Switching of the products by changing the size and shape of catalytic nanoparticles during CVD growth of MoS2 nanotubes

CrystEngComm ◽  
2017 ◽  
Vol 19 (28) ◽  
pp. 3915-3920 ◽  
Author(s):  
Weng Mengting ◽  
Takashi Yanase ◽  
Fumiya Uehara ◽  
Sho Watanabe ◽  
Takuya Miura ◽  
...  
Keyword(s):  
Catalyst Nanoparticles ◽  
Size And Shape ◽  
Catalytic Nanoparticles ◽  
Cvd Growth ◽  
Mos2 Nanotubes

MoS2 nanotubes are grown by CVD with FeO catalyst nanoparticles, which competes with the formation of SiO2 nanowires.

scholarly journals Potentiometric C2H4-Selective Detection on Solid-State Sensors Activated with Bifunctional Catalytic Nanoparticles

Chemosensors ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 274
Author(s):  
Fidel Toldra-Reig ◽  
Jose Manuel Serra
Keyword(s):  
Solid State ◽  
Electrochemical Impedance ◽  
Impedance Analysis ◽  
Selective Detection ◽  
Catalyst Nanoparticles ◽  
Cross Sensitivity ◽  
Car Exhaust ◽  
Catalytic Nanoparticles ◽  
Oxidation Properties ◽  
Insight Into

This work presents a solid-state ionic-based device to selectively detect C2H4 in car exhaust gases. The sensor consists of 8YSZ as the electrolyte and two electrodes: Fe0.7Cr1.3O3/8YSZ and LSM/8YSZ. The main aim of this work is to optimize the catalytic behavior of the working electrode to C2H4 and reduce cross-sensitivity toward CO and H2O. Several catalyst nanoparticles were infiltrated to tailor C2H4 adsorption and electrochemical oxidation properties while diminishing adsorption and conversion of other gas components such as CO. The infiltrated metal catalysts were selected, taking into account both adsorption and redox properties. Infiltration of Ti or Al, followed by a second infiltration of Ni, enabled the selective detection of C2H4 with low cross-sensitivity toward CO and H2O in a moist gas environment. Further insight into potentiometric C2H4 sensing is achieved by electrochemical impedance analysis of the electrodes activated with bifunctional catalysts.

Vapor-Phase Catalyst Delivery Method for Growing SiC Nanowires

2013 ◽  
Vol 740-742 ◽  
pp. 209-212 ◽  
Author(s):  
Rooban Venkatesh K.G. Thirumalai ◽  
Bharat Krishnan ◽  
Albert Davydov ◽  
Joseph Neil Merrett ◽  
Yaroslav Koshka
Keyword(s):  
Vapor Phase ◽  
Gas Flow ◽  
Substrate Surface ◽  
Metal Catalyst ◽  
Catalyst Nanoparticles ◽  
Sic Nanowires ◽  
Cvd Growth ◽  
Hot Zone

A method was developed for growing SiC nanowires without depositing a metal catalyst on the targeted surfaces prior to the CVD growth. The proposed method utilizes in-situ vapor-phase catalyst delivery via sublimation of the catalyst from a metal source placed in the hot zone of the CVD reactor, followed by condensation of the catalyst-rich vapor on the bare substrate surface to form the catalyst nanoparticles. The vapor-phase catalyst delivery and the resulting nanowire density was found to be influenced by both the gas flow rate and the catalyst diffusion through the boundary layer above the catalyst source. The origin of undesirable bushes of nanowires and the role of the C/Si ratio were established.

scholarly journals Heterometallic antenna−reactor complexes for photocatalysis

2016 ◽  
Vol 113 (32) ◽  
pp. 8916-8920 ◽  
Author(s):  
Dayne F. Swearer ◽  
Hangqi Zhao ◽  
Linan Zhou ◽  
Chao Zhang ◽  
Hossein Robatjazi ◽  
...  
Keyword(s):  
Cross Section ◽  
Metallic Nanoparticles ◽  
Hydrogen Desorption ◽  
Optical Antennas ◽  
Power Dependence ◽  
Hot Carriers ◽  
Catalyst Nanoparticles ◽  
Hot Carrier ◽  
Catalytic Nanoparticles ◽  
Entire Complex

