Influence of modifier (Mn, La, Ce, Zr and Y) on the performance of Cu/Zn/Al catalysts via hydrotalcite-like precursors for CO2 hydrogenation to methanol

A series of promoted Cu/Zn/Al catalysts derived from hydrotalcite-like precursors were synthesized by co-precipitation method and tested for the CO2 hydrogenation to methanol. The influence of modifier (Mn, La, Ce, Zr and Y) on the physicochemical properties of Cu/Zn/Al catalysts was studied in detail. The results show that the BET specific surface area, Cu surface area and Cu dispersion increase in the order of Cu/Zn/Al < Cu/Zn/Al/Mn < Cu/Zn/Al/La < Cu/Zn/Al/Ce < Cu/Zn/Al/Zr < Cu/Zn/Al/Y. The similar trend can be observed for the total number of basic sites, while the Zr-modified Cu/Zn/Al catalyst exhibits the highest density and proportion of strongly basic sites. It is also found that the CO2 conversion depends on the exposed Cu surface area and the CH3OH selectivity increases linearly with the increase of proportion of strongly basic sites to the total basic sites. The introduction of Mn, La, Ce, Zr and Y favors the production of methanol and the Y- and Zr-modified Cu/Zn/Al catalysts exhibit the highest CO2 conversion and CH3OH selectivity, respectively. (C) 2013 Published by Elsevier B.V.