Unveiling the electrochemical nitrogen reduction reaction mechanism in heteroatom-decorated-Mo2CS2–MXene: the synergistic effect of single-atom Fe and heteroatom

Abstract

Conversion of nitrogen (N₂) to ammonia (NH₃) is a significant process that occurs in environment and in the field of chemistry, but the traditional NH₃ synthesis method requires high energy and pollutes the environment. In this work, the charge, orbital and spin order of the single-atom Fe loaded on heteroatom (X) doped-Mo₂CS₂ (X = B, N, O, F, P and Se) and its synergistic effect on electrochemical nitrogen reduction reaction (eNRR) were investigated using well-defined density functional theory (DFT) calculations. Results revealed that the X-element modified the charge loss capability of Fe atoms and thereby introduced a net spin through heteroatom doping, resulting in the magnetic moment modulation of Fe. Upon incorporating N₂ molecule vertically into Fe@P-doped-Mo₂CS₂, the strongest eNRR performance and activation ability for the NN were achieved. This was due to the 1π_u antibonding orbitals being filled with extra charges from Fe atoms and the σ_2s bonding orbitals experiencing a splitting phenomenon as a result of net spin injection from P atoms. Thus, this work provides rational design principles for the development of non-noble metal eNRR electrocatalysts by ingeniously manipulating their spin order and local environments.