Ti/PbO2-Sm2O3 composite based electrode for highly efficient electrocatalytic degradation of alizarin yellow R

Abstract

In this work, a novel Ti/PbO2-Sm2O3 composite electrode with high electrocatalytic activity is successfully fabricated via simple electrodeposition method and further investigated for electrochemical degradation of alizarin yellow R (AYR) wastewater. The test results of X-ray diffraction, field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy confirm that Sm2O3 is successfully composited with PbO2. The coating of Ti/PbO2-Sm2O3 composite electrode stacked by typical pyramid-like micro-particles exhibits smooth and compact surface morphology which is conducive to enhancing the corrosion resistance of electrode. Furthermore, electrochemical performance tests indicate that Ti/PbO2-Sm2O3 composite electrode has advantages of higher oxygen evolution potential, lower charge transfer resistance and longer lifetime over Ti/PbO2 electrode. Electrolyte concentration, plate space, initial pH and cell voltage are assessed to optimize the degradation condition of AYR. The results show that COD removal efficiency and degradation efficiency of AYR on Ti/PbO2-Sm2O3 composite electrode reach up to 79.90% and 80.00% under the optimal conditions (Na2SO4 electrolyte concentration 9.0 g L−1, plate space 3.0 cm, initial pH 5, cell voltage 3.0 V and electrolysis time 150 min), respectively. The degradation of AYR follows pseudo-first-order reaction kinetics, and a plausible mineralization pathway of AYR is proposed on the basis of the identification of major intermediate products. These results suggest that Ti/PbO2-Sm2O3 composite electrode is a promising candidate for electrocatalytic degradation of AYR wastewater.