Surface hydroxyl synergistic oxygen vacancy to activate peroxydisulfate for enhancing the photocatalytic performance of Fe-ZnO/PEG-BiOCl: Catalytic and mechanistic study

The synthesis of environmentally friendly photocatalysts to synergistically activate peroxodisulfate has received widespread attention in recent years. In this study, type-Ⅱ Fe-ZnO/PEG-BiOCl heterojunction composites with abundant surface hydroxyl groups and oxygen vacancies are synthesized by a hydrothermal-precipitation method. The experimental results demonstrate that the presence of hydroxyl groups not only adsorbs the organic pollutants on the surface of the catalyst, but also cooperates with oxygen vacancies to activate peroxydisulfate for boosting the photocatalytic performance of Fe-ZnO/PEG-BiOCl. 98 % of rhodamine B (RhB) is removed within 20 min. The enhanced mechanism of the catalytic performance is further analyzed by a series of characterization techniques. In addition, the high removal efficiency is maintained over a broad pH range (3−9) and for diverse organic substrates, which illustrates the versatility and generalizability of the catalyst. Free radical quenching experiments and ESR tests indicate that h+ and •O2- play the critical roles in the degradation of RhB. The present study proposes an effective strategy to enhance the photocatalytic performance via the activation of peroxydisulfate by surface hydroxyl groups and oxygen vacancy. [Display omitted] •Fe-ZnO/PEG-BiOCl with abundant hydroxyl groups and oxygen vacancies is synthesized.•Photocatalysis cooperates with persulfate activation to enhance the catalytic performance.•PDS is activated by the hydroxyl groups and oxygen vacancies.•The adsorption capacity of catalysts is closely related to the hydroxyl content.•High removal efficiency is maintained over a broad pH range (3−9).