Designing a Mordenite Catalyst with Enhanced Acidity for Dimethyl Ether Carbonylation by Engineering Open Sn Sites
Ying Li,
Man Yu,
Guodong Qi,
Yunduo Liu,
Jing Lv,
Shouying Huang,
Xinbin Ma
Affiliations
Ying Li
Key Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; Inner Mongolia Key Laboratory of Industrial Catalysis, College of Chemical Engineering, Inner Mongolia University of Technology, Hohhot 010051, China
Man Yu
Key Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China
Guodong Qi
National Center for Magnetic Resonance in Wuhan & State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics & Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
Yunduo Liu
Key Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China
Jing Lv
Key Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China
Shouying Huang
Key Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; Corresponding authors.
Xinbin Ma
Key Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; Corresponding authors.
Due to their tunable acidity, shape selectivity, and excellent stability, zeolites are of great importance as solid acid materials in industrial catalysis. Tuning the properties of the acid sites in zeolites allows for the rational design and fabrication of catalysts for target reactions. Dimethyl ether (DME) carbonylation, a critical chain-growth reaction for C1 resource utilization, is selectively catalyzed by the Brønsted acid sites within the eight-membered rings (8-MRs) of mordenite (MOR). It is anticipated that strengthening the Brønsted acidity—particularly in 8-MRs—will improve the catalytic performance of MOR. In this work, density functional theory (DFT) calculations are first employed and the results used to design a modified MOR with stannum (Sn) and to predict the corresponding changes in acidity. Guided by the theoretical studies, a series of Sn-modified MOR are synthesized via a defect-engineering and subsequent heteroatom-substitution strategy. After partial desilication, isolated tetrahedral Sn species in an open configuration are successfully synthesized for the first time, within which tetrahedrally coordinated Al sites are preserved. An acidic characterization is used to confirm that the acidity of the Brønsted acid sites is enhanced by the introduction of the Sn species; as a result, the sample exhibits excellent activity in DME carbonylation reaction. Kinetic and DFT studies reveal that this strengthened acidity facilitates the adsorption of DME and reduces the activation barriers of DME dissociation and acetyl formation, accounting for the improved activity. The work demonstrates mechanistic insights into the promoting effects of strong acidity on DME carbonylation and offers a promising strategy to precisely control the acidic strength of zeolites.
