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Key Words:Zinc;Atoms - Carbides - Catalysts - Chemical bonds - Density functional theory - Electrolytes - Hydrogen - Molybdenum compounds - Nanosheets - Slope stability
Abstract:Developing non-precious metal catalysts with both high efficiency and long-term stability is the top priority for hydrogen evolution reactions (HER). Herein, we present a facile two-step method to synthesize Zn, N co-doped molybdenum carbide nanosheets (Zn-N-MoC-H NSs) by using bi-metal oxides of ZnMoO<inf>4</inf> as a unique precursor. Zn not only serves as a template to form a porous structure on MoC nanosheets during volatilizing at high temperatures, but also acts as a doping source for Zn doping in MoC. The N-containing carbon source realizes N doping of MoC. Benefitting from Zn, N co-doping and the porous nanosheet structure with a large electrochemical surface area, Zn-N-MoC-H NSs lead to enhanced HER activity in an acidic electrolyte (0.5 M H<inf>2</inf>SO<inf>4</inf>) with a low onset potential of -66 mV vs. RHE (1 mA cm<sup>-2</sup>), overpotential of 128 mV (10 mA cm<sup>-2</sup>), small Tafel slope of 52.1 mV dec<sup>-1</sup> and persistent long-term stability. Density functional theory calculations reveal that Zn, N co-doping can synergistically weaken the strong Mo-H bonding, improve absorbed hydrogen atom (H<inf>ads</inf>) desorption and lead to faster HER kinetics. This study provides new insights into the use of Zn as a template and electronic regulator toward efficient catalysis and applications in energy storage and conversion.<br/> © The Royal Society of Chemistry.
Volume:11
Issue:4
Translation or Not:no