In Situ Catalysis and Surface Science Methods

2004 ◽  
pp. 15-52
Author(s):  
P. Chen ◽  
G. A. Somorjai
Keyword(s):  
Surface Science ◽  
Science Methods ◽  
In Situ Catalysis

Initial Oxidation Kinetics of Copper (110) Thin Films As Investigated By IN SITU UHV-TEM

2001 ◽  
Vol 7 (S2) ◽  
pp. 1274-1275
Author(s):  
Guang-Wen Zhou ◽  
Mridula D.Bharadwaj ◽  
Judith C.Yang
Keyword(s):  
Surface Science ◽  
Room Temperature ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Science Methods ◽  
Metal Oxidation ◽  
Initial Oxidation ◽  
Transmission Electron ◽  
Kinetics Of

In the study of metal oxidation, there is a wide gap between information provided by surface science methods and that provided by bulk oxidation studies. The former have mostly examined the adsorption of up to ∽1 monolayer (ML) of oxygen on the metal surface, where as both low and high temperature bulk oxidation studies have mainly focused on the growth of an oxide layer at the later stages of oxidation. Hence, we are visualizing the initial oxidation stages of a model metal system by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM), where the surfaces are atomically clean, in order to gain new understanding of these ambiguous stages of oxidation. We have previously studied the growth of Cu2O islands during initial oxidation of Cu(100) film. We are presently investigating the initial stages of Cu(110) oxidation, from 10−4 Torr O2 to atmospheric pressures and temperature range from room temperature to 700 °C.

In Situ Uhv-Tem Oxidation And Reduction Of Metals

1999 ◽  
Vol 5 (S2) ◽  
pp. 132-133
Author(s):  
J. C. Yang ◽  
M Yeadon ◽  
B. Kolasa ◽  
J. M. Gibson
Keyword(s):  
Surface Science ◽  
Materials Science ◽  
Film Growth ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Science Methods ◽  
Copper Oxidation ◽  
Transmission Electron ◽  
Partial Pressures

In this proceedings, we present a review of our experimental results of our investigations of the mechanisms of the initial stages of copper oxidation. We examined the initial stages of Cu(001) oxidation and reduction by in situ ultra-high vacuum (UHV) transmission, electron microscopy (TEM). We observed surface reconstruction and nucleation and growth of copper oxide islands. We have examined the oxidation processes from oxygen partial pressures of 10-5 torr to atmospheric pressures and temperatures from 25°C to 600°C, in order to gain fundamental insights into this important gas-metal reaction.Fundamental knowledge of gas-metal reactions, in particular oxidation, is important for a wide variety of materials science fields, such as dry corrosion, catalysis, as well as some thin film growth, such as ferroelectrics. However, there is a wide gap between information provided by surface science methods and that provided by bulk oxidation studies. The former have mostly examined the adsorption of up to ˜1ML of oxygen on the metal surface.

Modifications of a JEOL 2000EX TEM for insSitu surface studies

1993 ◽  
Vol 51 ◽  
pp. 640-641
Author(s):  
Michael T. Marshall ◽  
Xianghong Tong ◽  
J. Murray Gibson
Keyword(s):  
Electron Diffraction ◽  
Surface Science ◽  
Film Growth ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Transmission Electron ◽  
Fundamental Insight

We have modified a JEOL 2000EX Transmission Electron Microscope (TEM) to allow in-situ ultra-high vacuum (UHV) surface science experiments as well as transmission electron diffraction and imaging. Our goal is to support research in the areas of in-situ film growth, oxidation, and etching on semiconducter surfaces and, hence, gain fundamental insight of the structural components involved with these processes. The large volume chamber needed for such experiments limits the resolution to about 30 Å, primarily due to electron optics. Figure 1 shows the standard JEOL 2000EX TEM. The UHV chamber in figure 2 replaces the specimen area of the TEM, as shown in figure 3. The chamber is outfitted with Low Energy Electron Diffraction (LEED), Auger Electron Spectroscopy (AES), Residual Gas Analyzer (RGA), gas dosing, and evaporation sources. Reflection Electron Microscopy (REM) is also possible. This instrument is referred to as SHEBA (Surface High-energy Electron Beam Apparatus).The UHV chamber measures 800 mm in diameter and 400 mm in height. JEOL provided adapter flanges for the column.

