You can try EMDI at Akure, Ondo State or PEDI in Ilesa, Osun State

They don't have the required facilities

Hi Oluwagbenga

To determine the particles size of nanoparticles, you should go for DLS (Malvern Zetasizer Nano) that describes the hydrodynamic particle size and zeta potential also to show particles stability. Moreover, do TEM of your samples that describes the internal structure and morphology of particles with their sizes. But keep in mind it is not necessary that the results of DLS and TEM should be same.

To determine the particles size of nanoparticles, you should go for XRD by using Shearer's formula.

If I recall correctly, and it's been a while, if you have dcosθ=Kλ/w, w has units of 2-theta, and if you have

dcosθ=Kλ/2w,

then w has units of theta.

Reference https://www.physicsforums.com/threads/scherrer-equation-question-xrd.223968/

To determine nanoparticle size by different X-Ray and microscopic techniques like XRD, AFM, SEM and TEM.

XRD is better to know crystalline nature of nanoparticles and calculate average size of the nanoparticles instead of a single particle. AFM is better tool to measure actual size of individual particle as well average size of the particles and we get 3D nature of the particles also. In SEM analysis we get higher magnification studies better than AFM. In TEM analysis also we get higher magnification than SEM and we know the SAED pattern of nanoparticles as well as 'd' spacing in the particles which are all correlated to crystalline structures of XRD once again proved by this TEM technique.

See the attached articles for your reference 

Hello Oluwagbenga,

Further to the other good suggestions, Izon do some great devices for determining nanoparticle properties. I have attached a link.

Kind regards,

Jules

http://www.izon.com/products/qnano/

Scherrer method results obtained from XRD data is just to get theorical particle size, witch you must confirm it by using TEM or SEM images 

At Omar Ben, can SEM image reveal the size of nano particles?

Hi Mr Oluwagbenga Fatile,

the response Yes it is : You can use "Image J" it a free sofware to mesure particle sizes from SEM  and TEM images

Dear Mr Fatile, it is possible to find the size using a software called "ZEN" manually. Please download this software. It works. All the best. 

There are several ways to determine nano particle size. The following are the method that I know. Hope this would give you some ideas to go on the work.

1. Atominc force Microscopy (AFM); a form of scaning probe microscopy. required less time and cost that TEM and SEM. Sensitivity is 1 nm - 8 um. Sample must adhere to a substrate and be rigid and disperse on the substrate.

2. Photon corelation spectroscopy (PCS); Used the concept of dynamics light scattering. Sensitivity is 1 nm - 10 um. Sample must be a very dilute suspension.

3. Differential Mobility analyzer; analyze particle size distribution. Sensitivity is down to 3 nm. Sample must be in aerosol.

4. Nano particle tracking analysis (NTA); analyze particle size and particle size distribution. Can be used with No. 2 PCS. Sensitivity is 10 nm - 1000 nm. Sample must be suspension and a wide range of solvent can be used.

Hope this helps.

Dear Dr. Fatile:

There are conventional methods as X-ray diffraction XRD but precision in not good if particle size values reach to unit. In this sense, some interesting measurements have been developed at nanoparticle system via Small angle X-ray diffraction, also consider download pdf copy at this technique in the below link:

http://www.hindawi.com/journals/jnp/2013/640436/

Typically, manipulate nanoparticle is powder nature is not good, then if nanoparticle are disperse in a liquid polar or apolar measurements of size can be feasible in liquid medium if zeta potential can be determined. Consider, read someone at this concept from RG link below:

https://www.researchgate.net/post/What_is_zeta_potential_and_its_theory_in_nanoparticle_physics

From above concepts exposed above, there are set of equipment dedicated to the physical properties characterization of submicrometric and/or nanometric particles.

Please consider see data feasible of access from links below, see there are other:

http://www.dispersion.com/

http://www.dispersion.com/zeta-potential-short-tutorial

http://www.dispersion.com/model-dt-1202

http://www.colloidal-dynamics.com/products.php

http://www.colloidal-dynamics.com/techniques.php

http://www.brookhaveninstruments.com/nanobrook-90plus-zeta-particle-size-analyzer

https://www.particle-metrix.de/en/products/zetaview-nanoparticle-tracking.html#c101

http://www.horiba.com/scientific/products/particle-characterization/particle-size-analysis/details/sz-100-7245/

 Best regards

Marcos Nobre

Dear Dr. Fatile:

There are conventional methods as X-ray diffraction XRD but precision in not good if particle size values reach to unit. In this sense, some interesting measurements have been developed at nanoparticle system via Small angle X-ray diffraction, also consider download pdf copy at this technique in the below link:

http://www.tribology.fink.rs/journals/2015/2015-2/14.pdf

You can use ImageJ software to determine the average size of nanoparticles in SEM, TEM image.

Link to download ImageJ: https://imagej.nih.gov/ij/download.html

Follow this video: http://bit.ly/2sbb5B5