Formamide-assisted one-pot synthesis of a Bi/Bi2O2CO3 heterojunction photocatalyst with enhanced photocatalytic activity

Highlights: • Bi/Bi₂O₂CO₃ heterojunction photocatalyst was prepared by a facile one-pot method. • Formamide was used as a carbon source, an alkali source and a reductant. • 12-h Bi/Bi₂O₂CO₃ heterojunction showed the best photodegradation activity. • The excellent photodegradation activity is ascribed to the SPR of Bi nanoparticles. Herein, we fabricate a Bi/Bi₂O₂CO₃ heterojunction via one-pot in situ deposition of Bi nanoparticles on Bi₂O₂CO₃ nanosheets, using formamide both as a carbon/alkali source and a reductant and demonstrate that the content of Bi in Bi/Bi₂O₂CO₃ composites can be tuned by adjusting the hydrothermal reaction time. Systematic characterization and analysis of as-prepared composites revealed that the initial in situ growth of Bi nanoparticles on BiOCOOH (an intermediate formed during the decomposition of formamide) was followed by the reaction of BiOCOOH with CO₃²⁻ to afford Bi₂O₂CO₃ nanosheets. The photocatalytic activity (PCA) of Bi/Bi₂O₂CO₃ was evaluated by degradation of rhodamine B (RhB) under simulated solar light irradiation, and the best result (99.61% degradation efficiency after 50-min irradiation) was observed for the photocatalyst obtained after 12-h hydrothermal treatment. The enhanced photocatalytic performance was ascribed to visible-light harvesting and electron-hole separation efficiency improvements caused by the surface plasmon resonance of Bi nanoparticles. Moreover, the developed photocatalyst displayed high photochemical stability and reusability during ten photocatalytic cycling runs and was therefore concluded to be well suited for practical wastewater purification applications. Thus, this work provides a new and facile method of utilizing non-noble Bi nanoparticles to optimize the PCA of semiconductor materials.