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

Abstract

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-FeO/TiO were grown on fluorine doped tin oxide (FTO) substrates by hydrothermal method for photoelectrochemical reduction of Cr(VI). Compared with the separate α-FeO and TiO electrodes, the composite α-FeO/TiO electrodes show higher photocurrent density. Under visible light irradiation, 100% removal efficiency of Cr(VI) was obtained after 40 min treatment. The composite α-FeO/TiO 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.

Organic acid mediated photoelectrochemical reduction of U(vi) to U(iv) in waste water: electrochemical parameters and spectroscopy

“…The α-Fe 2 O 3 /TiO 2 film on FTO glass was used as the photoanode, which was prepared according to the solvent-thermal methods in the published literatures. 19 Briefly, 1.0 mL TiCl 3 solution (15.0–20.0 wt%, Aldrich) was diluted with 5.0 mL ethylene glycol to form a precursor solution. 500 μL precursor solution was drop-cast onto the surface of FTO, and was annealed in air at 150 °C for 40 min followed by 550 °C for 2 h. Next, 1.08 g FeCl 3 ·6H 2 O (Aladdin, 99.9%) and 0.36 g NH 2 CONH 2 were dissolved in 20 mL distilled water.…”

“…In previous works, it has been proved that α-Fe 2 O 3 /TiO 2 film with mixed phase of hematite and anatase is advantageous for reducing the recombination of photo-excited electrons and holes and enhancing the visible-light-induced photocatalysis properties. 19 …”

“…Similarly, we use a-Fe 2 O 3 /TiO 2 as photocatalyst reduction and removal of Cr(VI), which exhibits a superior reduction performance. 19 Noteworthily, the combination of oxidation and reduction reactions would markedly improve the separation rate of photogenerated holes and electrons, enhance the quantum efficiency, leading to enhancement of removal rate of U(VI). In order to reduce the compound of hole and electron, the effective method has been proposed though adding hole scavenger in the reaction system.…”

“…Similarly, we use α-Fe 2 O 3 /TiO 2 as photocatalyst reduction and removal of Cr( vi ), which exhibits a superior reduction performance. 19 …”

Electrochemical Cr(VI) Reduction over Terpyridine-Derivatized Ti Sheets

“…The redox potential is known to be highly dependent on the electrode surface. Various electrodes have been developed, these include PANI/graphene QDs on screen-printed carbon electrodes (SPCEs) [20], α-Fe 2 O 3 /TiO 2 [21], Au-TiO 2 (rutile)/FTO [22], and BiVO 4 NP-modified SPCEs [23].…”