A Novel Tandem Reaction System for High-Concentration Acetic Acid Production from Methane and Oxygen

Directly converting methane into high-value products like CH₃COOH poses significant challenges owing to the kinetic limitations of C─H activation and C─C coupling in traditional single-catalysis methods. This work systematically studied the compatibility and effectiveness of plasma and thermocatalytic tandem systems. By optimizing the plasma process in a self-designed dielectric barrier discharge (DBD) reactor, we enhanced methane conversion (68.0%), methanol concentration (5.2 mol L^-1), and CO selectivity (56.9%), while preventing carbon deposition and CO₂ formation. In subsequent thermocatalysis, we developed the stearic acid-modified ReRh/ZSM-5-S hydrophobic catalyst to avoid the separation of methanol and CO from the mixture and minimize the influence of by-products (e.g., H₂O). This innovative approach achieved 52.0% CH₃COOH selectivity and 1.3 mol L^-1 concentrations, three orders of magnitude than traditional methods, meeting the preliminary industrial criteria. This study demonstrates the potential of tandem catalysis, offering valuable insights for the efficient utilization of methane and other challenging catalytic reactions.