Improving photoelectrochemical reduction of Cr(VI) ions by building α-Fe2O3/TiO2 electrode.

Photoelectrochemical process is an environmentally friendly technology and has a wide application in the control of environmental pollutants. Efficient nanophotocatalysts responsive to visible light are still highly attractive. In this work, α-Fe2O3/TiO2 were grown on fluorine doped tin oxide (FTO) substrates by hydrothermal method for photoelectrochemical reduction of Cr(VI). Compared with the separate α-Fe2O3 and TiO2 electrodes, the composite α-Fe2O3/TiO2 electrodes show higher photocurrent density. Under visible light irradiation, 100% removal efficiency of Cr(VI) was obtained after 40 min treatment. The composite α-Fe2O3/TiO2 electrodes showed an enhanced absorbance in visible light region and had good stability to photoelectrochemical reduction of Cr(VI). The role of hole scavengers (citric acid and oxalic acid) and pH values was systematically investigated. This novel intensification approach provides new insight on the application of photoelectrochemical reduction in environmental remediation.