Effect of fuel dosage in self-propagation combustion: evolution of BiOCl to BiOCl/Bi24O31Cl10 heterojunctions enriched with oxygen vacancies

Abstract

BiOCl has garnered considerable attention recently. However, its relatively wide bandgap and poor separation efficiency of charge carriers limit its application in the visible light range. Introducing oxygen vacancies (OVs) and constructing heterojunctions are both considered as viable modification approaches. In this study, oxygen vacancy-rich BiOCl/Bi₂₄O₃₁Cl₁₀ heterojunctions were synthesized using glycine as the fuel by a one-pot self-propagation method. Variations in the amount of fuel led to differences in OV concentration and heterojunction composition in the prepared samples. The XRD pattern, FTIR spectra and EDS confirmed the formation of BiOCl/Bi₂₄O₃₁Cl₁₀ heterojunctions. The XPS and ESR spectra proved the existence of oxygen vacancies. The BET results showed that the sample prepared with an appropriate amount of glycine exhibited a larger specific surface area. The most effective OVs-BiOCl/Bi₂₄O₃₁Cl₁₀ composite demonstrated improvements in degrading rhodamine B (RhB), showing 8.09 and 17.96 times greater efficiency compared to BiOCl and Bi₂₄O₃₁Cl₁₀, respectively. It achieved 93% dye degradation within 30 minutes.