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

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.