You can separately distribute silver and tantalum oxide nanoclusters by any method. Their sizes do not change in the mixture. I doubt that you can get a good size distribution by the method you propose.

First, you need to confirm the presence of AgNPs onto the surface of your support material (Ta2O5) by using the FTIR, EDX and XPS. If it is really present there you have to take TEM images carefully because the Ta2O5 particles are too big to observe in the usual range of resolutions. You may choose a single particle in the specimen for the TEM imaging and try to go slowly to the nanometre range resolution to observe the tiny AgNps. To minimize the high contrast level you may choose lower energy and relatively lower contrast region.

Xu Xuanwen One route to give the mean size (D[3,2]; the Sauter Mean Diameter) would be with a selective chemisorption akin to BET's physisorption. You may have access to such an equipment. You' d not get a distribution but maybe a clue as to the size of the clusters. In the experiment you'd need to reduce in situ the oxide layer on the silver with H2, followed by a heating stage. A gas such as O2 would then be absorbed on the silver and not (I think) to any extent on the Ta2O5 - of course, you could run a blank of silver-free Ta2O5 to quantify this. Your low silver loading of 1% will make life very difficult. What do you see with XRD? Line broadening of the silver peaks together with Williamson-Hall analysis would give the crystallite size but you may need 24 hours exposure. Back in the 70's (that's the 1970's; not my age), I made 5% Ag catalysts supported on silica. I attach one TEM micrograph from that time. Contrast is good.

What's the color of your bare Ta2O5? White?

Thank you very much Mr. Yuri Mirgorod. Ag NPs was photodeposited onto Ta2O5, so I cannot use this method. In the case of physical mixture method, I agree with your proposal. Thanks.@Yuri Mirgorod

Thanks a lot, Dr. Abdur Rahman. XPS showed Ag metals were there. I used 40 KeV, and observed the specimen under 300K to search the Ag NPs. But no Ag NPs could be found, then I increased the magnification to 800K, still no Ag Nps. going slowly to the nanometre range resolution you metioned means I should not increase the maginification so quickly? Thanks. Md. Abdur Rahman

How about your XRD result? did you compare the XRD spectrum of AgNPs doped Ta2O5 with bare Ta2O5?

Md. Abdur Rahman At 1% loading it’s very unlikely that the presence of Ag will be seen in the XRD patterns. XRF will quantify the presence of Ag but not a particle size distribution.