Marc Schrinner1, Frank Polzer1, Yu Mei1, Yan Lü1, Björn Haupt1, Matthias Ballauff1, Astrid Göldel2, Markus Drechsler2, Johannes Preußner3, Uwe Glatzel3
1Physikalische Chemie I, University of Bayreuth, 95440 Bayreuth,#N#Germany
2Makromolekulare Chemie II, University of Bayreuth, 95440, Bayreuth, Germany
3Metals and Alloys, University of Bayreuth, 95440 Bayreuth, Germany
Tóm tắt
AbstractWe present a comprehensive investigation on the formation of gold nanoparticles in spherical polyelectrolyte brushes. These colloidal carrier particles consist of a solid polystyrene core onto which long cationic polyelectrolyte chains are grafted. Immersed in water these polyelectrolyte chains can be used to enrich AuCl ions. The metal ions thus confined in the polyelectrolyte layer can be reduced to gold nanoparticles of approximately 1 nm diameter. Cryogenic transmission electron microscopy shows that the Au particles are located near the surface and exhibit a narrow size distribution. Measurements by dynamic light scattering demonstrate that the polyelectrolyte chains are located near the surface of the core particles. This is explained by a crosslinking of the cationic polyelectrolyte chains by the nanoparticles that carry a negative charge. If the Au nanoparticles are removed, the spherical polyelectrolyte brushes re‐expand. High‐resolution electron microscopy together with wide‐angle X‐ray scattering measurements demonstrates that the Au nanoparticles are amorphous. We demonstrate that these Au nanoparticles exhibit catalytic activity for hydrogenation reactions that is slightly below the one of Pt and Pd nanoparticles.magnified image
