MXene Quantum Dots/Copper Nanocomposites for Synergistically Enhanced N 2 Electroreduction

Electrocatalytic N 2 reduction reaction (NRR) represents an appealing solution for sustainable ammonia production, whereas exploring high‐efficiency NRR catalysts is highly desired but extremely challenging. Herein, we combine Ti 3 C 2 T x ‐MXene quantum dots (MQDs) with porous Cu nanosheets to design a novel heterostructured MQDs/Cu as an effective and durable NRR catalyst. Impressively, MQDs/Cu showed a synergistically enhanced NRR activity with an NH 3 yield of 78.5 μg h −1 mg −1 (−0.5 V) and a Faradaic efficiency of 21.3% (−0.4 V), far superior to pure MQDs and Cu, and outperforming the majority of the state‐of‐the‐art NRR catalysts. Density function theory computations demonstrated that the synergy of MQDs and Cu enabled the creation of interfacial Cu‐Ti dimer as dual‐active‐centers to strongly activate the absorbed N 2 and promote the *N 2 H formation, consequently resulting in the much reduced energy barriers and greatly enhanced NRR performance.