Oxygen-vacancy-enriched substrate-less SnO_x/La-Sb anode for high-performance electrocatalytic oxidation of...

Electrocatalytic oxidation is a promising technology for treating toxic organic pollutants in water and wastewater, but conventional Ti-based anodes often exhibit a short service life and low efficiency in application. Oxygen vacancy (O_V)-based defect engineering is an effective activation method for enhancing the electrocatalytic activity of electrodes. Herein, the controllable formation of O_V on the surface of a freestanding SnO₂-Sb anode was achieved by the quantitative doping of La³⁺ into the SnO₂ crystal structure of the anode for high-performance electrochemical wastewater treatment. The resultant SnO_x/La-Sb anode degraded nearly 100% moxifloxacin (MOX, 10 mg L^-1) in 30 min, with a low energy consumption of 0.09 kWh m^-3. The SnO_x/La-Sb anode with an O_V density of 1.09% had the highest degradation rate constant (0.226 min^-1), 8 times higher than that of the SnO₂-Sb anode and 16 times higher than that of the state-of-the-art boron-doped diamond anode. La³⁺ doping-induced O_V activated the anode surface for electrochemical reactions by boosting the interfacial electron transfer and •OH generation (103% increase). The novel 3D permeable SnO_x/La-Sb anode also exhibited remarkable stability (predicted service life of 59 years) and high-rate performance (>98%) in a continuous flow-through treatment system (<1 min through the anode).