Enhanced visible light photoelectrocatalytic degradation of o-chloronitrobenzene through surface plasmonic Au nanoparticles and g-C3N4 co-modified TiO2 nanotube arrays photoanode

Chloronitrobenzenes are typical refractory aromatic halogenated nitroaromatic and high-toxic contaminants. The reduction process of chloronitrobenzenes cannot realize their mineralization, and the existence of chlorine group is detrimental to degradation through single chemical oxidation technology. Herein, the Au nanoparticles and graphitic carbon nitride co-modified TiO2 nanotube arrays (Au/g-C3N4/TNAs) photoanodes were fabricated to degrade o-chloronitrobenzene (o-CNB) target pollutant in photoelectrocatalytic (PEC) system. The Au/g-C3N4/TNAs fabricated with 0.20 mM HAuCl40.4 H2O (Au/g-C3N4/TNAs-0.20) had more superior optical and photoelectrochemical properties than other fabricated photoanodes. Au/g-C3N4/TNAs-0.20 photoanode increased dechlorination efficiency through reduction process, which was beneficial to o-CNB degradation and TOC removal. The coexistence of anions and humic acid inhibited the PEC degradation of o-CNB. The photogenerated electron, •O2−, hole and •OH participated in o-CNB degradation in PEC system. The degradation pathway of o-CNB was inferred through GC-MS spectra and DFT calculation. The acute toxicity and bioaccumulation factor of o-CNB were effectively reduced by PEC degradation.