Use of Palladium-Modified Polyaniline Electrode as a Sensitive Element of Fire Sensor

Results of the development of a method for immobilizing nanosized palladium into an electrochemically synthesized polyaniline (PAn) electrically conductive porous matrix to create a sensitive element of an ignition sensor are presented. Two methods of manufacturing a sensitive element in the form of an electrode are investigated. The first method consists in the co-precipitation of polyaniline and palladium on a graphitized butyl rubber substrate in a mode of cycling of potential. It was shown that this method can be used to obtain a volume-porous electrode in which palladium nanoparticles are embedded in a polyaniline matrix. The second method involves the deposition of palladium on a polyaniline film formed on graphitized butyl rubber. It was shown that micron-sized island palladium conglomerates on the surface of a polyaniline film can be obtained by this method. The conclusions made are confirmed by physical research methods and the results of scanning electron microscopy. Investigations of the electrocatalytic properties of the electrode in the sensor model showed that with a change in the H2 concentration formed upon ignition, occurs change in the hydrogen concentration on the surface of metal-catalyst (Pd) and a linear change in the current of electrochemical reaction. Comparison of a composite volume-porous polyaniline electrode with embedded palladium showed its superior efficiency compared to a compact palladium electrode and an electrode in which palladium is deposited on the surface of a polyaniline film. The possibility of using an electrochemical detector based on polyaniline with immobilized palladium nanoparticles for a gas amperometric sensor of low hydrogen concentrations and a fire hazard detector is shown.

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Modeling of Microfluidic Fuel Cells With Flow-Through Porous Electrodes

ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 1 ◽

10.1115/fuelcell2010-33220 ◽

2010 ◽

Author(s):

Ali Ebrahimi Khabbazi ◽

Mina Hoorfar

Keyword(s):

Fuel Cell ◽

Solid Phase ◽

Porous Electrode ◽

Porous Electrodes ◽

Metal Catalyst ◽

Redox Species ◽

Redox Couples ◽

Flow Through ◽

Microfluidic Fuel Cell ◽

Vanadium Redox

This paper presents a modeling of a microfluidic fuel cell with flow-through porous electrodes using vanadium redox couples as the fuel and oxidant. There are advantages associated with the use of vanadium redox species in microfluidic fuel cell: 1) vanadium redox couples have the possibility of producing high open-circuit potential (up to 1.7 V at uniform PH [1]); 2) they have high solubility (up to 5.4 M) which causes more species available to the electrodes; 3) they do not require metal catalyst for electrochemical reactions so the reactions take place on the bare carbon electrodes. This characteristic of the vanadium redox couple make them a great candidate as reactants as they do not need expensive catalyst coatings on the electrodes. The fuel and the oxidant can be brought into contact with the electrode in two different ways: flowing over the electrodes or flowing through the electrodes. In the presented fuel cell design, the vanadium redox species are forced to flow through the porous electrodes. They finally come to meet each other in the middle microchannel and establish a side-by-side co-laminar flow traveling down the channel. In this paper, the effect of the inlet velocity and electrode porosity has been investigated. As it is expected, the higher velocity results in the higher power densities. For the porosity, however, there is an optimum value. In essence, there is a trade-off between the available electrode surface area and electric conductivity of the solid phase (i.e., the porous carbon electrode). The modeling shows that a porous electrode with a 67% porosity results in the highest power output.

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What catalysis needs from the electron microscopist

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105539 ◽

1988 ◽

Vol 46 ◽

pp. 694-695

Author(s):

Alexis T. Bell

Keyword(s):

Active Sites ◽

Heterogeneous Catalysts ◽

Catalyst Deactivation ◽

Surface Composition ◽

Internal Surface ◽

Active Phase ◽

Atomic Scale ◽

Metal Catalyst ◽

Internal Surface Area ◽

Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

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Elemental Distribution in Pt-Re:Al2O3 Naphtha Reforming Catalysts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600000866 ◽

1980 ◽

Vol 38 ◽

pp. 200-201

Author(s):

R. L. Freed ◽

M. J. Kelley

Keyword(s):

Bimetallic Catalyst ◽

Supported Catalysts ◽

Coke Formation ◽

Materials Characterization ◽

Metal Catalyst ◽

Elemental Distribution ◽

Exact Nature ◽

Naphtha Reforming ◽

Reforming Catalysts ◽

Commercial Introduction

The commercial introduction of Pt-Re supported catalysts to replace Pt alone on Al2O3 has brought improvements to naphtha reforming. The bimetallic catalyst can be operated continuously under conditions which lead to deactivation of the single metal catalyst by coke formation. Much disagreement still exists as to the exact nature of the bimetallic catalyst at a microscopic level and how it functions in the process so successfully. The overall purpose of this study was to develop the materials characterization tools necessary to study supported catalysts. Specifically with the Pt-Re:Al2O3 catalyst, we sought to elucidate the elemental distribution on the catalyst.

