An effective Pt–CoTe/NC catalyst of bifunctional methanol electrolysis for hydrogen generation

Abstract

Hydrogen production from water electrolysis is seriously restricted by the high energy consumption caused by water oxidation. Herein, an effective low-energy input for hydrogen generation via methanol-assisted water electrolysis catalyzed by bifunctional Pt–CoTe/NC nanospheres is demonstrated, which can be obtained by the ZIF-67 derived CoTe/NC supported ultrafine Pt nanoparticles. The experimental and density functional theory calculation analysis indicated that the optimized electronic structure of Pt–CoTe/NC modifies the adsorption energies of the intermediate (CO and H*), which exhibits superior catalytic activity and stability for methanol oxidation reaction (MOR) and hydrogen evolution reaction (HER). For MOR, the current density of Pt–CoTe/NC-800 is 102.2 mA cm−2, which is 3.7 times that of commercial Pt/C catalyst, and high anti-poisoning ability is also found in the CO-stripping technique. Moreover, the small overpotential of 28 mV is required to deliver a current density of 10 mA cm−2 for HER. When the optimal Pt–CoTe/NC serves as both cathode and anode in a two-electrode electrolyzer for methanol electrolysis, a low cell potential of 0.68 V is required to reach 10 mA cm−2, about 960 mV lower than that of water electrolysis, and the performance is also much better than that of Pt/C||Pt/C electrode system. The current work offers a robust platform of bifunctional catalyst for MOR coupled with HER for hydrogen generation.