Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume 143, Issue 23, Pages 8829-8837Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jacs.1c03283
Keywords
-
Categories
Funding
- National Natural Science Foundation
- Ministry of Science and Technology of the P. R. China [NSFC 22071207, NSFC 21721001, 2016YFA0200702]
Ask authors/readers for more resources
In this study, ZrZnOx was shown to be active in catalyzing the hydrogenation of CO2 to methanol through a synergy between ZnOx and ZrOx. The construction of Zn2+-O-Zr4+ sites in a metal-organic framework was achieved to reveal insights into the structural requirements for methanol production. The catalytic activity of the resulting MOF-808-Zn catalyst was stable and exhibited high selectivity and yield, with XAS analyses and TPD experiments providing important insights into the catalytic mechanism.
ZrZnOx is active in catalyzing carbon dioxide (CO2) hydrogenation to methanol (MeOH) via a synergy between ZnOx and ZrOx. Here we report the construction of Zn2+-O-Zr4+ sites in a metal-organic framework (MOF) to reveal insights into the structural requirement for MeOH production. The Zn2+-O-Zr4+ sites are obtained by postsynthetic treatment of Zr-6(mu(3)-O)(4)(mu(3)-OH)(4) nodes of MOF-808 by ZnEt2 and a mild thermal treatment to remove capping ligands and afford exposed metal sites for catalysis. The resultant MOF-808-Zn catalyst exhibits >99% MeOH selectivity in CO2 hydrogenation at 250 degrees C and a high space-time yield of up to 190.7 mgMeOH gZn(-1) h(-1). The catalytic activity is stable for at least 100 h. X-ray absorption spectroscopy (XAS) analyses indicate the presence of Zn2+-O-Zr4+ centers instead of ZnmOn clusters. Temperature-programmed desorption (TPD) of hydrogen and H/D exchange tests show the activation of H-2 by Zn2+ centers. Open Zr4+ sites are also critical, as Zn2+ centers supported on Zr-based nodes of other MOFs without open Zr4+ sites fail to produce MeOH. TPD of CO2 reveals the importance of bicarbonate decomposition under reaction conditions in generating open Zr4+ sites for CO2 activation. The well-defined local structures of metal-oxo nodes in MOFs provide a unique opportunity to elucidate structural details of bifunctional catalytic centers.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available