G
Geus
16 records found
1
The oxidation of a Cu/SiO2 catalyst with NO or O2 at temperatures varying from 313 to 513 K has been investigated using XPS. Upon admission of NO or O2 to a previously reduced catalyst, a rapid transformation of Cu(0) to Cu(I) is observed. This first stage is followed by slow oxi
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The IR absorbance of adsorbed CO is a suitable probe for evaluating the extent of oxidation of small supported copper particles. The residual absorbance of the main band at about 2120 cm-1 after evacuation of the gas phase and the presence of additional CO absorbance bands indica
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The kinetics of the adsorption of NO and O2, and of the subsequent reduction with CO have been studied on the stepped copper surfaces Cu(711) and Cu(710). The surfaces exhibit terraces with the (100) structure, and steps with the (111) and the (110) structure, respectively. Gases
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Exposure of NO or O2 to Cu(100) or Cu(110) (at temperatures between 370 and 670 K, pressures up to 0.1 Pa) leads to dissociative adsorption. Dissociation on Cu(110) is about an order of magnitude faster than on Cu(100). Saturation of the surface coverage (for both surfaces at abo
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The rate of methane formation by decomposition of methanol is studied at temperatures between 473 and 583 K and methanol pressures between 0.2 and 10.4 kPa. Coverages of adsorbed species are measured using temperature-programmed hydrogenation (TPH), temperature-programmed desorpt
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A model describing adsorption and desorption in a bed of porous catalyst pellets is presented. The model has been used to simulate temperature-programmed desorption. In particular the effect of a coverage-dependent heat of adsorption has been investigated and the consequences the
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NO interaction with Cu(111) is shown to be dissociative for temperatures varying from 320 to 570 K and for exposures up to 150 Pa·s. Upon adsorption a saturation surface coverage (0.5 monolayer) of adsorbed oxygen and nitrogen is obtained. After an incubation period penetration o
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The kinetics of the formation of methane from methanol have been studied on a 50 wt% Ni/SiO2, a 20 wt% Ni/SiO2, a 10 wt% Ni/Al2O3 and a 5 wt% Ni/TiO2 catalyst. Temperatures were typically between 475 and 585 K with methanol p
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