A major challenge in obtaining long-term durability in fuel cells is to discover catalyst supports that do not corrode, or corrode much more slowly than the current carbon blacks used in today's polymer electrolyte membrane fuel cells. Such materials must be sufficiently stable at low pH (acidic conditions) and high potential, in contact with the polymer membrane and under exposure to hydrogen ...

The phase transformation of aluminum hydrates yields various forms of alumina (d, q, K) and eventually alpha-alumina. The decrease in the specific surface area of alumina upon heat treatment is due to changes in crystalline structure and hence a decrease in the porosity of the material, Although the conversion of gamma-alumina to alpha-structure takes place with a lowering in surface area and p...

in this research iron manganese oxide nanocomposites were prepared by co-precipitation, sol-gel and mechanochemical methods by using iron (iii) nitrate, iron (ii) sulfate and manganese (ii) nitrate as starting materials. these nanocomposites were prepared in the presence of various catalyst beds. the polyvinyl pyrrolidon (pvp) was used as a capping agent to control the agglomeration of the nano...

To discuss the potential role of the support for iridium catalyst, we have proceeded to prepare a series of supported catalysts with the same active phase content, but different silica content, to elucidate the changes in surface structure and the reaction process of hydrous hydrazine decomposition on catalyst. The obtained iridium catalysts contained 20 wt% of nanoparticles dispersed on spheri...

Adsorption is a fundamental process which takes place on catalyst surface before it dissociates, diffuses over the and recombines with other adsorbed species to form final product. Therefore, in theoretical chemistry understanding of local geometrical electronic properties has been topic core focus. In this short review we briefly summarise some important developments studies related adsorption...

1. Introduction Porous solids with bimodal pore structures are widely used as catalyst supports. Examples are formed bodies, such as tablets, beads, extrudates, and monoliths, of molecular sieves, silica and alumina. The formed bodies are prepared usually by compacting fine micro-or mesoporous particles [1]. As a result, macropores are formed between the agglomerated particles. Recently, cataly...

ethylene polymerization was carried out using phillips chromium catalyst based on silica supports such as silicaaerogel, sio2 (grace 643), and titanium modified sio2 (g 643), and the results were compared with othercatalysts based on sio2 (aldrich), sba-15(hex), sba-15(sp) and mcm-41. a combination of tga, dsc, xrd,nitrogen adsorption, sem, icp, ftir and other analyses were used to characterize...