Theoretical Prediction Of Electrocatalytic Carbon Dioxide Reduction Based On Two-dimensional Materials

In recent years,the electrocatalytic conversion of carbon dioxide to high-added chemicals is one of the hottest topics.However,the reaction has challenges,such as low selectivity of products,high overpotential and so on.Therefore,it’s important to develop electrocatalysts with high selectivity,activity and low-cost.In this study,we constructed several catalysts based on two-dimensional materials,and investigated the effect of catalytic activity and reaction selectivity for carbon dioxide reduction（CO₂ER）,revealing the corresponding catalytic mechanism,and optimal path of these catalysts by means of density functional theory computations.The detailed contents were presented as follows:（1）Fistly,we constructed a catalyst by anchoring the Cu dimer on C₂N layer as catalyst for CO₂ER.Our results demonstrated that there is the strong hybridization between Cu 3d orbitals and N 2p orbitals of C₂N,thus ensuring the high stability of the Cu₂ supported on C₂N layer,which exhibits the efficient catalytic performance for CO₂ER.Furthermore,we found that CH₄ is the optimal product for CO₂ER on Cu₂@C₂N with a small limiting potential of-0.23 V,while the limiting potential for C₂H₄ product is-0.76 V.（2）Secondly,the boron and nitrogen atoms are introduced into GDY as actalysts for CO₂ER.The DFT results revealed that these doped GDYs have smaller formation energies,indicating their experimental availability.More importantly,the two kinds of catalysts exhibit highly electrocatalytic activity for CO₂ER,and the products are CH₄and C₂H₄,in which the C₂H₄ products is energetically favorable due to the lower limiting potential（-0.60 V）than that of CH₄ product.The superior catalytic activity of these doped GDYs can be attributed to the high electric conductivity and the higher active sites.We futher analysized the electronic properties,such as the band structures,charge distribution,to deeply understand the reaction mechanisms of electrocatlytic activities after the introducting of the doped boron and nitrogen atoms.（3）Finally,we investigated the application of C₂N layer anchored single atom Mn for carbon monoxide reduction reaction（COER）.Our results revealed that the single Mn atom can be stably anchored on C₂N monolayer.Interestingly,the synergistic effect of the anchored Mn atom and its adjacent N atoms on C₂N layer can give rise to the C-C coupling between adsorbed CO molecules,and kinetic process showed a lower energy barriers of C-C coupling during the formation of 2CO^*and3CO^*species,which are 0.89 eV and 1.21 eV,thus facilitating their subsequent hydrogenation to CH₄,C₂H₅OH and（especially）C₃H₆ with small limiting potentials of-0.69,-0.43 and-0.08 V,respectively.Furthermore,The thermodynamic formula can be utilized to estimate the distribution of different products according to their free energy difference,the C₃H₆:C₂H₅OH:CH₄ molar ratio is 1.96×10¹⁰:2.43×10⁴:1,indicating a high selectivity toward C₃ pathway on Mn@C₂N for the generation of C₃H₆.This study showed that these materilas could be quiet high catalytic activity and selectivity electrocatalysts for CO₂ER or COER.We hope that our studies could provide new vision and fessible methods for promoting the efficient conversion of carbon dioxide.