Size dependence of the lattice parameters of carbon supported platinum nanoparticles: X-ray diffraction analysis and theoretical considerations

• Published in: RSC advances Vol. 4; no. 68; pp. 35959 - 35965
• Main Authors: Leontyev, I. N., Kuriganova, A. B., Leontyev, N. G., Hennet, L., Rakhmatullin, A., Smirnova, N. V., Dmitriev, V.
• Format: Journal Article
• Language: English
• Published: 01.01.2014
• Subjects: Approximation; Carbon; Diffraction; Mathematical models; Nanoparticles; Platinum; Unit cell; X-rays
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C4RA04809A

Carbon supported Pt nanoparticles with diameters ranging from 2 to 28 nm have been studied using X-ray diffraction. The unit cell parameter of synthesized Pt/C nanoparticles is always lower than that of bulk Pt. By decreasing the average particle size D to approximately 2 nm, the unit cell parameter a nonlinearly decreases by about 0.03 Å which corresponds to a variation of 0.7% in comparison to bulk Pt, and the size effect is predominant for sizes ranging from 2 to 10 nm. The dependence a (1/ D ) is approximated well using a straight line with a slope of −0.0555 ± 0.0067 nm −1 and an intercept of −3.9230 ± 0.0017 Å. For interpreting the obtained experimental dependence of the unit cell parameter of Pt/C nanoparticles, four different theoretical approaches such as the thermal vacancy mechanism, continuous-medium model, Laplace pressure, and bond order–length–strength correlation mechanism, were used. Comparison of the calculated dependencies, based on the above models, with the experimental ones, shows that the continuous-medium model agrees best with the experimentally found unit cell parameter dependence of our carbon supported Pt nanoparticles.