Study of adsorption on metals by the contact potential technique

1953 ◽  
Vol 6 (2) ◽  
pp. 109 ◽  
Author(s):  
JR Anderson ◽  
AE Alexander
Keyword(s):  
Ethyl Acetate ◽  
Hysteresis Loop ◽  
Work Function ◽  
Vapour Pressure ◽  
Physical Adsorption ◽  
Surface Preparation ◽  
Gold Surface ◽  
Contact Potential ◽  
Relative Vapour Pressure ◽  
Adsorption Of Water

The change in contact potential between metals due to physical adsorption of water vapour, isopropanol, and ethyl acetate has been studied. The plot of contact potential against relative vapour pressure showed a hysteresis loop, the behaviour varying for different methods of surface preparation. An initial irreversible potential change was always found, due to chemisorption. By studying the dependence of the contact potential on the temperature of one of the metal surfaces it has been possible to determine the change in work function of a gold surface due to physical adsorption.

Study of the reaction CaSO4.½H2O (β-hemihydrate) = CaSO4 (β-soluble anhydrite)+½H2O in the temperature range 20–100° C

1965 ◽  
Vol 34 (268) ◽  
pp. 327-345 ◽  
Author(s):  
J. D. C. McConnell
Keyword(s):  
Water Vapour ◽  
Vapour Pressure ◽  
Physical Adsorption ◽  
Linear Increase ◽  
Water Vapour Pressure ◽  
Hydration Reaction ◽  
Temperature Range ◽  
Dehydration Reactions ◽  
Adsorption Of Water ◽  
Hydration And Dehydration

SummaryA thermogravimetric vacuum microbalance has been used to study the reaction between β-soluble anhydrite and water vapour in the temperature range 20–100° C. Equilibrium water-vapour pressures for the hydration reaction in this temperature range were determined directly and have been compared with available data obtained by Kelly, Southard, and Anderson (1941) in the temperature range 80–120° C. The kinetics of the hydration and dehydration reactions have also been studied in a series of isothermal experiments with varying water-vapour pressure. These experiments indicate that in a vapour-pressure range close to the equilibrium value very low rates for both hydration and dehydration are observed. Outside this range of vapour pressures both hydration and dehydration rates increase suddenly and show an approximately linear increase with imposed water-vapour pressure.At low temperatures (25° C) the dehydration reaction has an associated activation energy of approximately 10 kcal mole−1. In the same temperature range additional, physical adsorption of water vapour by the specimen was noted.

Drei Verfahren zur Messung der Änderung der Austrittsarbeit mit Hilfe der Oberflächenionisation

1972 ◽  
Vol 27 (5) ◽  
pp. 794-803 ◽  
Author(s):  
R Müller ◽  
W Walcher ◽  
H.-W Wassmuth
Keyword(s):  
Work Function ◽  
Mass Spectrometer ◽  
Reference Electrode ◽  
Surface Ionization ◽  
Contact Potential ◽  
External Voltage ◽  
The Third ◽  
Metal Atoms ◽  
Ion Emission

AbstractThree methods for the measurement of the change ΔΦ of the work function Φ of a metal surface due to the presence of adsorbed particles (e. g. oxygen) have been developed utilizing the surface ionization of a beam of metal atoms (e. g. In, Sr) as a probe. The experiments have been performed with a mass spectrometer at ultrahigh vacuum.In the first method the temperature dependency of the ion emission current is used for the determination of the work function Φ considering certain limiting conditions. The two other methods which may be applied simultaneously with the first one, involve a direct measurement of ΔΦ by compensating the change of the contact potential by an external voltage: In the second method the contact potential between the ionizing surface and a surrounding reference electrode is used to control the ion optical conditions for the ion emission, whereas in the third method the change in the kinetic energy of the ions caused by a change of the contact potential between the ionizing surface and the entrance slit of the mass spectrometer is used as a measure of ΔΦ

Work Function Changes of Azo-Derivatives Adsorbed on a Gold Surface

2014 ◽  
Vol 118 (45) ◽  
pp. 26033-26040 ◽  
Author(s):  
Enrico Benassi ◽  
Stefano Corni
Keyword(s):  
Work Function ◽  
Gold Surface ◽  
Azo Derivatives

Adsorption of water on clean gold by measurement of work function changes

1972 ◽  
Vol 32 (3) ◽  
pp. 554-560 ◽  
Author(s):  
Robert L. Wells ◽  
Tomlinson Fort
Keyword(s):  
Work Function ◽  
Adsorption Of Water
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