Sb-Substituted Cs₂AgBiBr₆/g-C₃N₄ Composite for Photocatalytic C(sp³)-H Bond Activation in Toluene

The visible-light-driven photocatalytic selective aromatic C(sp³)-H bond activation utilizing all-inorganic halide perovskites as photocatalysts is a sustainable and green approach to obtain value-added oxygenates. These catalysts, however, are restricted by low activity due to undesirable charge recombination and inefficient light absorption. In this research, we developed a Sb-substituted Cs₂AgBiBr₆/g-C₃N₄ composite to enhance the photocatalytic performance for toluene oxidation. The introduction of the Sb dopant extended the visible light absorbance to 650 nm, and the formation of the heterointerface and the staggered band structure between the two components substantially suppressed the charge recombination. This composite features a 2.3-fold and 72.5-fold higher visible light photocatalytic toluene oxidation rate toward benzaldehyde than that of either Sb-substituted Cs₂AgBiBr₆ or g-C₃N₄ alone, respectively, with a high selectivity of over 96%. The development of all-inorganic lead-free halide perovskite-based heterostructures for visible light photocatalytic organic transformations is expected to have wide-reaching application.