Structures of Co and Pt nanoclusters on a thin film of Al2O3/NiAl(1 0 0) from reflection high-energy electron diffraction and scanning-tunnelling microscopy

Luo, Meng Fan; Wen, Wei-Chih; Lin, Chern‐Sheng; Chiang, C.I.; Sartale, Shrikrishna D.; Zei, Mau-Scheng

doi:10.1016/j.susc.2007.03.016

Cited by 33 publications

(40 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, in the inverse system, no twinning occurs in the Ru deposit on Pt(111), while a stacking fault in thicker Ru islands has been observed. Moreover, twinned Pt clusters were absent in evaporated Pt films on γ-Al 2 O 3 oxide surface [56] and oxide film grown on NiAl(100) [55] under UHV conditions, where randomly oriented Pt clusters developed at 300 K as shown by the Debye-Scherre rings in RHEED [57]. It is likely that the random orientation of the Pt particles is due to the weak interaction between clusters and oxide substrate surfaces.…”

Section: Discussionmentioning

confidence: 99%

“…It is likely that the random orientation of the Pt particles is due to the weak interaction between clusters and oxide substrate surfaces. Nevertheless, the Pt [57] and Co [58] clusters grow with the (001) facets parallel to the (001) oxide film grown on NiAl(100), while the Pt clusters grow with the (111) facet on the γ-Al 2 O 3 oxide surface [56] in order to reduce the lattice mismatch. Similar trends have also been found for the Pt and Ru clusters growing with the facets of hexagonal unit mesh on the Ru(0001) and Pt(111) substrates, respectively.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

Zei

2010

Journal of Nanotechnology

View full text Add to dashboard Cite

The epitaxial growth of Pt and Ru deposits by spontaneous, as well as by dynamic, electrodeposition onto Ru(0001) and Pt(111), respectively, have been studied by reflection high energy electron diffraction (RHEED) and Auger electron spectroscopy (AES). For the Pt deposit on Ru(0001), at submonolayer range, it preferably grows compressed commensurate bilayer thick islands on Ru(0001). This is the first time that RHEED observation of the onset of Pt twinning occurs in ca. 2-3 layer thick islands on Ru at room temperature, at which the surface strain due to the 2.5% lattice mismatch of Pt and Ru remains intact. For multilayer thick islands (>6 ML) ordered reflection twins (diameter of ∼3 nm) develop and are embedded in a (111) matrix with an incoherent (11-2) twin plane normal to Ru(0001) and aligned with their [−110] direction parallel to the [11][12][13][14][15][16][17][18][19][20] Ru(0001) substrate direction. For the Ru deposit on Pt(111), at ∼0.2 ML a strained (1 × 1) monoatomic layer is formed due to the 2.5% lattice mismatch of Ru and Pt. Increasing the coverage up to ∼0.64, the second Ru layer is found to relieve the strain in the first layer, giving rise to dislocations and Ru relaxes to its bulk lattice constant. Multilayers of Ru (>1 ML) result in (0001) nanocluster formation aligned with its [11][12][13][14][15][16][17][18][19][20] direction parallel to the [−110] Pt(111) substrate direction.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

Zei

2010

Journal of Nanotechnology

View full text Add to dashboard Cite

show abstract

“…An ultra-thin q-Al 2 O 3 lm was formed on oxidation of a NiAl(100) alloy surface at 1000 K; the formation of Al 2 O 3 thin lms is described elsewhere. 42,43,45,48 To achieve a homogeneous crystalline Al 2 O 3 surface with no NiAl facets, 49,50 we refrained from protracted post-oxidation annealing of the oxide lms. The amorphous oxide surface was also negligible.…”

