Hydrogen production by photocatalysis using new composites based on SiO₂ coated by TiO₂

Abstract

In this study new TiO2 photocatalysts core@shell type were synthesized using SiO2 as structural support. The coating was confirmed by scanning electron microscopy and infrared spectroscopy. Adsorption isotherms revealed that the surface area of such composites is about 26% higher than pure oxide (W50). X-ray diffractograms combined with Raman spectroscopy revealed that the synthesized TiO2 presents a structure based on the coexistence of anatase and brookite. The composite W50S50 presented the best photocatalytic performance of H2 production, with 13.5 mmol in 5 h, corresponding to a specific rate of 32.5 mmol h−1g−1. In the reuse assays, this composite presented a good stability in the production of H2. However, its performance presented a reduction of 23% over the reuse cycles. Considering the H2 production in a solar simulator, W50S50 produced about 25.0 μmols, which is equivalent to 48.0 μmols h−1g−1, suggesting the good performance of this material for photocatalytic hydrogen production.