Highly efficient visible-light-driven photo-Fenton catalytic performance over FeOOH/Bi2WO6 composite for organic pollutant degradation

Abstract

Amorphous FeOOH quantum dots (QDs)-decorated Bi2WO6 nanosheet heterostructures (FeOOH/Bi2WO6) were successfully fabricated through a combined hydrothermal and impregnation approach, characterized by many modern techniques, and employed as an efficient visible-light-driven photo-Fenton catalyst for the degradation of organic pollutants including methylene blue, rhodamine B and tetracycline hydrochloride. The results showed that the photo-Fenton catalytic performance of FeOOH/Bi2WO6 composite is much higher than those of single FeOOH QDs, Bi2WO6 and their physical mixture. Especially, 0.9% FeOOH/Bi2WO6 composite indicated a highest photo-Fenton catalytic activity. This can be attributed to that the synergistic effects of FeOOH and Bi2WO6 can promote the rapid transfer of photo-generated electrons from Bi2WO6 to FeOOH QDs and accelerate the reduction of Fe (III) to Fe (II) by photo-generated electrons and the conversion of dissolved oxygen in water into the strong oxidant superoxide negative radicals (·O2−). The presence of hydrogen peroxide (H2O2) enables the oxidation of Fe (II) to Fe (III) and the formation of a great number of additional hydroxyl radicals (·OH). These active radicals ·OH and ·O2− confirmed by electron spinning resonance spectra greatly improved the degradation of organic pollutants. In addition, the dosage effect (catalyst, H2O2) and acidity-basicity effect were investigated and a reasonable mechanism of pollutant degradation was proposed. Finally, the superior stability and reusability of catalyst were confirmed by five-recycled use for a promising candidate for water remediation in industrial application.