TiO2 as a gas sensor: the novel carbon structures and noble metals as new elements for enhancing sensitivity – A Review

2021 ◽  
Author(s):  
Evelyn Alves Nunes Simonetti ◽  
Thais Cardoso de Oliveira ◽  
Ádamo Enrico do Carmo Machado ◽  
Amanda Alvarenga Coutinho Silva ◽  
Alan Silva dos Santos ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Noble Metals ◽  
The Novel ◽  
Carbon Structures

scholarly journals Graphene encapsulated low-load nitrogen-doped bimetallic magnetic Pd/Fe@N/C catalyst for the reductive amination of nitroarene under mild conditions

2021 ◽  
Author(s):  
Jianguo liu ◽  
Shanshan Lin ◽  
Longlong Ma
Keyword(s):  
Noble Metals ◽  
Reductive Amination ◽  
Bimetallic Catalyst ◽  
Environmentally Friendly ◽  
Pharmaceutical Products ◽  
The Novel ◽  
Reaction Conditions ◽  
Mild Conditions ◽  
Doped Graphene ◽  
Catalytic Reactivity

Aniline is a group of important platform molecules and is widely used in the synthesis of other high-value chemicals and pharmaceutical products. How to produce high-value anilines as the high-value chemical intermediates more efficiently and more environmentally has always been a research topic in the industry. Catalytic hydrogenation is an environmentally friendly method for preparing halogenated anilines. Traditional noble metals catalysis face cost and noble metals residue problems. To improve the purity of the product and the activity and recyclability of the catalyst, we prepared a Pd/Fe magnetic bimetallic catalyst supported on N-doped carbon materials to reduce nitrobenzene to aniline under mild conditions. The loading of Pd was very low, which was 1/10 of the content of common commercial precious metal Pd/C and Pt/C catalysts, which was only 0.5%. And the prepared bimetallic Pd/Fe@N/C catalyst showed excellent catalytic reactivity with the conversion rate of nitrobenzene > 99%, and the selectivity of aniline 99% under mild reaction conditions of 0.8 MPa H2 and 40 °C. A variety of halogenated and aliphatic nitro compounds were well tolerated and had been transformed to the corresponding target amine products with excellent selectivity. In addition, the novel N-doped graphene-encapsulated bimetallic magnetic Pd/Fe@N/C catalyst not only had magnetic physical properties, which was easy to separate, recover, and used for the recycling of the catalyst without metal leaching but also catalyzed highly selective reductive amination of aromatics was a green, economical and environmentally friendly reaction with the only H2O as a by-product.

scholarly journals Nitrogen Dioxide Gas Sensor Based on Ag-Doped Graphene: A First-Principle Study

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 227
Author(s):  
Qichao Li ◽  
Yamin Liu ◽  
Di Chen ◽  
Jianmin Miao ◽  
Xiao Zhi ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
High Performance ◽  
Density Functional ◽  
Noble Metals ◽  
Gas Sensing ◽  
Mulliken Charge ◽  
Chronic Obstructive ◽  
Doped Graphene ◽  
The Impact

High-performance tracking trace amounts of NO2 with gas sensors could be helpful in protecting human health since high levels of NO2 may increase the risk of developing acute exacerbation of chronic obstructive pulmonary disease. Among various gas sensors, Graphene-based sensors have attracted broad attention due to their sensitivity, particularly with the addition of noble metals (e.g., Ag). Nevertheless, the internal mechanism of improving the gas sensing behavior through doping Ag is still unclear. Herein, the impact of Ag doping on the sensing properties of Graphene-based sensors is systematically analyzed via first principles. Based on the density-functional theory (DFT), the adsorption behavior of specific gases (NO2, NH3, H2O, CO2, CH4, and C2H6) on Ag-doped Graphene (Ag–Gr) is calculated and compared. It is found that NO2 shows the strongest interaction and largest Mulliken charge transfer to Ag–Gr among these studied gases, which may directly result in the highest sensitivity toward NO2 for the Ag–Gr-based gas sensor.

