Basic features of Pt/C catalysts synthesised via the non-isothermal decomposition of platinum acetylacetonate

Abstract

Pt nanoparticles supported onto carbon black were synthesized via the non-isothermal decomposition of platinum acetylacetonate. The Pt loading of the as-synthesised Pt/C varied within the range of 10%–25%. Based on the refinement of X-ray patterns using the Rietveld method, it was shown that the average size of Pt nanocrystallites increased in the range of 1.4–2.0 nm with increasing Pt loading. This study presents a synthesis mechanism that describes the observed dependence. In addition, it was found that for the synthesized Pt nanoparticles, the unit cell parameter increased as the average size of the Pt nanoparticles decreased. This effect has not been previously observed for platinum nanoparticles. The reason for the observed increase in the unit cell parameter of the Pt nanoparticles was the dominance of the vacancy mechanism over the surface relaxation mechanism. Finally, this study presents a novel method for refining the X-ray patterns of Pt/C materials considering the contribution of the carbon support, enabling an accurate analysis of the treatment of the X-ray patterns of Pt/C materials with a low content of the metallic component.