Electrocatalytic Reduction of NO on the MnN 4 Single‐Atom Catalyst Interfacing With Metal Supports: A First‐Principles Study

ABSTRACT The electrocatalytic nitric oxide reduction reaction (NORR) presents a promising route for sustainable ammonia production. Transition metal (TM) single atoms coordinated with four pyridinic nitrogen atoms in a carbon matrix (denoted as TMN 4 –C) have emerged as a vital class of single‐atom catalysts (SACs). Recent studies shown that interfacing TMN 4 –C with TM surfaces can significantly boost catalytic performance in several reactions. However, whether such interfacial strategies can similarly enhance NORR activity remains unclear. Herein, we present a comprehensive theoretical investigation of the NORR on the MnN 4 –C SACs supported on various metal substrates. Constant‐potential first‐principles calculations reveal that metal supports, particularly Ag(111), markedly improve NORR performance, reducing the limiting potential from –0.69 V (free‐standing MnN 4 –G) to –0.39 V. Mechanistic analysis identifies the *NO → *NHO step as the potential‐determining step, with the metal–support interface modulating the binding strength and activation of NO intermediates. Electronic structure analysis combined with SISSO‐based symbolic regression highlights the spin magnetic moment and dz 2 ‐band center of the Mn active center, along with the total charge of the entire system, as key factors controlling activity. Bonding analyses further confirm a donation–backdonation interaction between NO and the Mn center as the underlying activation mechanism. This work provides fundamental insights into interfacial electronic modulation strategies for the rational design of high‐performance NORR graphene‐based single‐atom electrocatalysts.