Radiocatalytic Synthesis of Acetic Acid from CH₄ and CO₂

Abstract

The C-C coupling of methane (CH₄) and carbon dioxide (CO₂) to generate acetic acid (CH₃COOH) represents a highly atom-efficient chemical conversion, fostering the comprehensive utilization of greenhouse gases. However, the inherent thermodynamic stability and kinetic inertness of CH₄ and CO₂ present obstacles to achieving efficient and selective conversion at room temperature. Our study reveals that hydroxyl radicals (⋅OH) and hydrated electrons (e_aq ^-) produced by water radiolysis can effectively activate CH₄ and CO₂, yielding methyl radicals (⋅CH₃) and carbon dioxide radical anions(⋅CO₂ ^-) that facilitate the production of CH₃COOH at ambient temperature. The introduction of radiation-synthesized CuO-anchored TiO₂ bifunctional catalyst could further enhance reaction efficiency and selectivity remarkably by boosting radiation absorption and radical stability, resulting in a concentration of 7.1 mmol ⋅ L^-1 of CH₃COOH with near-unity selectivity (>95 %). These findings offer valuable insights for catalyst design and implementation in radiation-induced chemical conversion.