Sciencemadness Discussion Board

Preparation of platinized silica gel beads

Triflic Acid - 23-6-2021 at 09:58

I'm finally doing something I've wanted to do for a long time, buy a 1 gram bar of platinum. My plan is to convert some of this, maybe 0.1 grams, into a platinum on silica catalyst for some flow chemistry experiments following this prep. Generally, hydrazine sulfate is used as the reducing agent, but I don't have that rn. Could I get away with using formaldehyde solution, since I have a good amount of paraformaldehyde? Also, I'm using silica gel instead of silica wool, since it is easier to separate beads of silica then tiny wicks.. There shouldn't be too much of a difference, right?

wg48temp9 - 23-6-2021 at 10:35

Generally silica wool refers to fused quartz which is a silicon dioxide glass.

Silica gel is an amorphous and porous form of silicon dioxide that can absorb liquids which can cause it to crack and shatter. It is not as stable as quartz glass.

macckone - 23-6-2021 at 11:51

clay based raschig rings make a good support material.

for silica wool, you could use fiberglass building insulation that has been rinsed to remove any binder.
The binder is usually sodium silicate. When exposed to the air for a long time it converts to silica and sodium carbonate.

zed - 23-6-2021 at 20:20

Well first, that Platinum will need to be converted to Chloroplatinic Acid via Aqua Regia. NurdRage does a good job of that..

Then you wan't to deposit metallic Platinum on your substrate, via a reducing agent.

Got no Hydrazine? You could make some. I like to use NaBH4 as the reducing agent. Great if you have some. It doesn't take very much.

You could probably use Formaldehyde. Maybe, even Ascorbic Acid.

[Edited on 24-6-2021 by zed]

rockyit98 - 23-6-2021 at 21:24

kaowool is good since glass fiber tend to melt if you try to make nitric acid by oxidizing ammonia , also ZrO2 wool is available. i don't know for sure but carbon fiber should also work (not for nitric acid preparation I think) as support for day to day reductions . nickel powder or Mu-metal (from sanding down HDD disk magnet shield) powder can be coated with Pt at acidic conditions to make easy to separate magnetic catalyst powders for hydrogenations .

Triflic Acid - 24-6-2021 at 05:31

But I kind of liked the silica beads, given that they are separate. Will they reduce the catalytic activity?

rockyit98 - 24-6-2021 at 06:33

Quote: Originally posted by Triflic Acid  
But I kind of liked the silica beads, given that they are separate. Will they reduce the catalytic activity?

even SilicaGels have high surface area for liquids (eg water will get suck up due to Contact angle ~0°) they have poor contact with gases. my advice is not to use silicagel.

Triflic Acid - 24-6-2021 at 10:05

Ok, got it.

WGTR - 25-6-2021 at 08:45

Here is a thread/posts for your viewing enjoyment: