e\u003c/span\u003e values of reduction peak A and oxidation peak C are independent of changes in scanning rate, \u003csup\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/sup\u003e indicating that a simple charge transfer reaction \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\text{O+n}{\\text{e}}^{\\text{-}}\\text{⇌}\\text{R}\\)\u003c/span\u003e\u003c/span\u003e (on the electrode) is performed first, and the product R gradually diffuses from the electrode surface to the solution as the subsequent chemical reaction occurs. Therefore, the CV curve of this electrochemical reaction process has the characteristic of a larger oxidation current peak, so the ratio of peak current to C oxidation peak and A reduction peak is greater than 1.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eCombining electrochemical impedance spectroscopy data, use the equivalent circuit method to calculate solution resistance, reaction resistance, and other data. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the diffusion process on the electrode surface and the multi-step hydrogenation process of organic matter is reflected by fitting circuit R(Q(R(CR)) (Q(R(CR))). R\u003csub\u003e1\u003c/sub\u003e refers to the solution resistance, and the two trapezoidal circuits in series represent each hydrogenation reaction process. The actual reaction resistance and diffusion adsorption resistance are separated in the trapezoidal circuit, where R\u003csub\u003e2\u003c/sub\u003e represents the actual reaction resistance and R\u003csub\u003e3\u003c/sub\u003e represents the diffusion resistance on the electrode surface, Q is a constant phase angle element (CPE) used to characterize the dispersion effect and increase the accuracy of the equivalent circuit.\u003c/p\u003e\u003cp\u003eAccording to the equivalent circuit shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the electrochemical impedance spectroscopy is fitted. The Nyqiust plot of the fitted circuit are highly coincident with the real Nyqiust diagram, which proves the accuracy of the equivalent circuit. EIS data fitting results show that its error rate is extremely small because χ\u003csup\u003e2\u003c/sup\u003e is only 4.736\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e. R\u003csub\u003e3\u003c/sub\u003e and R\u003csub\u003e5\u003c/sub\u003e, representing diffusion resistance, respectively, which are particularly large, indicating that the H0-DBT electrochemical hydrogen storage reaction is controlled by the diffusion process.\u003c/p\u003e\u003cp\u003eFigure 4(a) shows that the current density of H0-DBT reduction increases continuously with increasing temperature. The increase in temperature leads to an increase in the diffusion coefficient of the reactant, a decrease in the viscosity of the liquid, an increase in the conductivity of the solution, and a decrease in the resistance, all of which are beneficial for improving the rate of electrochemical hydrogenation reaction. The relationship between current density and temperature is based on the Arrhenius equation \u003csup\u003e[27]\u003c/sup\u003e. The apparent activation energy of the reaction is about 6.66kJ/mol, and the activation energy of the H0-DBT electrochemical hydrogen storage reaction is less than 15kJ, which further indicates that the H0-DBT electrochemical hydrogen storage reaction process is controlled by the diffusion step. Figure 5(b) shows that as the concentration of proton donor (H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution) increases, the current density of H0-DBT reduction also continuously increases. From Figure 5(c), it can be seen that when the concentration is low, the current density increases sharply with the gradual increase of H0-DBT concentration. As the concentration gradually increases, the increase in current density also tends to be gradual, but the overall trend of current density gradually increases.\u003c/p\u003e\n\u003cp\u003eUnder appropriate conditions for the electrochemical hydrogenation reaction of H0-DBT, Plate and Frame Electrolyzer was used for the hydrogenation reaction. By analyzing the intermediate products during the hydrogenation process of H0-DBT, the hydrogenation efficiency and hydrogenation mechanism of H0-DBT were studied.