Preparation and performance of Cu-based monoliths for methanol synthesis

Methanol synthesis from syngas could be carried out in steel monoliths coated with CuO/ZnO/Al2O3 catalysts. The Cu-based coatings were prepared using different techniques: slurry coating of CuO/ZnO/Al2O3 obtained via 2-stage co-precipitation, sol–gel coating of Al2O3 followed by Cu–Zn impregnation, colloid coating of Al2O3 followed by Cu–Zn impregnation, and colloid coating of Al2O3 followed by deposition–precipitation of Cu–Zn. The coated monoliths were characterized (XRD, BET, N2O titration) and studied in the methanol synthesis reaction at 80 bar. Comparison was made to similarly prepared powder catalysts subjected to characterization and laboratory scale fixed bed reactor (FBR) experiments. Monoliths with high activity for the methanol synthesis reaction were obtained with slurry coating of CuO/ZnO/Al2O3, whereas the impregnation and deposition–precipitation methods gave insufficient Cu dispersion. Higher activity of the monolith relative to FBR experiments with the same catalyst was ascribed to the thermal properties of the steel monolith.

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► CuO/ZnO/Al2O3 coatings on metallic monoliths were prepared by different methods.
► The monoliths with slurry coating show high activity in methanol synthesis.
► Higher activity of the monolith vs. fixed bed attributed to thermal properties.