Design of Magnetic TiO ₂ @NiFe‐LDH/Fe ₃ O ₄ Heterostructures for Enhanced Photocatalytic Hydroxylation of Phenol

Abstract The efficiency of photocatalytic activity for hydroxylation of phenol is often hindered by rapid recombination of photogenerated charge carriers, posing a challenge for practical applications. Developing heterostructure photocatalysts that facilitate effective charge separation while ensuring ease of recovery is crucial. In this study, we report a TiO 2 @NiFe‐LDH/Fe 3 O 4 heterostructure photocatalyst with a 3D core‐shell architecture, fabricated via co‐precipitation of Fe 3 O 4 nanoparticles onto NiFe‐layered double hydroxide nanosheets (NiFe‐LDH) supported on TiO 2 nanorods (TiO 2 NRs). This magnetic heterostructure demonstrated prefect photocatalytic performance for hydroxylation of phenol to dihydroxybenzenes (DHB), where the phenol conversion and DHB selectivity achieved 51.2% and 91.2%, outperforming individual TiO 2 NRs, Fe 3 O 4 , NiFe‐LDH, and TiO 2 @NiFe‐LDH. The outstanding activity can be attributed to efficient charge separation and rapid redox capabilities. Moreover, recycling experiments confirmed the photocatalyst's robust stability and ease of recovery. This work underscores the potential of heterostructure strategies in developing high‐performance, recyclable photocatalysts for industrial applications.