Impact of the morphological and chemical properties of copper-zirconium-SBA-15 catalysts on the conversion and selectivity in carbon dioxide hydrogenation.

A hybrid catalyst consisting of Zr-doped mesoporous silica (Zr-SBA-15) supports with intergrown Cu nanoparticles was used to study the effects of a catalyst's chemical states on CO hydrogenation. The chemical state of the catalyst was altered by using tetraethyl orthosilicate (TEOS) or sodium metasilicate (SMS) as the silica precursor in the synthesis of the Zr-SBA-15 framework, and infiltration (Inf) or evaporation induced wetness impregnation (EIWI) as the Cu loading method. As a result, the silica precursor mainly affects the activity of the catalyst whereas the Cu loading method alters the selectivity of the products. TEOS materials exhibit a higher catalytic activity compared to SMS materials due to different Zr dispersion and bonding to the silica matrix. EIWI catalysts display selectivity for methanol formation, while the Inf ones enable methanol conversion to DME. This is correlated to a higher Zr content and lower Cu oxidation states of EIWI prepared catalysts.