(569cy) Microenvironmental Engineering Using Organic Additives in Electrolyte to Promote Electrochemical CH4 Production on Cu/N-Doped C

The electrochemical CO₂ reduction reaction (ECO₂RR) holds promise for producing CH₄ using renewable energy sources under ambient conditions. However, achieving selective CH₄ formation is hindered by the kinetically complex series of consecutive proton-coupled electron transfer (PCET) steps. To address this challenge, both catalysts and microenvironments must be carefully considered. Thus, this study presents a microenvironmentally engineered ECO₂RR system employing Cu-loaded N-doped C (Cu/N:C) electrocatalysts and electrolytes containing organic additives. The mixed valence state of Cu in Cu/N:C, interacting coordinately with nitrogen, serves as active sites facilitating CO₂ adsorption and subsequent PCET steps. Density functional theory (DFT) calculations demonstrated that the organic additive near the catalyst surface alters the electronic structure of the catalyst and forms hydrogen bonds with reactant species affecting intermediates stabilization. The microenvironmentally engineered Cu/N:C catalysts demonstrate significantly enhanced faradaic efficiency (FE) of 48% and partial current density of 15.0 mA/cm² for CH₄ production. The experimental and theoretical insights presented in this study contribute to the development of efficient ECO₂RR systems.