Metal storage capacity

Catalyst D presents meso/microporous structure (10) with 100% of pore volume below 150 A as a result its metal storage capacity is the lowest. Catalyst C is also considered of meso/microporous structure with 64% of pore volume below 150 A. Catalyst B presents a considerable fraction of larger pores (60% pore volume between 150-300 A). Catalyst A presents a bimodai porous structure with 33% of pore volume larger than 300 A. 

The relatively uniform profiles of nickel and vanadium are desirable, because this pattern results in maximum metals storage capacity without pore mouth plugging. The strong rinding tendency of iron can be a problem in commercial use, because it can accelerate pore mouth plugging and lead to degradation of the catalyst support... 

Because porosity and metal-storage capacity associated with it are crucial for HDM reactions, carbon supports may offer some advantages compared with y-Al203 supports. Thus, various methods suitable for tailor-making of the surface properties of carbons have been developed and successfully applied. 

High levels of sulfur not only form dangerous oxides, but they also tend to poison the catalyst in the catalytic converter. As it flows over the catalyst in the exliaust system, the sulfur decreases conversion efficiency and limits the catalyst s oxygen storage capacity. With the converter working at less than maximum efficiency, the exhaust entering the atmosphere contains increased concentrations, not only of the sulfur oxides but also, of hydrocarbons, nitrogen oxides, carbon monoxides, toxic metals, and particulate matter. 

Cobalt is invariably present in commercial MHt battery electrodes. It tends to increase hydride thermodynamic stability and inhibit corrosion. However, it is also expensive and substantially increases battery costs thus, the substitution of Co by a lower/cost metal is desirable. Willems and Buschow [40] attributed reduced corrosion in LaNi 5 vCoi (x= 1 -5) to low Vn. Sakai et al. [47 J noted that LaNi25Co25 was the most durable of a number of substituted LaNi5 iCoi alloys but it also had the lowest storage capacity. 

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