XPS, UPS and thermal desorption studies of alcohol adsorption on Cu(110)

Bowker, Michael; Madix, Robert J.

doi:10.1016/0039-6028(80)90135-1

Cited by 340 publications

(196 citation statements)

References 19 publications

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“…For methanol adsorbed on clean Au surface, no oxidation products other than methanol was observed at low temperature or during heating [21][22][23][24][25], similar phenomena were also reported on other coinage metal surfaces [26][27][28][29][30]. Surprisingly, methanol will dissociate on the oxygen-covered Au surface to form a variety of oxidation products and intermediates, namely methoxy, formaldehyde, formate, methyl formate, CO, CO 2 , and H 2 O [21][22][23][24][25].…”

Section: Introductionsupporting

confidence: 70%

Reaction mechanism for methanol oxidation on Au(111): A density functional theory study

Liu¹,

Jin²,

Zhang³

et al. 2013

Applied Surface Science

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Section: Introductionsupporting

confidence: 70%

Reaction mechanism for methanol oxidation on Au(111): A density functional theory study

Liu¹,

Jin²,

Zhang³

et al. 2013

Applied Surface Science

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“…It is not a reaction partner in the catalytic reaction (unlike O ads in the model discussed in Refs. [19] and [20]), but, together with the neighboring Cu atoms, forms the active center where the reaction takes place. The presence of oxygen species at and below the Cu surface (as found in our in situ XPS experiments using nondestructive depth profiling) is also supported by scanning electron microscopy (SEM) investigations of the morphology of Cu foils that were used in atmospheric pressure conversion experiments.…”

Section: Resultsmentioning

confidence: 99%

“…[19,20] In the UHV-XPS experiments at room temperature different Cu surfaces [(110), (111), and polycrystalline Cu] were predosed with oxygen, which dissociated and adsorbed on the surface. When the oxygenpredosed surface was exposed to methanol, methoxy (the intermediate for formaldehyde formation) was formed on all three surfaces.…”

Section: Resultsmentioning

confidence: 99%

Methanol Oxidation on a Copper Catalyst Investigated Using in Situ X-ray Photoelectron Spectroscopy

Bluhm¹,

Hävecker²,

et al. 2004

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The surface and near-surface region of an active catalyst and the adjacent gas-phase reactants were investigated simultaneously under reaction conditions using in situ X-ray photoelectron spectroscopy (XPS). This investigation of methanol oxidation on a copper catalyst showed that there was a linear correlation between the catalytic activity of the sample and the presence of a sub-surface oxygen species that can only be observed in situ. The concentration profile of the sub-surface oxygen species within the first few nanometers below the surface was determined using photon energy-dependent depth-profiling. The chemical composition of the surface and the near-surface region varied strongly with the oxygen-tomethanol ratio in the reactant stream. The experiments show that the pure metal is not an active catalyst for the methanol oxidation reaction, but that a certain amount of oxygen has to be present in the sub-surface region to activate the catalytic reaction. Oxide formation was found to be detrimental to formaldehyde production. Our results demonstrate also that for an understanding of heterogeneous catalysts a characterization of the surface alone may not be sufficient, and that sub-surface characterization is essential.

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“…The stability of methoxy on Au is in analogy with its stability on other group II metals, Cu [19], Ag [20] for which elements decomposition in TPD occurs above 300K. Thus it is likely that methoxy decomposes only slowly on gold at 300K and that its decomposition is speeded up in the presence of light in the following manner.…”

Section: Introductionmentioning

confidence: 96%

Photocatalysis by au nanoparticles: Reforming of methanol

et al. 2004

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Au/TiO2 catalysts were prepared by incipient wetness impregnation and tested for the room temperature photocatalytic reforming of methanol in aqueous solution to produce hydrogen. These catalysts proved to be active for this reaction, with the dependence on loading of gold showing a double maximum in yield at 0.2 and 2 weight % with a low rate below 0.01% and above 10%. A model is proposed for the reaction, involving band gap excitation of titania electrons to produce O -species which are then used to oxidise the methanol via adsorbed methoxy, which is formed by dehydrogenation on the metal component. The reaction is truly bi-functional and only takes place at the interface between the metal and the support.An ideal for the future well-being of the human population of the world (and for the biota as a whole) is to find an energy source which has the following properties: 1 It must be environmentally benign, producing minimal pollution of any kind, and taking up as little useful space as possible; 2 It must have usable energy density; 3 It should be usable on a local basis -strategically eliminating dependence upon external influences; 4 It should be economically viable, which is not as simple a point as might at first be imagined, since it involves future costs of materials and government subsidies which are currently in place for various energy sources (nuclear, for instance) and which will, in turn, relate closely to item 3;5 It needs to be technologically feasible and available. In many ways hydrogen best fits most of these points, except for 4. It fits 1, provided that it is part of a cycle, that is hydrogen is produced from water and is burned back to water to produce energy from the exothermic oxidation of hydrogen. 2 also applies, but only if the hydrogen is used at the source of production, or is transported in a densified form (for instance, as a liquid, a high pressure gas, or condensed into a microporous high surface area solid). The technology is currently available to achieve 3 and 5, though the technology certainly can be improved. 4 is the main problem, but as stated above, hydrogen may well become economically viable in the event of a big increase in the price of oil or big taxes on fossil fuels more generally, related to the pollution they cause and their strong connection to global warming. More importantly for the West, that part of the world is currently unrealistically dependent on oil supplies from unstable parts of the world. Any responsible Western state should be investing VERY heavily, right now, in alternative energy sources, one of these being renewable and minimally-polluting hydrogen production.The objective of this paper, then, is to describe one method of producing hydrogen, that is, by using photocatalysis, which has the potential to be used to split water using sunlight. However, the rates of this reaction are quite low and so the work described here focuses on the room temperature reforming of methanol, which does effectively split water. Previous work in this group [1]...

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XPS, UPS and thermal desorption studies of alcohol adsorption on Cu(110)

Cited by 340 publications

References 19 publications

Reaction mechanism for methanol oxidation on Au(111): A density functional theory study

Reaction mechanism for methanol oxidation on Au(111): A density functional theory study

Methanol Oxidation on a Copper Catalyst Investigated Using in Situ X-ray Photoelectron Spectroscopy

Photocatalysis by au nanoparticles: Reforming of methanol

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