Interface engineering: Construction of an effective interfacial charge transfer channel via CeO2/CoSx S-scheme heterojunction

Designing of an appropriate interface could significantly improve performance for photocatalyst. Here, a core shell structure of ceria (CeO2)-cerium hydrocarbonate (CeCO3OH) is synthesized utilizing ribbon-like CeO2 as the precursor. At the same time, amorphous CoSx ultrafine nanoparticles are grown in-situ on the surface of as synthesized core-shell structure, forming an S-scheme heterojunction with appropriate interface. In the heterojunction, the conduction band of CeCO3OH acts as a mid-gap channel to store photogenerated electrons, which are subsequently transferred to the valence bands of CeO2 and CoSx, inhibiting the recombination rate of the photogenerated electron-hole pairs in the heterojunction. Photocatalytic hydrogen evolution (HER) performances of the samples with and without CeCO3OH are assessed, the results reveal that the HER performance of the samples containing CeCO3OH is superior to that of samples without CeCO3OH, indicating the indispensability of CeCO3OH in assisting to construct the heterojunction to enhance the photocatalytic hydrogen evolution performance. This work provides methods and guidance for constructing S-scheme heterojunction composed of multivariate photocatalysts by in-situ method.