Independent Cr2O3 functions as efficient cocatalyst on the crystal facets engineered TiO2 for photocatalytic CO2 reduction

Abstract Implanting cocatalysts on semiconductor photocatalysts is considered as an essential strategy to promote reaction activity. However, the development of highly efficient cocatalysts remains challenging. In the present work, we construct independent Cr2O3 as an efficient cocatalyst on the crystal facets engineered TiO2 for photocatalytic CO2 reduction for the first time. Moreover, a combined strategy of crystal facets engineering of TiO2 and loading of Cr2O3 cocatalyst is adopted to further promote the charge carriers’ separation/transfer. In comparison with the cocatalyst-free TiO2 without facets engineering, 2HF-TiO2/0.2Cr2O3 exhibits near 30-fold enhancement on the CO2 conversion efficiency. The enhanced photocatalytic activity is attributed to the maximal synergy of crystal facets engineering and cocatalyst loading for well-matched CO2 reduction half-reaction and H2O oxidation half-reaction. These findings not only provide new insights for understanding the role of Cr2O3 in photocatalytic systems but also may shed light on the design of photocatalysts from the perspective of overall photocatalytic CO2 reduction.