Photo-Redeposition Synthesis of Bimetal Pt-Cu Co-catalysts for TiO2 Photocatalytic Solar-Fuel Production

Photocatalytic water splitting for the production of H-2 and the reduction of CO2 into carbon compounds via solar energy exhibits possible widespread applications in the energy sector because of their application as so-called solar fuels. However, so far, the efficiency of these processes is low and in need of further improvement. Herein, we report a strategy for boosting the solar fuel generation rate of TiO2 by loading cocatalysts, specifically bimetallic Cu-Pt and CuO, via two-step photodeposition processes. Intriguingly, we can for the first time observe that the Cu2O nanoparticles present on the surface of TiO2 are partially redissolved into the solution because of the weak acidity induced by the Pt precursor. The sample of Cu-Pt/TiO2-CuO shows a photocatalytic H-2 generation rate of 173.7 mu mol/g.h under simulated sunlight conditions. For the photocatalytic CO2 reduction by water, the sample of Cu-Pt/TiO2-CuO shows the release of H-2, O-2, CO, CH4, and CH3OH, whereby CO is the main reaction product. Typically, the yields of O-2 and CO are 4.2 and 6.2 and 2.1 and 3.2 mu mol/h.g under LED-405 and LED-425, respectively; the CO2-to-CO conversion ratios with respect to separated carriers are 73.8 and 76.19%.