Broad spectrum driven Y doped BiO2−x for enhanced degradation of tetracycline: Synergy between singlet oxygen and free radicals

The synergy of singlet oxygen and free radicals is crucial to driving organic pollutant degradation in water contain complex natural organic matter. In this study, the rare earth element yttrium doped bismuth oxide (Y-BiO2−x) photocatalyst was prepared by a hydrothermal method. Y doped BiO2−x enables produce oxygen vacancies and possess up-conversion property. The superoxide radicals (O2−), singlet oxygen (1O2), hydroxyl radicals (OH) and hole (h+) play a crucial role in photocatalytic reaction process. The increased 1O2 and hydrogen peroxide are mainly originated from O2−. The degradation efficiency of tetracycline (TC) reached 70.45 % and 40.17 % under Vis and NIR light, respectively. Notably, the TC removal efficiency of Y-BiO2−x maintained 65.92 % in the actual wastewater containing various anions and humic acid (HA), which originate from synergy of singlet oxygen and free radicals. This study provides a new strategy for synergistic singlet oxygen and free radicals to degradation of organic pollutants in complex water matrix.