Halogen‐Terminated Ti 3 C 2 T x MXene Electrocatalysts for Continuous Co‐Generation of Ammonia and Electricity

Abstract Aqueous rechargeable Zn‐N 2 batteries with a unique configuration can realize co‐generation of NH 3 and electricity, of which the key is the design and fabrication of active N 2 electroreduction electrocatalysts. Here, a halogen‐capping engineering approach to fabricate halogen‐terminated Ti 3 C 2 T x MXenes for Zn‐N 2 batteries is reported, showing that the halogen terminals of Ti 3 C 2 T x (T = F, Cl, Br, and I) play a significant role in enhancing the N 2 adsorption on Ti active sites and the electron transfer from Ti to N 2 . The Ti 3 C 2 Cl x catalyst is the best in terms of both N 2 electroreduction and the Faradic efficiency among all reported MXene‐based catalysts due to the moderate electronegativity and small steric hindrance of Cl‐terminal. Impressively, the Ti 3 C 2 Cl x ‐based Zn‐N 2 battery with high power density can continuously produce NH 3 in high capacity in an alkaline electrolyte. This work will help to develop high‐performance MXene‐based NRR electrocatalysts and Zn‐N 2 batteries for continuous green NH 3 and electricity production.