Efficient Conversion of CO2 to Methane Photocatalyzed by Conductive Black Titania

One of the major challenges encountered in CO2 utilization is the development of available and cost-efficient catalysts with sufficient activity, selectivity, and stability for the generation of useful methane. Here, conductive black titania, TiO2-x, is found to be efficient in photocatalyzing the reduction of CO2 to CH4. This unique material comprises a crystalline core-amorphous shell structure (TiO2@TiO2-x) with numerous surface oxygen vacancies, which facilitates the adsorption and chemical activation of CO2 molecules. Under full solar irradiation, the optimized 500-TiO2-x material with narrowed band gap and intermediate states below the conduction band tail exhibits a high space-time yield of CH4 of 14.3molg(-1)h(-1), with 74% selectivity and excellent photostability. The present findings can make a significant contribution, not only to develop the surface electron-modified black TiO2 catalyst to boost photocatalytic efficiency, but also to establish a really viable and convenient CH4 production process for CO2 conversion and renewable solar energy storage.