Improved the methanol electrooxidation and carbon monoxide tolerance for direct methanol fuel cells using strontium molybdate

Abstract Electrocatalysts possess high methanol electrooxidation (MOR) and carbon monoxide (CO) tolerance abilities to meet application requirements for enhanced performance of direct methanol fuel cells (DMFCs). Higher MOR and CO tolerance activities measured via cyclic voltammetry (CV) are achieved based on a strontium molybdate (SrMoO4) mixed with Vulcan XC-72 carbon and loaded with 20% Pt. The synergistic effect of the bifunctional mechanism inducing the strontium molybdate is beneficial for removing CO-like intermediate products on the Pt surface, which leads to more Pt active sites released during MOR. The simultaneous unique structural formation of HxMoO3/HyMoO3 and SrMoO3 in uncalcined Sr0.5Mo0.5O4−δ provides key synergistic effects for the 20%-Pt/uncalcined Sr0.5Mo0.5O4−δ-C electrocatalysts, improving DMFCs performance. Results show that the 20%-Pt/uncalcined Sr0.5Mo0.5O4−δ-C electrocatalysts exhibit excellent electrocatalytic activity for MOR (with a forward peak current density of 12.56 mA/cm2 and large electrochemically active surface area (ECSAH) of 116.53 m2/g, the best CO tolerance for electrooxidation of carbon monoxide (largest ECSACO of 116.53 m2/g), and the highest electric conductivity (Rct of 940 Ω∙cm2). Furthermore, the fabricated DMFC shows excellent long-term electrochemical stability after 1000 cycles and a maximum power density (1.42 mW/cm2) higher than that with commercial 20%-Pt/C (1.27 mW/cm2).