You can dissolve the platinum salt in a solvent then reduce it with dithionite, for example, in the presence of your catalyst support.

Lots of thanks for your answer

I think, If we add Pt salt in to autoclave with other materials, the Pt particles can disperse more uniform, but i'm worried about reacting Pt with COOH and Benzene ring (eg. MIL-101), what is your opinions?

these groups can complex with Pt on the surface

Lots of thanks for your helpful answer.

I again come to ask you some more questions:

1. what is the meaning of selectivity in catalytic paper?

2. when we let the autoclave to become cool, is the time important? in other words, Should I cool my autoclave for all runs with the same time?

3. the procedure told us wash your product 4 times a day with deionized water, if we wash it more than, is it problematic?

4. I stirring my solution after each wash, Is it important that how long do i?

There are different types of selectivity, but generally, it is the production of a specific type of products.

If you want to get uniform results you should use the same time and number of washes.