Effect of Functionalized Benzene Derivatives as Potential Hole Scavengers for BiVO(4) and rGO-BiVO(4) Photoelectrocatalytic Hydrogen Evolution

Sustainable hydrogen production is one of the main challenges today in the transition to a green and sustainable economy. Photocatalytic hydrogen production is one of the most promising technologies, amongst which BiVO(4)-based processes are highly attractive due to their suitable band gap for solar-driven processes. However, the performance of BiVO(4) alone in this role is often unsatisfactory. Herein we report the improvement of BiVO(4) performance with reduced graphene oxide (rGO) as a co-catalyst for the photoelectrochemical water splitting (PEC-WS) in the presence of simple functionalized benzene derivatives (SFBDs), i.e., phenol (PH), benzoic acid (BA), salicylic acid (SA), and 5-aminosalicylic acid (5-ASA) as potential photogenerated hole scavengers from contaminated wastewaters. Linear sweep voltammetry and chronoamperometry, along with electrochemical impedance spectroscopy were utilized to elucidate PEC-WS performance under illumination. rGO has remarkably improved the performance of BiVO(4) in this role by decreasing photogenerated charge recombination. In addition, 5-ASA greatly improved current densities. After 120 min under LED illumination, 0.53 μmol of H(2) was produced. The type and concentration of SFBDs can have significant and at times opposite effects on the PEC-WS performance of both BiVO(4) and rGO-BiVO(4).