Broad-spectrum solar conversion towards photothermal catalytic reforming hydrogen production with in-situ thermal regulation over core-shell nanocomposites

Photothermal catalytic hydrogen production is regarded as an effective conversion of solar energy into clean energy carrier. However, the uncontrollable in-situ photo-thermal effect would cause overheating of the catalytic site, thereby reducing the electron transfer efficiency, and the vast amount of energy contained in the near-infrared thermal effect has not been fully utilized. In this study, an Au/TiO2 nanorod catalyst and n-eicosane were employed to establish a core-shell structure to enhance solar energy conversion and regulating in-situ temperature rise during the photothermal catalytic process. The results revealed that the core-shell structure offered an efficient reaction area and high dispersion stability, while the amount of photothermal catalyst loaded also influenced the photothermal catalytic performance. Also, the in-situ overheating is effectively regulated to help enhance efficient electron transfer for hydrogen production. The core-shell structures with Au/TiO2 loading amounts of 9.3%, 14.5%, and 20.2% enhanced hydrogen yields by 30.3%, 42.2%, and 53.8%, respectively, compared to that of pure photothermal catalyst suspension. Meanwhile, the photothermal conversion efficiencies were 33.3%, 64.5% and 88.1% higher than those of 10 vol% glycerol solution. Thus, the photothermal effect has been shown to be effective for improving the performance of photothermal glycerol reforming for hydrogen production, and photothermal catalyst-phase change material composite structures can provide a new idea for promoting solar energy into thermal and chemical energy.