Petaloid Defect-Rich Coconut Shell Derived Carbon as Profitable Catalyst Support for MoSe2 in Electrocatalytic Hydrogen Production

MoSe2 demonstrates considerable potential for electrocatalytic hydrogen evolution reaction (HER) due to its intrinsic catalytic activity and excellent chemical stability. However, the poor conductivity of bulk MoSe2 and the scarcity of active sites limit its catalytic performance. Herein, a petaloid defect-rich carbon carrier designed as coconut shell-based carbon (CBC) is obtained and applied as support to improve the HER performance of MoSe2. Experimental data and density functional theory calculations reveal that the defects in CBC are more effective to regulate the nucleation and growth of MoSe2 than defect-free commercial graphite nanosheets (CGN), promoting vertical orientation of MoSe2 and exposing more active sites. More importantly, the defects facilitate the formation of Mo-C bonds on the boundaries between CBC and MoSe2, accelerating the electron transportation and regulating the electron structure on the boundary, while the formation of Mo-C bonds induced Mo/Se vacancies also optimize the Gibbs free energy of hydrogen adsorption near the boundaries. Consequently, the MoSe2/CBC catalyst exhibits a low overpotential of 132 mV at 10 mA cm−2 in 0.5 M H2SO4 electrolyte, significantly improved over the 245 mV of MoSe2/CGN. Remarkably, it also achieves an overpotential of only 984 mV at a high current density of 600 mA cm−2.