Inverse opal-like marcoporous RuO2 electrodes for enhancing the mass transfer in electro-oxidation of tricyclazole

Abstract

In order to improve the mass transfer of anodic oxidation, an inverse opal-like marcoporous RuO2 electrode (IOMP-RuO2) was designed to enhance the concentration diffusion and molecule-to-electrode collision. Characterization methods including SEM, XRD, BET, LSV, CV, EIS and CA were performed to evaluate the properties of the IOMP-RuO2. In addition, the electro-oxidation capacity of the RuO2 electrode prepared at varying calcination temperature was also investigated. Results show that calcination temperature can affect the electro-oxidation performance of IOMP-RuO2 from the specific surface area, crystallinity of RuO2, voltammetric charge and impedance. Thereinto, crystallinity of RuO2 and impedance played decisive roles in the electrochemical oxidation. The fine crystallinity and lower impedance of IOMP-RuO2 acquired by 450 °C increased the electronic transport rate and allowed less redox couple to be involved in oxygen evolution, contributing to the best oxidation performance amongst others. Under this calcination temperature, the IOMP-RuO2 possesses larger electro-active areas, smaller electric resistance and enhanced mass transfer as compared to the planar RuO2 electrode. Furthermore, the IOMP-RuO2 gave a 42.7% higher degradation rate than that observed for the planar RuO2 electrode in the abatement of tricyclazole (TC) after 180 min. The high rate constant (2.14 × 10–2 min−1) and current efficiency (61.1%) achieved by IOMP-RuO2 contributed to a low energy consumption of 0.04744 kWh mg−1. Thus, these findings promoted the IOMP-RuO2 as an alternative electrode for wastewater decontamination.