A novel ZnFe2O4 intermediate layer for improving the electrocatalytic performance of Ti/Ce-PbO2 anode toward Levofloxacin removal

Abstract

The exploration of cost-expensive and efficient electrocatalyst is extremely crucial for electrocatalytic degradation of refractory organic wastewater. Herein, a novel laminated electrocatalyst was constructed via consecutively electrodepositing the ZnFe2O4 as the inter-layer and Ce-PbO2 as top-layer on Ti substrate (Ti/ZnFe2O4/Ce-PbO2, TZCP). Compared with those of the Ti/ZnFe2O4 (TZ) and Ti/Ce-PbO2 (TCP), the TZCP has higher electrocatalytic degradation activity toward levofloxacin (LEX), endowing 93.24% for the removal rates of LEX within 120 min, whereas the TZ and TCP are merely 71.88% and 69.13%. The enhanced electrocatalytic property of TZCP can mainly be attributed to the higher oxygen evolution potential (OEP), lower charges transfer resistance and bigger electrochemical active surface area (ECSA) than those of the TZ and TCP. Furthermore, the TZCP shows a negligible decrease ranging from 93.24% to 91.20% after repeatedly running 5 times, manifesting the prominent stability of TZCP. The reactive radical capturing experiments verify that the·OH is the dominant reactive species of LEX degradation. The possible degradation pathway is also examined by analyzing the intermediates via liquid chromatography-mass spectrometry (LC-MS). Consequently, this work provides a novel guideline for ameliorating the electrocatalytic performance of PbO2 by developing the laminated construction.