Enhanced photothermal catalytic performance of dry reforming of methane over Ni/mesoporous TiO2 composite catalyst

Abstract Developing new highly efficient catalytic technique is critical for solar photo -thermal -chemical conversion. Among kinds of techniques, photothermal catalysis attracts an increasing attention. In this paper, a Ni/mesoporous TiO2 photothermal catalyst was prepared and applied for methane dry reforming reaction under high temperature environment. Catalytic activities of the prepared catalyst were investigated in a homemade fixed bed photothermal reactor under different temperatures and lighting conditions. And mechanism of photothermal synergistic effect was characterized by using scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), BET, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis-Nir spectrophotometer and Photoluminescence spectra. The results shown that (1) Catalytic activity of the prepared photothermal catalyst in present work performs better than the public reported catalysts in literatures. (2) Comparisons of light and dark experiments of different catalysts proved that the synergistic effect of photothermal catalysis could significantly improve the formation rates of products, and increase the conversions of reactants. The reason is attributed to the formation of Ni-TiO2 heterogeneous structure, which can broaden the optical response range of incident light, as well as enhance the separation of excited e−/h+ pairs in the semiconductor TiO2. (3) Increasing lighting intensity could enhance the formation rates of CO/H2 correspondingly. (4) Compared to catalytic performances of the catalyst under ultraviolet and visible-near-infrared conditions, full spectrum incident light could improve the formation rates of products under the cooperative effect of different spectrum. The testing results indicate that utilizing photothermal synergistic effects to realize the process intensification is beneficial and instructive for the future solar photo -thermal -chemical conversion.