CO2 hydrogenation to methanol over partially embedded Cu within Zn-Al oxide and the effect of indium

Developing effective catalysts for CO2 hydrogenation to methanol is an important step to improve the efficiency of a promising process for green synthesis of fuels and chemicals. Optimizing the Cu dispersion is often the main goal in preparing Cu/ZnO-based catalysts due to the strong dependence of the catalytic activity on the Cu surface area. However, the catalytic properties are also related to the nature of the Cu-ZnO interface. Herein, a series of hydrotalcite-derived Cu/ZnO/Al2O3 catalysts were prepared for CO2 hydrogenation to methanol. The preparation method results in partially embedded Cu particles within the Zn-Al oxide matrix. This microstructure exhibits significantly enhanced intrinsic activity and methanol selectivity. Loss of the interfacial area between Cu and Zn-Al mixed oxide phase due to sintering of Zn-Al matrix is identified as the main reason for deactivation of the HT-derived catalysts. The influence of In on Cu/ZnO-based catalysts is also investigated. It is found that In decreases the activity but increases the methanol selectivity and stabilizes the Cu particles and the Zn-Al mixed oxide phase. The lower activity of the In-containing catalysts is linked to the inhibition of Cu active sites by CuxIny species.publishedVersio

Cu-ZrO2 catalysts with highly dispersed Cu nanoclusters derived from ZrO2@ HKUST-1 composites for the enhanced CO2 hydrogenation to methanol

In this study, a series of Cu-ZrO2 catalysts with highly dispersed Cu nanoclusters were prepared via the calcination and reduction of ZrO2@HKUST-1 precursors. These catalysts demonstrated an outstanding selectivity in the yield of methanol during CO2 hydrogenation. The space-time yield (STY) of methanol is 5.2 times higher than that of those similar catalysts reported by other researchers, which were prepared using conventional method and tested under the same testing conditions. Density functional theory (DFT) study revealed that the activation of CO2 occurs at the Cu-ZrO2 interfaces and facilitates the hydrogenation of CO2 to methanol. It is concluded that the controlled formation of the highly dispersed Cu nanoclusters not only provides a large number of highly efficient active centers for CO2 hydrogenation, but also leads the generation of more Cu-ZrO2 interfaces. These two effects contribute to the superior catalytic performance of the nano Cu-ZrO2 catalyst in CO2 hydrogenation