Compositions without noble metals for thick film gas sensor heater fabrication

1996 ◽  
Vol 35 (1-3) ◽  
pp. 244-246 ◽  
Author(s):  
D Dyshel ◽  
L Yeremina ◽  
E Tel'nikov ◽  
B Rud'
Keyword(s):  
Thick Film ◽  
Gas Sensor ◽  
Noble Metals

scholarly journals Electrodeposition of electrocatalytic coatings in systems based on deep eutectic solvents: a review

2021 ◽  
pp. 4-22
Author(s):  
V.S. Protsenko ◽  
Keyword(s):  
Ionic Liquids ◽  
Noble Metals ◽  
Environmental Issues ◽  
Deep Eutectic Solvents ◽  
Controlled Synthesis ◽  
The Novel ◽  
Electrochemical Systems ◽  
High Efficient ◽  
Shape Controlled ◽  
Surface Morphologies

This review systematizes literature data on the use of electrochemical systems based on the novel generation of ionic liquids, deep eutectic solvents, for electrodeposition of coatings exhibiting improved electrocatalytic properties. It is shown that most published works on the topic are connected with deposition of coatings based on noble metals and iron family metals as well as their alloys and composites. The main advantages of the use of deep eutectic solvents for electrochemical synthesis of electrocatalysts are as follows: the possibility to prepare nanostructured coatings having compositions, structures and surface morphologies that cannot be achieved when using water electrolytes (including deposition of very electronegative metals); the size- and shape-controlled synthesis of deposited nanocrystals, which ensures improved electrocatalytic behavior; no need to use toxic and expensive additives, stabilizers, precursors, surfactants, etc.; and environmental issues (low hazard and fast biodegradability of the constituents of deep eutectic solvents). The prospects of creation of new high-efficient electrocatalytic coatings from electrolytes based on deep eutectic solvents are considered.

Material and Structural Engineering of Metal Oxides Aimed for Gas Sensor Applications

2014 ◽  
Vol 974 ◽  
pp. 76-85 ◽  
Author(s):  
Ghenadii Korotcenkov ◽  
B.K. Cho
Keyword(s):  
Metal Oxides ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Noble Metals ◽  
Structural Engineering ◽  
Gas Sensing ◽  
Sensor Applications ◽  
Sensing Characteristics

In this review different aspects of material and structural engineering of metal oxides aimed for application in conductometric gas sensors (chemiresistors) were analyzed. Results, mainly obtained for SnO2and In2O3–based sensors during surface functionalizing by noble metals have been used for showing an opportunity of material and structural engineering of metal oxides to optimize gas sensing characteristics.

Design of the novel polyaniline/polysiloxane flexible nanocomposite film and its application in gas sensor

2020 ◽  
Vol 196 ◽  
pp. 108131
Author(s):  
Tong Zhang ◽  
Qiancun Cheng ◽  
Bo Jiang ◽  
Yudong Huang
Keyword(s):  
Gas Sensor ◽  
Nanocomposite Film ◽  
The Novel

Growth of near noble metal Pd and Pt thin film silicides morphology and structure

1984 ◽  
Vol 42 ◽  
pp. 498-499
Author(s):  
E. I. Alessandrini ◽  
M. O. Aboelfotoh
Keyword(s):  
Noble Metals ◽  
Annealing Temperature ◽  
Chemical Compounds ◽  
Barrier Properties ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Stable Chemical ◽  
Metal Thickness ◽  
Amorphous Si ◽  
Si Films

Considerable interest has been generated in solid state reactions between thin films of near noble metals and silicon. These metals deposited on Si form numerous stable chemical compounds at low temperatures and have found applications as Schottky barrier contacts to silicon in VLSI devices. Since the very first phase that nucleates in contact with Si determines the barrier properties, the purpose of our study was to investigate the silicide formation of the near noble metals, Pd and Pt, at very thin thickness of the metal films on amorphous silicon.Films of Pd and Pt in the thickness range of 0.5nm to 20nm were made by room temperature evaporation on 40nm thick amorphous Si films, which were first deposited on 30nm thick amorphous Si3N4 membranes in a window configuration. The deposition rate was 0.1 to 0.5nm/sec and the pressure during deposition was 3 x 10 -7 Torr. The samples were annealed at temperatures in the range from 200° to 650°C in a furnace with helium purified by hot (950°C) Ti particles. Transmission electron microscopy and diffraction techniques were used to evaluate changes in structure and morphology of the phases formed as a function of metal thickness and annealing temperature.

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