Periodic Macroporous ZnS-In2O3 heterojunctions based on double Z-scheme for improved photocatalytic performances on H2 evolution and Cr (VI) reduction

To achieve controllable transport of photogenerated carriers in heterojunctions and improve their photocatalytic performance, we construct a new type of periodic macroporous (PM) heterojunctions through the pyrolysis of the solid solution to obtain a number of alternating heterojunctions composed of ZnS and In2O3. The quantum wells can be constructed based on double Z-scheme in the alternating heterojunctions. This design restricts the degree of freedom of the carriers in the vertical direction, suppresses the recombination of photogenerated carriers, achieves their spatial separation, and thus improves the redox ability. The PM structure with efficient mass transfer in PM ZnS-In2O3 (PZI) enables photogenerated carriers to easily migrate to the surface. The photocatalytic H2 evolution rate and reduction of Cr (Ⅵ) of the PZI heterojunctions are considerably improved by the combined effects of the quantum wells and PM structures. This work proposes a novel idea for adjusting the transport process of photogenerated carriers and then improving photocatalytic performance.