نتایج جستجو برای: magnetic nanocatalysts
تعداد نتایج: 339453 فیلتر نتایج به سال:
The search for active catalysts that efficiently oxidize methane under ambient conditions remains a challenging task for both C1 utilization and atmospheric cleansing. Here, we show that when the particle size of zinc oxide is reduced down to the nanoscale, it exhibits high activity for methane oxidation under simulated sunlight illumination, and nano silver decoration further enhances the phot...
A series of ceria nanocatalysts have been prepared to study the structure dependency of the CO oxidation reaction. The ceria samples with well-defined nanostructures (nanocubes/Ce-NC and nanorods/Ce-NR) have been prepared using the hydrothermal method. Mesoporous ceria (Ce-MES) and ceria synthesized with solution combustion technique (Ce-SCS) have also been prepared for comparison. The lowest C...
Alloy Pt–M (M = Co, Ni) nanocatalysts, supported on carbon Vulcan XC-72, were synthesized using the carbonyl chemical route. A high dispersion on such substrate was revealed by transmission electron microscopy (TEM). Alloy formation on the nanometre scale length was shown by high-resolution transmission microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDX) on a nanoparticle. The met...
Exploring the reactivity of metal clusters is an important task in cluster science, while only a few previous studies involve the reactions of nano-sized ones. Here we report a kinetic measurement on reactions of Ag(n)(-) (n = 6-69) with O2 using a flow reactor running at 120 K. Their relative rates were obtained by fitting decay processes of parent ions at different O2 flow rates. Comparing th...
Molecular dynamics simulation of PEMFC cathodes based on ternary Pt70Pd15Au15 and Pt50Pd25Au25 nanocatalysts dispersed on carbon indicate systematic Au segregation from the particle bulk to the surface, leading to an Au layer coating the cluster surface and to the spontaneous formation of a Pt@Pd@Au core-shell structure. For Au content below 25at%, surface PtxPdy active sites are available for ...
Colloidal or heterogeneous nanocatalysts can improve the range and diversity of Cu(I)-catalysed click reactions and facilitate catalyst separation and reuse. Catalysis by metal nanoparticles raises the question as to whether heterogeneous catalysts may cause homogeneous catalysis through metal ion leaching, since the catalytic process could be mediated by the particle, or by metal ions released...
این پایان¬نامه شامل دو قسمت به قرار ذیل می¬باشد: 1-نانو¬ذرات fe3o4 به روش هم¬رسوبی سنتز شده و در محلولی از استیک اسید شامل کیتوسان¬، پراکنده می¬شود. در ادامه از glyoxal به عنوان عامل متصل¬کننده برای سنتز دو فیلم magnetic chitosan/glyoxal و magnetic chitosan/glyoxal/pva استفاده شده¬است. از فیلم¬های سنتز شده فوق به عنوان جاذبی کارآمد¬، قابل بازیافت و زیست¬سازگار جهت حذف فلز کروم¬(vi) از محلول¬ها...
Metal nanoparticles are used as catalysts in a variety of important chemical reactions, and can have a range of different shapes, with facets and sites that differ in catalytic reactivity. To develop better catalysts it is necessary to determine where catalysis occurs on such nanoparticles and what structures are more reactive. Surface science experiments or theory can be used to predict the re...
A novel strategy was proposed to anchor ultrafine metal nanoparticles (NPs) on thin carbon sheets for highly stable and efficient heterogeneous catalysts. In this facile approach, a dense monolayer of ultrafine AuNPs was sandwiched between a silica core and a resin shell, followed by carbonization of the shell at a high temperature and then selective removal of the silica core. The shrinkage of...
Conductive and porous polythiophene (PTh) films, which are used as host matrices for Pt and Pt/Pd nanoparticles, are synthesized electrochemically. PTh films containing nanometre-sized Pt and Pt/Pd bimetallic particles are electro synthesized on an indium tin oxide (ITO) glass plate by voltammetric cycling between –0.1 to +1V (Vs Ag/AgCl / 2M NaCl). The ensuing PTh electrode, modified with nano...
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