Extended Data Table 1 Hydrogen chemisorption results on various supported metal catalysts

From: Rare-earth–platinum alloy nanoparticles in mesoporous zeolite for catalysis

  1. This table shows hydrogen sorption results obtained at room temperature for various Pt–REE-supported zeolite and alumina samples. Except for PtLa/deGa and PtY/deGa, all the samples listed in the table showed that a substantial portion (60–70%) of initially adsorbed hydrogen was not desorbed upon evacuation for 1 h at room temperature, thereby resulting in considerably lowered H/Pt2nd values compared to those of H/Ptini. The irreversible hydrogen sorption could be explained by the formation of a strong chemisorption bond of Pt–H. By contrast, the PtLa/mz-deGa and PtY/mz-deGa samples showed totally reversible hydrogen chemisorption behaviour, where the initial hydrogen uptakes were identical to those of the second hydrogen uptakes, which were taken after evacuation of the initially hydrogen sorption-measured samples for 1 h at room temperature. The completely reversible hydrogen sorption behaviours could indicate that the PtLa/mz-deGa and PtY/mz-deGa samples contained all the Pt nanoparticles as intermetallic compounds of Pt3La and Pt3Y. Therefore, all of the Pt portions in PtLa/mz-deGa and PtY/mz-deGa appeared to be alloyed with La or Y metal, forming Pt3La or Pt3Y intermetallic compounds. Considering this, ~70 mol% of La and ~80 mol% of Y would exist in PtLa/mz-deGa and PtY/mz-deGa, respectively, as isolated from Pt. The remaining REEs appeared as single atomic species on the zeolite supports.
  2. aMolar H/Pt value at the initial chemisorption measurement at room temperature.
  3. bMolar H/Pt value at the second chemisorption measurement after hydrogen desorption by evacuation for 1 h.
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