(583fi) Characterization of Supported Gold Nanoparticles Via Advanced X-Ray Diffraction Analysis

The use of XRD patterns to determine the size of small nanoparticles (<3 nm) using

standard scintillating detectors can be very difficult due to large background signal intensity

and a large signal to noise ratio. While STEM imaging is an expensive and tedious process.

The use of an advanced detector i.e. D/teX Ultra has two orders of magnitude stronger

detection of X-ray intensity and a vastly reduced noise ratio. This increase in detector efficacy

along with ease of use can make XRD particle size analysis a more accurate technique. To

account for particle broadening affects the Rietveld method [1]was also used in determining

particle size supported gold nanoparticles.

Carbon supported gold nanoparticles (AuNP) were synthesized using strong electrostatic

adsorption (SEA) of bis(ethylenediamine)gold(III) chloride and were compared to a typical

synthesis method of incipient wetness impregnation (IWI). AuNPs ranging in size from 1-10

nm and weight loading from 0.3-3% were characterized by XRD using a high speed one dimension

Rigaku D/teX Ultra detector to determine average particle size from full width at

half max(FWHM)

Gold catalysts were analyzed by XRD and STEM imaging to determine particle size

and different metal loadings while using preparation method and reduction temperature to

adjust particle size. The particle size determination between XRD and STEM for higher  weight

loadings i.e. 1-3% leading to good correlation between XRD and STEM analysis.

Advanced XRD detectors such as the D/teX Ultra can be used for effective confirmation of

particle sizes of supported metal catalysts below ~ 2nm; providing a cost effective and

time efficient method for characterization