Mxene-Cu Electrified Membranes with Confined Lamellar Channels for the Flow-through Electrochemical Reduction of Nitrate to Ammonia

Abstract

Electrochemical conversion of nitrate to valuable ammonia is a promising but challenging study of wastewater treatment and resource recovery. Herein, we reported an MXene-Cu lamellar electrified membrane with confined channels as a flow-through electrode for ammonia (NH3) synthesis by nitrate (NO3–) reduction. The introduction of Cu nanoparticles into Ti3C2Tx-stacked membranes could broaden their plane channels to improve the mass transfer while confining their permeability to achieve modulation of the water flux. By coordination of the catalytic capacity of Cu nanoparticles as well as the tunable water flux, the Ti3C2Tx-Cu flow-through membrane electrodes exhibited excellent electrocatalytic performance. Particularly, in a closed-cycle flow-through mode, the optimized Ti3C2Tx-Cu membranes were able to convert NO3– to NH3 efficiently, even at high feed concentrations. In addition, these membrane electrodes possessed not only excellent long-term durability but also resistance to organic dye contaminations due to their inherent rejection capability, which allowed them to maintain stable electrocatalytic properties in complex solutions. This work demonstrates that the use of MXene-based electrified membranes with confined channels as flow-through electrodes may be an alternative strategy to achieve sustainable NO3– decontamination and NH3 synthesis, which will conduce to the practical application of specific electrified membranes in the electrochemistry field.