Dynamic Etching‐Induced Cl‐Terminated Ti ₃ C ₂ Cl x /Ti ₃ ZnC ₂ Heterostructure for Ammonia Electrosynthesis and Zinc‐Nitrogen Batteries

ABSTRACT 2D Ti 3 C 2 T x MXenes are of great potential in catalysis, energy storage, and conversion, yet the controlled tuning of their structure, intrinsic activity, and stability remains a challenge. Herein, we address this challenge through a dual‐modification strategy, synthesizing a Cl‐terminated MXene/MAX (Ti 3 C 2 Cl x /Ti 3 ZnC 2 ) heterostructure by a dynamic etching approach for efficient electrocatalytic nitrogen reduction reaction (NRR). This catalyst achieves an NH 3 yield of 20.1 µg h −1 mg −1 and a Faradaic efficiency of 38.1% at −0.2 V vs. RHE in 0.1 m KOH electrolyte, with high stability for over 70 h, positioning it among the top‐performing MXene‐based NRR electrocatalysts. Experimental and theoretical analyses demonstrate that the Ti 3 C 2 Cl x /Ti 3 ZnC 2 heterostructure modulates the electronic structure of Ti sites, thus optimizing the intermediate adsorption and reducing the energy barrier of *NH 2 → NH 3 conversion in the distal pathway to 0.7 eV. The Zn‐N 2 battery assembled with Ti 3 C 2 Cl x /Ti 3 ZnC 2 can reach a peak power density of 36.5 µW cm −2 , with an NH 3 yield of 13.1 µg h −1 mg −1 . This study has demonstrated that the dual modification strategy involving surface terminations regulation and heterostructure construction is effective to improve both NRR activity and stability of MXene‐based electrocatalysts, which is crucial for efficient NH 3 production and energy generation. This improvement paves the way for efficient ammonia and energy co‐generation, providing a viable materials design strategy and deeper mechanistic insights.