Work Function, Band Bending, and Microwave Conductivity Studies on the Selective Alkane Oxidation Catalyst MoVTeNb Oxide (Orthorhombic M1 Phase) under Operation Conditions

2013 ◽  
Vol 117 (51) ◽  
pp. 26988-26997 ◽  
Author(s):  
Christian Heine ◽  
Michael Hävecker ◽  
Maricruz Sanchez-Sanchez ◽  
Annette Trunschke ◽  
Robert Schlögl ◽  
...  
Keyword(s):  
Work Function ◽  
Oxidation Catalyst ◽  
Alkane Oxidation ◽  
M1 Phase ◽  
Microwave Conductivity ◽  
Band Bending ◽  
Operation Conditions

Built-in Potential of a Pentacene Pin Homojunction Studied by Ultraviolet Photoemission Spectroscopy

2010 ◽  
Vol 1270 ◽  
Author(s):  
Selina Olthof ◽  
Hans Kleemann ◽  
Björn Lüssem ◽  
Karl Leo
Keyword(s):  
Small Molecules ◽  
Work Function ◽  
Photoelectron Spectroscopy ◽  
Photoemission Spectroscopy ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Organic P ◽  
Band Bending ◽  
Silver Substrate ◽  
N Doping ◽  
Ultraviolet Photoemission Spectroscopy

AbstractIn this paper we investigate the energetic alignment in an organic p-i-n homojunction using ultraviolet photoelectron spectroscopy. The device is made of pentacene and we emploay the small molecules NDN1 for n-doping and NDP2 for p-doping the layers. The full p-i-n structure is deposited stepwise on a silver substrate to learn about the interface dipoles and band bending effects present in the device. From the change in work function between the p- and n-doped layers we gain knowledge of the built-in potential of this junction.

scholarly journals The impact of steam on the electronic structure of the selective propane oxidation catalyst MoVTeNb oxide (orthorhombic M1 phase)

2015 ◽  
Vol 17 (14) ◽  
pp. 8983-8993 ◽  
Author(s):  
Christian Heine ◽  
Michael Hävecker ◽  
Annette Trunschke ◽  
Robert Schlögl ◽  
Maik Eichelbaum
Keyword(s):  
Electronic Structure ◽  
Acrylic Acid ◽  
Surface Structure ◽  
Propane Oxidation ◽  
Oxidation Catalyst ◽  
M1 Phase ◽  
The Impact

Steam modifies the surface structure of the propane oxidation catalyst MoVTeNbOx and increases the selectivity to the product acrylic acid.

scholarly journals How to control selectivity in alkane oxidation?

2019 ◽  
Vol 10 (8) ◽  
pp. 2429-2443 ◽  
Author(s):  
Xuan Li ◽  
Detre Teschner ◽  
Verena Streibel ◽  
Thomas Lunkenbein ◽  
Liudmyla Masliuk ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Catalytic Performance ◽  
Oxidation Catalysis ◽  
Bulk Crystal ◽  
Oxidation Catalyst ◽  
Alkane Oxidation

The bulk crystal structure of an oxidation catalyst as the most popular descriptor in oxidation catalysis is not solely responsible for catalytic performance.

The effect of Nb or Ta substitution into the M1 phase of the MoV(Nb,Ta)TeO selective oxidation catalyst

2009 ◽  
Vol 142 (3-4) ◽  
pp. 320-328 ◽  
Author(s):  
William D. Pyrz ◽  
Douglas A. Blom ◽  
N. Raveendran Shiju ◽  
Vadim V. Guliants ◽  
Thomas Vogt ◽  
...  
Keyword(s):  
Selective Oxidation ◽  
Oxidation Catalyst ◽  
M1 Phase

Improvement of the Structural Model for the M1 Phase Mo–V–Nb–Te–O Propane (Amm)oxidation Catalyst

2011 ◽  
Vol 54 (10-12) ◽  
pp. 614-626 ◽  
Author(s):  
Xin Li ◽  
Douglas J. Buttrey ◽  
Douglas A. Blom ◽  
Thomas Vogt
Keyword(s):  
Structural Model ◽  
Oxidation Catalyst ◽  
M1 Phase

Geometric ordering, surface chemistry, band bending, and work function at decapped GaAs(100) surfaces

