Efficient CO2 reduction with H2O via photothermal chemical reaction based on Au-MgO dual catalytic site on TiO2

Using solar energy for the conversion of H2O and CO2 into H2, CO, CH4, and other solar fuels have attracted great interest worldwide. However, the greatest challenge is how to use both the light energy and the heat energy to improve the utilization efficiency of solar energy. Photo-thermal chemical reaction has been used for conversing H2O and CO2 into H2, CO, CH4, and other solar fuels and improved by Au and MgO co-loaded TiO2(AuMgTi). The average yields of CO, H2, and CH4 on AuMgTi were estimated to 45.495 umol/g, 45.072 umol/g, and 6.624 umol/g, respectively. Also, the selectivities of carbon-containing products increased from 29 % to 53.6 % when compared to P25. MgO on the surface of AuMgTi can enhance the chemisorption of CO2 and initiated the CO2 reduction reaction to converse CO2 into CO and CH4. Au can improve the utilization of visible light through the Localized Surface Plasmon Resonance (LSPR) effect, and reduce the recombination rate of photogenerated carriers due to the existence of the Schottky barrier. Moreover, Au might act as a catalytically active center on the surface to assist in the formation of the intermediate groups and facilitate the reaction. This study demonstrated that the AuMgTi catalyst can effectively utilize full spectrum solar energy for CO2 reduction by photo-thermal chemical reaction.