Reduced 3d Transition Metal Oxides Work as Solid‐State Sources of Solvated Electrons and Directly Inject Electrons into Water for H₂ Production under Mild Thermal or IR Excitation

Abstract Stabilizing excess electrons in a solid provides great opportunities for the design of new materials with precisely tuned electronic and magnetic properties. Herein, it is demonstrated heavily reduced 3d transition metal oxides (HRTMOs) particles can be used as a kind of novel solid‐state sources of solvated electrons, which are capable of injecting electrons directly into water upon mild thermal or near infrared light (IR) excitation. The structural characteristics and electronic properties of the reduced metal oxides related with the stabilization of excess electrons are investigated in detail. As a proof‐of‐concept example, H₂ generation from water triggered by thermal excitation is tested for evaluating the potential applications of solvated electrons and the characteristics of electrons trapping and release in 3d HRTMOs. The trapping and release of electrons, corresponding to defects formation upon reduction and defects removal upon oxidation, respectively, are facile and repeatable without reducing the storage capacity during multicycle tests. The special characteristics of thermal/IR‐driven electron injection from the metal oxides solids into solution have great application potentials in areas of energy conversion, organic synthesis, and medical treatment, etc.