Defect Engineered MXenes for Electrochemical N ₂ to NH ₃ Conversion: A Perspective

Ambient ammonia (NH3) synthesis via the electrochemical nitrogen reduction reaction (eNRR) presents a green alternative to the energy-intensive Haber–Bosch process. eNRR is fundamentally constrained by the inertness of the N≡N triple bond and competing hydrogen evolution reaction (HER). Two-dimensional (2D) MXenes are a compelling catalyst class for eNRR. Although the catalytic activity of pristine MXene basal planes is often insufficient, leading to a defect engineering strategy to enhance their performance. This work analyses how defects modulate the local charge density of MXenes, essential for optimizing N2 adsorption and activation while selectively suppressing HER. We evaluated synthetic methodologies for defect engineering along with advanced characterization techniques required to elucidate their atomic and electronic configurations. This work concludes by addressing the critical bottlenecks and their plausible mitigation strategies.