Perovskite-Like Strontium Bismuth Oxyhalides: Synthesis, Characterisation, Photocatalytic Activity and Degradation Mechanism

Recent studies have demonstrated that bismuth oxyhalides with a 2D structure inhibit the recombination of electron-hole pairs. Further, perovskite-like strontium bismuth-based compounds with a special layered Sillen X1 structure have shown potential for use as effective visible-light photocatalysts. Here, a series of strontium bismuth oxyhalide composites were prepared under different calcination conditions. The sample compositions were controlled by modulating the calcination temperature and the secondary calcination time. The synthesised catalysts were characterised by various techniques to identify the product compositions. Under visible-light irradiation, the degradation efficiencies and photocatalytic activities of the different catalysts towards rhodamine B (RhB) and 2-hydroxybenzoic acid (2-HBA) were measured via UV-Vis PDA and electron paramagnetic resonance analyses. To explore the degradation mechanism, scavengers were utilised to detect the radicals produced in the photodegradation test. SrBiO2Cl exhibited the best RhB degradation efficiency, of 0.0685 h (-1), and SrBiO2Br exhibited a rate of 0.0984 h (-1). At 25 degrees C and 1 atm, the CO2-CH4 photocatalytic conversion efficiencies of the optimised SrBiO2Cl and SrBiO2Br samples increased to 0.037 and 0.053 mu mol g (-1) h (-1), respectively. The findings confirm that the catalysts are highly recyclable and effective for environmental remediation, achieving the objectives of green chemistry.

Automated summary

Recent studies have found that 2D bismuth oxyhalides can inhibit electron-hole pair recombination, and perovskite-like strontium bismuth-based compounds with a layered Sillen X1 structure show promise as effective visible-light photocatalysts. In this study, a series of strontium bismuth oxyhalide composites were prepared, and their compositions were controlled by adjusting the calcination conditions. The catalysts exhibited high degradation efficiencies and photocatalytic activities for rhodamine B and 2-hydroxybenzoic acid under visible-light irradiation, making them highly effective for environmental remediation.