Role of Additives in Tin Oxide-Based Sensors for Alcohols

2005 ◽  
Vol 277-279 ◽  
pp. 403-409 ◽  
Author(s):  
Hae Won Cheong ◽  
Hee Sook Park Kim ◽  
Ki Hyun Yoon
Keyword(s):  
Tin Oxide ◽  
Bond Cleavage ◽  
Cleavage Product ◽  
Oxidation Products ◽  
Oxygen Species ◽  
Enhanced Sensitivity ◽  
Adsorbed Oxygen Species ◽  
Ethanol Sensing ◽  
Sensing Characteristics

Using gas chromatographic analyses, the effects of additives (PdCl2, Al2O3, or La2O3) on the alcohol sensing properties of SnO2-based sensors were investigated with respect to the distribution and the reaction steps of the products formed from the reactions of alcohols over the SnO2-based powder. Ethanol was catalytically oxidized with the SnO2-based powders. With the PdCl2-doped SnO2, the C–C bond cleavage product, methane, was produced. This seems to be related with the significant promotional role of PdCl2-doping in ethanol sensing especially at temperatures below 300 oC. For the La2O3-doped SnO2, relatively large amounts of CO and CO2 were produced, resulting in an enhanced sensitivity. On the other hand, for the Al2O3-doped SnO2, selective dehydration, which consumes smaller amounts of the adsorbed oxygen species (O- ads), seems to degrade the sensitivity. When exposed to methanol, the SnO2-based sensors showed oxidation products consisting of CO, CO2 and H2O and sensing characteristics similar to those observed with ethanol.

On the role of the surface oxygen species during A–H (A = C, N, O) bond activation: a density functional theory study

2015 ◽  
Vol 51 (13) ◽  
pp. 2621-2624 ◽  
Author(s):  
Jong Suk Yoo ◽  
Tuhin S. Khan ◽  
Frank Abild-Pedersen ◽  
Jens K. Nørskov ◽  
Felix Studt
Keyword(s):  
Density Functional ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Oxygen Species ◽  
Final States ◽  
Surface Oxygen ◽  
Density Functional Theory Study ◽  
Reaction Energy ◽  
Functional Theory

During A–H (A = C, N, O) bond cleavage on O* or OH* pre-covered (111) surfaces, the oxygen species play the role of modifying the reaction energy by changing the species involved in the initial and final states of the reaction.

Sensing Characteristics of Cubic and Rhombohedral Nanocrystalline ITO Thick Films

2001 ◽  
Vol 704 ◽  
Author(s):  
Jeung-Soo Huh ◽  
Bong-Chull Kim ◽  
Jae-Yeol Kim ◽  
Jeong-Ok Lim
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Binding Energy ◽  
Surface Structure ◽  
Crystal Structures ◽  
Aging Time ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Ethanol Sensing ◽  
Sensing Characteristics

AbstractTwo kinds of nanocrystalline Tin doped indium oxide (or indium tin oxide: denoted ITO hereafter) powders with different crystal structures – rhombohedral and cubic – were prepared using a coprecipitation method through the control of pH of a mixing solution and aging time after coprecipitation. The two powders have the same particle size of 15 nm in diameter but different morphologies (spherical for rhomboheral and rectangular for cubic). The gaseous ethanol sensing characteristics of the sensors prepared by the two ITO powders were quite different. The sensitivity of rhombohedral ITO sensor was high compared to that of the cubic ITO sensor across all temperatures. The reason for this is explained through the viewpoint of the binding energy of XPS and the surface structure relating to the crystal structure.

Electrospun tailored ZnO nanostructures – role of chloride ions

RSC Advances ◽  
2015 ◽  
Vol 5 (104) ◽  
pp. 85363-85372 ◽  
Author(s):  
Prabakaran Shankar ◽  
John Bosco Balaguru Rayappan
Keyword(s):  
Chloride Ions ◽  
Zno Nanostructures ◽  
Ethanol Sensing ◽  
Sensing Characteristics

The role of ligands in tailoring ZnO morphology and ethanol sensing characteristics of ZnO nanospheres.

The role of peroxidases, radical cations and oxygen in the degradation of lignin

1987 ◽  
Vol 321 (1561) ◽  
pp. 495-505 ◽  
Keyword(s):  
Radical Cation ◽  
Active Oxygen Species ◽  
Bond Cleavage ◽  
White Rot Fungi ◽  
Radical Cations ◽  
Veratryl Alcohol ◽  
White Rot ◽  
Oxygen Species ◽  
Lignin Model

Ligninase is an extracellular peroxidase produced by several species of white-rot fungi. It is able to oxidize methoxylated substrates to radical cation intermediates that can undergo C—H or C—C bond cleavage, thereby providing the basis for the oxidation of veratryl alcohol or degradation of lignin model compounds respectively. In some cases, the radical cation intermediate can act as an oxidant, accepting an electron from a suitable donor. It can thus function as a mediator, causing oxidation in a polymer not immediately accessible to the enzyme. This could be important in the degradation of natural lignocellulose substrates. However, the removal of a single electron by a mediator would leave a radical in the polymer. We propose that oxygen will bind to this radical to generate active oxygen species. This provides a potential mechanism for the auto-oxidation of lignin at a distance from the enzyme. A scheme is presented to account for the observation that ligninase can open the ring of veratryl alcohol.

Scavenging Reactive Lipids to Prevent Oxidative Injury

2021 ◽  
Vol 61 (1) ◽  
pp. 291-308 ◽  
Author(s):  
Linda S. May-Zhang ◽  
Annet Kirabo ◽  
Jiansheng Huang ◽  
MacRae F. Linton ◽  
Sean S. Davies ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Host Defense ◽  
Reactive Oxygen ◽  
Oxidative Injury ◽  
Oxidation Products ◽  
Oxygen Species ◽  
The Past ◽  
Lipid Oxidation Products ◽  
Induce Lipid Peroxidation

Oxidative injury due to elevated levels of reactive oxygen species is implicated in cardiovascular diseases, Alzheimer's disease, lung and liver diseases, and many cancers. Antioxidant therapies have generally been ineffective at treating these diseases, potentially due to ineffective doses but also due to interference with critical host defense and signaling processes. Therefore, alternative strategies to prevent oxidative injury are needed. Elevated levels of reactive oxygen species induce lipid peroxidation, generating reactive lipid dicarbonyls. These lipid oxidation products may be the most salient mediators of oxidative injury, as they cause cellular and organ dysfunction by adducting to proteins, lipids, and DNA. Small-molecule compounds have been developed in the past decade to selectively and effectively scavenge these reactive lipid dicarbonyls. This review outlines evidence supporting the role of lipid dicarbonyls in disease pathogenesis, as well as preclinical data supporting the efficacy of novel dicarbonyl scavengers in treating or preventing disease.

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