Z-Scheme Flower-Like SnO₂/g-C₃N₄ Composite with Sn²⁺ Active Center for Enhanced Visible-Light Photocatalytic Activity

The invention of defect-engineering motivated Z-scheme photocatalytic complexes has been treated as an emerging opportunity to accomplish effective carrier separation and electron transfer in hybrid heterojunctions, contributing a novel approach to accomplish modified visible-light driven photocatalytic performance compared to traditional nanocomposites. Exploring a desired carrier medium is crucial to support impressive electron transportation in Z-scheme photocatalytic nanocomposites. Here, the role that the Sn²⁺/Sn⁴⁺ redox couple plays in the photocatalytic process is systematically studied by taking the flower-like SnO₂/layered g-C₃N₄ with deficient Sn²⁺ reactive sites as an example, where the defect-engineering can be introduced by heat treatment. The experimental results and computational simulations demonstrate that the deficient Sn²⁺ reactive sites can facilitate small molecule adsorption and boost the interfacial carrier separation and transfer in the photocatalytic procedure by bringing in the Sn²⁺/Sn⁴⁺ redox couple. This work provides a more in-depth exploration of Z-scheme photocatalytic-system construction and is helpful to the development of defect-engineering approaches with high photocatalysis performance.