Synthesis of Efficient S-Scheme Heterostructures Composed of BiPO<sub>4</sub> and KNbO<sub>3</sub> for Photocatalytic N<sub>2</sub> Fixation and Water Purification
Lin Yue, Zhihao Zeng, Xujie Ren, Shude Yuan, Chuanqi Xia, Xin Hu, Leihong Zhao, Lyuchao Zhuang, Yiming He
Abstract
The preparation of catalysts with heterojunction structures is a strategy to achieve efficient charge separation and high photocatalytic activity of photocatalysts. In this work, BiPO 4 /KNbO 3 heterostructure photocatalysts were fabricated by a combination of hydrothermal and precipitation methods and subsequently employed in catalyzing N 2 -to-NH 3 conversion and RhB degradation under light illumination. Morphological analysis revealed the effective dispersion of BiPO 4 on KNbO 3 nanocubes. Band structure analysis suggests that KNbO 3 and BiPO 4 exhibit suitable band potentials to form an S-scheme heterojunction. Under the joint action of the built-in electric field at the interface, energy band bending, and Coulomb attraction force, photogenerated electrons and holes with low redox performance are consumed, while those with high redox performance are effectively spatially separated. Consequently, the BiPO 4 /KNbO 3 shows enhanced photocatalytic activity. The NH 3 production rate of the optimal sample is 2.6 and 5.8 times higher than that of KNbO 3 and BiPO 4, respectively. The enhanced photoactivity of BiPO 4 /KNbO 3 is also observed in the photocatalytic degradation of RhB. This study offers valuable insights for the design and preparation of S-scheme heterojunction photocatalysts.