Hydrothermal synthesis of Nd³⁺-doped heterojunction ms/tz-BiVO₄ and its enhanced photocatalytic performance

BiVO₄ photocatalysts with different Nd³⁺ doping content were prepared by a hydrothermal method with varied hydrothermal reaction time. The effects of Nd³⁺ doping on phase transformation, morphology, chemical valence, optical properties and photocatalytic activities were investigated. With different reaction time, phase transformation from tetragonal zircon (tz-BiVO₄) to monoclinic scheelite (ms-BiVO₄) could be found, and Nd³⁺ doping played a suppressive role in this process. Scanning electron microscopy showed the morphology evolved from irregular structure to rod-like shapes with phase transformation. The photoluminescence induced by Nd³⁺ doping could be confirmed by UV–vis diffuse reflectance spectra. Photocatalytic performance tests had been performed under simulated solar conditions and sample with 1 at% Nd³⁺ doping and 5 h reaction time showed the best performance (89% degradation rate in 90 min). The pH also showed great influence on morphology and phase transformation of samples. Finally, the phyotocatalytic mechanism and effects of Nd³⁺ in phase transformation were discussed.