The influence of Mg/Al molar ratio on the performance of CuMgAl-x catalysts for CO₂ hydrogenation to methanol.

ABSTRACT: The CuMgAl-x catalysts derived from hydrotalcite precursors with different Mg/Al molar ratios were synthesized and applied to CO₂ hydrogenation to methanol reaction. In this study, the effects of Mg/Al molar ratio on the structure and surface properties of CuMgAl-x catalysts were investigated by XRD, N₂ adsorption-desorption, SEM, TEM, H₂-TPR, CO₂-TPD, XPS, and in situ DRIFTS characterization methods. The results showed that an appropriate Mg/Al molar ratio can enhance the Cu-MgO interaction, increasing the basic sites and obtaining suitable acid sites. The dispersion of active Cu on the CuMgAl-x catalysts can be improved by strong Cu-MgO interaction, which enhances the adsorption capacity of CO₂ and makes H₂ activation easier, accelerates the conversion of intermediate species CO₃ ^* and HCO₃ ^*to HCOO^*, and facilitates further conversion to CH₃O^* and CH₃OH. The strong interaction between Cu and MgO was conducive to the formation of Cu⁺, which can inhibit the desorption of CO in the reverse water gas shift reaction. The CuMgAl-3 catalyst showed the highest CO₂ Conversion rate (14.3%), methanol selectivity (94.5%), and STY of methanol (419.3 g⋅kg_cat. ^-1⋅h^-1) at 240°C and 2.5 MPa. The results obtained in this paper can provide a new idea for the design of high-performance catalysts for CO₂ hydrogenation to methanol.

SUBMITTER: Liu H 

PROVIDER: S-EPMC10973157 | biostudies-literature | 2024

REPOSITORIES: biostudies-literature