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Effect of Pd dispersion on the catalytic activity of Pd/Al2O3 for C3H6 and CO oxidation

“…An exposure of CO to Pd/Al 2 O 3 with D Pd = 0.41 gave the IR bands assignable to CO species linearly boned on Pd 0 at 2071 cm −1 and to CO species bridge-bonded on Pd 0 sites at 1969 and 1930 cm −1 (spectrum a). This is in accordance with literature [27][28][29][30][31]. As can be seen in Fig.…”

Hydrogen production from formic acid vapour over a Pd/C catalyst promoted by potassium salts: Evidence for participation of buffer-like solution in the pores of the catalyst

“…(6) The sequence of reactions presented is supported by the observation reported above that a significant fraction of the formic acid is condensed in the pores of the catalysts during the early stages of reaction after introducing formic acid to the samples and relatively small dependence of the rate of reaction on the formic acid partial pressure. Other research groups have reported that a condensed formic acid can be observed by "in situ" infrared (IR) spectroscopy on SiO2-based catalysts [21,31,32] under conditions close to ours. In all these cases, the IR results obtained showed the presence of a stretching vibration of a hydrogenbonded carbonyl group (C=O) at a wavenumber of 1715-1735 cm -1 , this being shifted with respect to the corresponding band for gaseous formic acid (1770-1790 cm -1 ) and confirming the existence of formic acid in a condensed phase.…”

Mechanism of the decomposition of adsorbed methanol over a Pd/α,β-Ga2O3 catalyst

“…1). The integrated intensity of these signals increased during the exposure to gaseous methanol and then remained constant throughout the He purge at 323 K. These bands, at 2060, 1930 (broad and overlapped), and 1875 cm À1 are due to CH 3 OH decomposition on the palladium surface and correspond to chemisorbed carbon monoxide (CO S ) on Pd [21]. The band above 2000 cm À1 is attributed to terminal, mono-coordinated or linearly bonded CO (CO L ), while the broad, convoluted bands below 2000 cm À1 are assigned to multi-coordinated, bridging CO (CO B ).…”

“…The band above 2000 cm À1 is attributed to terminal, mono-coordinated or linearly bonded CO (CO L ), while the broad, convoluted bands below 2000 cm À1 are assigned to multi-coordinated, bridging CO (CO B ). The latter have been further classified from single-crystal studies as CO B1 , corresponding to dicoordinated bridging CO on structurally open crystal planes such as (1 0 0) or (2 1 0), close to 1970 cm À1 , and CO B2 , corresponding to dicoordinated CO on Pd(1 1 1), around 1900 cm À1 [21].…”