1992 ◽  
Vol 46 (20) ◽  
pp. 13293-13302 ◽  
Author(s):  
I. M. Vitomirov ◽  
A. Raisanen ◽  
A. C. Finnefrock ◽  
R. E. Viturro ◽  
L. J. Brillson ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Work Function ◽  
Band Bending

Very Low Pressure Oxidation of Si and Ge Surfaces

1990 ◽  
Vol 204 ◽  
Author(s):  
Iain D. Baikie
Keyword(s):  
Work Function ◽  
Substantial Reduction ◽  
Second Phase ◽  
Kelvin Probe ◽  
Band Bending ◽  
Effective Electron ◽  
Adsorption Phase ◽  
Dipole Layer ◽  
Function Change ◽  
Work Function Change

ABSTRACTAlthough the oxidation of Si(111) 7×7, Ge(111) 2×8 surfaces are relatively well understood very little work has been performed at sub monolayer coverage. We have utillsed a custom-built high resolution Kelvin probe to follow the changes in work function, and changes in band-bending and surface state occupancy via Surface Photovoltage Spectroscopy (SPV). The Kelvin probe Is an Ideal tool for such analysis due to Its extremely high surface sensitivity, equivalent to 4×1010 molecules/cm2, or 0.01% of the available sites.We observe a very rapid initial adsorption phase, which has not been found by other surface probes, e.g., AES, EELS, etc, corresponding to the formation of an elementary dipole layer. During this phase the Increase In the effective electron affinity with oxygen uptake achieves a maximum of 1V at 0.3 monolayer (ML), on SI(111) at 300 K. We report, for the first time, SPV spectra of SI(111), at 100 K, indicating quenching of a band of surface states centered around the fermi-level, quenching Is completed at the max-Imum of the work function change.The second adsorption phase, involving oxygen penetration through the surface layer and incorporation Into the lattice, commences at 0.25 ML for Si(111) at 300 K. a much earlier stage than previously reported. Further. we find evidence of a metastable SiO2 precursor at coverages below 1 ML. The dipole layer formation (and breakup) is shown to be very sensitive to both temperature and amount of surface Carbon contamination. The second phase also Involves a substantial reduction In band-bending to nearly flat bands at 2 ML, accounting for 20% of the work function change In the case of SI and almost 90% for Ge.

Role of Surfaces and Interfaces for the Electronic Properties of Conducting Oxides

2001 ◽  
Vol 666 ◽  
Author(s):  
Andreas Klein
Keyword(s):  
Work Function ◽  
Electronic Properties ◽  
Photoelectron Spectroscopy ◽  
Band Alignment ◽  
Surface Band ◽  
Band Bending ◽  
Conducting Oxides ◽  
Degenerate Semiconductors ◽  
Surfaces And Interfaces

ABSTRACTTransparent conductive oxides (TCOs) are generally considered as degenerate semiconductors doped intrinsically by oxygen vacancies and by intentionally added dopants. For some applications a high work function is required in addition to high conductivity and it is desired to tune both properties independently. To increase the work function, the distance between the Fermi energy and the vacuum level must increase, which can be realized either by electronic surface dipoles or by space charge layers. Photoelectron spectroscopy data of in-situ prepared samples clearly show that highly doped TCOs can show surface band bending of the order of 1 eV. It is further shown that the band alignment at heterointerfaces between TCOs and other materials, which are crucial for many devices, are also affected by such band bending. The origin of the band bending, which seems to be general to all TCOs, depends on TCO thin film and surface processing conditions. The implication of surface band bending on the electronic properties of thin films and interfaces are discussed.

Using Aberration-corrected STEM Imaging to Explore Chemical and Structural Variations in the M1 Phase of the MoVNbTeO Oxidation Catalyst

2008 ◽  
Vol 14 (S2) ◽  
pp. 2-3 ◽  
Author(s):  
WD Pyrz ◽  
DA Blom ◽  
VV Guliants ◽  
T Vogt ◽  
DJ Buttrey
Keyword(s):  
New Mexico ◽  
Oxidation Catalyst ◽  
M1 Phase ◽  
Structural Variations ◽  
Aberration Corrected Stem ◽  
Aberration Corrected

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

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