Synthesis of C2 oxygenates from syngas over monodispersed SiO2 supported Rh-based catalysts: Effect of calcination temperature of SiO2

The effect of calcination temperature of the monodispersed SiO2 synthesized by the Stöber method on the catalytic performance of RhMnLi/SiO2 for CO hydrogenation to C2 oxygenates was investigated. The means of N2 adsorption-desorption, in-situ FT-IR, H2-TPD, H2-TPR, CO-TPD, and TPSR were used to characterize the physico-chemical properties of SiO2 supports and the corresponding RhMnLi/SiO2 catalysts. The results showed that the amount of surface Si-OH groups on SiO2 affects the Rh dispersion and RhMn interaction. The increase in the number of SiOH groups on the SiO2 was favorable for the Rh dispersion and CO adsorption, further enhanced the activity of the catalyst. In addition, an appropriate amount of surface SiOH groups on the SiO2 calcined at 350°C can gain a moderate RhMn interaction. This interaction is conducive to achieve the right hydrogenation ability, which is favorable for the CO insertion into metal-CHx band, and ultimately increases the selectivity of C2 oxygenates. [Display omitted] ► The amount of surface Si-OH group on SiO2 decreased with calcination temperature. ► Increase in amount of Si-OH group is favorable for Rh dispersion and CO adsorption. ► An appropriate amount of surface Si-OH group gains a moderate RhMn interaction. ► The moderate RhMn interaction is conducive to synthesize C2 oxygenates.