نتایج جستجو برای: catalyst layer
تعداد نتایج: 325011 فیلتر نتایج به سال:
Simple, cheap and green protocol for effective conversion of alcohols to corresponding carbonyl compounds in the presence of H14[NaP5W30O110] and ammonium nitrate is reported. The products were characterized by FT-IR and comparison of their physical properties with those reported in the literatures. The progress of the reaction was monitored by thin layer chromatography (TLC) technique. The ali...
In this study PtFeCo ternary alloys nanoparticles of three dimentional (3D) rhombus shapes dispersed on graphene nanosheets (PtFeCo/Gr) were successfully prepared and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer-electrolyte fuel cells. A combination of analytical techniques including powder X-ray diffraction, X-ray photoelectron spectra, inductively coupled plasma-...
We report the growth of high density silicon Oxide (SiOx) nanowires at an elevated temperature. The nanowires density is enhanced by inserting a thin layer of chromium metal in gold/Si catalyst system. The SiOx nanowires were grown with gold/chromium catalysts stack layer on the Si substrate at different temperatures ranging from 1050oC to 1150oC. Under the catalysis reaction of the gold/chromi...
A systematic study was conducted to understand the influences of catalyst combination as Ni-Co NPs on carbon nanotubes (CNTs) grown by Chemical Vapor Deposition (TCVD). The DC-sputtering system was used to prepare Co and Ni-Co thin films on silicon substrate. Ni- Co nanoparticles were used as metal catalyst for growing carbon nanotubes from acetylene (C2H2) gas in 850 ̊ C during 15 min. Carb...
The effects of various additives, such as an inorganic alkali and metal catalyst, on the hydrothermal process were examined to recover hydrogen from biomass with high efficiency and selectivity at relatively low temperatures around 400°C. At first, a cellulose sample as a model biomass was subjected to the hydrothermal process at 400°C under 25 MPa in the presence of an alkali, sodium carbonate...
CdS nanoneedles with different morphologies, structures, and growth modes have been grown on Ni-coated Si(100) surface under different experimental conditions by pulsed laser deposition method. The effects of catalyst layer, substrate temperature, and laser pulse energy on the growth of the CdS nanoneedles were studied in detail. It was confirmed that the formation of the molten catalyst sphere...
Atomically thin graphene holds exceptional promise to enable new functionalities and drastically improve performance of electronic, energy, sensing, and bio-medical devices. One of the most promising approaches to device-compatible graphene synthesis is chemical vapour deposition on a copper catalyst; this technique however is limited by very high temperatures (∼900 °C) and a lack of control as...
A new approach based on pulse electrodeposition is demonstrated to be an attractive technique to replace conventional powder type membrane electrode assembly (MEA) preparation methods. The performance of the catalyst layer is optimized by controlling the pulse deposition parameters such as the peak current density, duty cycle and the total charge density. The peak current density and the pulse ...
Oxygen transport across the cathode gas diffusion layer (GDL) in polymer electrolyte membrane (PEM) fuel cells was examined by varying the O2/N2 ratio and by varying the area of the GDL extending laterally from the gas flow channel under the bipolar plate (under the land). As the cathode is depleted of oxygen, the current density becomes limited by oxygen transport across the GDL. Oxygen deplet...
Pt-Ru supported on carbon nanotubes (CNTs) (single-walled nanotubes, double-walled nanotubes (DWNTs), and multi-walled nanotubes) catalysts are prepared by an ethylene glycol reduction method. Pt-Ru nanoparticles with a diameter of 2-3 nm and narrow particle size distributions are uniformly deposited onto the CNTs. A simple and fast filtration method followed by a hot-press film transfer is emp...
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