Activity of Cu{sup 2+} ions on the tetrahedral and octahedral sites of spinel oxide catalysts for CO oxidation

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1996.0293· OSTI ID:494287

Ghose, J ^[1]; Murthy, K S.R.C. ^[2]

---

1. Indian Institute of Technology, Kharagpur (India)
2. Indian Telephone Industries, Ltd., Bangalore (India)

In studies of CO oxidation on substituted copper chromite spinel oxide catalyst decreases as the Cu{sup 2+} content of the catalyst decreases, either by substitution with a divalent ion, i.e., Cu{sub 1-x} Mg{sub x} [Cr{sub 2}]O{sub 4}, or by reduction of Cu{sup 2+} to Cu{sup 1+}. Crystallographic studies have shown that Cu[Cr{sub 2}]O{sub 4} changes from normal to partially inverse when Cr{sup 3+} is replaced by Al{sup 3+}. Thus, in aluminum-substituted copper chromite catalysts, copper is present on both tetrahedral and octahedral sites of the spinel lattice, i.e., Cu{sub 1-x}Al{sub x} [Cu{sub x}Cr{sub 2-(x+y)}Al{sub y}]O{sub 4}. ESCA studies have shown that upon Al substitution some of the tetrahedral Cu{sup 2+} ions are reduced to Cu{sup 1+} and this causes a reduction in the catalytic activity of the catalysts. The present work was taken up to compare the activity of Cu{sup 2+} on tetrahedral sites with that on octahedral sites of the spinel oxide catalysts. For this, CO oxidation studies were carried out on the inverse spinel CuFe{sub 2}O{sub 4} and on the normal spinel CuRh{sub 2}O{sub 4} catalysts. 7 refs., 1 fig.

• OSTI ID: 494287
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 2 Vol. 162; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
40 CHEMISTRY
CARBON MONOXIDE
CATALYTIC EFFECTS
CHROMIUM OXIDES
COPPER OXIDES
ELECTRON SPECTROSCOPY
HETEROGENEOUS CATALYSIS
OXIDATION