In this paper we report a comparative study of different procedures for the inter-matrix synthesis (IMS) of monometallic Pd-Polymer-Stabilized Metal NanoParticles (PSMNPs) in sulfonated polyetherether ketone (SPEEK) as stabilizing polymeric matrix. The IMS technique consists in consecutive metal loading-reduction cycles and can be realized by using two different versions: (i) in situ and (ii) ex situ. For in situ IMS the bare polymeric material is first deposited onto the electrode surface followed by metal loading and reduction. The last step (reduction of metal ions to PSMNPs) can be done either chemically or electrochemically. Pd-PSMNPs were synthesized by varying both the Pd concentration in the loading solution and the IMS procedure. MNPs were characterized by TEM, XRD, ICP-OES and EDS techniques and the main differences found are related to MNPs size and their spatial distribution inside the polymeric matrix. The catalytic activity of Pd-PSMNPs synthesized by different versions of the IMS technique was evaluated by using PSMNPs modified electrodes as amperometric sensors.