Strategies on improving the electrocatalytic hydrogen evolution performances of metal phosphides

Among the sustainable energy sources, hydrogen is the one most promising for alleviating the pollution issues related to the usage of conventional fuels, as it can be produced in an efficient and eco-friendly way via electrocatalytic water splitting. The hydrogen evolution reaction (HER, a half-reaction of water splitting) plays a pivotal role in decreasing the price and increasing the catalytic efficiency of hydrogen production and is efficiently promoted by metal phosphides in different electrolytes. Herein, we summarize the recent advances in the development of metal phosphides as HER electrocatalysts, focus on their synthesis (post-treatment, in situ generation, and electrodeposition methods) and the enhancement of their electrocatalytic activity (via elemental doping, interface and vacancy engineering, construction of specific supports and nanostructures, and the design of bi- or polymetallic phosphides), and highlight the crucial issues and challenges of future development.