The superior photocatalytic performance and DFT insights of S-scheme CuO@TiO₂ heterojunction composites for simultaneous degradation of organics

The necessity to resolve the issue of rapid charge carrier recombination for boosting photocatalytic performance is a vigorous and challenging research field. To address this, the construction of a binary system of step-scheme (S-scheme) CuO@TiO₂ heterostructure composite has been demonstrated through a facile solid-state route. The remarkably enhanced photocatalytic performance of CuO@TiO₂, compared with single TiO₂, which can consequence in the more efficient separation of photoinduced charge carriers, reduced the band gap of TiO₂, improved the electrical transport performance, and improved the lifetimes, thus donating it with the much more powerful oxidation and reduction capability. A photocatalytic mechanism was proposed to explain the boosted photocatalytic performance of CuO@TiO₂ on a complete analysis of physicochemical, DFT calculations, and electrochemical properties. In addition, this work focused on the investigation of the stability and recyclability of CuO@TiO₂ in terms of efficiency and its physical origin using XRD, BET, and XPS. It is found that the removal efficiency diminishes 4.5% upon five recycling runs. The current study not only promoted our knowledge of the binary system of S-scheme CuO@TiO₂ heterojunction composite photocatalyst but also shed new light on the design of heterostructure photocatalysts with high-performance and high stability.