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

Electrochemical disinfection via in-situ H 2 O 2 generation through two-electron oxygen reduction (2e--ORR) is deemed as an alternative to traditional chemical dosing disinfection methods. However, its disinfection performance is still confined by its low H 2 O 2 yield, which largely relies on the electronic structure of cathode along with O 2 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-Ti 3 C 2 MXene/CF) was designed by electrodeposition monolayer Ti 3 C 2 T x 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, H 2 O 2 production was evaluated by pulsed-assisted MXene-based electrochemical configuration, where H 2 O 2 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 constant mode system. This enhancement could be attributed to pulse primarily enhancing 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. [Display omitted] [ABSTRACT FROM AUTHOR]