Stoichiometric catalytic decomposition of nitric oxide over copper-exchanged zeolite (CuZSM-5) catalysts

An operando optical fiber UV–vis spectroscopic study of the catalytic decomposition of NO and N2O over Cu-ZSM-5

“…In the 773-623 K range, the O 2 yield is always lower than the N 2 yield, by a value of about 10%. In correspondence with the literature [21,24], the latter discrepancy can be assigned to the reaction of produced O 2 with unreacted NO forming NO 2 in the cool exit zone of the reactor and in the GC. Below 673 K, the formation of N 2 O is observed with a maximum yield at 623 K. At 773 K, the TOF (molecules NO converted to N 2 per hour per Cu atom) amounts to 1.8 h −1 .…”

“…Several explanations for this profile have been proposed, such as (1) the desorption of oxygen [21], (2) the instability or surface nitrates [22], and (3) the adsorption equilibrium of NO [23]. Li and Hall [24] suggested that the NO 2 production observed in case of incomplete NO decomposition results from the reaction of NO with produced O 2 in the cool exit zone of the reactor. It is known that the equilibrium-controlled reaction (2NO + O 2 ↔ 2NO 2 ) favors NO 2 formation at room temperature; however, this reaction does not proceed far to the right at elevated temperatures (K (298 K) = 2.4 × 10 12 atm −1 ; K (773 K) = 0.82 atm −1 ) [24].…”

Erratum

“…The reaction gas containing 1.00 vol% NO, 10.0 vol% 02, and 1320 ppm cetane (n-C16H34) diluted with He was allowed to flow with a space velocity of 2500 h-1 at a temperature range from 150 to 600~ with a constant heating rate of 2.5~ NO has a potential to convert N2, NO2, and N2, however, N20 usually formed only at lower NO conversion condition such as at lower reaction temperature [15,16]. The possibility to form NO 2 at higher temperature condition under coexistence of excess O 2 cannot be eliminated, however, the focus was put in this study on the NO conversion to N2, therefore, the measurement of NO 2 was omitted for the convenience of the analysis.…”

Direct Decomposition of Nitric Oxide over C‐Type Cubic (Gd1–x–yYxBay)2O3–y Solid Solutions

“…[15,16,19] [16,19,23] The formation of NO 2 was confirmed by analyzing the streaming gas passing through the catalyst at 900°C using gas chromatography (GC) and NO x analysis. At 900°C, neither NO or N 2 O were detected by GC, but the analyzer indicated the existence of NO x species.…”