Photoelectrocatalytic activity of perovskite YFeO3/carbon fiber composite electrode under visible light irradiation for organic wastewater treatment

Abstract

BackgroundA considerable amount of azo dye wastewater is generated from textile industry every day, which jeopardizes human health and environment. To treat azo dye-containing wastewater in visible-light environment, a perovskite YFeO3/carbon fiber (CF) electrode was developed. MethodsA sol-gel process combined with calcination was adopted to synthesize YFeO3 catalysts, and the composite electrode was fabricated using a facile dip-coating method. Significant findingsThe YFeO3 powder that was calcined at 700 °C consisted of mixed hexagonal and orthorhombic phases with crystallite sizes of 15–30 nm. The particles tended to aggregate, forming a porous structure, and they exhibited a photocatalytic degradation capability for Reactive Black 5 (RB5) dyes. Notably, the YFeO3/CF composite electrode enabled significant photoelectrocatalytic activity over RB5 under visible light irradiation, with a removal efficiency of 99% in a 60 min treatment. In addition, the composite electrode demonstrated its high stability during the repeated treatments. The synergetic effect of photo- and electrocatalysis accounted for breaking the N=N bonds, as well as the benzene and naphthalene structures of RB5, resulting in a favorable pollutant degradation. Moreover, the photoelectrocatalytic treatment system kinetics followed a pseudo-first-order rate equation, corresponding to a single-molecule reaction. The improved photoelectrocatalytic activity of the composite electrode can be attributed to the reduced surface and charge transfer resistances during the photoelectrocatalysis process.