Author Topic: WC - and all that  (Read 2567 times)

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jimwig

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WC - and all that
« on: September 22, 2002, 01:13:00 PM »
i have posted something to this tune previously but without the specific ref. sure would like to know.

Electronic structure and catalytic behavior of tungsten carbide-

Abstract. (abstracted) Tungsten carbide has been shown to be an effective catalyst for a number of reactions that are readily catalyzed by platinum,l but not at all by tungsten, and it was speculated that this behavior is due to changes int he electron distribution when carbon is added to tungsten.  ................. shows that near the Fermi level, the electron density of states of tungsten carbide  more nearly resembles that of platinum than that of tungsten

Science v184,p563- Bennet, et al


so i am asking - does this lead toward a viable substitute for platinum in its various forms for bees poiposes?

and one other thing - is this now a non-objective something?
aka  does abstract abstracted = non-objective  ? 

====================

the good doctors pressed a coating of powder (99.9 pure WC) onto a annealed gold substrate (anode?)
and then they did LOT OF PHYSICS AND LARGE WORDS PERTAINING TO SWIJIMWIG DOESN'T KNOW SQUAT ABOUT.

so er what'd ya think.

GC_MS

  • Guest
Depends...
« Reply #1 on: September 22, 2002, 11:39:00 PM »
SWiM thinks it depends on how Pt interacts with other substances as a catalyst. If the orbital models for Pt and WC closely resemeble eachother, there might be a chance that WC can be used as a substitute. But on the other hand, you have to take into account that both Pt and WC have different crystal structures: Pt is ccp (cubic close packed) while WC is bh (hexagonal). This is important if stereochemical aspects are important during the catalyzation.

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jimwig

  • Guest
ok
« Reply #2 on: October 08, 2002, 07:25:00 PM »
i had this vague idea that catalyst relationship with the hydrogen molecules were most important.

the shape or rather the structure of the molecule is most bearing on this hydrogen thing???

hey I AM lost.

GC_MS

  • Guest
depends
« Reply #3 on: October 08, 2002, 11:10:00 PM »
It really depends on your type of reaction. A catalyst is nothing but a general name for a substance that accelerates your reaction, or makes a reaction possible due to thermodynamical/thermokinetic aspects. Refer to any modern Organic Chemistry student book, it should be explained in the nucleo/electrophilic substitution/elimination/addition chapter.
H2SO4 can be a catalyst only because it can give H+. Other substances, like Pt and Pd, are sometimes catalyst because they have 'special electron orbitals' which makes them fit for certain reaction typs. Other substances can be a catalyst because they have a certain 3D-structure that enables them to react with compounds in a particular way. A very good example: enzymes. Considering organic chemistry, the stereochemistry and electron configuration are very important. Especially atoms with outer d or f shells can be very interesting.
This is very vague though. If you have access to an academic library with a chemistry section, check out some specialized books about catalysts. That is the best advice I can give you  ;) .

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