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 (O_v) via Ce atoms in microchannels of Sb-SnO₂ anode to boost •OH generation. Both H₂O and O₂ adsorption on the Ce–O_v–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.