With the implementation of the goals of carbon peaking and carbon neutrality and the construction of a new energy-oriented power system, the renewable energy generation technology with a focus on wind energy and solar energy is developing rapidly. However, the intermittence and fluctuation of renewable energy impacts the electric power and energy balance. Hydrogen production by water electrolysis has been regarded as one of the key technical means to realize the rebalancing of energy in a longer time and in a wider space. The main forms of electrolysis stacks, alkaline electrolysis, proton exchange membrane electrolysis and solid oxide electrolysis, are introduced and analyzed. Based on the reaction mechanism of water electrolysis, the importance of electrocatalysts in the reaction is pointed out.The development and improvement strategies of various novel electrocatalysts which include alloy materials, metal oxides, metal sulfides, metal phosphides, metal carbides and carbides are highlighted and reviewed here. And in-situ characterization techniques play vital roles in this development. Finally, the current problems and future perspectives of the catalysts for water splitting are proposed according to the forecasting on hydrogen production from water splitting.
