Tailoring bismuth defects in Bi2WO6 nanosheets for photocatalytic C–H activation

Abstract

Functionalizing sp³ C–H bonds in toluene through photocatalysis poses a significant challenge in organic synthesis, garnering substantial research attention. Nevertheless, the inert nature of the C–H bond restricts the photocatalytic conversion efficiency. Here, we construct bismuth defect modified ultrathin Bi₂WO₆ nanosheets (BT-48) for the conversion of toluene into benzaldehyde under light irradiation. Density functional theory (DFT) calculations validate the effectiveness of Bi defects in Bi₂WO₆ in activating the C–H bond in toluene. Moreover, a comprehensive physiochemical analysis shows that the introduction of bismuth defects in ultrathin Bi₂WO₆ nanosheets could promote the separation of photoexcited charge carriers. As a result, the optimal BT-48 sample exhibits an impressive benzaldehyde formation (6781 μmol g⁻¹ h⁻¹) with a high selectivity of 96%, which is 6 times higher than that of Bi₂WO₆ (1109 μmol g⁻¹ h⁻¹) and surpasses those of all the previously reported Bi₂WO₆-based photocatalysts. It is expected that this work could enhance our understanding of designing efficient photocatalysts for the activation of C–H bonds under light illumination.