Comparison of the preparation methods for a highly efficient CuO/TiO2 photocatalyst for hydrogen generation from water

摘要

Efficient and visible-light responsive CuO/TiO2 photocatalysts were fabricated by six methods: simple wet impregnation (SWI), ethanol impregnation (EI), stepwise impregnation (SI), in situ sol-gel (SG), chemical adsorption decomposition (CAD), and composite precipitation (CP). The prepared CuO/TiO2 composites were characterized using X-ray diffraction, nitrogen adsorption desorption isotherms, transmission electron microscopy, UV-Vis diffuse reflectance spectra, and H2-temperature programmed reduction. Due to the different preparation processes, the hydrogen evolution rate from water splitting on the as-prepared CuO/TiO2 nanocomposites was recorded. The results showed that the photocatalytic hydrogen evolution rate decreased in the sequence of CAD sample > CP sample > EI sample > SWI sample > SI sample > SG sample. The hydrogen evolution rate of the CAD sample was proved to be the highest among the samples and reached 3155.7 μmol/(g-h), which was 2.46 times larger than that of SG sample. In addition, the stability of the CAD sample and the EI sample was compared. The addition of copper could efficiently suppress the recombination of electron/hole pairs in titanium dioxide, improve the transfer of interfacial charge, enhance visible-light adsorption and provide plentiful photo-catalytic reaction active sites.