\u003c/p\u003e\n\u003cp\u003eThe chromatograms before and after electrolytic hydrogenation are shown in Figure 5, Figure 6 and Figure 7 are the mass spectra of the reactants and products after hydrogenation. Chromatography-mass spectrometry analysis revealed that the hydrogenation products of H0-DBT included incomplete hydrogenation products H12-DBT and complete hydrogenation products H18-DBT, but no hydrogenation products H6-DBT were detected. The mass fraction of incomplete hydrogenation product H12-DBT is 1.99% wt, and the mass fraction of complete hydrogenation product H18-DBT is 0.22% wt, resulting in an H0-DBT hydrogenation current efficiency of 33.70% and a hydrogenation rate of 2.155\u0026times;10\u003csup\u003e-4\u003c/sup\u003emol/h.\u003c/p\u003e\n\u003cp\u003eThe products of electrochemical hydrogen storage of H0-DBT in SPE electrolytic cells are more H12-DBT and a small amount of H18-DBT. It can be inferred that the lower the saturation of H0-DBT, the faster the electrochemical hydrogen storage rate. As the electrochemical hydrogen storage reaction progresses, the higher the saturation, resulting in a slower electrochemical hydrogen storage rate. Therefore, the process of hydrogenation from H0-DBT to H12-DBT is faster, while the process of hydrogenation from H12-DBT to H18-DBT is slower.\u003c/p\u003e\n\u003cp\u003eH0-DBT is a polycyclic aromatic compound with three benzene rings in its structural formula. When ignoring its partial hydrogenation ring and regional isomers during the hydrogen storage reaction, there are six DBT derivatives in the hydrogenation process from H0-DBT to H18-DBT. From the intermediate products, it can be inferred that there are two possibilities for the hydrogenation process of H0-DBT. One is that the middle ring and one side ring are first hydrogenated, followed by the other side ring. The second hydrogenation process involves the hydrogenation of the two sides rings first, followed by the hydrogenation of the intermediate ring. This hydrogenation path is also the H0-DBT thermochemistry hydrogenation path on Ru catalyst. \u003csup\u003e[28]\u003c/sup\u003e The first step of each possible hydrogenation process reacts quickly due to the high degree of unsaturation of reactants, and the next step reacts slowly. Taking 3,5-dibenzyl toluene as an example, the process may be shown in Figure 8.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eH0-DBT is completely feasible as an electrochemical liquid organic hydrogen carrier, providing new ideas and directions for the selection of future electrochemical liquid organic hydrogen carriers. The study by Cyclic voltammetry and EIS shows that the hydrogenation of H0-DBT on the surface of the cathode Ru-Ti-Ir composite electrode is carried out step by step, and the diffusion resistance is far greater than the reaction resistance. The electrochemical hydrogen storage reaction is a process controlled by the diffusion process. The effect of H0-DBT on the hydrogen storage reaction on the electrode surface increases with the increase in temperature, proton donor (H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e solution) concentration, and H0-DBT concentration. Chromatography-mass spectrometry analysis results showed that the hydrogenation products of H0-DBT were incomplete hydrogenation product H12-DBT and complete hydrogenation product H18-DBT. The current efficiency of H0-DBT hydrogenation was 33.70%, and the hydrogenation rate was 2.155\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003emol/h. The current efficiency and hydrogenation rate are relatively low and can be further improved by improving mass transfer and modifying electrodes in the future. The lower the saturation of H0-DBT, the faster the electrochemical hydrogen storage rate. The process of hydrogenation from H0-DBT to H12-DBT is faster, while the process of hydrogenation from H12-DBT to H18-DBT is slower.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eH. Huang and S. Zheng designed and conceived the experiments. S. Zheng and Z. Cheng carried out the experiments and data processing. H. Huang wrote the main manuscript text and S. Zheng prepared figures. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003eThis work was supported by State Key Laboratory of Heavy Oil Processing of Project 1158, SKLHOP2023115802.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLi L, Yang M, Dong Y, et al. Hydrogen storage and release from a new promising Liquid Organic Hydrogen Storage Carrier (LOHC): 2-methylindole[J]. International Journal of Hydrogen Energy, 2016,41(36):16129-16134.\u003c/li\u003e\n\u003cli\u003eModisha P M, Ouma C N M, Garidzirai R, et al. The Prospect of Hydrogen Storage Using Liquid Organic Hydrogen Carriers[J]. Energy \u0026amp; Fuels, 2019,33(4):2778-2796.