Theoretical study the component and facet dependence of HER performance on nickel phosphides surfaces

Energy depletion and environmental pollution are still serious challenges for human beings. The application of hydrogen energy should be a promising strategy to address this issue. However, the hydrogen production should be one shortcoming for hydrogen energy. The hydrogen evolution reaction (HER) based on electrocatalysis is an effective way to enhance the hydrogen generation with small energy consumption under ambient conditions. Many works have been devoted to develop high performance catalysts to satisfy the HER processes. Nevertheless, the mechanism about facet-dependence and composition-dependence influence is still need to deeply study. Hereon, based on density functional theory calculations, the [100], [110], and [111] facets of NixPy (Ni3P, Ni2P, NiP, NiP2, NiP3) systems were created and their HER catalytic activity were used to reveal the underline mechanism. By analyzing the variation of Gibbs free energy, it was found that the structural composition has a greater effect on HER than the facet. Significantly, the Ni2P(111) surface with Ni/P-termination has the best HER performance for all samples in present work. Through exploring the electron transfer of H with surrounding atoms during the HER process, the H adsorption mechanism as well as its reaction mechanism has been revealed. The deep insights in this work provide an important fundamental that the contents of non-metal for compounds catalysts can heavily influence the performance of HER, which should give more guidance for designing new catalysts. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Energy depletion and environmental pollution are serious challenges for humans. The application of hydrogen energy is a promising strategy to address these issues. However, hydrogen production is a drawback for hydrogen energy. The hydrogen evolution reaction (HER) based on electrocatalysis is an effective way to enhance hydrogen generation with low energy consumption. Many efforts have been made to develop high-performance catalysts for HER processes.