P-n Heterojunctions between NiO and Ni-Bi₂O₂CO₃ (or Bi₂O₂CO₃) for enhanced MB photodegradation—the effect of Ni modification on Bi₂O₂CO₃

The p-n heterojunctions of NiO/Ni-Bi₂O₂CO₃, NiO/Bi₂O₂CO₃ or Bi₂O₂CO₃/NiO/Ni-Bi₂O₂CO₃ were synthesized via a facile one-step solvothermal strategy, which were first reported among all Bi₂O₂CO₃-based catalysts. The Ni-modification strategy not only regulate the morphology from the flocculence-like of Bi₂O₂CO₃ into Ni-Bi₂O₂CO₃ nanorod, but also introduces p-type NiO contributing to the formation of p-n heterojunctions. Besides, Ni-modification strategy widens the light response range and enhances the carrier separation and transfer efficiency of Bi₂O₂CO₃. The photodegradation degree was enhanced from 70% of Bi₂O₂CO₃ to 95% of 0.2Ni/Bi₂O₂CO₃ under photoirradiation (λ > 400 nm). The mechanisms of p-n or n-p-n heterojunction were proposed for the enhanced photodegradation.