Bimetallic Cu-Fe catalysts on MXene for synergistically electrocatalytic conversion of nitrate to ammonia

NO3- is a common water pollutant that can serve as a potential nitrogen source for electrocatalytic NH3 production. However, an efficient and complete removal of low NO3- concentrations remains a challenge. Fe1Cu2@MXene bimetallic catalysts were constructed on two-dimensional Ti3C2Tx MXene carriers via a simple solution-based synthetic method and used for the electrocatalytic reduction of NO3-. The combination of the rich functional groups, high electronic conductivity on the MXene surface, and the synergistic effect between the Cu and Fe sites enabled the composite to effectively catalyse NH3 synthesis, with a 98% conversion of NO3- in 8 h and a selectivity for NH3 of up to 99.6%. In addition, Fe1Cu2@MXene showed excellent environmental and cyclic stability at various pH values and temperatures over multiple (14) cycles. Semiconductor analysis techniques and electrochemical impedance spectroscopy confirmed that the synergistic effect provided by the dual active sites of the bimetallic catalyst enabled fast electron transport. This study provides new insights into the synergistic promotion of NO3- reduction reactions using bimetals.