Dispersion measurement of platinum supported on Yttria-Stabilised Zirconia by pulse H2 chemisorption

Platinum nanoparticles were dispersed by wet impregnation on YSZ (8 mol% Y2O3) an ionically conducting support. The Pt dispersion of a series of catalysts was determined by using H2 pulse chemisorption. Temperature Programmed Reduction (TPR) experiments were performed to characterize the pre-reduction step before dispersion measurements. Finally, a fast and reliable procedure was defined for the Pt dispersion measurements consisting in a pre-reduction step in hydrogen at 500 °C before the H2 pulse chemisorption performed at −28 °C. Reproducible Pt dispersion values were obtained in good agreement with those measured by pulse CO chemisorptions and static volumetric titration. In addition, the combination of Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and TPR has evidenced the role of surface oxygen vacancies on YSZ support for both H2 and CO chemisorptions.

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► A reliable procedure was defined to measure the dispersion of Pt nanoparticles supported on Yttria-Stabilised Zirconia.
► A pre-reduction step in hydrogen at 500 °C and a H2 pulse chemisorption at −28 °C are required.
► Surface oxygen vacancies on the YSZ support are involved in H2 and CO chemisorption.