Thermodynamic investigation of the CO2 electrochemical reduction on copper based alloys: Theoretical insight

P. Hirunsit
National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), TH

Keywords: electroreduction, density functional theory, catalysis

Summary:

One of promising processes capable of efficiently recycling CO2 waste and converting it into hydrocarbon fuel is the electrochemical reduction of CO2. The electrochemical process has an appealing advantage because it does not require high temperature reactions. However, many scientific challenges are needed to be overcome. The electrode material plays a crucial role in determining the primary product and selectivity. The overpotential to achieve this reaction on Cu which is the best known metal catalyst is excessively high. The development of a catalyst that can efficiently catalyze the conversion with a low overpotential is needed and many aspects of the molecular details of the reaction are still unclear. By applying density functional theory (DFT) calculations associated with the hydrogen electrode free energy model, this work is aimed to provide thermodynamic point of view of CO2 conversion to methane on stepped surface Cu3X(211) where X is in group 9-11. The free energy diagrams reveal different favorable CO2 conversion pathways on Cu3X. The competitive reaction of H2 evolution reaction and the tendency of surface poisoning by intermediate species are also discussed. This analysis preliminary determine the feasibility of Cu3X as catalysts for CO2 electroreduction and provide guidance for catalyst design.