Complete removal of phenolic contaminants from bismuth-modified TiO2 single-crystal photocatalysts

Abstract Exploring low-cost and highly active photocatalysts is very urgent to accomplish complete removal of phenolic contaminants and overcome the limitations of the existing photocatalysts. In this study, we designed and synthesized noble metal-free TiO2 photocatalysts by introducing bismuth nanoparticles as modifiers of a TiO2 single crystal (Bi-SCTiO2). The Bi-SCTiO2 can make full use of the synergistic effect of a small band overlap and low charge carrier density (Bi) with a high conductivity (single crystal), significantly boosting the separation and migration of the photogenerated charge pairs. Therefore, the Bi-SCTiO2 photocatalyst exhibits a significantly enhanced degradation rate (12 times faster) of 4-nitrophenol than a TiO2 single crystal under simulated sunlight irradiation. Notably, the complete removal of phenolic contaminants is achieved in various water matrices, which not only successfully overcomes the incomplete degradation in many reported photocatalytic systems, but also manifests a significant practical potential for sewage disposal. Therefore, this work presents a new insight in designing and constructing noble metal-free decorated semiconductor single-crystal photocatalysts with excellent activity and cyclability.