Efficient bifunctional catalysts of CoSe/N-doped carbon nanospheres supported Pt nanoparticles for methanol electrolysis of hydrogen generation

Methanol electrolysis is significant but challenging as an energy-saving technique for electrochemical hydrogen production. Herein, we demonstrated a novel and efficient bifunctional catalyst of CoSe/N-doped carbon nanospheres supported Pt nanoparticles for hydrogen generation via methanol electrolysis; high catalytic performance for both methanol oxidation (MOR) and hydrogen evolution (HER) was observed benefitting from the effective interaction of metal and support effect as well as the oxophilic characteristics of cobalt selenide. Theoretical calculation disclosed the increased charge density of Pt induced by the CoSe/NC support has a bifunctional ability for optimizing the H* adsorption energy for hydrogen evolution reaction and weakening the CO adsorption energy of methanol oxidation reaction. Specifically, the largely improved CO-tolerance ability was observed in the CO-stripping technique, where about 90 mV less of the peak potential for CO oxidation than that of Pt/C catalyst was observed, resulting from a strong electronic effect as indicated by the spectroscopic analysis. The peak current density of 84.2 mA.cm(-2) was found for MOR, which was about 3.1 times higher than that of Pt/C; and a low overpotential of 32 mV was required to reach 10 mA.cm(-2) for HER in 0.5 mol.L-1 H2SO4 with 1.0 mol.L-1 CH3OH. When serviced as both anode and cathode catalyst in a methanol electrolyzer, a low cell potential of 0.67 V to offer 10 mA cm(-2) was obtained, about 170 mV less than that of Pt/C catalyst; moreover, it was 1.1 V lower than that of water-splitting (1.77 V), indicating a promising energy-saving technique for hydrogen generation. They also showed very good catalytic stability and anti-poisoning ability during the catalysis process. This work would help understand the metal-support interaction for hydrogen generation vis methanol electrolysis.

Automated summary

In this study, a novel and efficient bifunctional catalyst supported by cobalt selenide was demonstrated for hydrogen generation via methanol electrolysis. The catalyst showed high catalytic performance for both methanol oxidation and hydrogen evolution, with improved CO-tolerance ability and a promising energy-saving potential compared to traditional Pt/C catalysts. This work provides insights into metal-support interactions in hydrogen generation through methanol electrolysis.