Methanol Synthesis on Potassium-Modified Cu(100) from CO + H₂ and CO + CO₂ + H₂

Abstract

Methanol cannot be produced from CO + H₂ on a clean copper surface, but a promotional effect of potassium on methanol synthesis from mixtures of CO + H₂ and CO + CO₂ + H₂ at a total pressure of 1.5 bar on a Cu(100) surface is shown in this work. The experiments are performed in a UHV chamber connected with a high-pressure cell (HPC). The methanol produced is measured with a gas chromatograph and the surface is characterized with surface science techniques. The results show that potassium is a promoter for the methanol synthesis from CO + H₂, and that the influence of CO₂ is negligible. Investigation of the post-reaction surface with TPD indicates that potassium carbonate is present and plays an important role. The activation energy is determined as 42 ± 3 kJ/mol for methanol synthesis on K/Cu(100) from CO + H₂.