Preparation of a novel Ni/Sb co-doped Ti/SnO2 electrode with carbon nanotubes as growth template by electrodeposition in a deep eutectic solvent

Abstract

Ti/SnO2–Sb electrodes have shown many practical advantages in the field of electrocatalytic oxidation for the treatment of organic wastewater. However, the short lifetime of the Ti/SnO2–Sb electrode seriously restricts its industrial application. To improve the stability of the Ti/SnO2–Sb electrode, a novel Ni/Sb co-doped Ti/SnO2 electrode (Ti/CNT–Ni–SnO2–Sb–DES) with carbon nanotubes (CNTs) as the guiding template was prepared in this study using a deep eutectic solvent (DES) instead of the conventional aqueous electrodeposition system and used for the degradation of simulated phenol wastewater. The stability test results showed that this novel electrode achieved an accelerated lifetime of 208 min (1 M H2SO4, 1 A/cm2), which was 40.78 times higher than that of the Ti/SnO2–Sb–WT electrode. The electrocatalytic performance was further tested, and the results showed that the degradation rate of phenol was 98.09% and the chemical oxygen demand (COD) removal rate was 85.36% within 2 h for the Ti/CNT–Ni–SnO2–Sb–DES electrode. It was found that the enhanced performance of the Ti/CNT–Ni–SnO2–Sb–DES electrode was related to its rough surface, high coating hardness and bond strength, fine and uniform coating structure, abundant adsorbed hydroxyl species, more reactive oxygen species (OH and ozone) and high rate of charge transfer. This study is expected to open up a new pathway for the preparation of Ti/SnO2–Sb electrodes with excellent performance in an efficient, simple and economical way.