Self-assembled fabrication of a polycrystalline boron-doped diamond surface supporting Pt (or Pd)/Au-shell/core nanoparticles on the (111) facets and Au nanoparticles on the (100) facets

Modified boron-doped diamond (BDD) surfaces supporting different, carefully selected types of metal nanoparticles on different types of crystal facets were fabricated via a self-assembly method. A hydrogen plasma-treated BDD surface was treated with UV/ozone for 10 s followed by immersion in a Au nanoparticle (AuNP) solution to fabricate a BDD surface selectively and densely supporting AuNPs on the (111) facet (AuNP(111)-BDD). The AuNP(111)-BDD sample was then immersed in H(2)PtCl(6)/ascorbic acid or H(2)PdCl(4)/sodium citrate to cover the AuNP surface with Pt or Pd (Pt/AuNP(111)-BDD or Pd/AuNP(111)-BDD). These samples were treated with UV/ozone for 40s followed by re-immersion in the AuNP solution to immobilize AuNPs on the (100) facets (Pt/AuNP(111)-AuNP(100)-BDD or Pd/AuNP(111)-AuNP(100)-BDD). The metal nanoparticles supported on the BDD surface were confirmed by cyclic voltammetry to be electrochemically active. The crystal-facet-selective support of the metal nanoparticles was also confirmed by two-dimensional elemental mapping via field emission Auger electron spectroscopy. The macro procedures used for the crystal-facet-selective immobilization of the AuNPs was reproducible, and this technique should be applicable to the creation of a new class of advanced materials in such fields as optics, electronics, sensing, and (electro)catalysis. (C) 2011 Elsevier B.V. All rights reserved.