Single Mn Atom Anchored on Nitrogen‐Doped Graphene as a Highly Efficient Electrocatalyst for Oxygen Reduction Reaction

Abstract

Single Mn atom on nitrogen‐doped graphene (MnN4‐G) has exhibited good structural stability and high activity for the adsorption and dissociation of an O2 molecule, becoming a promising single‐atom catalyst (SAC) candidate for oxygen reduction reaction (ORR). However, the catalytic activity of MnN4‐G for the ORR and the optimal reaction pathway remain obscure. In this work, density‐functional theory calculations were employed to comprehensively investigate all the possible pathways and intermediate reactions of the ORR on MnN4‐G. The feasible active sites and the most stable adsorption configurations of the intermediates and transition states during the ORR were identified. Screened from all the possibilities, three optimal four‐electron O2 hydrogenation pathways with an ultralow energy barrier of 0.13 eV were discovered that are energetically more favorable than direct O2 dissociation pathways. Analysis of the free energy diagram further verified the thermodynamical feasibility of the three pathways. Thus, MnN4‐G possesses superior ORR activity. This study provides a fundamental understanding of the design of highly efficient SACs for the ORR.

Constructing atomically-dispersed Mn on ZIF-derived nitrogen-doped carbon for boosting oxygen reduction

“…Manganese (Mn) adjacent to Fe on the periodic table has the outer layer electrons of 3d 5 4s 2 . The adsorption energy of Mn-N-C for *OH is lower than that of Fe-N-C, which is consistent with the density functional theory (DFT) analyses ( Xiong et al, 2019 ; Hu et al, 2021 ; Li et al, 2021 ; Peng et al, 2021 ; Zhou et al, 2022 ). Besides, Mn is among the richest metals on earth.…”

Different Bonding Defects on Dual‐Metal Single‐Atom Electrocatalyst CoZnN6(OH) for Oxygen Reduction Reaction

“…The adsorption energies (E ads ) of these intermediates are obtained similar to the previous studies. [7,[16][17][18][19] The computational hydrogen electrode (CHE) model is used to calculate the free energy variation (ΔG) of different intermediates based on Equation ( 5):…”

“…Single‐atom catalysts (SACs) have been reported as highly active non‐precious electrocatalysts for ORR, OER and CO 2 RR etc, due to their abundant atomically‐ homogenized active centers [1–11] . As one of the most intriguing SACs, the transition metal−nitrogen−carbon (TM‐N x −C) system exhibited promising electrocatalytic activity, in which the transition metals are atomically distributed as isolated atoms supported by N‐doped carbon materials [12] .…”

“…Single-atom catalysts (SACs) have been reported as highly active non-precious electrocatalysts for ORR, OER and CO 2 RR etc, due to their abundant atomically-homogenized active centers. [1][2][3][4][5][6][7][8][9][10][11] As one of the most intriguing SACs, the transition metalÀ nitrogenÀ carbon (TM-N x À C) system exhibited promising electrocatalytic activity, in which the transition metals are atomically distributed as isolated atoms supported by N-doped carbon materials. [12] FeÀ N x À C was synthesized to display good ORR performance, where FeN 4 was regarded as the dominated active coordinated structure with the onset potential of 0.93 V. [2] Dual-metal nitrogen-carbon (TM 2 N 6 À C) materials were shown to further enhance ORR performance by experiments and DFT calculations.…”

Homogeneous catalysis of dioxygen reduction by molecular Mn complexes

“…For the purposes of this perspective, we are excluding Cu-based systems, 26 heterogeneous systems based on molecular Mn active sites, and single atom Mn catalysts, but we direct interested readers to a number of relevant reviews and articles on heterogeneous and immobilized Mn-based catalysts for the ORR. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]…”