Tuning electronegativity environment of asymmetric oxygen vacancies in Sb-SnO2 promotes electrofiltration oxidation at low potential

Abstract

Development of a 3D self-standing porous anode that can efficiently generate •OH at low potential remains exceptionally challenging for the electrofiltration technology. Herein, we propose a local microenvironment regulation strategy for precisely tuning electronegativity of asymmetric oxygen vacancy (Ov) via Ce atoms in microchannels of Sb-SnO2 anode to boost •OH generation. Both H2O and O2 adsorption on the Ce–Ov–Sn sites can be improved, and the asymmetric sites along with electrophilic O2 synergistically withdrew electrons from adsorbed H2O. Consequently, a 9.2 folds increase in the •OH yield is achieved for Ce-Sb-SnO2 compared with Sb-SnO2 at 1.62 V vs. SHE. Integrating Ce-Sb-SnO2 anode into electrofiltration system, the removal efficiency of 2,4-dichlorophenol reached 99.0 % (k = 0.233 min−1) with only 0.02 kWh·m−3 under high water flux of 1500 L·m−2·h−1. This work inspires us to design metal oxide electrodes from the view of tuning metal electronegativity differences and vacancies to achieve high performance.