Elucidating Semiconducting Properties and Photocatalytic Performance of Surface-Decorated BiVO4 for the Removal of Contaminants of Emerging Concern.

Abstract

Photocatalysis has been shown to be a promising and ecofriendly approach to the removal of contaminants of emerging concern (CECs). However, preventing the recombination of photogenerated charge carriers and achievement of suitable band edge positions are still major challenges to ensuring better performance. Herein, we report the preparation of surface-decorated BiVO₄ with both a noble metal (Ag) and transition metal (Fe). The structural, morphological, and semiconducting features of the material were examined employing various techniques (XRD, SEM, UV-DRS, PL, and photoelectrochemical tests). The band gap of surface-modified BiVO₄ is slightly narrower compared to pristine material, which is further validated by HOMO-LUMO gaps obtained through theoretical modeling approaches. The recombination of photogenerated charges was successfully reduced in the case of Ag-Fe-BiVO₄, as proven by lower PL intensity and increased current density. The comparative photocatalytic degradation of the CECs ciprofloxacin (CIP) and perfluorooctanoic acid (PFOA) was conducted employing pristine BiVO₄ and its two surface-modified analogues (Ag-BiVO₄, and Ag-Fe-BiVO₄) under solar light. Ag-Fe-BiVO₄ was shown to be the most efficient; however, its effectiveness differed depending on CEC type. Under the same process conditions, degradation of CIP reached 93.9%, while PFOA was degraded only partially (22.9%).