Influence of fluorine on the performance of fluorine-modified Cu/Zn/Al catalysts for CO2 hydrogenation to methanol

Fluorine-modified Cu/Zn/Al catalyst was prepared by calcination of the fluorine-containing Cu/Zn/Al hydrotalcite-like precursor and tested for CO2 hydrogenation to methanol. The introduction of fluorine into Cu/Zn/Al catalyst led to lower CO2 conversion mainly due to the decrease of the exposed copper surface area. However, the turnover frequency increased remarkably owing to the higher amount of easily reducible CuO. In addition, the CH3OH selectivity was greatly improved by the remarkable increase of the proportion of strongly basic sites to the total basic sites. As a result, the presence of fluorine in Cu/Zn/Al catalyst was favorable for CO2 hydrogenation to methanol, and the CH3OH yield for the fluorine-modified Cu/Zn/Al catalyst was higher than that for the fluorine-free Cu/Zn/Al catalyst.