The use of an Rh-intercalated SiC/graphene interface for CO2 electrochemical reduction: A theoretical investigation

Electrochemical reduction of CO₂ to valuable fuels and chemicals is a promising way to reuse CO₂. The mechanism of CO₂ reduction on the Rh-intercalated SiC/graphene surface has here been investigated using spin-polarized DFT calculations. The energetically preferred pathways for the electrochemical CO₂ reduction to products like CO, HCOOH, CH₃OH, and CH₄ were then explored. The results showed that the production of CH₄ was more preferred compared to the other products for this specific catalyst material. The reaction pathway via an intermediate HCOOH adsorbate was found to be more favored, as compared with an intermediate CO adsorbate. Also, the formation of an intermediate COOH adsorbate was identified as the free energy rate-limiting step in the complete reduction reaction. The calculated limiting potential for the SiC/Rh/graphene catalyst was 0.36 V, and this catalyst was also found to exhibit a competitive selectivity with respect to the hydrogen evolution reaction.