Synthetic strategy and evaluation of hierarchical nanoporous NiO/NiCoP microspheres as efficient electrocatalysts for hydrogen evolution reaction

The development of efficient hydrogen evolution reaction (HER) catalysts based on non-precious metal alternative to noble metal is significant for booming energy conversion/storage systems. Here, we report a facile strategy to design a novel hierarchical nanoporous (HNP) HER electrocatalyst by incorporating transition metal oxide (TMO) NiO and complex phosphide (TMP) NiCoP. With the HNP NiCo2O4 products via a facile solvothermal and annealing method, the NiO/NiCoP composite was easily obtained through a simple subsequent phosphorization process at the optimized temperature. Owing to various factors such as the strong synergetic coupling effects between TMO and TMP, electron interaction between TMPs, unique HNP structure features and increased active sites, the resulting HNP NiO/NiCoP composite demonstrated significantly enhanced electrocatalytic HER activities with a current density of 10 mAcm(-2) at a small overpotential of 112 mV, a low Tafel slope of about 56 mV dec(-1) and satisfactory stability. We expect that this facile synthetic strategy of active binary TMPs functionalized hierarchical porous TMOs will provide a promising prospect for the development of non-precious HER electrocatalysts. (C) 2018 Elsevier Ltd. All rights reserved.