Electrochemical CO₂ Reduction Reaction on 3d Transition Metal Single-Atom Catalysts Supported on Graphdiyne: A DFT Study

Abstract

In the electrochemical CO2 reduction reaction (CO2RR), single atom catalysts (SACs) supported on carbon materials have exhibited high activity and selectivity. However, the carbon supports are mainly graphene and carbon nanotubes, which are composed of sp2-hybridized carbon. Graphdiyne with sp-hybridization has been investigated as a promising carbon material for various catalytic reactions. In this study, the effect of sp-hybridization on graphdiyne was investigated using density functional theoretical (DFT) calculations for the CO2RR reactivity of Mn, Fe, Co, Ni, Cu, and Zn SACs supported on graphdiyne (M–graphdiyne). Among them, Co–graphdiyne exhibits a high activity and selectivity for CH3OH product, with remarkably low free energy barrier of 0.31 eV, which is superior to SACs supported on graphene with sp2-hybridization. The d-band center and atomic number of the metal atom, and the charge redistribution on sp-hybridization exert significant influence to the energy of intermediates, which are key to understanding the activity and selectivity of SACs in CO2RR.

Cation-Coordinated Inner-Sphere CO2 Electroreduction at Au–Water Interfaces

“…The electroreduction of carbon dioxide has become one of the critical technologies of the clean energy economy, holding promise to reduce and mitigate the carbon footprint resulting from the use of chemicals and fuels. − Understanding the CO 2 reduction reaction (CO 2 RR) mechanism at the atomic level is instrumental for catalyst design and catalytic system’s optimization. Theoretical approaches are promising for studying reaction mechanisms of various electrochemical reactions, including CO 2 electroreductions. − CO 2 RR on Au surfaces is of great interest to convert CO 2 to the valuable chemical (CO, a critical component of syngas). , So far, many simulations performed at solid–gas interfaces using density functional theory (DFT) focus on the thermodynamics of reaction intermediates without considering reaction kinetics. − Such simplified models are insufficient to capture interfacial behaviors and evaluate atomic-scale mechanisms of electrocatalytic reactions at complex electrode–electrolyte interfaces. , …”

First-row transition metal embedded pyrazine-based graphynes as high-performance single atom catalysts for the CO2reduction reaction

“…8b and c. For HCOOH generation, the U L on Mn/Fe/Ni-pyGYs is lower than those of many CO 2 RR electrocatalysts, such as Ni/Co/Fe-C 3 N 4 (À0.77 to À1.09 V), 44 Mn/Ni/Cugraphdiyne (À0.45 to À0.64 V), 45 and metal porphyrin (M-PP) sheets (À0.52 to À1.06 V), 30 as shown in Fig. 8b.…”

Advancing the Electrochemistry of Gas‐Involved Reactions through Theoretical Calculations and Simulations from Microscopic to Macroscopic

“…Meanwhile, Bao's team utilized DFT to systematically investigate the effect of Mn, Fe, Co, Ni, Cu, and Zn single-atom catalysts (SACs) on CO 2 RR to methanol using graphdiyne carriers (M-graphdiyne), which effectively inhibited HER competition. [96] The significant orbital hybridization and delocalized charge distribution indicated that sp-hybridized actively participates in changing the electronic structure of metal atoms. The free energy diagram obtained by DFT showed that the energy barrier of Co-graphdiyne was only 0.3 eV, which was more active than other SACs and indicated high selectivity for reducing CO 2 to CH 3 OH (Figure 3e).…”