\u003c/li\u003e\n\u003cli\u003eCacciola G, Giordano N, Restuccia G. Cyclohexane as a liquid phase carrier in hydrogen storage and transport[J]. 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Reaction Chemistry \u0026amp; Engineering, 2016, 1, 313\u0026ndash;320.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-applied-electrochemistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jach","sideBox":"Learn more about [Journal of Applied Electrochemistry](http://link.springer.com/journal/10800)","snPcode":"10800","submissionUrl":"https://submission.nature.com/new-submission/10800/3","title":"Journal of Applied Electrochemistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Liquid Organic Hydrogen Carriers (LOHC), Electrochemical hydrogen storage, Hydrogenation, Dibenzyltoluene(H0-DBT), Electrodes","lastPublishedDoi":"10.21203/rs.3.rs-7003084/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7003084/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eLiquid organic hydrogen carriers (LOHC) are an important development direction for diversified hydrogen storage and transportation technologies. Electrochemical in-situ hydrogenation of liquid organic compounds can effectively couple hydrogen production and storage processes, which has important research significance and potential application prospects. This paper uses dibenzyl toluene (H0-DBT) as an electrochemical liquid organic in-situ hydrogen storage material, which is a new attempt and provides new ideas for the selection of future electrochemical liquid organic hydrogen storage materials. The research results indicate that in situ electrochemical hydrogenation of H0-DBT is feasible. Through the analysis of cyclic voltammetry and electrochemical impedance spectroscopy, the hydrogenation reduction of DBT on the Ru-Ti-Ir electrode surface is carried out in multiple steps controlled by diffusion. With the increase of temperature, proton donor concentration and H0-DBT concentration, the hydrogenation current density of H0-DBT increases. The hydrogenation products of H0-DBT are incomplete hydrogenation product H12-DBT and complete hydrogenation product H18-DBT. The process of hydrogenation from H0-DBT to H12-DBT is faster, while the process of hydrogenation from H12-DBT to H18-DBT is slower.\u003c/p\u003e","manuscriptTitle":"In situ electrochemical hydrogenation of dibenzyl toluene as liquid organic hydrogen carriers","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-21 13:06:53","doi":"10.21203/rs.3.rs-7003084/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-11-09T12:17:14+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-03T20:30:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"201561715841953774435013137038394093610","date":"2025-10-18T20:37:29+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-07T09:53:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"337602864522650277194894920676409144639","date":"2025-08-18T05:35:33+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-14T05:20:23+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-04T16:57:53+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-01T05:17:39+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Applied Electrochemistry","date":"2025-06-29T13:50:31+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-applied-electrochemistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jach","sideBox":"Learn more about [Journal of Applied Electrochemistry](http://link.springer.com/journal/10800)","snPcode":"10800","submissionUrl":"https://submission.nature.com/new-submission/10800/3","title":"Journal of Applied Electrochemistry","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"e9661eea-1e60-4d65-be6f-f7cac5cf78bf","owner":[],"postedDate":"August 21st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-01-19T17:08:08+00:00","versionOfRecord":{"articleIdentity":"rs-7003084","link":"https://doi.org/10.1007/s10800-025-02397-9","journal":{"identity":"journal-of-applied-electrochemistry","isVorOnly":false,"title":"Journal of Applied Electrochemistry"},"publishedOn":"2026-01-14 16:30:32","publishedOnDateReadable":"January 14th, 2026"},"versionCreatedAt":"2025-08-21 13:06:53","video":"","vorDoi":"10.1007/s10800-025-02397-9","vorDoiUrl":"https://doi.org/10.1007/s10800-025-02397-9","workflowStages":[]},"version":"v1","identity":"rs-7003084","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7003084","identity":"rs-7003084","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}