Abstract
Mesoporous TiO2 frameworks incorporated with diverse percentages of Cr2O3 nanoparticles (NPs) were achieved through the one-step sol-gel approach for photocatalytic H2 evolution under visible-light exposure. The obtained isotherms could be classified as type IV, indicating mesopore 2D-hexagonal symmetry. The H2 evolution rate over mesoporous Cr2O3/TiO2 photocatalyst was observably promoted employing glycerol as a sacrificial agent, providing a comparatively high H2 yield of 14300 mu molg- 1. The highest photocatalytic efficiency was achieved with an optimal 4% Cr2O3/TiO2 photocatalyst, and the evolution rate was enhanced 1430-fold compared to pristine TiO2. The eminent photocatalytic performance of mesoporous Cr2O3/TiO2 was ascribable to different key factors such as the narrow bandgap, wide visible light photoresponse, Cr2O3 as photosensitizer, synergistic effect and high surface area. The recycle tests for five times over synthesized photocatalyst revealed excellent durability and stability without loss in H2 evolution. The photocatalytic mechanisms for H2 evolution over Cr2O3/TiO2 photocatalyst were proposed according to the photocurrent transient and photoluminescence measurements and photocatalytic H2 evolution results.