Casting light on black phosphorus-based catalysts for water electrolysis: Approaches, promotion manners, and perspectives

Low-dimensional black phosphorus (BP) has attracted surging interest for electronics, optoelectronics, and catalysts. It has been regarded as a promising candidate in electrical device since 2014 due to its high carrier mobility and controllable band gap, especially in the application of water splitting electrocatalysis. However, the low intrinsic activity and weak stability of low-dimensional BP severely hinder its further application as efficient electrocatalyst. To improve the hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and overall water splitting activity of low-dimensional BP, many facile methods have been developed and explored for preparation of BP-based activated catalysts. In this regards, certain strategies have been tried to overcome their weaknesses of intrinsic activity and stability, including metal/nonmetal doping, building of heterostructure, and covalent functionalization. This work discusses the promotion strategies of high-efficient electrocatalysts for HER/OER and overall water splitting based on low-dimensional BP materials, providing an effective orientation of development and practical application of low-dimensional BP-based materials. Finally, a comment is also made on the recent developments, future outlook and challenges ahead in BP-based electrocatalysts.