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Copper Dimer Supported on a C2N Layer as an Efficient Electrocatalyst for CO2 Reduction Reaction: A Computational Study C

Zhao, Jia, Zhao, Jingxiang, Li, Fengyu, Chen, Zhongfang
Journal of physical chemistry 2018 v.122 no.34 pp. 19712-19721
Gibbs free energy, active sites, carbon dioxide, carbon monoxide, catalysts, copper, density functional theory, electrochemistry, ethylene, fuels, hydrogenation, methane, renewable electricity
The carbon dioxide electrochemical reduction (CO₂RR) to useful fuels and chemicals with renewable electricity offers a promising strategy for resolving energy security and environmental issues. Searching for low-cost catalysts with high efficiency and high selectivity is crucial to achieve this goal. Here, by means of comprehensive density functional theory computations, we systematically investigated the potential of several transition metal dimers supported on a porous C₂N layer (Cu₂@C₂N) as the CO₂RR electrocatalysts. Our results revealed that the Cu dimer can be stably embedded in the porous C₂N monolayer because of the strong hybridization between Cu 3d orbitals and N 2p orbitals, thus ensuring its high stability. On the basis of the computed free energy changes, we found that Cu₂@C₂N exhibits superior performance for the CO₂RR with a small limiting potential of −0.23 V and the CO₂ → HCOO* → HCOOH* → H₂COOH* → H₂CO* → H₂COH* → CH₂* → CH₃* → CH₄ route is the most favorable, among which the hydrogenation of HCOO* to HCOOH* is the potential-determining step. In addition, C₂H₄ can also be yielded, as the formed CO* provides active sites for the coupling with another CO species with the limiting potential of −0.76 V. Therefore, Cu₂@C₂N layer is a quite promising bi-atom catalyst for the electrochemical reduction of CO₂ to hydrocarbons.