Preparation of Ti/SnO₂-Sb₂O₄-La Electrode with TiO₂ Nanotubes Intermediate Layer and the Electrochemical Oxidation Performance of Rhodamine B

Abstract

A La-doped Ti/SnO 2 -Sb 2 O 4 electrode with TiO 2 -NTs intermediate layer (Ti/TiO 2 -NTs/SnO 2 -Sb 2 O 4 -La) was created via the electrodeposition technique. The physicochemical and electrochemical properties of the electrode were analyzed through FESEM, XRD, XPS, CV, and LSV electrochemical tests. The results showed that TiO 2 -NTs were tightly packed on the surface of Ti substrate, thus improving the binding force of the SnO 2 -Sb 2 O 4 -La coating, offering greater specific surface area, more active spots, higher current response, and longer lifespan for the degradation of rhodamine B. The lifespan of the Ti/TiO 2 -NTs/ SnO 2 -Sb 2 O 4 -La electrode reached 200 min (1000 mA cm −2 , 1 M H 2 SO 4 ), while the actual service life was up to 3699 h. Under the conditions of initial pH 3.0, Na 2 SO 4 concentration of 0.1 M, current density of 30 mA cm −2 , and initial rhodamine B concentration of 20 mg L −1 , the color and TOC removal rate of rhodamine B reached 100% and 86.13% within 15 and 30 min, respectively. Rhodamine B was decomposed into acids, esters, and other molecular compounds under the action of •OH and SO 4•− free radicals and electrocatalysis, and finally completely mineralized into CO 2 and H 2 O. It is anticipated that this work will yield a novel research concept for producing DSA electrodes with superior catalytic efficacy and elevated stability.