Metallic nanoparticles with strong optically resonant properties behave as nanoscale optical antennas, and have recently shown extraordinary promise as light-driven catalysts. Traditionally, however, heterogeneous catalysis has relied upon weakly light-absorbing metals such as Pd, Pt, Ru, or Rh to lower the activation energy for chemical reactions. Here we show that coupling a plasmonic nanoantenna directly to catalytic nanoparticles enables the light-induced generation of hot carriers within the catalyst nanoparticles, transforming the entire complex into an efficient light-controlled reactive catalyst. In Pd-decorated Al nanocrystals, photocatalytic hydrogen desorption closely follows the antenna-induced local absorption cross-section of the Pd islands, and a supralinear power dependence strongly suggests that hot-carrier-induced desorption occurs at the Pd island surface. When acetylene is present along with hydrogen, the selectivity for photocatalytic ethylene production relative to ethane is strongly enhanced, approaching 40:1. These observations indicate that antenna−reactor complexes may greatly expand possibilities for developing designer photocatalytic substrates.

scholarly journals Metastable morphological states of catalytic nanoparticles

Nanoscale ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 4528-4537 ◽  
Author(s):  
Pin Ann Lin ◽  
Bharath Natarajan ◽  
Michael Zwolak ◽  
Renu Sharma
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metastable States ◽  
Catalyst Nanoparticles ◽  
Environmental Transmission ◽  
Transmission Electron ◽  
Catalytic Nanoparticles ◽  
Environmental Transmission Electron Microscopy

We demonstrate, using environmental transmission electron microscopy and modeling, that catalyst nanoparticles display functional, metastable states during CNT growth.

Size- and shape-dependent catalytic performances of oxidation and reduction reactions on nanocatalysts

2016 ◽  
Vol 45 (17) ◽  
pp. 4747-4765 ◽  
Author(s):  
Shaowen Cao ◽  
Franklin (Feng) Tao ◽  
Yu Tang ◽  
Yuting Li ◽  
Jiaguo Yu
Keyword(s):  
Heterogeneous Catalysis ◽  
Chemical Processes ◽  
Catalyst Nanoparticles ◽  
Reduction Reactions ◽  
Size And Shape ◽  
Important Chemical ◽  
Catalytic Performances

Heterogeneous catalysis is one of the most important chemical processes of various industries performed on catalyst nanoparticles with different sizes or/and shapes.

Unbiased estimation of particle number and sizes using the new stereological tools: the disector, the fractionator, the selector, and the nucleator — or just point-sampled intercepts

1988 ◽  
Vol 46 ◽  
pp. 428-429
Author(s):  
H.J.G. Gundersen
Keyword(s):  
Particle Number ◽  
Small Distance ◽  
Parallel Plane ◽  
Unbiased Estimation ◽  
Severe Problem ◽  
New Era ◽  
Size And Shape ◽  
Distinct Property ◽  
Sectioned Tissue

Previously, all stereological estimation of particle number and sizes were based on models and notoriously gave biased results, were very inefficient to use and difficult to justify. For all references to old methods and a direct comparison with unbiased methods see recent reviews.The publication in 1984 of the DISECTOR, the first unbiased stereological probe for sampling and counting 3—D objects irrespective of their size and shape, signalled the new era in stereology — and give rise to a number of remarkably simple and efficient techniques based on its distinct property: It is the only known way to obtain an unbiased sample of 3-D objects (cells, organelles, etc). The principle is simple: within a 2-D unbiased frame count or sample only cells which are not hit by a parallel plane at a known, small distance h.The area of the frame and h must be known, which might sometimes in itself be a problem, albeit usually a small one. A more severe problem may arise because these constants are known at the scale of the fixed, embedded and sectioned tissue which is often shrunken considerably.

The influence of confocal microscope design on imaging performance

1993 ◽  
Vol 51 ◽  
pp. 144-145
Author(s):  
C J R Sheppard
Keyword(s):  
Image Quality ◽  
Fluorescence Imaging ◽  
Confocal Microscope ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Design Parameters ◽  
Weak Signals ◽  
Size And Shape ◽  
Imaging Performance ◽  
Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

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