Rational design of dynamic Z-scheme heterojunction composites for photocatalytic Cr(VI) reduction and H2 production: an experimental and computational study

Abstract

This study established a dynamic Z-scheme driven heterostructure of ZnO-ZnS (ZnOS) nanoparticles (NPs) by sulfidation of ZnO NPs. The ZnOS composites with different atomic ratios of S/O were analyzed with multiple characterization techniques. The composite materials with a S/O atomic ratio of 1:1 yielded the best photocatalytic results for toxic Cr(VI) removal from water and H2 production from water under UV light. This study examined a dynamic Z-scheme energy transfer behavior at the junction of ZnOS composites for the first time via atomic and electronic structure modeling using density functional theory (DFT) simulations. ZnOS NPs were further immobilized on polyvinylidene fluoride (PVDF) via a non-solvent-induced phase separation method for functional recovery after photocatalysis.

Keywords

• Dynamic Z-scheme
• Cr(VI) reduction
• H2 production
• Photocatalysis
• ZnO-ZnS heterostructure