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Modeling of a sensitive element on a planar mushroom-shaped metamaterial for non-destructive testing and searching for inhomogeneities in technological media

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2020-10-54-59 ◽

2020 ◽

pp. 54-59

Author(s):

A. A. Yelizarov ◽

A. A. Skuridin ◽

E. A. Zakirova

Keyword(s):

Sensitive Element ◽

Non Destructive Testing ◽

Destructive Testing ◽

Resonant Frequency Shift ◽

Maltese Cross ◽

Informative Parameters ◽

Non Destructive ◽

Cross Type ◽

Electrodynamic Structure ◽

Electrophysical Parameters

A computer model and the results of a numerical experiment for a sensitive element on a planar mushroom-shaped metamaterial with cells of the “Maltese cross” type are presented. The proposed electrodynamic structure is shown to be applicable for nondestructive testing of geometric and electrophysical parameters of technological media, as well as searching for inhomogeneities in them. Resonant frequency shift and change of the attenuation coefficient value of the structure serve as informative parameters.

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NANOELECTROCATALYSTS BASED PALLADIUM FOR FUEL CELLS WITH DIRECT OXIDATION OF FORMIC ACID

Computational nanotechnology ◽

10.33693/2313-223x-2019-6-3-104-107 ◽

2019 ◽

Vol 6 (3) ◽

pp. 104-107

Author(s):

Marina Vladimirovna Lebedeva ◽

Alexey Petrovich Antropov ◽

Alexander Victorovich Ragutkin ◽

Nicolay Andreevich Yashtulov

Keyword(s):

Formic Acid ◽

Palladium Nanoparticles ◽

Oxidation Reaction ◽

Electrode Materials ◽

Formic Acid Oxidation ◽

Energy Sources ◽

Acid Oxidation ◽

Direct Oxidation ◽

Atomic Force ◽

Formic Acid Oxidation Reaction

In paper electrode materials with palladium nanoparticles on polymer matrix substrates for energy sources have been formed. Nanocomposites were investigated by atomic force and scanning electron microscopy. The catalytic activity of formed electrodes in the formic acid oxidation reaction was evaluated by voltammetry method.

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Preparation and Application of Carbon Nanofibers-supported Palladium Nanoparticles Catalysts Based on Electrospinning

Journal of Inorganic Materials ◽

10.15541/jim20130556 ◽

2014 ◽

Vol 29 (8) ◽

pp. 814 ◽

Cited By ~ 4

Author(s):

GUO Li-Ping ◽

BAI Jie ◽

LIANG Hai-Ou ◽

LI Chun-Ping ◽

SUN Wei-Yan ◽

...

Keyword(s):

Carbon Nanofibers ◽

Palladium Nanoparticles ◽

Supported Palladium

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Fabrication of Carbon Nanotube Triode Using Helicon Plasma Cvd with Electroplated Nico Catalyst

MRS Proceedings ◽

10.1557/proc-772-m7.4 ◽

2003 ◽

Vol 772 ◽

Author(s):

Masakazu Muroyama ◽

Kazuto Kimura ◽

Takao Yagi ◽

Ichiro Saito

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

Metal Catalyst ◽

Ni Catalyst ◽

Plasma Cvd ◽

Helicon Plasma ◽

Plasma Enhanced Cvd ◽

Turn On ◽

Aligned Carbon Nanotubes ◽

Vertically Aligned

AbstractA carbon nanotube triode using Helicon Plasma-enhanced CVD with electroplated NiCo catalyst has been successfully fabricated. Isolated NiCo based metal catalyst was deposited at the bottom of the cathode wells by electroplating methods to control the density of carbon nanotubes and also reduce the activation energy of its growth. Helicon Plasma-enhanced CVD (HPECVD) has been used to deposit nanotubes at 400°C. Vertically aligned carbon nanotubes were then grown selectively on the electroplated Ni catalyst. Field emission measurements were performed with a triode structure. At a cathode to anode gap of 1.1mm, the turn on voltage for the gate was 170V.

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