Atomically dispersed Cu and Fe on N-doped carbon materials for CO2 electroreduction: insight into the curvature effect on activity and selectivity

Abstract

CO₂ electroreduction reaction (CO₂ER) by single metal sites embedded in N-doped graphene (M@N-Gr, M = Cu and Fe) and carbon nanotubes (M@N-CNT, M = Cu and Fe) has been explored by extensive first-principles calculations in combination with the computational hydrogen electrode model. Both atomically dispersed Cu and Fe nanostructures, as the single atom catalysts (SACs), have higher selectivity towards CO₂ER, compared to hydrogen evolution reduction (HER), and they can catalyze CO₂ER to CO, HCOOH, and CH₃OH. In comparison with Cu@N-Gr, the limiting potentials for generating CO, HCOOH, and CH₃OH are reduced obviously on the high-curvature Cu@N-CNT. However, the curvature effect is less notable for the single-Fe-atom catalysts. Such discrepancies can be attributed to the d-band center changes of the single Cu and Fe sites and their different dependences on the curvature of carbon-based support materials.