Visible-Light-Driven Selective Oxidation of Toluene to Benzaldehyde over CeO2@NiFe-LDH Heterostructure

The transformation of toluene to benzaldehyde via green and sustainable routes is of great significance in the fine chemical industry. However, hard activation of benzylic C(sp3)-H bonds and facile overoxidation of the generated benzaldehyde collectively render the selective oxidation of toluene extremely challenging. In this study, we constructed a core–shell heterostructure photocatalyst, CeO2@NiFe-LDH, employing molecular oxygen as the oxidant. Under mild conditions of room temperature and visible-light illumination, the catalyst achieves a toluene conversion rate of 1.936 mmol·g−1·h−1 with an excellent benzaldehyde selectivity of 81.0%, and its catalytic performance is significantly superior to that of the individual single-phase materials and the simple physical mixture. Optical and electrochemical measurements confirm enhanced visible-light absorption and utilization, as well as greatly improved separation and migration efficiency of photogenerated charge carriers. Furthermore, the CeO2@NiFe-LDH heterostructure features staggered band alignment, promoting S-scheme charge transfer across the heterointerface, thereby substantially boosting the redox capacity of the composite catalyst. Consequently, the photogenerated carriers with high reactivity are fully engaged in catalytic reactions, enabling efficient carrier utilization and ultimately leading to a significantly enhanced photocatalytic performance. This study not only demonstrates the outstanding application potential of CeO2@NiFe-LDH for the visible-light-driven selective oxidation of toluene to benzaldehyde, but also offers a novel strategy for enhancing the photocatalytic performance of LDH-based materials.