Preparation of ternary Cr2O3-SiC-TiO2 composites for the photocatalytic production of hydrogen

Novel ternary Cr2O3-SiC-TiO2 composites were synthesized by implanting Cr3+ into SiC-TiO2 via sol-gel and impregnation approaches. The results from X-ray diffraction, scanning electron microscopy and transmission electron microscopy show that the Cr3+ species were doped onto the surface of the SiC-TiO2 carrier. The diffuse reflectance ultraviolet-visible absorption spectra revealed that the absorption edges of the ternary Cr2O3-SiC-TiO2 composites were gradually shifted red with increasing chromium content. The luminescence intensities of the composites decreased with increasing doped Cr3+ content due to the reduction in the number of recombination sites of electron-hole pairs. The ternary Cr2O3-SiC-TiO2 composites showed high hydrogen-producing activities, which probably results from the formation of donor levels of the Cr3+ species in the forbidden band of the SiC semiconductor. (C) 2011 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.