Effective Screening Route for Highly Active and Selective Metal−Nitrogen‐Doped Carbon Catalysts in CO₂ Electrochemical Reduction

Abstract

to CO suffer from sluggish reaction kinetics and ambiguous mechanism. [5] Therefore, efficient and selective electrocatalysts for the reduction of CO 2 to CO should be found.Metal-nitrogen−doped carbon (M-N-C) catalysts are promising candidates as catalysts for electrochemical conversion of CO 2 to CO. [6] M-N-C catalysts that include M-N 4 centers are similar to molecular metalloenzyme systems, which have tremendous potential for CO production. [7] Recently, numerous studies have constructed noble metal (Au, Ag, Pt, Pd, and Ir), [8] transition metal (Fe, Co, Ni, Cu, Zn, Mn, Cd, and Cr), [9] and p-block metal (Bi, Sn, and Sb) [10] based M-N-C electrocatalysis for CO 2 RR to produce CO. [11] Theoretical calculations and experimental verifications have identified that the metal centers in the M-N 4 -C matrix are primary catalytic active sites for CO 2 adsorption and reduction. [12] Nevertheless, previous studies evaluated the CO 2 -to-CO efficiency of M-N-C catalysts merely by changing metals, without a systematic screening process. [13] For example, Ju et al. has compared the CO 2 RR activity of M-N-C (M = Fe, Co, Ni, Mn, and Cu) catalysts and analyzed reactivity trends according to various overpotential ranges. [14] More recently, Wang et al. has reported M-N-C catalysts (M = Fe, Co, and Ni) with a metal-pyridine N structure and demonstrated their selectivity order for CO 2 -to-CO conversion. [15] Moreover, most typically theoretical studies have proposed a single descriptor such as the difference between limiting potentials for CO 2 RR and the hydrogen evolution reaction (HER), which was denoted as U L (CO 2 )-U L (H 2 ), to quantify the selectivity of CO 2 RR limitedly. [16] However, the selectivity of CO generation in experiments varies with electrochemical potential so U L (CO 2 )-U L (H 2 ) as a descriptor does not completely describe the efficiency of the reaction. As a result, a general descriptor should be sought, and a systematic screening approach should be developed to find superior M-N 4 -C for CO 2 RR to CO production.Here, we used theoretical studies to develop a universal procedure for screening suitable M-N 4 -C electrocatalysts, which could transform CO 2 to CO with high activity and selectivity. Twenty-three M-N 4 -C candidates were chosen and input into this screening system. The selectivity, activity, and structural stability for CO 2 RR-to-CO were evaluated in a systematic sequence To identify high-efficiency metal-nitrogen-doped (M-N-C) electrocatalysts for the electrochemical CO 2 -to-CO reduction reaction (CO 2 RR), a method that uses density functional theory calculation is presented to evaluate their selectivity, activity, and structural stability. Twenty-three M-N 4 -C catalysts are evaluated, and three of them (M = Fe, Co, or Ni) are identified as promising candidates. They are synthesized and tested as proof-of-concept catalysts for CO 2 -to-CO conversion. Different key descriptors, including the maximum reaction energy, differences of the *H and *CO binding energy (ΔG *H −ΔG *CO ...

Unravelling intrinsic descriptors based on a two-stage activity regulation of bimetallic 2D c-MOFs for CO2RR

“…All twelve active sites show that Δ G *H–*CO > 0, indicating that all of them are prone to CO 2 RR selectivity. 49 Although the lower HER energy barrier is considered to be conducive to the protonation process, it is undeniable that it brings greater HER selectivity. Herein, the intrinsic CO 2 RR activity of the sites was focused to reveal the activity regulatory mechanism controlled by dual M 1 /M 2 centers.…”

Computational Screening of Single-Metal-Atom Embedded Graphene-Based Electrocatalysts Stabilized by Heteroatoms

“…From the results, there were 700 possible combinations (= 28 transition metals × 5 host heteroatoms × 5 dopant heteroatoms). The variation of the d- orbital for transition metals ultimately increases the catalytic performance by controlling the binding strength of electrocatalytic reaction intermediates in the hydrogen evolution reaction (HER), ORR, the oxygen evolution reaction (OER), and the carbon dioxide reduction reaction (CO 2 RR) ( Xu et al, 2018 ; Zhu et al, 2019 ; Park et al, 2021 ). Therefore, we considered 28 d -block transition metal elements, including 3 d (from Sc to Zn), 4 d (from Y to Cd), and 5 d (from Hf to Au).…”

M−N−C Materials for Electrochemical Reduction Reactions: Recent Strategies for Improving Electrocatalytic Activity and Stability

“…Nevertheless, DFT-based screening analyses have demonstrated that the MÀ NÀ C (M=Fe, Co, or Ni) materials are among the most structurally stable and experimentally operable (see Figure 13a). [106] In a recent study, it has been achieved good stability over 50 h for CO 2 -to-CO conversion on an SACbased NiÀ NÀ C catalyst featuring a pyrrole-type NiÀ N 4 structure. Additionally, a slight attenuation in both j and FE CO was observed, which resulted in ca.…”