Solar-driven multifunctional Au/TiO2@PCM towards bio-glycerol photothermal reforming hydrogen production and thermal storage

Photocatalytic hydrogen production and thermal storage are effective ways to convert solar energy into storable chemical energy and thermal energy, but they only respond to specific spectrum. In order to improve the energy conversion and storage efficiency of solar energy in the solar spectrum, hydrothermal and photo-deposition method were employed to synthesized photothermal catalyst while and Au/TiO2@PCM composite microcapsules were fabricated by electrostatic adsorption self-assembly methods. Micro-morphologies and structures were detailed characterized by SEM, XRD, UV-Vis, etc. As calculated from the DSC results for effective, enthalpy value, the loading rates of Au/TiO2 shell for the microcapsule were 12.6% and 15.4% corresponding to rod-shaped and sheet-shaped samples. To test their catalytic performance, the samples were dispersed in the same concentration of glycerol solution, and showed that the light to hydrogen efficiencies were 11.4‰ and 5.0‰ for [email protected] and [email protected], respectively with the increasement of 53.8% and 56.1% comparing to their corresponding catalyst nanoparticle suspensions. Photo-thermal conversion efficiencies of [email protected] and [email protected] were 62.74% and 53.32% after 60 min-irradiations, and they were 48.22% and 25.96% higher than that of Me-PCM. Therefore, it was confirmed that the composite phase change microcapsules prepared in this study have the dual functions of energy storage and photothermal catalysis. Higher solar light to hydrogen energy conversion efficiency may be attained in future study if the stored thermal energy can be successfully employed to activate organic components for helping catalytic hydrogen generation.