Effect of metal loading and carbon support microstructure on the dispersion of Pt/C catalysts prepared viaadsorption of chloroplatinic acid

Summary

Adsorption of<span lang=EN-US style='mso-ansi-language:EN-US'>H₂PtCl₆onto a carbon support followed by reduction of the adsorbed platinum species with H₂at 250°C leads to<span lang=EN-GB style='mso-ansi-language:EN-GB'>Pt/C catalysts, which show universal volcano-like dependence of platinum dispersion on the metal loading in the range from 0.01 to 0.55mmol (Pt)/m²(S _BET)<span lang=EN-GB style='mso-ansi-language:EN-GB'>when highly disordered carbons, namely, active carbons and carbon blacks, are used as supports. The maximal dispersion D(CO/Pt) = 0.8 is attained at<span lang=EN-US style='mso-ansi-language:EN-US'>0.18mmol (Pt)/m² (S _BET). With<span lang=EN-GB style='mso-ansi-language:EN-GB'>other factors being equal, the dispersion of platinum supported on carbons with a more regular crystal structure, especially Sibunit-type supports, proves to be the highest and independent of the metal loading.The differences between the two groups of carbon supports are explained by the differences in the state of the adsorbed platinum precursors.