Interface engineering on Magnéli Ti4O7 electrodes by doping with waste MOF-recycled N-doped carbon polyhedrons toward efficient electrooxidation of tetracycline

ABSTRACT Interface engineering is an effective strategy for improving the catalytic activity of electrocatalysts. Herein, an enhanced binder-free Ti 4 O 7 electrode doped with waste MOF-recycled N-doped carbon polyhedrons (Dr-CN) was developed and denoted as Dr-CN@Ti 4 O 7 . The chemical-bond formation at the interface of Ti 4 O 7 and Dr-CN led to a significant acceleration of charge transfer and higher •OH yield at 1.55-2.75 times rate in comparison with pristine Ti 4 O 7 . At 0.5%Dr-CN@Ti 4 O 7 electrode, the oxidation rate of tetracycline (TCH) was about 3 times that of pristine Ti 4 O 7 , especially when doped with 2   wt% Dr-CN, the kinetic rate can be comparable to that of BDD electrode. Furthermore, the 0.5%Dr-CN@Ti 4 O 7 anode exhibited desirable stability and durability in consecutive 20 cycle tests and was shown to effectively mineralize refractory organic matters in actual livestock and coking wastewater. Energy consumption for TCH removal by 0.5%Dr-CN@Ti 4 O 7 electrode was calculated as 3.02 kWh m -3 , with a 73.5-77.6% reduction compared to some previous electrodes. These results suggested that the interface chemical-bonded engineering strategy via doping MOF-derived carbon can effectively improve the Magnéli-phase Ti 4 O 7 electrode with satisfying electrochemical reactivity and stability.