Particle size distribution of Pt–Cu bimetallic nanoparticles by fractal analysis

•Box-counting and information dimension of the Pt-Cu nanoparticles are computed.•Both box-counting and information dimension increase as Cu-content increases.•Particles size distributions from image analysis are achieved.•Particle size distributions from fractal analysis are computed.

The fractal dimensions, obtained from analyzing the transmission electron micrographs (TEM) of the Pt–Cu bimetallic nanoparticles at different weight ratios, stabilized by PVP (polyvinyl pyrrolidone), are computed. The analysis indicates a bimodal fractal behavior characterized by a small fractal dimension at low scales and a higher fractal dimension for higher self-similarity domains. This behavior is probably due to a mixed-fractal structure, rather than a lack in instrument resolution. Results also indicate that both box-counting fractal dimension and information dimension increase as Cu concentration increases. A method to compute the distribution of the number of particles versus the radius from fractal analysis is developed; results are in good agreement with the direct analysis of the images.

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