Suitable energy platform significantly improves charge separation of g-C3N4 for CO2 reduction and pollutant oxidation under visible-light

The photocatalytic activities of g-C3N4 can be significantly improved by increasing life time of the photo-generated charges. Here, in this work we introduced TiO2 as proper energy platform to accept the photo-generated electrons from g-C3N4 during photocatalysis. The nanophotocatalysts formed from the combination of a suitable amount of TiO2 nanoparticles and g-C3N4 nanosheets showed 8.75 and 4.22% enhancement in photocatalytic activities for CO2 reduction and 2-chlorophenol (2-CP) degradation under visible light illumination as compared to bare g-C3N4. Based on the surface photovoltage spectra, photoluminescence spectra and examination of formed hydroxyl radicals, it was confirmed that these enhanced photoactivities were attributed to the much-improved charge separation via the electron transfer from g-C3N4 to TiO2. From trapping experiments, it was found that hydroxyl radicals were the major species involved in the photocatalytic degradation of 2-CP. This study is helpful to synthesize efficient photocatalysts to cope with energy and environmental issues.