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Title: Modelling and validation of particle size distributions of supported nanoparticles using the pair distribution function technique

Abstract

The particle size of supported catalysts is a key characteristic for determining structure–property relationships. It is a challenge to obtain this information accurately and in situ using crystallographic methods owing to the small size of such particles (<5 nm) and the fact that they are supported. In this work, the pair distribution function (PDF) technique was used to obtain the particle size distribution of supported Pt catalysts as they grow under typical synthesis conditions. The PDF of Pt nanoparticles grown on zeolite X was isolated and refined using two models: a monodisperse spherical model (single particle size) and a lognormal size distribution. The results were compared and validated using scanning transmission electron microscopy (STEM) results. Both models describe the same trends in average particle size with temperature, but the results of the number-weighted lognormal size distributions can also accurately describe the mean size and the width of the size distributions obtained from STEM. Since the PDF yields crystallite sizes, these results suggest that the grown Pt nanoparticles are monocrystalline. As a result, this work shows that refinement of the PDF of small supported monocrystalline nanoparticles can yield accurate mean particle sizes and distributions.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [1]
  1. Univ. of Puerto Rico, Mayaguez (Puerto Rico)
  2. Columbia Univ., New York, NY (United States)
  3. Columbia Univ., New York, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1357953
Report Number(s):
BNL-113663-2017-JA
Journal ID: ISSN 1600-5767; JACGAR; R&D Project: PM032; KC0202010
Grant/Contract Number:
SC00112704
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Applied Crystallography (Online)
Additional Journal Information:
Journal Name: Journal of Applied Crystallography (Online); Journal Volume: 50; Journal Issue: 3; Journal ID: ISSN 1600-5767
Publisher:
International Union of Crystallography
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; pair distribution function; particle size distribution; supported catalyst; scanning transmission electron microscopy

Citation Formats

Gamez-Mendoza, Liliana, Terban, Maxwell W., Billinge, Simon J. L., and Martinez-Inesta, Maria. Modelling and validation of particle size distributions of supported nanoparticles using the pair distribution function technique. United States: N. p., 2017. Web. doi:10.1107/S1600576717003715.
Gamez-Mendoza, Liliana, Terban, Maxwell W., Billinge, Simon J. L., & Martinez-Inesta, Maria. Modelling and validation of particle size distributions of supported nanoparticles using the pair distribution function technique. United States. doi:10.1107/S1600576717003715.
Gamez-Mendoza, Liliana, Terban, Maxwell W., Billinge, Simon J. L., and Martinez-Inesta, Maria. Thu . "Modelling and validation of particle size distributions of supported nanoparticles using the pair distribution function technique". United States. doi:10.1107/S1600576717003715. https://www.osti.gov/servlets/purl/1357953.
@article{osti_1357953,
title = {Modelling and validation of particle size distributions of supported nanoparticles using the pair distribution function technique},
author = {Gamez-Mendoza, Liliana and Terban, Maxwell W. and Billinge, Simon J. L. and Martinez-Inesta, Maria},
abstractNote = {The particle size of supported catalysts is a key characteristic for determining structure–property relationships. It is a challenge to obtain this information accurately and in situ using crystallographic methods owing to the small size of such particles (<5 nm) and the fact that they are supported. In this work, the pair distribution function (PDF) technique was used to obtain the particle size distribution of supported Pt catalysts as they grow under typical synthesis conditions. The PDF of Pt nanoparticles grown on zeolite X was isolated and refined using two models: a monodisperse spherical model (single particle size) and a lognormal size distribution. The results were compared and validated using scanning transmission electron microscopy (STEM) results. Both models describe the same trends in average particle size with temperature, but the results of the number-weighted lognormal size distributions can also accurately describe the mean size and the width of the size distributions obtained from STEM. Since the PDF yields crystallite sizes, these results suggest that the grown Pt nanoparticles are monocrystalline. As a result, this work shows that refinement of the PDF of small supported monocrystalline nanoparticles can yield accurate mean particle sizes and distributions.},
doi = {10.1107/S1600576717003715},
journal = {Journal of Applied Crystallography (Online)},
number = 3,
volume = 50,
place = {United States},
year = {Thu Apr 13 00:00:00 EDT 2017},
month = {Thu Apr 13 00:00:00 EDT 2017}
}

Journal Article:
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  • The particle size of supported catalysts is a key characteristic for determining structure–property relationships. It is a challenge to obtain this information accurately andin situusing crystallographic methods owing to the small size of such particles (<5 nm) and the fact that they are supported. In this work, the pair distribution function (PDF) technique was used to obtain the particle size distribution of supported Pt catalysts as they grow under typical synthesis conditions. The PDF of Pt nanoparticles grown on zeolite X was isolated and refined using two models: a monodisperse spherical model (single particle size) and a lognormal size distribution.more » The results were compared and validated using scanning transmission electron microscopy (STEM) results. Both models describe the same trends in average particle size with temperature, but the results of the number-weighted lognormal size distributions can also accurately describe the mean size and the width of the size distributions obtained from STEM. Since the PDF yields crystallite sizes, these results suggest that the grown Pt nanoparticles are monocrystalline. This work shows that refinement of the PDF of small supported monocrystalline nanoparticles can yield accurate mean particle sizes and distributions.« less
  • The size-dependent structure of CdSe nanoparticles, with diameters ranging from 2 to 4 nm, has been studied using the atomic pair distribution function (PDF) method. The core structure of the measured CdSe nanoparticles can be described in terms of the wurtzite atomic structure with extensive stacking faults. The density of faults in the nanoparticles is {approx}50%. The diameter of the core region was extracted directly from the PDF data and is in good agreement with the diameter obtained from standard characterization methods, suggesting that there is little surface amorphous region. A compressive strain was measured in the Cd-Se bond lengthmore » that increases with decreasing particle size being 0.5% with respect to bulk CdSe for the 2 nm diameter particles. This study demonstrates the size-dependent quantitative structural information that can be obtained even from very small nanoparticles using the PDF approach.« less
  • Total scattering experiments are used with pair distribution function analysis to study nanoscale structure and morphology in highly disordered samples. We investigate sensitivity for the case of organic nanoparticles in dilute solution.
  • Kapton HN-type polyimide capillaries are commonly used as sample holders for transmission X-ray experiments at temperatures below 673 K because of their thermal stability, high X-ray transmittance and low cost. Using high-angle annular dark field scanning high-resolution transmission electron microscopy and thermogravimetric analysis, this work shows that using polyimide capillaries leads to the overgrowth of supported Pt nanoparticles during reduction at temperatures below the glass transition temperature (T g= 658 K) owing to an outgassing of water from the polyimide. Quartz capillaries were also studied and this overgrowth was not observed.