<p>Efficient plasma-catalysis of CH₄ and CO₂ to value-added oxygenates remains challenging due to limited research on the activation and conversion mechanism of the ^*CO intermediate. The rational design of catalysts at the atomic level can improve mechanistic understanding. In this study, an atomically dispersed catalyst with diatomic Cu centers anchored on carbon nitride nanosheet is developed. The coordination structure of Cu diatoms with four N atoms and two C atoms provides a new channel for efficient charge transfer and separation, enhancing CH₄ and CO₂ conversion. Additionally, CO-DRIFT and theoretical calculations demonstrate that strong CO adsorption and the stable ^*CH₃OH intermediate on Cu diatomic sites promote CH₃OH generation. This study presents a viable strategy for designing novel diatomic catalyst for CH₄ and CO₂ conversion into value-added products, and expands understanding of the plasma-catalysis mechanism at the atomic level.</p>