The term decorated is rarely used for nanoparticles. To decorate means to cover the surface of a nanoparticle. For such a nanoparticle, the term core (what is inside) is used - shell (what is outside, what you decorate with). You need to take an XRD spectrum and use standard spectra to determine the presence of metal oxide and metal microphases.
There are two mathematical tools, High score, and Maud, that can help you determine the composition and phase of materials identified in the diffractogram. If you are interested, I believe I can help you. Let me know if you would be willing to form a partnership.
According to what Yuri Mirgorod said, in your XRD you should see two different phases (metal and metal oxide) with different crystallite sizes (broadenings). You may use rietveld refinement to get good data out of your XRD. Hope this helps
Rieltiveld methodology have been a mathematical mecanism to incrementing a statistical inference identification nanoparticles. The auxiliares softwares resolution a identification NPs was a hishscore and a GSASII pack.