See the methodology for platinum. It is similar to Pd

Article Preparation of Nanomaterials from Aqueous Solutions Imitatin...

There are various ways to let use NaBH4 as a reductant of metal precursor. One famous way is drop-wise addition to the Pd precursor solution.

Hi Ahmed M Elsheikh :

I wonder is it necessary to add surfactants such as PVP to stabilize the Pd particles and prevent them from agglomeration due to the strong reducing effect of NaBH4?

Dear Ruichen Zhang adding any "surfactant" will not prevent the particle agglomeration altogether but it will decrease its severity. Plus, there is a particular problem with PVP that its washing out (even with acetone) after synthesis is problematic.If you are starting out with this, I suggest you spend a good time of reading and reflection on the recent synthesis methods.

Hope this helps

Dear Ruichen Zhang

There is good recommendation from Ahmed M Elsheikh .

At the same time, your question must be described in detail to obtain more correct answers.

For example, if you want to obtain some material modified by Pd nanoparticles then stabilizers may be not necessary and needed size and concentration of Pd nanos can be achieved by variation of concentrations of precursor and/or reducing agent only.

With kind regards,

Liliya