The visible-light-driven photocatalytic reduction of Cr using BiVO: assessing the effect of Au deposition and the reaction parameters.

In this work, fern-leaf-like BiVO was used to photocatalytically reduce Cr in water. Nanosized BiVO displayed bandgap energy and specific surface area of 2.49 eV and 5.65 m g, respectively. Metallic Au nanoparticles were deposited on the BiVO to increase the photocatalytic performance. To optimize the reaction conditions, the sacrificial agents methanol, ethanol, formic acid, dimethyl sulfoxide, and KI were tested, while different catalyst dosages and Au loadings were assessed. The best sacrificial agent was formic acid, which was used at an optimal concentration of 0.01 mol L. The complete removal of Cr was attained after 90 min of visible light irradiation using a catalyst dosage of 1.5 g L. Depositing metallic Au nanoparticles barely improved the photocatalytic performance, thus unmodified BiVO was used to remove Cr in tap water. The matrix effect slowed the photocatalytic process, and the complete removal of Cr was achieved in 120 min. Cr and Cr species were precipitated on the catalyst surface at the end of the photocatalytic process; still, BiVO displayed high stability after three reaction cycles.