Synthesis of Efficient S-Scheme Heterostructures Composed of BiPO₄ and KNbO₃ for Photocatalytic N₂ Fixation and Water Purification

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.

Synergistic Engineering of Energy Band Alignment and Interfacial Electric Field Distribution over Bi-bismuth-Based Hetero-nanofibers for Boosting Visible-Light-Driven Photocatalytic Ammonia Synthesis and Antibiotic Removal

“…Studies suggest that designing appropriate energy band alignment can modulate redox potentials and improve sluggish redox reactions. , Additionally, the heterogeneous interface plays a pivotal role in carrier separation, migration, and recombination, highlighting the need for precise control over space charges at the binary interface . Tuning the interfacial electric field (IEF) distribution can facilitate carrier separation and optimize charge transport behavior, ultimately increasing the quantum efficiency of the photocatalytic process. , Implementing energy band regulation and IEF modulation in a synergistic engineering strategy can not only enhance photocatalysts’ redox ability but also accelerate their photogenerated carrier separation, leading to a remarkable improvement in photocatalytic performance. This synergistic engineering can offer profound insights into the meticulous design of efficient photocatalysts.…”