Characterization of the surface of a Cu/SiO2 catalyst exposed to NO and CO using IR spectroscopy

Identification of Neutral and Charged NxOySurface Species by IR Spectroscopy

“…These are a band at 2207 cm Ϫ1 appearing after adsorption of small amounts of NO 2 on TiO 2 [100,103], a broad band in the 2220-1800-cm Ϫ1 region observed after NO 2 adsorption on V 2 O 5 /TiO 2 [94,226], a band at 2250 cm Ϫ1 detected after NO adsorption on Mn/MgO [194], and a band at 2260 cm Ϫ1 , also detected after NO adsorption but on Cr/Al 2 O 3 [186], a band at 2133 cm Ϫ1 , detected after NO adsorption on a reduced Cu/SiO 2 catalyst [181], and a band at 2162 cm Ϫ1 , registered after NO 2 adsorption on a Pt/BaCl 2 /SiO 2 sample [118]. Bands in the 2265-2100-cm Ϫ1 region have been observed on nonzeolitic systems and, as a rule, attributed to NO ϩ .…”

Copper-modified mesoporous MCM-41 silica: FTIR and catalytic study

“…The Cu 0 -CO type carbonyls are usually detected below 2100 cm −1 [72]. However, in some cases (when the copper dispersion is high or the surface is rough) the Cu 0 -CO bands can be found at higher frequencies, in the region where the Cu + -CO species absorb [73]. In this case a criterion for discrimination between the Cu + -CO and Cu 0 -CO species is their stability: the carbonyls of metallic copper are easily decomposed during evacuation [57].…”

Fe-modified CuMnZrO2 catalysts for higher alcohols synthesis from syngas

“…With the temperature up to 333 K two adsorption bands appeared at 2109 and 2098 cm −1 , corresponding to linear CO species on different copper sites [28]. The band at 2109 cm −1 was caused by the formation of adsorbed CO on highly dispersed copper sites, and the band at 2098 cm −1 was assigned to the species formed on densely packed surface [29,30]. This result was in the agreement with the findings of TPR study, which indicated the copper oxide was present in highly dispersed CuO and bulk CuO.…”