Photoelectrochemical Degradation of Organic Pollutants on a La3+ Doped BiFeO3 Perovskite

Abstract

Towards nonconventional wastewater treatment methods for the degradation of organic pollutants in wastewater, a perovskite-based photoelectrochemical system was developed. Bismuth ferrite doped with lanthanum (La-BiFeO3, La-BFO) perovskite was synthesised through a hydrothermal method with low calcination temperature for the photoelectrochemical degradation of orange II dye and other cocktails of dyes. Photoanodes were prepared by the deposition of the perovskites on a fluorine-doped tin oxide (FTO) substrate. The photoanodes were characterised using XRD, FESEM, FTIR and UV-vis diffuse reflectance. The photoelectrochemical properties of the synthesised photoanodes were investigated with chronoamperometry and electrochemical impedance spectroscopy (including Mott–Schottky analysis). The results show that all La3+-doped BFO photoanodes exhibited a higher absorption edge in the visible light region than the undoped BFO. The photocurrent response of 10% La-BFO (the best performing electrode) exhibited a three times higher current response than the pure BFO. In addition, the electrode exhibited a good degradation efficiency of 84.2% within 120 min with applied bias potential of 2 V at a pH of 7. EIS studies showed a significant enhancement of the interfacial electron transfer of the charge carriers. The enhancements in electrode performances were attributed to the synergistic effect of the applied bias potential and the introduction of La3+ into the BFO matrix. This study therefore shows that the photoelectrocatalytic performance of BFO for water treatment can be improved by the introduction of perovskites-doping ions such as La3+.

Experimental and Theoretical Investigations of Low-Dimensional BiFeO3 System for Photocatalytic Applications

“…Furthermore, the BFO photocatalyst has already been demonstrated for the degradation of organic compounds such as dyes [21][22][23], antibiotics [24], and antibacterials [25], as well as a photoanode for hydrogen production [26]. The BFO photocatalytic activity (band gap engineering and restriction of the recombination rate) was also found to be improved by the incorporation of doping agents such as La [27][28][29], Sm [30], co-catalyst [31], metallic nanoparticles such as gold [32] or silver [33] or by the production of n/p heterojunction [34][35][36].…”

A Review on Synthesis, Properties, and Environmental Application of Fe-Based Perovskite

“…10% La doping has enhanced the photoelectrocatalytic efficiency by reducing the band-gap. e schematic representation of its mechanism and photoelectrocatalytic efficiency is given in Figure 6 [113].…”

“…Figure6: Schematic representation of photoelectrocatalytic degradation of dyes and pharmaceutical pollutants using BiFeO 3 and 10% La doped BiFeO 3[113].…”

Titanium dioxide - activated carbon composite for photoelectrochemical degradation of phenol

“…Difficult recovery and fast photoexcited electron-hole pairs recombination of catalysts are two considerable drawbacks of photocatalysis, which can be minimized with the photoelectrochemical (PEC) method [13,14]. According to the PEC principle, a photocatalyst is coated onto a photoelectrode, to which a bias voltage is applied to improve photogenerated charge carrier separation, thus enhancing the activity of the photocatalyst [15,16].…”

“…According to the PEC principle, a photocatalyst is coated onto a photoelectrode, to which a bias voltage is applied to improve photogenerated charge carrier separation, thus enhancing the activity of the photocatalyst [15,16]. Therefore, the PEC method has attracted considerable interest in water splitting [17] as well as organic pollutants degradation [13]. Us-2 of 11 ing a TiO2-based photoanode for the PEC experiment, phenol degradation achieved 73.76% after 120 minutes of UV illumination under 0.8 V of applied voltage [18].…”