S-Scheme MnO2/Co3O4 Sugar-Gourd Nanohybrids with Abundant Oxygen Vacancies for Efficient Visible-Light-Driven CO2 Reduction

Converting CO2 to carbon-based fuels using solar energy via photocatalysis is a promising approach to boost carbon neutrality. However, the solar-to-chemical conversion efficiency is hampered by interconnected multiple factors including insufficient light absorption, low separation efficiency of photogenerated carriers as well as complex and sluggish surface reaction kinetics. Herein, we incorporate MnO2 nanowires and Co3O4 hollow polyhedrons with abundant oxygen vacancies (V-O) into MnO2/Co3O4 sugar-gourd nanohybrids for boosting CO2 photoreduction. The MnO2/Co3O4 nanohybrids not only display strong absorption in the visible-near infrared region, but also facilitate the separation of photogenerated carriers in terms of S-scheme transfer pathway, supplying abundant electrons for CO2 reduction reaction. Furthermore, the presence of V-O enhances the separation efficiency of photogenerated carriers and promotes the chemical adsorption to CO2 molecules. In addition, the interfacial electronic interaction between MnO2 and Co3O4 also contributes to the chemical adsorption and activation to CO2. Owing to the synergy of S-scheme transfer pathway and V-O, the MnO2/Co3O4 hybrids exhibit greatly enhanced photocatalytic activity towards CO2 reduction under the irradiation of visible light in comparison with bare MnO2 and Co3O4, delivering a CO evolution rate of 15.9 umol g(-1) h(-1) with a 100 % selectivity.