Light‐Induced Synthesis of Oxygen‐Vacancy‐Functionalized Ni(OH)2 Nanosheets for Highly Selective CO2 Reduction

Abstract Solar‐driven CO2 reduction into fuels and chemicals has gained increasing attention in recent years. In this study, oxygen‐vacancies‐functionalized Ni(OH)2 (OVs−Ni(OH)2) nanosheets are synthesized by a photochemical method to serve as a catalyst for CO2 reduction. Characterization reveals that COOH* is the key intermediate for CO2‐to‐CO photoreduction. Experimental results and theoretical calculations confirm that OVs modification can greatly modulate the interaction strength between the OVs−Ni(OH)2 and CO2, while lowering the energy barrier for COOH* formation, thereby preferentially facilitating CO2 reduction. As a result, the OVs−Ni(OH)2 catalyst exhibits outstanding activity and selectivity for CO2‐to‐CO photoreduction with visible light. A CO evolution rate of 31.58 μmol h−1 (0.35 mg catalyst, 90228 μmol h−1 g−1) with a selectivity of 98 % over OVs−Ni(OH)2 was achieved, outperforming most analogous reported catalysts. Moreover, even under a low CO2 concentration of 0.04 % (representative of the CO2 concentration in air) and low reaction temperature (273 K, 0 °C), this catalyst can still trigger CO2 reduction. This work provides a new method to synthesize OVs−Ni(OH)2 catalysts for efficient CO2 reduction and establishes a relationship between the OVs and the catalytic activity, which may guide the design of highly selective CO2 reduction catalysts.