LAUSR

Solar-driven CO2 reduction into fuels and chemicals has gained ever-increasing attention. Herein, we report the synthesis of oxygen-vacancies-functionalized Ni(OH)2 (OVs-Ni(OH)2) nanosheets by a novel photochemical method to act as a catalyst for CO2 reduction. Various characterization techniques reveal that the COOH* is the key intermediate for CO2-to-CO photoreduction. Importantly, experimental results and theoretical calculations confirm that the 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 the OVs-Ni(OH)2 was achieved, outperforming most of analogous catalysts in literatures. Moreover, Moreover, even under ultralow CO2 concentration of 0.04% (representative CO2 concentration of air) and low reaction temperature (273 K, 0 °C), this catalyst can still trigger CO2 reduction. Our work provides a new methodology to synthesize OVs-Ni(OH)2 catalyst for efficient CO2 reduction. More significantly, the relationship between the OVs and the catalytic activity has been established, which may guide the design of highly-selective CO2 reduction catalysts.