TM₂−B₂ Quadruple Active Sites Supported on a Defective C₃N Monolayer as Catalyst for the Electrochemical CO₂ Reduction: A Theoretical Perspective

Abstract

Developing high‐performance electrocatalysts for the CO2 reduction reaction (CO2RR) holds great potential to mitigate the depletion of fossil feedstocks and abate the emission of CO2. In this contribution, using density functional theory calculations, we systematically investigated the CO2RR performance catalyzed by TM2−B2 (TM=Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu) supported on a defective C3N monolayer (V‐C3N). Through the screening in terms of stability of catalyst, activity towards CO2 adsorption, and selectivity against hydrogen evolution reaction, Mn2−, Fe2−, Co2−, and Ni2−B2@V−C3N were demonstrated to be a highly promising CO2RR electrocatalyst. Due to quadruple active sites, these candidates can adsorb two or three CO2 molecules. Strikingly, different products, distributing from C1 to C2+, can be generated. The high activity originates from the synergistic effect of TM and B atoms, in which they serve as adsorption sites for the C‐ and O‐species, respectively. The high selectivity towards C2+ products at the Fe2−, and Ni2−B2 sites stems from moderate C adsorption strength but relatively weak O adsorption strength, in which a universal descriptor, that is, 0.6 ΔEC−0.4 ΔEO=−1.77 eV (ΔEC/ΔEO is the adsorption energy of C/O), was proposed. This work would offer a novel perspective for the design of high active electrocatalysts towards CO2RR and for the synthesis of C2+ compounds.

Bidirectional electron transfer boosts Li–CO2 electrochemistry

“…For each intermediate adsorption, the Gibbs free energy Δ G was illustrated by the equation: 43 Δ G = Δ E + Δ E ZPE − T Δ S + Δ G U where Δ E , Δ E ZPE and Δ S are the changes in total energy, zero-point energy and entropy at 298.15 K, respectively, induced by the reaction. The terms of zero-point energy and entropy were obtained from the calculations of vibrational frequency.…”

“…The DN values were extracted using LOBSTER. 40,41 In particular, the heterometal dopant with unpaired valence electrons 43,45,63 is promising to regulate the BET behavior between catalysts and adsorbents (Fig. 1c), but there is little research on their effect on the Li-CO 2 electrochemical performance.…”

A DFT Investigation of B‐Doped C3N as Single Atom Electrocatalysts for N2‐to‐NH3 Conversion

“…Through screening for catalyst stability, CO 2 adsorption activity and hydrogen reaction selectivity, Mn 2 À , Fe 2 À , Co 2 À , and Ni 2 -B 2 @V-C 3 N were promising electro-catalysts for the CO 2 RR. [18] Moreover, Zhang et. al.…”

“…For example, the catalytic performance of TM 2 ‐B 2 (TM=Sc−Cu) loaded with C 3 N was studied for carbon dioxide reduction reaction (CO 2 RR). Through screening for catalyst stability, CO 2 adsorption activity and hydrogen reaction selectivity, Mn 2 − , Fe 2 − , Co 2 − , and Ni 2 ‐B 2 @V–C 3 N were promising electrocatalysts for the CO 2 RR [18] . Moreover, Zhang et.…”