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

Abstract

The role of the bis(µ-oxo)dicopper core, i.e., [Cu 2 (µ-O) 2 ] 2+ , in the decomposition of NO and N 2 O by the Cu-ZSM-5 zeolite has been studied with combined operando UV-vis monitoring of the catalyst and on-line GC analysis. An optical fiber was mounted on the outer surface of the quartz wall of the plug-flow reactor and collected the UV-vis diffuse reflectance spectra under true catalytic conditions.

Fe, Co and Cu-incorporated TUD-1: Synthesis, characterization and catalytic performance in N2O decomposition and cyclohexane oxidation

“…5B, by increasing the loading from Cu-1 to Cu-2 might be related to this necessity of having neighbouring Cu-sites, although an increment of the 460 nm band in the respective UV-vis spectra is not obvious, and extended characterization, e.g. using the procedures of Groothaert et al [23] are needed to support this hypothesis. CuO containing mesoporous silica structures have been reported previously by [36], who claim to have synthesized mesoporous silica spheres containing nano-dispersed copper oxides.…”

“…Similar to Fe-based catalysts, most of the research in the use of Cu-based catalysts for N 2 O decomposition has been directed at ZSM-5. In a recent study of Groothaert et al [23] it was claimed that catalytic activity is predominantly induced by active species containing two copper ions. Measurement under transient reaction conditions indicated that [Cu 2 (m-O) 2 ] 2+ is formed by O abstraction of N 2 O.…”

“…The presence of these components significantly deteriorates the performance of noble metal catalysts (Rh, Ru), which intrinsically have the highest N 2 O decomposition activity [16][17][18]. Other, more cost-effective catalysts, such as Fe [19,20], Co [21,22] or Cu [23,24] based zeolites, have been evaluated extensively in the literature for their performance in N 2 O decomposition, of which Fe is the most promising in nitric acid tail gas conditions, because of the promoting effect of NO on the N 2 O decomposition rate. Mesoporous analogues of the zeolite catalysts (mainly ZSM-5) have not been studied extensively in relation to N 2 O decomposition, besides Fe-MCM-41 [25], although also this study is more focussed on the characterization of the material, than on the catalytic performance [25].…”

Cu-ZSM-5 Zeolites for the Formation of Methanol from Methane and Oxygen: Probing the Active Sites and Spectator Species

“…Several assignments have been reported for this band. Some authors ascribed the band to the presence of (Cu-O-Cu) 2? species [21][22][23], while other groups assigned it to a bis(l-oxo) dicopper species [18,19,24,25]. Recently, Woertink et al [26] presented additional information on the origin of copper species using a combination of resonance Raman (rR) spectroscopy and density functional theory (DFT).…”

Adsorption of molecular hydrogen on aluminophosphate zeolites at 77 K

“…Noteworthy ones are CuZSM 5 catalysts, which are used in the decompo sition of NO [1,2] and N 2 O [3] to N 2 and O 2 , in the selective reduction of NO x with hydrocarbons [4][5][6], in ethylene aromatization [7], and in other applica tions. Along with aluminosilicate zeolites, alumino phosphate (AlPO) zeolites have also found wide use, including in ethylene oligomerization [8], n butene isomerization [9], and N 2 O decomposition [10].…”