FTO-TiO2 Photoelectrocatalytic Degradation of Triphenyltin Chloride Coupled to Photoelectro-Fenton: a mechanistic study

Abstract A powerful, simple and stable transparent photoanode based on TiO2 nanoparticles deposited on fluorine-doped tin oxide (FTO) was synthesized for the photoelectrocatalytic degradation of the organometallic pollutant triphenyltin chloride (TPTCl). Contrasting with most of the works on photoelectrocatalysis (PEC), FTO-TiO2 was found to be an excellent anode material for the degradation/mineralization of organic pollutants at high anodic potentials through the formation of electrochemically-induced hVB+ (dark PEC), showing a similar behavior as the so-called “non-active” anodes like the powerful boron doped diamond electrode (BDD). The electrocatalytic efficiency was enhanced by the photoexcitation of TiO2 under UV light (PEC) and by coupling with photoelectro-Fenton (PEC-PEF): this resulted in complete degradation of TPTCl in 15 min (kapp =0.274 min−1) and total mineralization in 2 h. The mechanisms governing the photoelectrocatalytic processes are investigated in detail by means of electrochemical measurements and chemical probes, and a mineralization pathway for TPTCl is proposed.