Synergistic electronic modulation of active sites in CsCuCl3 via Zn doping for photocatalytic oxidation of toluene to benzaldehyde

Abstract

Photocatalytic selective oxidation represents a sustainable approach for valuable chemical transformations, yet achieving high yield and selectivity of products remains a significant challenge. In this work, we demonstrate that electronic structure modulation of CsCuCl₃ halide perovskites enables highly selective photocatalytic oxidation of toluene to benzaldehyde (BD). By strategically doping Zn into CsCuCl₃, we achieved control over the electronic modulation of catalytic sites, leading to a remarkable BD yield of 4.08 mmol g⁻¹ h⁻¹ with 85.4 % selectivity under visible light irradiation. Mechanistic investigations revealed that Zn doping creates an optimal electronic structure, which simultaneously facilitates O₂ activation to form superoxide radicals and promotes selective C–H bond activation of toluene. Density functional theory calculations showed that Zn doping induces charge redistribution at Cu and Cl sites, optimizing surface energetics for both O₂ and toluene adsorption while lowering kinetic barriers for the rate-determining steps. The enhanced charge carrier separation efficiency, confirmed by spectroscopic and electrochemical analyses, further contributes to the superior catalytic performance. This work establishes electronic structure engineering as a powerful strategy for developing high-performance single-component photocatalysts and provides new insights into the selective photocatalytic oxidation reactions.