Dual channel construction of WO3 photocatalysts by solution plasma for the persulfate-enhanced photodegradation of bisphenol A

A facile solution plasma method was used to activate the surface reactivity of photocatalysts. Take WO3 as an example, we found that reductive hydrogen radicals from electrical discharge were highly energetic and favored the formation of oxygen vacancies, whereas synergistic effect between these defects and plasma-activated water created abundant bridging hydroxyls via surface hydroxylation. When used for the removal of BPA pollutants, synergistic oxidation exhibited 6 and 12 times higher reaction rates than the individual persulfate oxidation and photodegradation, respectively. Surface activation of WO3 photocatalysts contributed to the 4-fold increase of the catalytic activity. Mechanism study demonstrated that oxygen vacancies and hydrated bridging hydroxyls provided unique channels for electron and hole extraction. The enhanced generation of oxidative species was responsible for the significantly increased photoactivity for bisphenol A (BPA) degradation. This work provides a versatile and universal strategy for the active site engineering of catalysts.