Steady-state isotopic transient kinetic analysis of steam reforming of methanol over Cu-based catalysts

Mechanistic aspects of steam reforming of methanol were studied via steady-state isotopic transient kinetic analysis over three copper-based catalysts, namely combustion-synthesized Cu-Ce-O and Cu-Mn-O, and commercial Cu-ZnO-Al2O3. The “C-path” and “O-path” for the production of CO2 via steam reforming of methanol was analysed with the following step changes in the feed: 12CH3OH/H2O/Ar/He → 13CH3OH/H2O/He and CH3OH/H216O/Ar/He → CH3OH/H216O/H218O/He. The presence of CH318OH in the products after the switch to 18O-labeled water indicates that a major path of the reaction is the one involving a methyl formate intermediate. This appears to be the main path over the Cu-Mn-O catalyst, while parallel paths via dioxomethylene and methyl formate intermediates appear to be operative over Cu-Ce-O and Cu-ZnO-Al2O3 catalysts.