Significantly Enhanced Photocatalytic Hydrogen Evolution over Cu2O Embedded on TiO2 Aerogels under Simulated Solar Light Irradiation

A high surface area mesoporous Cu2O embedded on TiO2 (Cu2O-TiO2) aerogel was prepared and used in photocatalytic splitting of water under simulated solar light irradiation. Highly efficient hydrogen production was achieved over 3 wt% Cu2O-modified TiO2 aerogel photocatalyst with a high rate of 1.40 mmol/(g·h) under simulated solar irradiation. The hydrogen production efficiency of 3 wt% Cu2O-modified TiO2 aerogel was about 33 and 9 times higher than those of pure TiO2 aerogels (0.043 mmol/g·h) and Cu2O-modified commercial TiO2, Degussa P25 (0.15 mmol/g·h) with the same ratio, respectively. For comparison, no hydrogen was detected when Cu2O was used alone as the catalyst, and the activity of Cu2O mechanically mixed TiO2 aerogel with the same ratio was 13 times lower than Cu2O-TiO2 aerogel. This result implied that the Cu2O loading was benefit to promote the separation and migration of electron-hole pair. Furthermore, the Cu2O loading enhanced the absorbance in 300-800 nm region as compared to pure TiO2 aerogel. Cu2O-TiO2 aerogels have very high specific surface area (400-500 m2/g) and good recyclability for at least 3 cycles, which suggests that the materials have promising prospects in photocatalytic hydrogen production.