Dual-function oxygen vacancy of BiOBr intensifies pollutant adsorption and molecular oxygen activation to remove tetracycline hydrochloride

Oxygen vacancy is an important factor for pollutant adsorption and molecular oxygen activation. How to construct the dual-function oxygen vacancy is still a challenge for environmental remediation. Here, BiOBr (3D-self-assembled nanospheres) with different contents of oxygen vacancies was prepared via solvothermal method and calcination, which intensified antibiotic adsorption and molecular oxygen activation to remove tetracycline hydrochloride. Adsorption experiments and theoretical calculations revealed that oxygen vacancies enhanced the adsorption of pollutants via ion exchange. Furthermore, surface complexation due to adsorption facilitated degradation through faster charge transfer, which was proven by photoelectrochemical tests and TRPL spectroscopy. Quenching experiments, EPR and photoelectrochemical measurement indicated that oxygen vacancies facilitated charge transfer, to increase the activation of molecular oxygen and subsequent ∙O2- and 1O2 production for pollutant degradation. This study provides an in-depth explanation of the role of oxygen vacancies in tetracycline adsorption, surface complex due to the intermediate state in adsorption and molecular oxygen activation, as well as a reference for antibiotic removal via adsorption coupling degradation.