The size effect of Pt/C nanoparticles with diameters ranging from 2 to 28 nm have been studied using X-ray diffraction.

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High-pressure behavior of carbon supported Pt nanoparticles (Pt/C) with an average particle size of 10.6 nm was investigated by in situ high-pressure synchrotron radiation x-ray diffraction up to 14 GPa at ambient temperature. Our results show that the compressibility of Pt/C nanoparticles decreases substantially as the particle size decreases. An interpretation based upon the available mechanisms of structural compliance in nanoscale vs bulk materials was proposed.

Three 40 wt % Pt/C electrocatalysts prepared using two different approaches—the polyol process and electrochemical dispersion of platinum under pulse alternating current—and a commercial Pt/C catalyst (Johnson Matthey prod.) were examined via X-ray diffraction (XRD) and transmission electron microscopy (TEM). The stability characteristics of the Pt/C catalysts were studied via long-term cycling, revealing that, for all cycling modes, the best stability was achieved for the Pt/C catalyst with the largest platinum nanoparticle sizes, which was synthesized via electrochemical dispersion of platinum under pulse alternating current. Our results show that the mass and specific electrocatalytic activities of Pt/C catalysts toward ethanol electrooxidation are determined by the value of the electrochemically active Pt surface area in the catalysts.

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The thermal expansion of carbon‐supported Pt nanoparticles with different particle size has been studied in‐situ via X‐ray diffraction at temperatures from 100 to 300 K. The thermal expansion coefficient (TEC) of investigated Pt/C nanoparticles is always superior to that of bulk Pt. When the grain size D decreases from 11 to 3 nm, the TEC nonlinearly increases by about 1.66 × 10−6 K−1 which corresponds to a variation of ∼20% from bulk Pt. The obtained experimental dependence of TEC for Pt/C nanoparticles has been interpreted using different theoretical approaches. A comparison of the considered models with the experimental data reveals the best agreement from the binding order–length–strength model with the size dependence of TEC experimentally found in carbon‐supported Pt nanoparticles.