An effective strategy for CO2 reduction to C1 products using Cu-embedded MoS2 electrocatalyst: DFT study

Abstract

Excessive emission of CO₂ has caused a critical greenhouse effect that is emerging as a major threat to the environment. Electrocatalytic reduction of CO₂ is an advanced technology where chemically inert CO₂ is reduced and can be used to produce value-added fuels or chemicals. In this work, the electrocatalytic performance of a single Cu atom embedded in a MoS₂ monolayer with a sulfur vacancy for the electroreduction of CO₂ is studied using density functional theory (DFT) with dispersion correction. The single Cu atom is stably located in the sulfur vacancy of the MoS₂ monolayer. The multiple pathways explored here involve proton–electron pair transfer in the CO₂ reduction reaction (CO₂RR) to yield a variety of C1 products, such as HCOOH, CO, CH₃OH and CH₄. These pathways were examined using the corresponding free energy profiles and overpotentials. Among the different C1 products, CH₄ formation is more favored via the following optimized pathway: *CO₂ → *OCHO → *OCHOH → *OCH₂OH → *OCH₂ → *OCH₃ → *OHCH₃ → *OH + CH₄ → H₂O. The MoS₂ monolayer with embedded Cu has enhanced CO₂RR activity with an appreciably low overpotential compared to pristine MoS₂. This study provides a deep understanding of the structure–reaction relationships and various mechanistic pathways of the CO₂RR, and could aid in the design of high-performance single-atom electrocatalysts.