Integration of heterointerface and porosity engineering to achieve efficient hydrogen evolution of 2D porous NiMoN nanobelts coupled with Ni particles

Abstract

The design of the electrocatalysts with the plentiful heterojuctional interface and large-accessible surface is desired to boost the HER performance, but it remains a challenge. Herein, we showed the design of 2D Ni/Ni0.2Mo0.8N porous heterojunction nanobelts as effective catalyst for the HER. The intimate combination of Ni and Ni0.2Mo0.8N can make the formation of the heterojuctional interface with plentiful active sites. The 2D porous structure can provide large accessible surface with less resistance for the transmission of the electrolytes, thus promoting the mass/charge transfer. The ratio of Ni and Ni0.2Mo0.8N can be easily tuned by regulating the precursor composition, which is important to give catalysts with optimized interface and suitable pores. Density functional theory calculations reveal that the interaction between Ni and Ni0.2Mo0.8N at the heterointerface can largely improve the intermediate H* adsorption kinetics (ΔGH* = -0.07 eV). Due to the above advantages, the optimized catalysts exhibited excellent HER activity with a low overpotential of 48 mV in 1 M KOH at 10 mA cm−2 (without iR correction), which is superior to the most reported non-noble metal-based catalysts, and the long-term durability with no obvious degradation after continual operation of 48 h Notably, an electrolyzer assembled by the optimized Ni/Ni0.2Mo0.8N cathode with NiFe-LDH anode only requires a low operating voltage of 1.47 V to deliver 10 mA cm−2 in 1 M KOH, surpassing the corresponding Pt/NF||RuO2/NF electrolyzer (1.61 V) and most of reported electrolyzers.