DFT Investigation of Single Metal Atom-Doped 2D MA2Z4 Materials for NO Electrocatalytic Reduction to NH3

Electrochemical reduction of nitric oxide (NO) to ammonia (NH3) remains a great challenge due to the difficulty of searching highly stable and active electrocatalysts. To this end, single metal atom-doped 2D MA2Z4 (TM1/MA2Z4) materials were systematically studied through density functional theory (DFT) calculations. Cr1/HfSi2N4 was screened out to be the ideal candidate from 15 TM1/MA2Z4 in the NO reduction reaction (NORR), with the lowest limiting potential of 0.11 V along the A-A-O-H pathway compared to the other nine NORR pathways. From the analysis using the molecular orbital theory, the electronic structures reveal that the surface (Z element) and sublayer (A element) atoms play a crucial role in regulating the NORR performance with different NH2* adsorption configurations, respectively. Our calculations provide a new design strategy of single metal atom-doped catalysts for NO electrocatalytic conversion into NH3.