WO3/SnO2 n–n Heterojunction Photoanode for Clean Selective Photochemical Preparation of Benzaldehyde

Abstract

Benzaldehyde is a vital intermediate for the synthesis of pharmaceuticals and agrochemicals. Traditional chemical synthesis methods are costly and cause environmental pollution. Therefore, developing novel green synthesis approaches is growing increasingly important. A photoelectrochemical (PEC) system was constructed using a WO₃/SnO₂ n–n heterojunction photoanode, with N-hydroxysuccinimide (NHS) acting as a selective hydrogen-atom-transfer mediator. The preparation parameters were optimized, and the material was characterized by SEM, TEM, XRD, XPS, and UV–vis diffuse reflectance spectroscopy. PEC properties and catalytic performance were evaluated. The optimized WO₃/SnO₂ exhibited extended light absorption and efficient charge separation. Under ambient conditions, the PEC system delivered 98% yield and 100% selectivity for benzaldehyde without using hazardous oxidants or causing substrate overoxidation. This work provides a green and efficient approach for benzaldehyde synthesis, offering theoretical and technical support for the PEC production of high-value fine chemicals and pharmaceutical intermediates.