Recent Advances in Cu‐Based Cocatalysts toward Solar‐to‐Hydrogen Evolution: Categories and Roles

Abstract

Solar-to-hydrogen production is one of the most promising solutions for global energy shortages and the environmental crisis because it utilizes solar energy to the fullest extent. Photocatalytically splitting water to hydrogen involves three crucial processes: solar light harvesting, charge separation/migration, and the catalytic H 2 production reaction. In the past few years, much attention is paid to investigating noble metal cocatalysts for solar photoreduction, but much less attention is paid to transition metal-based cocatalysts. Nevertheless, great and significant advances are achieved using a copperbased cocatalyst for solar-to-hydrogen evolution, as it possesses a suitable binding energy for the hydrogen intermediate according to density functional theory calculations. This review summarizes recent studies and progress on the copper-based cocatalytic materials as well as discusses the roles and functional mechanisms for photocatalytic H 2 evolution. It begins with discussing basic principles for the use of cocatalysts for photocatalytic hydrogen evolution and points out opportunities to use non-noble metal cocatalysts for hydrogen evolution. Then, it explains the construction and structural features of a photocatalysis system with semiconductor-Cu-based cocatalyst, and how the functional mechanisms work to enhance the hydrogenproduction-related reactions. Finally, some challenges and perspectives are also given to promote further exploration of this emerging research area. Usually, the following three parts are considered: 1) improving

2D Titanium/Niobium Metal Oxide‐Based Materials for Photocatalytic Application

“…It is a major challenge to utilize solar energy for water splitting. Based on the thermodynamic requirement, the CB and VB potentials should be more negative than the reduction potential of H 2 O (0 V vs NHE) for H 2 generation and more positive than the oxidation potential of H 2 O (1.23 V vs NHE) for O 2 generation . The pure 2D TNMOs generally show the relatively low photocatalytic efficiency for water splitting due to the limited light‐harvesting ability, relatively low specific surface area, and separation rate of charge carriers.…”

Defect Engineering of Photocatalysts for Solar Energy Conversion

“…Generally, solar energy conversion system always involves three different steps about charge generation, charge separation, and catalytic reactions . A substantial proportion of the efforts were conducted to exploit the promising semiconductors . However, the low efficiency is mainly ascribed to wide bandgap, poor charge transfer, and poor stability.…”

Per‐6‐Thiol‐Cyclodextrin Engineered [FeFe]‐Hydrogenase Mimic/CdSe Quantum Dot Assembly for Photocatalytic Hydrogen Production

“…An efficient and low‐cost photocatalyst for hydrogen (H 2 ) production, particularly from water splitting using solar energy, is one of the most promising approaches for sustainable fuels production. [ 1–5 ] In a biological system, the formation and uptake of H 2 are carried out by hydrogenase (H 2 ase). [ 6–8 ] High‐resolution X‐ray crystallography reveals that the active center (called as H‐cluster) of natural H 2 ase, taking [FeFe]‐H 2 ase as an example, features a butterfly [Fe 2 S 2 ] subunit and a cubic [Fe 4 S 4 ] cluster.…”