Periodic Table Exploration of MXenes for Efficient Electrochemical Nitrate Reduction to Ammonia

Applying electrochemical nitrate reduction reaction (NO₃RR) to produce ammonia offers a sustainable alternative to the energy-intensive Haber-Bosch process, which is crucial for clean energy and agricultural applications. While 2D MXenes hold great promise as electrocatalysts for NO₃RR, their application for ammonia production remains underexplored. This study combines experimental and theoretical approaches to evaluate the catalytic performance of a series of MXenes with different central metal atoms for NO₃RR. Among the materials studied (Ti₃C₂T_x, Ti₃CNT_x, Ti₂CT_x, V₂CT_x, Cr₂CT_x, Nb₂CT_x, and Ta₂CT_x), Ti₃-based MXenes exhibit superior faradaic efficiency, ammonia yield rate, and stability. Density functional theory calculations offer further insights explaining the structure-activity-based observations. This research establishes a foundation for future studies aimed at leveraging MXenes for electrochemical nitrate reduction for green synthesis of ammonia.