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

• Published in: Frontiers in chemistry 2024-03, Vol.12, p.1361930-1361930
• Main Authors: Liu, Haoran, Huang, Wenbin, Xu, Zhen, Jia, Yijing, Huang, Meng, Liu, Xiaoyue, Yang, Han, Li, Rongrong, Wei, Qiang, Zhou, Yasong
• Format: Article
• Language: English
• Subjects: Chemistry; CO2 hydrogenation; Cu+ species; Cu-MgO interaction; CuMgAl-x catalysts; methanol; Mg/Al molar ratio
• ISSN: 2296-2646; 2296-2646
• DOI: 10.3389/fchem.2024.1361930

The CuMgAl-x catalysts derived from hydrotalcite precursors with different Mg/Al molar ratios were synthesized and applied to CO 2 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, N 2 adsorption-desorption, SEM, TEM, H 2 -TPR, CO 2 -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 CO 2 and makes H 2 activation easier, accelerates the conversion of intermediate species CO 3 * and HCO 3 * to HCOO * , and facilitates further conversion to CH 3 O * and CH 3 OH. 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 CO 2 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 CO 2 hydrogenation to methanol.