Electrocatalytic degradation of pesticide micropollutants in water by high energy pulse magnetron sputtered Pt/Ti anode

摘要

The increasing occurrence of pesticide micropollutants highlights the need for innovative water treatment technologies,particularly for small-community and household applications.Electro-oxidation is being widely studied in this area,unfortunately,safe,stable and efficient electrocatalytic anodes without released heavy metal ions are still highly required.In this study,we fabricated a Pt/Ti anode by high energy pulse magnetron sputtering(HiPIMS-PtTi)which was used to decompose dichlorvos(DDVP)and azoxystrobin(AZX)in water.The results show that the reaction rate constant(kENR)on HIPIMS was 35.7 min-1(DDVP)and 41.3 min-1(AZX),respectively,superior to electroplating Pt/Ti anode(EP-PtTi).The identification of radicals(^(·)OH,^(1)O_(2),^(·)O_(2)-)and micro-area analyses evidenced that Pt atoms were embedded into the TiO_(2) lattice on the surface of Ti plate by high-energy ions,which resulted in more adsorbed hydroxyls,and higher production of·OH under polarization conditions.Besides,the electro-oxidation intermediates of DDVP and AZX were identified and the degradation pathways were speculated:(1)indirect oxidation dominated by·OH attack,and(2)direct electron transfer reaction of pesticides on the anode surface.The cooperated reactions achieve the complete degradation and highly efficient mineralization of DDVP and AZX.