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Evidence for Copper Dimers in Low-Loaded CuOx/SiO2 Catalysts for Cyclohexane Oxidative Dehydrogenation

Authors :
Peter C. Stair
Hacksung Kim
Scott L. Nauert
Justin M. Notestein
Randall Q. Snurr
Andrew S. Rosen
Source :
ACS Catalysis. 8:9775
Publication Year :
2018
Publisher :
American Chemical Society (ACS), 2018.

Abstract

Copper oxide catalysts supported on KIT-6 silica were evaluated for cyclohexane oxidative dehydrogenation (ODH) to determine the effects of copper oxide domain size on ODH activity and selectivity. The catalysts were prepared by incipient wetness impregnation of KIT-6 at copper surface densities spanning 0.01–0.7 Cu/nm2 with carefully controlled drying and calcination conditions to systematically vary the average local copper oxide domain size. A distinct copper oxide active site exhibiting an order of magnitude higher activity than large copper oxide domains was identified by model cyclohexane ODH studies coupled with in situ X-ray absorption and UV–visible spectroscopies during reduction in H2. The structure of this site is experimentally identified by a combination of extended X-ray absorption fine structure analysis, resonant Raman studies, and modeling by density functional theory. All constraints imposed by these techniques indicate the active site is a mono(μ-oxo)dicopper(II) structure with copper ...

Details

ISSN :
21555435
Volume :
8
Database :
OpenAIRE
Journal :
ACS Catalysis
Accession number :
edsair.doi...........529507010f40e0e91d764dbbf2b056d9
Full Text :
https://doi.org/10.1021/acscatal.8b02532