Synergistic enhancement of the catalytic performance of BiOBr: The role of surface hydroxyl groups and amorphous FeOOH

The performance of photocatalysts need to be further improved in sewage treatment. In this study, polyethylene glycol (PEG) and zinc nitrate hexahydrate (Zn(NO3)2•6 H2O) co-modified BiOBr with deposition of amorphous FeOOH (AF/ZPBB) is synthesized via precipitation-immersion method. Amazingly, the adsorption capacity of catalysts for organic pollutants is enhanced through surface hydroxyl (-OH) induced by PEG and Zn2+. Meanwhile, the photocatalytic performance of AF/ZPBB is improved by reducing its energy gap (Eg) and suppressing the recombination of photogenerated carriers owing to the presence of amorphous FeOOH. Specifically, the degradation rates for rhodamine B (RhB) and tetracycline hydrochloride (TCH) are 5.5 times and 4.2 times higher than those of pure BiOBr catalyst, respectively. In addition, AF/ZPBB displays pH stability in the pH range of 2–10. After 5 cycles of reaction, only a slight catalytic performance is reduced. The reason is mainly attributed to the reduction of the -OH content, thus inhibiting the synergistic effect of adsorption and photocatalysis. Finally, •O2- is confirmed to be the main active species using ESR and active species capture tests. This work provides a new design approach for effectively enhancing catalytic performances of inorganic semiconductor photocatalysts. [Display omitted] •The adsorption capacity of BiOBr is enhanced induced by hydroxyl group.•The deposition of amorphous FeOOH contributes to the boosted catalytic performance.•The catalytic ability of AF/ZPBB maintains stable at pH of 2–10.