Selective chemisorption and oxidation/reduction kinetics of supported copper oxide catalysts prepared from copper(II) acetylacetonate

Journal Article · Thu Aug 01 04:00:00 EDT 1991 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(91)90127-P· OSTI ID:5731262

Kenvin, J C; White, M G ^[1]

---

1. Georgia Inst. of Tech., Atlanta (United States)

Copper(II) oxide catalysts, prepared by non-aqueous adsorption of Cu(acac){sub 2} on Cab-O-Sil followed by thermal decomposition, were titrated by NO and N{sub 2}O to characterize the dispersion of the copper ions. These catalysts showed molar ratios of NO/Cu close to unity when the Cu loadings were less than 2.5 wt%. For samples having loadings greater than 3.8 wt% cu, the NO/CU molar ratios were near 0.7. The NO/Cu molar ratio also depended upon the catalyst preparation technique subsequent to the initial impregnation with Cu(acac){sub 2} when the Cu loadings were {ge} 3.5 wt%. Samples washed with fresh acetonitrile showed NO/Cu ratios close to unity, whereas, those not so washed showed NO/Cu ratios near 0.7. IR spectra of NO sorbed on partially decomposed samples showed only bent Cu-N-O, whereas, NO sorbed to the sample which was totally decomposed showed both linear and bent Cu-N-O. Selected samples (3.8 and 8.6 wt% Cu) were reacted with N{sub 2}O to determine the dispersion of the Cu. The sample having 8.6 wt% Cu reacted with the N{sub 2}O to give a dispersion of 0.43; whereas the other sample (3.8 wt%) did not react with the N{sub 2}O. This dispersion determined by N{sub 2}O agreed with that calculated from NO titration (0.47) if the NO/Cu stoichiometry was assumed equal to unity. Subsequently, these catalysts were reduced in H{sub 2} and reoxidized in O{sub 2} to determine the oxidation and reduction kinetics as a function of copper loading. The 3.8 wt% Cu sample lost 1 O/Cu upon reduction in H{sub 2} and gained 1 O/Cu for reoxidation in O{sub 2} for up to five redox cycles; whereas, the 8.6 wt% Cu sample showed a stoichiometry of O/Cu which decreased from 1.00 to 0.57 after five redox cycles.

• OSTI ID: 5731262
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 130:2; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISORPTION
COPPER COMPOUNDS
COPPER OXIDES
IMPREGNATION
KINETICS
LOADING RATE
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
OXIDATION
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
REDOX REACTIONS
REDUCTION
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
STOICHIOMETRY
SURFACE PROPERTIES
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS