Publication: By-product co-feeding

By-product co-feeding reveals insights into the role of zinc on methanol synthesis catalysts

Authors: Marta Santiago, Katia Barbera, Cristina Ferreira, Daniel Curulla-Ferré, Peter Kolb,
Javier Pérez-Ramírez

Catalysis Communications, Article first published online, February 2012

Co-feeding of two relevant by-products of methanol synthesis, viz. dimethyl ether and methyl formate, in CO + H₂ and CO + CO₂ + H₂ streams was used as a strategy to gain understanding of the reaction over ternary Cu/ZnO/Al₂O₃ and binary Cu/ZnO, Cu/Al₂O₃, and ZnO/Al₂O₃ catalysts. While dimethyl ether does not participate in the process, the addition of methyl formate remarkably increases the MeOH production by its oxygen-assisted split into active intermediate species (CH₃O^⁎ and HCOO^⁎). Specifically, a breakthrough role was assigned to ZnO as catalytic partner for methyl formate conversion to methanol, since even the Cu-free ZnO/Al₂O₃ sample shows a considerable MeOH yield on MeF co-feeding. Alternatively, in the Zn-free Cu/Al₂O₃ sample, the presence of carbon dioxide in the inlet mixture was crucial to activate the methyl formate conversion path, likely because CO₂ provides readily available oxygen to the Cu surface.