Density Functional Theory Insights on the Electroreduction of Carbon Dioxide on Gold without Metal or Organic Cations

The (electrochemical) carbon dioxide reduction reaction [(e)CO₂RR] has been extensively researched to optimize the efficiency of the reaction and attain a reliable, cost-effective route towards industrial decarbonization. First principles simulation offers insight into the energetics of relevant transition states as determined by the local (sub-nanometer) environment. Here, we illustrate how Density Functional Theory (DFT) and DFT molecular dynamics can provide rationalization of recent evidence of eCO₂RR on gold electrodes in the absence of metal cations, observed through electrochemical measurements and vibrational sum frequency spectroscopy. Notably, and in complement to the experimental characterization, DFT simulations can disentangle electronic structure and electrostatic field effects on the frontier molecular orbitals of the interfacial CO₂ induced by the cation species and gold surface. These observations inform on the origin of the eCO₂RR reaction overpotential and invite strategies for its minimization, contributing simulation-derived guidelines for more efficient catalysis through surface modification.