Design of Single-Atom and Frustrated-Lewis-Pair dual active sites for direct conversion of CH₄ and CO₂ to acetic acid

Direct conversion of CH₄ and CO₂ into acetic acid is an emerging attractive process but remains a significant challenge due to the inherent stability of both molecules. Hence, developing active and stable catalysts is crucial for the simultaneous activation of CO₂ and CH₄. Herein, we designed the “Single-Atom” - “Frustrated-Lewis-Pair” (SA-FLP) dual-active-site catalysts for the co-conversion of CH₄ and CO₂ to acetic acid based on density functional theory (DFT) calculations. The SA sites were introduced by doping the transition-metal (TM) atoms (TM = Fe, Co, Ni, Cu; Ru, Rh, Pd, Ag; Os, Ir, Pt, Au) into CeO₂(1 1 0) surface, and the FLP sites were constructed by the regulation of surface oxygen vacancies. Our results demonstrate the introduction of SA into CeO₂ surface could facilitate the formation of oxygen vacancies, and thus promotes the formation of FLP sites. The SA-FLP dual active sites can concurrently activate CH₄ and CO₂ with CH₄ preferentially activated at SA sites and CO₂ preferentially activated at FLP sites. Among the twelve SA-FLP catalysts, Ag₁-FLP catalyst exhibits the best performance in the reaction of CH₄ and CO₂ to acetic acid with a rate-determining barrier of 1.12 eV and a turnover frequency of 2.52 × 10^–3 s⁻¹ at 573 K and 2 bar. This work not only offers a novel catalyst prototype for the co-conversion of CH₄ and CO₂ to acetic acid but also provides insights into developing dual-active-site catalysts on earth-abundant metal oxide materials.