Surface electronic structure of NiO: Defect states,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>O int

McKay, Jeffrey M.; Henrich, Victor E.

doi:10.1103/physrevb.32.6764

Cited by 154 publications

(50 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is attributed to adsorbed OH species resulting from dissociation of water to form OH+H. The two peaks are due to the 1π and 3σ orbitals of OH as interpreted similarly for OH in NaOH [341] and on other metal-oxides [58,[342][343][344]. We also attribute the features between -5 and -10 eV to adsorbate induced changes in the substrate emission and possibly to emission from the coadsorbed H atom.…”

Section: (I) Electronic Structures Of Adsorbatesmentioning

confidence: 77%

“…For this reason, water dissociation on metals is often observed only when O is preadsorbed [58], as was observed first on Pt(111) [351]. On non-polar oxide surfaces, such as CoO(100) [342] and NiO(100) [64,344] dissociative adsorption is found to occur only at defects, whereas the corresponding regular surface areas are inert. Dissociative adsorption was observed on Ti 3+ rich Ar + -bombarded surfaces, such as Ti 2 O 3 (047) [352], TiO 2 (100) [353], SrTiO 3 (100) [354], whereas molecular adsorption was observed on the respective stoichiometric regular surfaces.…”

Section: Discussionmentioning

confidence: 96%

See 1 more Smart Citation

Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

Weiß

Ranke

2002

Progress in Surface Science

584

610

View full text Add to dashboard Cite

Metal-oxide based catalysts are used for many important synthesis reactions in the chemical industry. A better understanding of the catalyst operation can be achieved by studying elemantary reaction steps on well-defined model catalyst systems. For the dehydrogenation of ethylbenzene to styrene in the presence of steam both unpromoted and potassium promoted iron-oxide catalysts are active. Here we review the work done over unpromoted single-crystalline FeO(111), Fe 3 O 4 (111) and α-Fe 2 O 3 (0001) films grown epitaxially on Pt(111) substrates. Their geometric and electronic surface structures were characterized by STM, LEED, electron microscopy and electron spectroscopic techniques. In an integrative approach, the interaction of water, ethylbenzene and styrene with these films was investigated mainly by thermal desorption and photoelectron emission spectroscopy. The adsorptiondesorption energetics and kinetics depend on the oxide surface terminations and are correlated to the electronic structures and acid-base properties of the corresponding oxide phases, which reveal insight into the nature of the active sites and into the catalytic function of semiconducting oxides in general. Catalytic studies, using a batch reactor arrangement at high gas pressures and post reaction surface analysis, showed that only α-Fe 2 O 3 (0001) containing surface defects is catalytically active, whereas Fe 3 O 4 (111) is always inactive. This can be related to the elementary adsorption and desorption properties observed in ultrahigh vacuum, which indicates that the surface chemical properties of the iron-oxide films do not change significantly across the "pressure-gap". A model is proposed according to which the active site involves a regular acidic surface sites and a defect site next to it. The results on metal-oxide surface chemistry also have implications for other fields, such as environmental science, biophysics and chemical sensors.-2 -"2kyEi9FYSQjBVrZxIPQ.FHIAC_WRa02_review.doc", Datum: 19.02.03

show abstract

Section: (I) Electronic Structures Of Adsorbatesmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 96%

Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

Weiß

Ranke

2002

Progress in Surface Science

584

610

View full text Add to dashboard Cite

show abstract

“…4). The reported E f for undoped NiO ranges from 3.8 eV (49) to 5.4 eV (50) and has been found to depend on the deposition substrate (51) and the NiO surface treatment (49). A frequently cited value is 5.0 eV (20,23,44,52) while the valence band maximum (VBM) of undoped NiO is ϳ0.4 eV below E f (Fig.…”

Section: ϫ4mentioning

confidence: 99%

p -Type semiconducting nickel oxide as an efficiency-enhancing anode interfacial layer in polymer bulk-heterojunction solar cells

Irwin

Buchholz

Hains

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

1,328

800

View full text Add to dashboard Cite

show abstract

“…Indeed, there is a consensus both from experimental investigations and theoretical calculations that water adsorbs molecularly on NiO(100) surfaces and that a dissociation reaction can only take place at defect sites. [92][93][94][95] Simpson's theoretical calculation by using the semi-empirical SCFMO method MSINDO shows that water dissociation is unlikely on the planar surface of NiO(100) and the associated activation energy for dissociation is high due to the rigidity of the NiO(100) lattice which prevents water molecule from adopting a stable transition state, 96 suggesting by analogy that Ni(bdc)(ted) 0.5 is more stable in water vapor. These conclusions are also supported by considering the metal-oxygen strength from the dissociation energy for diatomic molecules: Zn-O(<250.4 kj/mol), Cu-O(~287.4 kj/mol), Ni-O(~366 kj/mol),Co-O(~397.4 kj/mol).…”

Section: Effects Of Metal Ions On Stability and Reaction Pathwaymentioning

confidence: 99%

Stability and Hydrolyzation of Metal Organic Frameworks with Paddle-Wheel SBUs upon Hydration

et al. 2012

View full text Add to dashboard Cite

Instability of most prototypical metal organic frameworks (MOFs) in the presence of moisture is always a limitation for industrial scale development. In this work, we examine the dissociation mechanism of microporous paddle wheel frameworks M(bdc)(ted) 0.5 [M=Cu, Zn, Ni, Co; bdc= 1,4-benzenedicarboxylate; ted= triethylenediamine] in controlled humidity environments. Combined in-situ IR spectroscopy, Raman, and Powder x-ray diffraction measurements show that the stability and modification of isostructual M(bdc)(ted) 0.5 compounds upon exposure to water vapor critically depend on the central metal ion. A hydrolysis reaction of water molecules with Cu-O-C is observed in the case of Cu(bdc)(ted) 0.5 . Displacement reactions of ted linkers by water molecules are identified with Zn(bdc)(ted) 0.5 and Co(bdc)(ted) 0.5 . In contrast, . Ni(bdc)(ted) 0.5 is less susceptible to reaction with water vapors than the other three compounds. In addition, the condensation of water vapors into the framework is necessary to initiate the dissociation reaction. These findings, supported by supported by first principles theoretical van der Waals density functional (vdW-DF) calculations of overall reaction enthalpies, provide the necessary information for determining operation conditions of this class of MOFs with paddle wheel secondary building units and guidance for developing more robust units.

show abstract

Surface electronic structure of NiO: Defect states,O2andH2O int

Cited by 154 publications

References 65 publications

Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

p -Type semiconducting nickel oxide as an efficiency-enhancing anode interfacial layer in polymer bulk-heterojunction solar cells

Stability and Hydrolyzation of Metal Organic Frameworks with Paddle-Wheel SBUs upon Hydration

Contact Info

Product

Resources

About