Rational Design and Mechanistic Insights Into Transition Metal-Based Spin-Modulated Oxygen Evolution Electrocatalysts

Harnessing secondary energy sources for water electrolysis to generate "green hydrogen" is instrumental in constructing a zero-carbon-emission hydrogen value chain. However, the anodic oxygen evolution reaction (OER) presents a bottleneck due to its complex four-step proton-coupled electron transfer process. Investigation of high-performance anodic OER catalysts has developed into a hot research field. The high kinetic barrier associated with OER is strongly linked to the interplay between the singlet state of OH^-/H₂O and the triplet state of O₂, this interconversion process is significantly influenced by the spin states of metal centers in catalysts. In this short review, the fundamental mechanisms of spin effects in oxygen evolution are briefly discussed with respect to the thermodynamics, active species formation, and reaction mechanisms. In addition, the recent approaches to modulate spin configuration of electrocatalysts are summarized, such as lattice substitution, defect engineering, interface regulation, ligand adsorption, and size modulation. In the last section, the challenges and perspectives for future development of spin-related catalysis are discussed, aiming to provide insights into spin effects in water oxidation and guidance for designing efficient OER catalysts.