Using a Moderate Vacuum, Hot/Cryo-Stage Equipped AFM for In-Situ Observation of α-Phase Growth In 60SN40PB Hypoeutectic Solder

1998 ◽  
Vol 4 (S2) ◽  
pp. 316-317
Author(s):  
D. N. Leonard ◽  
P.E. Russell
Keyword(s):  
Surface Science ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
In Situ Observation ◽  
Atmospheric Conditions ◽  
Tunneling Microscopy ◽  
Wide Range ◽  
Gas Environment

Atomic force microscopy (AFM) was introduced in 1984, and proved to be more versatile than scanning tunneling microscopy (STM) due to the AFM's capabilities to scan non-conductive samples under atmospheric conditions and achieve atomic resolution. Ultra high vacuum (UHV) AFM has been used in surface science applications when control of oxidation and corrosion of a sample's surface are required. Expensive equipment and time consuming sample exchanges are two drawbacks of the UHV AFM system that limit its use. Until recently, no hot/cryo-stage, moderate vacuum, controlled gas environment AFM was commonly available.We have demonstrated that phase transformations are easily observable in metal alloys and polymers with the use of a moderate vacuum AFM that has in-situ heating/cooling capabilities and quick (within minutes) sample exchange times. This talk will describe the results of experiments involving a wide range of samples designed to make use of the full capabilities of a hot/cryo-stage, controlled gas environment AFM.

LVSEM Surface Sampling, Preparation, Peak Overlap, Convergent Analysis and Covering up the FESTEM Aperture Charging Problem

2000 ◽  
Vol 6 (S2) ◽  
pp. 762-763
Author(s):  
E D Boyes
Keyword(s):  
Surface Science ◽  
Significant Contribution ◽  
Low Voltage ◽  
Science Methods ◽  
Light Elements ◽  
Surface Sampling ◽  
Peak Overlap ◽  
Reactive Sample ◽  
Primary Electrons

Surfaces The majority of the SEM secondary electron signal (SE) comes from the first few (<2nm) nanometers of the surface. The quality of the outermost few atomic layers of an exposed and reactive sample can therefore have a profound effect on image contrast. With light elements and low voltages the SE signal is dominated by scattering at the point of incidence of the primary probe, but more generally there is a significant contribution to surface SE generation by primary electrons backscattered from deeper in the sample. With the advent of very low voltage EDS, and the application of more conventional surface science methods, we learn that even without a coating the surface of a sample may be atypical of the bulk (Fig. 1). Contamination of an otherwise clean surface occurs by transport of the sample through the air, leading to oxidation, hydrocarbon accumulation, and occasionally to rather more dramatic pyrophoric effects.

Applications of Synchrotron Surface X-Ray Scattering Studies of Electrochemical Interfaces

MRS Bulletin ◽  
1999 ◽  
Vol 24 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Hoydoo You ◽  
Zoltán Nagy
Keyword(s):  
Surface Science ◽  
Region Of Interest ◽  
Atomic Layer ◽  
Living Environment ◽  
Ex Situ ◽  
Spectroscopic Techniques ◽  
Engineering Research ◽  
Significant Intensity ◽  
Electrochemical Interfaces

Aqueous-solution/solid interfaces are ubiquitous in modern manufacturing environments as well as in our living environment, and studies of such interfaces are an active area of science and engineering research. An important area is the study of liquid/solid interfaces under active electrochemical control, which has many immediate technological implications, for example, corrosion/passivation of metals and energy storage in batteries and ultracapacitors. The central phenomenon of electrochemistry is the charge transfer at the interface, and the region of interest is usually wider than a single atomic layer, ranging from a monolayer to thousands of angstroms, extending into both phases.Despite the technological and environmental importance of liquid/solid interfaces, the atomic level understanding of such interfaces had been very much hampered by the absence of nondestructive, in situ experimental techniques. The situation has changed somewhat in recent decades with the development of the largely ex situ ultrahigh vacuum (UHV) surface science, modern spectroscopic techniques, and modern surface microscopy.However in situ experiments of electrochemical interfaces are difficult, stemming from the special nature of these interfaces. These are so-called buried interfaces in which the solid electrode surface is covered by a relatively thick liquid layer. For this reason, the probe we use in the structural investigation must satisfy simultaneously two conditions: (1) the technique must be surface/interface sensitive, and (2) absorption of the probe in the liquid phase must be sufficiently small for penetration to and from the interface of interest without significant intensity loss.

scholarly journals Effect of palygorskite clay on pyrolysis of rape straw: An in situ catalysis study

2014 ◽  
Vol 417 ◽  
pp. 264-269 ◽  
Author(s):  
Haibo Liu ◽  
Tianhu Chen ◽  
Dongyin Chang ◽  
Dong Chen ◽  
Jingjing Xie ◽  
...  
Keyword(s):  
Rape Straw ◽  
Palygorskite Clay ◽  
In Situ Catalysis

A new surface science in situ transmission and reflection electron microscope

1998 ◽  
Vol 69 (2) ◽  
pp. 440-447 ◽  
Author(s):  
M. T. Marshall ◽  
M. L. McDonald ◽  
X. Tong ◽  
M. Yeadon ◽  
J. M. Gibson
Keyword(s):  
Electron Microscope ◽  
Surface Science ◽  
Transmission And Reflection
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