Boosting photothermal-assisted photocatalytic water/seawater splitting into hydrogen based on greenhouse-induced photothermal effect

Photothermal-assisted photocatalytic hydrogen production is a very promising way to maximize solar energy utilization to obtain clean energy. Herein, we designed a composite photocatalyst with coating core-shell Fe3O4@SiO2 nanoparticles on the surface of ZnIn2S4 micro-flowers for high-efficient photothermal-assisted photocatalytic water/seawater splitting. Experimental results reveal that in the core-shell structure of Fe3O4@SiO2, the addition of the SiO2 shell in Fe3O4@SiO2 not only separates the photothermal and photochemical components, avoiding competition between them, but also further increases the temperature of the core in a manner similar to the greenhouse effect, which was used as a hot core to provide heat to the ZnIn2S4 photocatalyst to increase the surface reaction temperature and enhance the collision chances of photo-generated carriers into causing severe recombination of carriers, thus promoting the hydrogen generation. Significantly, the optimal photocatalytic water/seawater splitting into hydrogen production rates over Fe3O4@SiO2/ZnIn2S4 are up to 1258.5 and 1108.5 mu mol g-1 h-1, which are 11.9 and 14.7 times higher than that of pristine ZnIn2S4, respectively. This study provides an idea for the design of highly efficient photothermal-assisted photocatalysts.