Section: Methodsmentioning

confidence: 99%

The interaction of CO molecules on Au–Rh bimetallic nanoclusters supported on a thin film of Al₂O₃/NiAl(100)

et al. 2017

View full text Add to dashboard Cite

The interaction of CO molecules adsorbed on Au-Rh bimetallic nanoclusters supported on an ordered thin film of Al 2 O 3 /NiAl(100) was studied, primarily with infrared reflection absorption spectroscopy and densityfunctional-theory calculations. The bimetallic clusters, grown by sequential deposition of vapor Au and Rh onto the Al 2 O 3 /NiAl(100) surface at 300 K, had diameters of 1.2-3.0 nm and heights of 0.4-1.2 nm; they had a fcc phase and grew in the orientation (100). The infrared absorption line for CO adsorbed on Au sites (CO Au ) of the bimetallic clusters at 110 K was narrow (centered about 2100 cm À1) and intense, which results largely from the small adsorption energy and large dipole moment of CO Au , whereas that on Rh sites (CO Rh ) was broad (1880-2100 cm À1) and weak, which contrasts also with its counterpart on pure Rh clusters. Upon increasing the temperature to remove CO Au , the absorption line for CO Rh narrowed and the intensity increased; at 300 K, the line width decreased by 30-40% and the absorption intensity was enhanced by 40-60%. The former arose, after the desorption of CO Au , from a decreased CO-CO interaction and inhomogeneous broadening; the latter corresponded to an enhanced dipole moment of CO Rh , attributed to a promoted charge transfer from the CO Rh -binding Rh to the neighboring Au and consequently increased charge donated from CO Rh to Rh. The varied IR absorption for adsorbed CO can thus serve as an indicator for the charge transfer between the components in bimetallic clusters.

show abstract

“…All experiments were conducted in UHV chambers with base vacuum better than 1 · 10 -9 torr. The deposition of Pt and the growth of a h-Al 2 O 3 thin film on NiAl(100) were performed as described previously [19][20][21][22]; the only difference is that the Al 2 O 3 thin film on NiAl(100) was not subjected to protracted annealing post oxidation, thus preventing NiAl facets becoming exposed on the surface [21,22].…”

Section: Methodsmentioning

confidence: 99%

“…The Pt clusters were formed by vapor deposition; their morphologies and crystallinity were characterized with a scanning-tunneling microscope (STM) and reflection high-energy electron diffraction (RHEED), respectively [19,20] [20]. We investigated the temperature dependence of the cyclohexene dehydrogenation by increasing the sample temperature in a stepwise manner and recording a photoelectron spectrum from the reaction mixture on the surface at each temperature step.…”

Section: Introductionmentioning

confidence: 99%

Dehydrogenation of Cyclohexene on Platinum Nanoclusters on a Thin Film of Al2O3/NiAl(100)

et al. 2007

View full text Add to dashboard Cite

Using a scanning-tunneling microscope, reflection high-energy electron diffraction and photoelectron spectra with synchrotron radiation, we investigated the temperature dependence of the dehydrogenation of cyclohexene (C 6 H 10 ) adsorbed on Pt nanoclusters supported on an ultra-thin film of Al 2 O 3 /NiAl(100). The Pt clusters, grown by vapor deposition, are structurally ordered and exhibit a mean diameter 2.2 nm and height 0.4 nm. The progress of dehydrogenation was monitored through the temporal variation of C 1s photoelectron spectra; analysis of these features revealed that the dehydrogenation of cyclohexene with increasing sample temperature occurs as a sequential process beginning around 150 K, a temperature significantly less than that for Pt single-crystal surfaces. The dehydrogenation behavior, particularly the decomposition into elemental carbon, is found to vary with Pt coverage.

show abstract

Structures of Co and Pt nanoclusters on a thin film of Al2O3/NiAl(1 0 0) from reflection high-energy electron diffraction and scanning-tunnelling microscopy

Cited by 33 publications

References 28 publications

Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

The interaction of CO molecules on Au–Rh bimetallic nanoclusters supported on a thin film of Al₂O₃/NiAl(100)

Dehydrogenation of Cyclohexene on Platinum Nanoclusters on a Thin Film of Al2O3/NiAl(100)

Contact Info

Product

Resources

About

Structures of Co and Pt nanoclusters on a thin film of Al2O3/NiAl(1 0 0) from reflection high-energy electron diffraction and scanning-tunnelling microscopy

Cited by 33 publications

References 28 publications

Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

The interaction of CO molecules on Au–Rh bimetallic nanoclusters supported on a thin film of Al2O3/NiAl(100)

Dehydrogenation of Cyclohexene on Platinum Nanoclusters on a Thin Film of Al2O3/NiAl(100)

Contact Info

Product

Resources

About

The interaction of CO molecules on Au–Rh bimetallic nanoclusters supported on a thin film of Al₂O₃/NiAl(100)