Strongly coupled hybrid nanostructures for selective hydrogen detection – understanding the role of noble metals in reducing cross-sensitivity

Nanoscale ◽  
2014 ◽  
Vol 6 (9) ◽  
pp. 4758-4764 ◽  
Author(s):  
Bin Liu ◽  
Daoping Cai ◽  
Yuan Liu ◽  
Dandan Wang ◽  
Lingling Wang ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Noble Metals ◽  
Dft Calculation ◽  
Hybrid Nanostructures ◽  
Cross Sensitivity ◽  
Strongly Coupled ◽  
Thermally Activated ◽  
Calculation Results ◽  
Excellent Selectivity

New insights into the cross-sensitivity of gas sensors are provided based on experimental and DFT calculation results. Compared with traditional thermally activated sensors, the sensor based on the hybrid nanostructures exhibits high response and excellent selectivity towards hydrogen.

scholarly journals Nanocrystalline Metal Oxides for Methane Sensors: Role of Noble Metals

2009 ◽  
Vol 2009 ◽  
pp. 1-20 ◽  
Author(s):  
S. Basu ◽  
P. K. Basu
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Noble Metal ◽  
Gas Sensors ◽  
Noble Metals ◽  
Industrial Applications ◽  
Metal Catalyst ◽  
Nanocrystalline Metal ◽  
Sensing Properties

Methane is an important gas for domestic and industrial applications and its source is mainly coalmines. Since methane is extremely inflammable in the coalmine atmosphere, it is essential to develop a reliable and relatively inexpensive chemical gas sensor to detect this inflammable gas below its explosion amount in air. The metal oxides have been proved to be potential materials for the development of commercial gas sensors. The functional properties of the metal oxide-based gas sensors can be improved not only by tailoring the crystal size of metal oxides but also by incorporating the noble metal catalyst on nanocrystalline metal oxide matrix. It was observed that the surface modification of nanocrystalline metal oxide thin films by noble metal sensitizers and the use of a noble metal catalytic contact as electrode reduce the operating temperatures appreciably and improve the sensing properties. This review article concentrates on the nanocrystalline metal oxide methane sensors and the role of noble metals on the sensing properties.

scholarly journals An analytic study on the two-temperature model for electron-lattice thermal dynamic process

2017 ◽  
Vol 21 (4) ◽  
pp. 1777-1782
Author(s):  
Da-Quan Xian ◽  
Xiao-Hong Li
Keyword(s):  
Femtosecond Laser ◽  
Dynamic Process ◽  
Noble Metals ◽  
Dominant Role ◽  
Periodic Surface ◽  
Electron Phonon Coupling ◽  
Calculation Results ◽  
Morphological Differences ◽  
Two Temperature

In this paper, we study the TTM arising in electron-lattice thermal dynamic process by two methods. A new exact traveling solution and variable separation solutions are obtained. They can help us to understand morphological differences in femtosecond laser inducing periodic surface structures on noble metals. Our study examines the role of two competing ultrafast processes following femtosecond laser heating of metals thoroughly. The calculation results confirm the previous experimental work, which is the electron-phonon coupling strength plays a dominant role in the process.

Microstructure and reactivity of small metal particles: The role of Ce additives

1992 ◽  
Vol 50 (1) ◽  
pp. 318-319
Author(s):  
L.D. Schmidt ◽  
K. R. Krause ◽  
J. M. Schwartz ◽  
X. Chu
Keyword(s):  
Atmospheric Pressure ◽  
Noble Metals ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Chemical Shifts ◽  
Catalytic Converter ◽  
Structural Evolution ◽  
Single Particles ◽  
Small Metal Particles

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

Effect of grain size on the vapour phase hydration of monoclinic and triclinic modifications of tricalcium silicate; role of high temperature activation

1991 ◽  
Vol 56 (10) ◽  
pp. 1993-2008
Author(s):  
S. Hanafi ◽  
G. M. S. El-Shafei ◽  
B. Abd El-Hamid
Keyword(s):  
Particle Size ◽  
Vapour Phase ◽  
Tricalcium Silicate ◽  
Active Centers ◽  
Thermally Activated ◽  
Grain Sizes ◽  
Intermediate Size ◽  
Surface Active ◽  
Temperature Activation

The hydration of tricalcium silicate (C3S) with three grain sizes of monoclinic (M) and triclinic (T) modifications and on their thermally activated samples were investigated by exposure to water vapour at 80°C for 60 days. The products were investigated by XRD, TG and N2 adsorption. The smaller the particle size the greater was the hydration for both dried and activated samples from (M). In the activated samples a hydrate with 2θ values of 38.4°, 44.6° and 48.6° could be identified. Hydration increased with particle size for the unactivated (T) samples but after activation the intermediate size exhibited enhanced hydration. Thermal treatment at 950°C of (T) samples increased the surface active centers on the expense of those in the bulk. Changes produced in surface texture upon activation and/or hydration are discussed.

scholarly journals What Density of Magnetosheath Sodium Ions Can Provide the Observed Decrease in the Magnetic Field of the “Double Magnetopause” during the First MESSENGER Flyby?

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1168
Author(s):  
Elena Belenkaya ◽  
Ivan Pensionerov
Keyword(s):  
Magnetic Field ◽  
Analytical Approach ◽  
Field Structure ◽  
Sodium Ions ◽  
Plasma Parameters ◽  
Calculation Results ◽  
Magnetizing Current ◽  
The Magnetic Field ◽  
Density Excess

On 14 January 2008, the MESSENGER spacecraft, during its first flyby around Mercury, recorded the magnetic field structure, which was later called the “double magnetopause”. The role of sodium ions penetrating into the Hermean magnetosphere from the magnetosheath in generation of this structure has been discussed since then. The violation of the symmetry of the plasma parameters at the magnetopause is the cause of the magnetizing current generation. Here, we consider whether the change in the density of sodium ions on both sides of the Hermean magnetopause could be the cause of a wide diamagnetic current in the magnetosphere at its dawn-side boundary observed during the first MESSENGER flyby. In the present paper, we propose an analytical approach that made it possible to determine the magnetosheath Na+ density excess providing the best agreement between the calculation results and the observed magnetic field in the double magnetopause.

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