Catalytic reduction of N2O and NO2 with methane over sol–gel palladium-based catalysts

Effect of Ru Species on N2O Decomposition over Ru/Al2O3 Catalysts

“…Figure 9 shows the DRIFTS recorded with the support Al 2 O 3 and Ru/Al 2 O 3 under N 2 O atmospheres. Generally, the N-N stretching frequency of adsorbed N 2 O on metal oxides was reported within a wide range of frequencies between 2400 and 2150 cm −1 , and typical bands of the nitrites, nitrates and nitro species were located below 1700 cm −1 [41][42][43][44][45]. In Figure 9a, two quite intense absorption bands were observed at 2237 and 2212 cm −1 , which could be assigned to the N-N stretching of adsorbed N 2 O [46].…”

“…Four intense peaks at 1871, 1650, 1533 and 1410 cm −1 were observed along with characteristic peaks of gas-phase N 2 O at 2237 and 2212 cm −1 . The bands at 1650, 1533 and 1410 cm −1 can be assigned to nitrate and nitrite species, monodentate nitrate species and nitro species, respectively [41][42][43][44][45][46][47][48]. The band at 1871 cm −1 can be attributed to the Ru-ON species [49].…”

Preparation and characterisation of γ-Al2O3 particles-supported Rh/Ce0.9Pr0.1O2 catalyst for N2O decomposition in the presence of O2, H2O and NOx

“…All spectra in Figs. 10 and 11, regardless the gas composition, temperature and sample, show bands in the range 2400-2100 cm −1 attributed to chemisorbed N 2 and/or N 2 O (Hadjiivanov, 2000;Oktar et al, 2006;Wang et al, 2010;Haq and Hodgson, 2000). The formation of these bans in the Rh-free sample, where N 2 O decomposition does not occurs, suggests that they should be attributed to N 2 O rather than to N 2 .…”

“…10 and 11. In general, there are three regions of the spectra that require special attention: (i) 2400-2100 cm −1 , assigned to the N N stretching frequency of adsorbed N 2 or N 2 O (Hadjiivanov, 2000;Oktar et al, 2006;Wang et al, 2010;Haq and Hodgson, 2000), (ii) below 1700 cm −1 , attributed to oxidised nitrogen species (nitrite, nitrate and/or nitro compounds) and (iii) 3800-3600 cm −1 correspond to hydroxyl groups (Djinović et al, 2009;Menacherry and Haller, 1997). All spectra in Figs.…”

Surface enhanced Raman spectroscopy (SERS) sensors for gas analysis

“…The study of NO x and CO x adsorption on Pd, Pt and Rh catalyst surfaces is of key interest to the automobile industry towards understanding the catalytic mechanisms of the breakdown of these pollutant gases. [10][11][12] SERS studies of these gases have been reported using SERS active, mixed coinage/transition metal substrates. 12,13 Other examples of SERS analysis of gases concern gases condensed onto surfaces through substrate cooling, or dissolved in an electrolyte for electrochemical analysis.…”