XPS/FTIR study of the interaction between NO and YBa[sub 2]Cu[sub 3]O[sub 7]

Journal Article · Wed Nov 24 00:00:00 EST 1993 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00076a019· OSTI ID:7165073

Lin, Jianyi; Wee, A T.S.; Tan, Kuang Lee; Neoh, Koon Gee; Teo, Wah Koon ^[1]

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1. National Univ. of Singapore, Kent Ridge Cresent (Singapore)

The combination of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and simultaneous thermal analysis (STA) studies has shown that the interaction between NO and YBa[sub 2]Cu[sub 3]O[sub 7] occurs at room temperature and above, resulting in the formation of the nitride, nitrate, nitrite (NO[sub 2][sup [minus]]), and nitrito (-ONO) groups, as well as in the release of N[sub 2], NO[sub 2], and N[sub 2]O. The nitride species are observed at temperatures between 300 and 540 K but not at higher temperatures. The nitrate ion is the predominant nitrogen-containing species at temperatures below 540 K, and its concentration decays at elevated temperatures (>820 K). The nitrito group can be found at room temperature as well as elevated temperatures. The nitrite ion is observed with relatively low concentrations at lower temperatures but becomes the predominant nitrogen-containing species at high temperatures. The maximum increase in the sample weight ([approximately]7%) as measured by thermogravimetry (TG) corresponds to a net uptake of a NO[sub 2] group (or an NO molecule plus an O atom) per unit cell of YBa[sub 2]Cu[sub 3]O[sub 7]. The NO interaction also results in the oxidation of a small portion (<24%) of the lattice Cu(II) ions and, to a lesser extent, the oxidation of the lattice barium atoms. At 830-920 K the surface segregation of the barium atoms is evident and is thought to be indicative of the matrix degradation due to the formation of barium nitrite. A detailed mechanism of the interaction between YBa[sub 2]Cu[sub 3]O[sub 7] and NO is postulated and applied to explain the high catalytic activity for the selective reduction of NO on YBa[sub 2]Cu[sub 3]O[sub 7].

• OSTI ID: 7165073
• Journal Information: Inorganic Chemistry; (United States), Vol. 32:24; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BARIUM OXIDES
CHEMICAL REACTIONS
COPPER OXIDES
NITRIC OXIDE
YTTRIUM OXIDES
ABSORPTION SPECTROSCOPY
CATALYTIC EFFECTS
OXIDATION
PHOTOELECTRON SPECTROSCOPY
REDUCTION
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
X-RAY SPECTROSCOPY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL ANALYSIS
COPPER COMPOUNDS
ELECTRON SPECTROSCOPY
GRAVIMETRIC ANALYSIS
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
400201* - Chemical &amp; Physicochemical Properties