Low temperature catalytic conversion of CH4, CO2, and C2H4 to value-added C3 oxygenates and olefins via C1-C2 coupling on Pd-Au/CeO2

The catalytic conversion of CH 4 and CO 2 in the presence of more reactive co-reactants C 2 H 4 and O 2 on Pd-Au/CeO 2 is achieved at 200°C and elevated pressures. Propene and acetone were produced from the catalyzed reaction of CH 4 +C 2 H 4 +O 2 ; addition of CO 2 to the reactant stream produced methyl acetate (MAc) but it significantly reduced the C-selectivities of propene and acetone. DRIFTS experiments confirmed the formation of methoxy species from CH 4 +CO 2 at 200°C, which is an intermediate in the formation of MAc. Control experiments with blanks, and with CeO 2 did not show any propene, acetone, or MAc products. The complete oxidation of C 2 H 4 was avoided; the catalyst is stable, and reactant conversions and product yields were sustained for the observed 1200 minutes time-on-stream, indicating that there is little or no carbon deposition and sintering. This direct coupling of CH 4 and C 2 H 4 intermediates to higher carbon-number products at 200°C is significant. • CH 4 and CO 2 were activated and converted at a mild temperature of 200°C on Pd-Au/CeO 2 . • More reactive co-reactants (C 2 H 4 and O 2 ) activate and couple CH 4 and C 2 H 4 intermediates forming propene, acetone, and methyl acetate at 200°C and 12 barg. • In-situ DRIFTS show bound methoxy (CH 3 O ⁎ ) species from the reaction of CH 4 and CO 2 at 200°C, which is an intermediate in methyl acetate formation. • Control experiments confirm the role of Pd-Au/CeO 2 and C 1 -C 2 coupling.