Electrochemical CO2Conversion via MXenes: A DFT Perspective

The electrochemical conversion of carbon dioxide (CO2) to produce clean fuels and high-value chemicals have received great attention for the generation of green and sustainable energy. Developing highly efficient and low-cost electrocatalysts mainly depends on fundamental understanding of catalytic mechanisms and their structure-activity relationships. Recently, density functional theory (DFT) has significantly transformed our fundamental understanding of atomic-scale details to develop these relationships for revealing the possible mechanisms involved in the catalytic reactions. In this chapter, we briefly summarize the application of DFT in electrocatalysis to analyze the reaction mechanisms in transition metal carbides/nitrides (also known as MXenes) for CO2 conversion into 'green' fuels. Some useful tools for theoretical analysis were highlighted for evaluating the electrocatalytic performances. The potential ability of MXenes to capture, activate, and dissociate CO2 is mainly due to Dewar interactions involving hybridization between d-orbitals of metals and CO2 π orbitals. The catalytic selectivity of MXenes towards CO2 conversion is higher than hydrogen evolution reaction (HER), signifying the efficiency of the catalyst for CO2RR. Overall, the theoretical findings discussed in the present chapter can provide useful insights to rationalize the development of MXene based electrocatalysts for CO2RR into renewable fuels and chemicals.