High photocatalytic hydrogen production over the band gap-tuned urchin-like Bi2S3-loaded TiO2 composites system

Abstract

A new system using Bi2S3-loaded TiO2 photocatalysts (Bi2S3/TiO2) was developed to enhance the production of hydrogen. The Bi2S3 (5, 10, 15 wt%) particles in an urchin-like morphology with a length of about 2∼3 μm and a diameter of 15–20 nm, which can absorb all wavelengths in UV–visible radiation, were prepared by solvothermal method and loaded onto nano-sized TiO2 (10∼15 nm) for photocatalysis on hydrogen production. The evolution of H2 from methanol/water (1:1) photo splitting over the Bi2S3/TiO2 composite in the liquid system was enhanced, compared with that over pure TiO2 and Bi2S3. In particular, 14.2 ml of H2 gas was produced after 12 h when 0.5 g of a 10 wt% Bi2S3/TiO2 composite was used. On the basis of cyclic voltammetry (CV) results, the high photoactivity was attributed to the increase of band gap in the Bi2S3/TiO2 composite, due to the decreased recombination between the excited electrons and holes.