Electrochemical disinfection boosting by a pulsed-assisted MXene-based cathode

Electrochemical disinfection via in-situ H2O2 via two electron oxygen reduction (2e−-ORR) is deem as an alternative to traditional chemical dosing disinfection methods. However, its disinfection performance is still confined by its low H2O2 yield, which largely relies on the electronic structure of cathode along with O2 mass transport, especially for immersed cathode. To tackle this concern, we developed a pulsed-assisted MXene-based electrochemical system with both electronic effect and mass transport being taken into consideration. MXene-based cathode (F-Ti3C2 MXene/CF) was designed by electrodeposition monolayer Ti3C2Tx MXene onto different substrates, which endowed surface groups good for 2e−-ORR. Firstly, electrodeposition parameters were investigated including electrodeposition voltage, time and two porous substrates (carbon-based carbon fiber and metal-base nickel foam). Then, H2O2 production was evaluated by pulsed-assisted MXene-based electrochemical system, where H2O2 achieved an unprecedented 16.87 mg/L under the conditions of a pulse potential of -0.6 V vs SCE, pulse width of 1 s, and a duty cycle of 50%. It witnessed a 314.7% upsurge compared to the direct constant current mode system. This enhancement could be attributed to pulses primarily enhance the non-Faradaic process by facilitating electron transfer at the three-phase interface on the electrode surface and promoting mass transfer of reactants. In the final section, a 99.99% deactivation efficiency against E. coli within 60 min was obtained.