Thermal and Photon-Induced Chemistry of Adsorbed Cadmium and Tellurium Alkyls

1987 ◽  
Vol 101 ◽  
Author(s):  
C.D. Stinespring ◽  
A. Freedman
Keyword(s):  
Surface Chemistry ◽  
Photoelectron Spectroscopy ◽  
Single Photon ◽  
Experimental Studies ◽  
Ultrahigh Vacuum ◽  
Dissociative Chemisorption ◽  
X Ray ◽  
Organometallic Molecules ◽  
Uv Photons ◽  
193 Nm

ABSTRACTExperimental studies of the thermal and photon-induced surface chemistry of two organometallic molecules, dimethyl cadmium and dimethyl tellurium, are reported for a variety of surfaces including Au, GaAs, Si, and SiO£. These studies followed ultrahigh vacuum compatible procedures and used x-ray photoelectron spectroscopy to characterize the chemical state and coverage of the adspecies formed at 295 K. The results showed considerable diversity in the thermal surface chemistry of the systems investigated. Depending on the substrate, physisorption and dissociative chemisorption to yield monomethyl and metal adspecies were observed. Irradiation of the physisorbed adspecies with 193 nm UV photons led to single photon photodecomposition and limited photodesorption. Similar irradiation of the monomethyl-adspecies caused only limited photodesorption.

scholarly journals Effect of Nitric Acid Modification on Characteristics and Adsorption Properties of Lignite

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 167 ◽  
Author(s):  
Bo Huang ◽  
Guowei Liu ◽  
Penghui Wang ◽  
Xiang Zhao ◽  
Hongxiang Xu
Keyword(s):  
Nitric Acid ◽  
Surface Chemistry ◽  
Pore Structure ◽  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Metal Ion ◽  
Adsorption Properties ◽  
Acid Modification ◽  
X Ray ◽  
Adsorption Performance

The objective of this research was to explore the changes of the pore structure and surface properties of nitric-modified lignite and base the adsorption performance on physical and chemical adsorbent characteristics. To systematically evaluate pore structure and surface chemistry effects, several lignite samples were treated with different concentrations of nitric acid in order to get different pore structure and surface chemistry adsorbent levels. A common heavy metal ion contaminant in water, Pb2+, served as an adsorbate probe to demonstrate the change of modified lignite adsorption properties. The pore structure and surface properties of lignite samples before and after modification were characterized by static nitrogen adsorption, X-ray diffraction, Scanning electron microscope, Fourier transform infrared spectroscopy, zeta potential, and X-ray photoelectron spectroscopy. The experimental results showed that nitric acid modification can increase the ability of lignite to adsorb Pb2+. The adsorption amount of Pb2+ increased from 14.45 mg·g−1 to 30.68 mg·g−1. Nitric acid reacted with inorganic mineral impurities such as iron dolomite in lignite and organic components in coal, which caused an increase in pore size and a decrease in specific surface areas. A hydrophilic adsorbent surface more effectively removed Pb2+ from aqueous solution. Nitric acid treatment increased the content of polar oxygen-containing functional groups such as hydroxyl, carbonyl, and carboxyl groups on the surface of lignite. Treatment introduced nitro groups, which enhanced the negative electrical properties, the polarity of the lignite surface, and its metal ion adsorption performance, a result that can be explained by enhanced water adsorption on hydrophilic surfaces.

Surface Analysis, Microstructural Characterization and Local Corrosion Processes in Decarburized SAE 9254 Spring Steel

CORROSION ◽  
10.5006/3234 ◽  
2019 ◽  
Vol 75 (12) ◽  
pp. 1474-1486
Author(s):  
Jéssica Cristina Costa de Castro Santana ◽  
Rejane Maria Pereira da Silva ◽  
Renato Altobelli Antunes ◽  
Sydney Ferreira Santos
Keyword(s):  
Surface Chemistry ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Microstructural Characterization ◽  
Spring Steel ◽  
Laser Scanning Microscopy ◽  
Local Corrosion ◽  
Confocal Laser ◽  
X Ray ◽  
Decarburized Layer

The aim of the present work was to study the surface chemistry, microstructure, and local corrosion processes at the decarburized layer of the SAE 9254 automotive spring steel. The samples were austenitized at 850°C and 900°C, and oil quenched. The microstructure was investigated using confocal laser scanning microscopy and scanning electron microscopy. The surface chemistry was analyzed by x-ray photoelectron spectroscopy. Electrochemical impedance spectroscopy and potentiodynamic polarization were used to assess the global corrosion behavior of the decarburized samples. Scanning electrochemical microscopy was used to evaluate the influence of decarburization on the local corrosion activity. Microstructural characterization and x-ray photoelectron spectroscopy analysis indicate a dependence of the local electrochemical processes with the steel microconstituents and Si oxides in the decarburized layer.

Unexpected Pyramid Texturization of n-Type Ge (100) via Electrochemical Etching: Bridging Surface Chemistry and Morphology

2018 ◽  
Vol 282 ◽  
pp. 94-98
Author(s):  
Graniel Harne A. Abrenica ◽  
Mikhail V. Lebedev ◽  
Hy Le ◽  
Andreas Hajduk ◽  
Mathias Fingerle ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Surface Chemistry ◽  
Photoelectron Spectroscopy ◽  
Chemical Etching ◽  
Electrochemical Etching ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Etching Behavior ◽  
Effect Of Oxygen

We report on the (electro) chemical etching behavior, surface morphology and composition of n-type Ge (100) in acidic halide solutions using various analytical and spectroscopic techniques. The use of an integrated (electro) chemical etching chamber connected to X-ray photoelectron spectroscopy instrument to exclude the effect of oxygen from atmosphere is highlighted.

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