Infrared spectroscopic study of NO reduction by H2 on supported gold catalysts

Abstract

In siru Fourier transform infrared spectroscopy is used to study the reduction of NO by HI on Au/SiO* and AuiMgO catalysts. On these catalysts, large differences in selectivity toward Nz formation had been found depending on the nature of the support. These differences are correlated with transient infrared spectral features which appear during reaction. NO by itself does not give rise to a band attributable to NO adsorbed on Au, however, exposure of supported Au to NO renders the catalyst unable to adsorb CO. Preadsorbed CO, on the other hand, is displaced from the Au catalysts by NO.

Structure control of silica-supported mono and bimetallic Au–Pt catalysts via mercapto capping synthesis

“…As shown in Fig. 8, all the IR signals are completely removed by the evacuation, confirming the reversible character of CO adsorption on gold over silica [41]. Fig.…”

“…Low-frequency shift of the CO stretching bands has been attributed to the negatively charged gold particles supported over reducible oxides [38][39][40]. Some authors attributed these low-frequency bands to bridged CO adsorbed on big gold particles [41,42]. In the present case, considered the inert nature of the silica support, it is reasonable to attribute the low-frequency bands to bridge-bonded CO.…”

The oxamate route, a versatile post-functionalization for metal incorporation in MIL-101(Cr): Catalytic applications of Cu, Pd, and Au

“…Upon heating up to 323 and 373 K, the CO band at 1960 cm À1 disappears, while the intensity of the band at 2050 decreases significantly. The main band at 2040 cm À1 can be ascribed to linearly bonded CO on Au 0 sites, while the contribution at 1960 cm À1 is caused by bridge adsorption of CO on gold [59][60][61][62][63]. The fact that one single band is found near 2040 is attributed to a very homogeneous Au particle size distribution.…”

Surface chemistry of catalysis by gold

“…Lee and Schwank were among the first to suggest that such cationic species acted as the active sites in gold catalysis (444). Based on IR data which showed CO adsorption 2040 cm -1 , considered to be on sites other than metallic gold, and considering the lack of activity for unsupported bulk gold, the authors proposed that these adsorption sites may be related to gold that is electronically modified by the support due to charge transfer.…”