Structure and catalytic performance of Mn- and La-modified Cu/ZrO₂ catalysts for methanol synthesis

Cu/ZrO₂ is a good catalyst for methanol synthesis from CO/CO₂ hydrogenation. To improve its catalytic performance, the effects of the addition of Mn and La promoters to Cu/ZrO₂ catalyst were studied. Both the promoters possessed separately the capacity of improving the catalyst activity with the La component being better dopant. The catalyst activity was improved by the addition of Mn and La together. A synergistic effect in La and Mn co-modified Cu/ZrO₂ catalyst was suggested. On the one hand, the interaction of Cu and Mn enhanced the dispersion of the active component due to the formation of CuMnO composite, which prevented active phase Cu from crystallizing and sintering. On the other hand, the presence of La effectively increased the strength of the interaction between Cu and ZrO₂, and thus stabilized the active center of the catalyst, and facilitated the spillover between Cu and ZrO₂.