Effect of Al-containing precursors on Cu/ZnO/Al2O3 catalyst for methanol production

Aluminum is an essential ingredient in the ternary Cu/ZnO/Al2O3 catalyst for methanol synthesis from syngas. This work investigated the effect of Al-containing precursors on Cu/ZnO/Al2O3 catalysts during catalyst preparation. A series of Cu0.6Zn0.3Al0.1 catalysts with various Al-containing precursors, including Cu-Zn-Al hydrotalcite, aluminum hydroxide and Zn-Al hydrotalcite, were prepared by co-precipitation and fractional-precipitation, respectively. The catalysts were characterized with XRD, TG, XRF, N2 physisorption, N2O chemisorption, SEM, TEM/EDS and TPR. Results show that the Al-containing precursor has an important effect on the Cu substitution by Zn in malachite lattice, leading to various performances of the obtained catalysts. The catalyst with Al existing as aluminum hydroxide performed high Cu substitution in the co-precipitated zinc malachite, and exhibits better catalyst performance compared to its counterparts. Aluminum hydroxide can be a suitable Al-containing precursor for preparing the Cu/Zn/Al methanol-synthesis catalyst.