The interaction of oxygen with Ni(111) and the reduction of the surface oxide by carbon monoxide and by hydrogen

et al. 1984

Self Cite

The thermal decomposition of ethylene on Ni(lll) at 250°C is shown to lead to carbon deposition on and -in a later stage -below the surface. Independent of the amount of carbon below the surface, CO is adsorbed with an isosteric heat of adsorption of 105 kJ/mol. The surface carbon reacts with oxygen at 25O'C. The reaction rate is independent of the surface carbon coverage and first order in oxygen pressure. The subsurface carbon segregates to the surface after removal of the surface carbon layer.

Section: The Reaction Of the Carbide Layer On Ni(ll1) With Oxygensupporting

confidence: 92%

Section: The Reaction Of the Carbide Layer On Ni(ll1) With Oxygensupporting

confidence: 89%

The interaction of oxygen and carbon monoxide with a carbided Ni(111) surface

Vink

Zandvoort

et al. 1984

Self Cite

“…Rather. it is similar to the reduction of O/Ni (lll) and O/Ni(lOO) [5,9]. This may not be surprising, considering the fact that on Cu(lll)-Ni(0.4') a larger amount of Ni is present in the near surface region compared with Cu(llO)-Ni(1") [ll], and an oxygen induced Ni segregation occurs on the (111) alloy surface (c.f.…”

Section: Discussionmentioning

confidence: 68%

“…The model used to describe the reduction of oxidised Ni surfaces is a nucleation and growth type mechanism [25], or a more refined version of this [9]. For the sake of simplicity we will use the original approach.…”

Section: Discussionmentioning

confidence: 99%

Sorption of oxygen on Cu(111)-Ni surfaces and its reaction with hydrogen

Mesters

Koster

et al. 1984

The interaction of 0, with a Cu(lll)-Ni alloy and the reaction of sorbed oxygen with H, has been investigated with ellipsometry and AES. The surface alloys were prepared by dissociation of nickel carbonyl on a clean Cu(ll1) surface. Sorption of 0, can be described by a precursor state model for dissociative chemisorption followed by a first order reaction of adsorbed oxygen atoms to incorporated oxygen atoms. The initial sticking probability is 10-a at room temperature and increases with increasing crystal temperature.The first chemisorption of 0, on a freshly prepared alloy surface causes an irreversible surface reconstruction.The amount of oxygen in the near surface layer decreases with increasing crystal temperature.The reaction of sorbed oxygen with H, can be described by a nucleation and growth mechanism with a time dependent number of growth centers. The rate is strongly affected by an operating ionisation gauge.

“…Detailed reaction kinetics have been proposed for CO-O/Ni(lll) [7], whereas O/Ni(lOO) cannot be reduced with carbon monoxide [8]. Kinetic data for the reaction of carbon monoxide with O/Ni(llO) are unknown, although the reduction by CO is reported 191.…”

Section: Cmam Mesters Et Al / Inteructmn Of Co With Cu(lll)-nimentioning

confidence: 99%

Interaction of carbon monoxide with clean and oxygen covered Cu(111)-Ni surface alloys

Mesters

Koster

et al. 1984

Cu(lll)-Ni surface alloys were prepared by dissociation of nickel carbonyl on clean Cu(ll1). The adsorption of CO is studied with AES and ellipsometry. At pressures higher than lo-* Pa CO, migration of Ni to surface layers occurs, which makes it impossible to measure adsorption isotherms. The removal of preadsorbed oxygen on Cu(lll)-Ni with CO is also studied with AES and ellipsometry.A reaction scheme is proposed to describe the two different types of reaction curves. At temperatures below 200 o C, the overall apparent activation energy is 40 kJ/mol, at higher crystal temperatures this value drops to 10 kJ/mol. CO is found to react with oxygen on the surface, which is replenished by incorporated (subsurface) oxygen.