Platinum metal was dispersed on microporous, mesoporous, and nonporous support materials including the zeolites Na-Y, Ba-Y, Ferrierite, ZSM-22, ETS-10, and AIPO-11, alumina, and titania. The oxidation of carbon black loosely mixed with catalyst powder was monitored gravimetrically in a gas stream containing nitric oxide, oxygen, and water. The carbon oxidation activity of the catalysts was foun...

Fuel cell is a promising choice for clean energy because of its eco-friendly system, high energy conversion efficiency and high power density. Recently, much of the research work is focused on the system of combining metal oxides to increase the durability and surface area and to reduce the cost. In this study, among the various fabrication methods, we used the precipitation method to synthesis...

introduction: particle size and distribution can influence the properties of materials. this study analyzed and compared the particle size of root mta, calcium hydroxide (ch), and a new endodontic cement called calcium enriched material (cem). materials and methods: the particle size of each material was analyzed three times using 0.05 mg of test material with a particle size analyzer. the part...

Understanding and improving durability of fuel cell catalysts are currently one of the major goals in fuel cell research. Here, we present a comparative stability study of multi walled carbon nanotube (MWCNT) and conventional carbon supported platinum nanoparticle electrocatalysts for the oxygen reduction reaction (ORR). The aim of this study was to obtain insight into the mechanisms controllin...

In our previous work, the effect of use of a water soluble CDI/NHS system as nontoxic cross-linking agent on fabrication of gelatin nanoparticles was investigated. In this research, the effect of variation in some synthetic parameters of gelatin nanoparticles cross-linked by CDI/NHS system such as type of gelatin and formulation of cross- linking agent on their size and distribution was examine...

tehran is located in a valley at the foot of the alborz mountains in northern iran (35 degrees latitude north). urban expansion in tehran resulted from a high rate of population growth and rural-urban migration combined with a strong tradition of centralization in the capital. airborne particulate of tehran's atmosphere was fractionated in a 6-stage high-volume cascade impactor. the first ...

The identity of active species in supported gold catalysts for low temperature carbon monoxide oxidation remains an unsettled debate. With large amounts of experimental evidence supporting theories of either gold nanoparticles or sub-nm gold species being active, it was recently proposed that a size-dependent activity hierarchy should exist. Here we study the diverging catalytic behaviours afte...

The molecular dynamics method, based on an empirical potential energy surface, was used to study the effect of catalyst particle size on the growth mechanism and structure of single-walled carbon nanotubes (SWNTs). The temperature for nanotube nucleation (800-1100 K), which occurs on the surface of the cluster, is similar to that used in catalyst chemical vapor deposition experiments, and the g...

The development of active and durable catalysts with reduced platinum content is essential for fuel cell commercialization. Herein we report that the dealloyed PtCo/HSC and PtCo3/HSC nanoparticle (NP) catalysts exhibit the same levels of enhancement in oxygen reduction activity (∼4-fold) and durability over pure Pt/C NPs. Surprisingly, ex situ high-angle annular dark field scanning transmission...