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Preparation and Characterization of Copper/Zinc Oxide/Alumina Catalysts for Methanol Synthesis

1987; Elsevier BV; Linguagem: Inglês

10.1016/s0167-2991(08)65452-x

2542-6613

E.B.M. Doesburg, R.H. Höppener, B. de Koning, Xiao‐Ding Xu, J.J.F. Schölten,

Nanomaterials for catalytic reactions

A series of Cu/ZnO/Al2O3 catalysts for the low pressure methanol synthesis has been prepared by coprecipitation with a sodium carbonate solution from solutions of a mixture of the corresponding metal nitrates, followed by ageing in the mother liquor, drying, calcination and reduction. The catalysts and their precursors were analyzed by techniques like X-ray diffraction (XRD), X-ray line broadening (XLB), differential scanning calorimetry (DSC), chemical analysis, adsorptive decomposition of N2O and B.E.T.-measurements. The catalytic activity for the methanol synthesis was determined in a flow reactor under industrial conditions. (change-para-here) Depending on the ratio of the metal ions in the initial metal nitrate solutions different compounds were formed during coprecipitation, like rosasite, (Cu, Zn)2(OH)2CO3, malachite, Cu2(OH)2CO3, Cu, Zn-hydrotalcite, (Cu, Zn)6Al2CO3(OH)164H2O and a ternary compound which we called roderite. Its structure is unknown and it contains, besides Zn2+, up to 28 at.% Cu2+ and up to 17 at.% Al3+. Addition of 7 at.% Mg2+ stabilizes the Cu, Zn-hydrotalcite structure but leads to a drastic decrease in catalytic activity. The rate of methanol production depends on the phase composition of the precursors. Rosasite-containing precursors give the highest activity; hydrotalcite proves to be an excellent catalyst stabilizer which evokes the formation of small Cu and ZnO particles. Mg2+ inhibits methanol production.