image: The Cu ions exclusively situated in the center of six-membered ring, shared by the sodalite cage and supercage of zeolite. view more
Credit: ©Science China Press
This study is led by Prof. Landong Li (Key Laboratory of Advanced Energy Materials Chemistry of Ministry of Education, College of Chemistry, Nankai University). The team demonstrates the design of uniform Cu ions confined in faujasite, namely Cu@FAU, for the selective hydrogenation of CO2 to CH3OH. Stable methanol space-time-yield (STY) of 12.8 mmol/gcat/h and methanol selectivity of 89.5 % are simultaneously achieved at a relatively low reaction temperature of 513 K, making Cu@FAU a potential methanol synthesis catalyst from CO2 hydrogenation.
The reaction sequence of CO2 hydrogenation over well-defined Cu@FAU catalyst and the full catalytic cycle are successfully determined. It is confirmed that all the reaction steps can take place on Cu cation sites and the adjacent zeolite framework O atoms play indispensable roles by constructing Cu-O pairs to induce dihydrogen activation. The CO2 reactant and C-containing intermediates can adsorb on Cu sites and assist the dihydrogen activation on Cu-O pairs for subsequent hydrogenation. The unique zeolite catalyst system and reaction pathway contribute to the success of CO2-to-CH3OH process for carbon neutral, and may trigger some new thoughts for other complex chemical transformations.
The success of zeolite-confined mononuclear Cu ions in the hydrogenation of CO2 to methanol will bring some new ideas on the debates of Cu active sites for methanol synthesis from CO2 and/or CO. Meanwhile, Cu@FAU catalyzed CO2 hydrogenation follows the mechanism of coordination catalysis, and the involved structures in the zeolite system bear a resemblance to those in homogeneous catalysis. Accordingly, Cu@FAU is expected to share the advantages of homogeneous catalysis. The concept and strategy presented here may shed light on the rational design of active and selective zeolite catalysts for target reactions.
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See the article:
Zeolite-encaged mononuclear copper centers catalyze CO2 selective hydrogenation to methanol
https://doi.org/10.1093/nsr/nwad043
Journal
National Science Review