Methanol synthesis from CO2, CO and H-2 over Cu(100) and Cu(100) modified by Ni and Co

The present work has investigated the influence of CO on the conventional m ethanol synthesis from CO2 and H-2 On CU(1 0 0) and the possibilities for h ydrogenating CO directly into methanol on modified Cu(1 0 0) single crystal s. Adding increased pressures of CO to the reaction proved to be a non-triv ial problem due to formation of Ni-carbonyls on the stainless steel parts. The problems encountered using high pressures of CO in such experiments are discussed and solutions for avoiding Ni contamination from Ni-carbonyls ar e presented. Having this under control, it was shown that the conventional rate of methanol formation from H-2 and CO2 is not influenced at all by the presence of CO. Modifying the Cu(1 0 0) surface by adding Ni and Co strong ly changes the reactivity of the surface. Previous work where Ni was used a s modifier is reviewed briefly and used to understand the results obtained using Co as a modifier. In none of the cases discussed here was it possible to open a new reaction pathway for hydrogenatings CO directly, although a much deeper understanding of the influence of the chemical potential on the surface composition of alloys was gained. (C) 2000 Elsevier Science B.V. A ll rights reserved.