Nickel-Based (Photo)Electrocatalysts for Hydrogen Production.

Hydrogen is considered a promising energy carrier for replacing traditional fossil fuels. Electrochemical or solar-driven water splitting is a green and sustainable method of producing hydrogen. To lower the overpotential and minimize energy costs, numerous reports have focused on developing noble-metal-free catalysts for hydrogen production, with special attention paid to nickel-based materials. Herein, the current state of research on the use of Ni-based materials as electrocatalysts, cocatalysts, and photoactive materials in hydrogen production is reviewed. Recent research efforts toward the development of various Ni-based (photo)electrocatalysts, their applications in hydrogen production, and the corresponding mechanisms are covered. The approaches used to improve or optimize these materials are summarized, and the key remaining challenges are discussed.