Heterojunction Mo-based binary and ternary nitride catalysts with Pt-like activity for the hydrogen evolution reaction

The development of earth-abundant electrocatalysts with Pt-like catalytic activity for the hydrogen evolution reaction (HER) is of great significance to green hydrogen production. Herein, a novel strategy is described to construct dual-phase nitride nanobelts composed of Mo2N and Ni0.2Mo0.8N by nitridation of Ni2+ intercalated layered MoO3 nanobelts (NBs). The Mo2N/Ni0.2Mo0.8N catalyst exhibits superior stability and a low over-potential of 26 mV at 10 mA cm(-2) and Tafel slope of 31 mV dec(-1) in both the alkaline electrolyte and simulated seawater, which is comparable to or better than that of the benchmark Pt/C catalyst. The excellent alkaline HER characteristics is attributed to the Mo2N/Ni0.2Mo0.8N heterostructure with adjustable content and robust interfaces and without metal Ni segregation and structure collapse during nitridation. Density-functional theory (DFT) calculations and experiments reveal that the Mo2N/Ni0.2Mo0.8N interface with strong electronic interactions optimizes H adsorption/desorption yielding moderately weak bonding metal sites with positive Delta G(H)* as the catalytic centers, thereby accelerating the HER kinetics and boosting the HER activity. The results reveal a simple strategy for the preparation of heterostructured nitride-based catalysts with Pt-like activity for hydrogen evolution.

Automated summary

In this study, a novel strategy is utilized to synthesize dual-phase nitride nanobelts (NBs) composed of Mo2N and Ni0.2Mo0.8N, by nitridation of Ni2+ intercalated layered MoO3 NBs. The Mo2N/Ni0.2Mo0.8N catalyst exhibits excellent stability and performance in alkaline electrolyte and simulated seawater, comparable to or better than Pt/C catalyst. The high catalytic activity is attributed to the heterostructure of Mo2N/Ni0.2Mo0.8N with adjustable content and robust interfaces, as well as the absence of metal Ni segregation and structure collapse during nitridation.