THE INCORPORATION OF Pt AND Pt/Ru PARTICLES IN BORON-DOPED DIAMOND THIN-FILMS: APPLICATIONS IN ELECTROCATALYSIS

摘要

Polycrystalline, boron-doped diamond thin films were co-deposited with Pt particles on either conducting Si (100) or Pt substrates. These dimensionally stable and corrosion-resistant diamond thin-films consist of well-faceted microcrystallites with dispersed Pt particles incorporated into the surface. The metal particles are anchored into the diamond surface and range from 10 to 500 nm in diameter. The active Pt metal loading was in the range of 200 to 400 ng/cm~2 (diamond electrode geometric area); however, the real catalyst loading was estimated to be near 0.1 mg/cm~2. Importantly, the Pt particles at the surface were in electronic communication with the current collecting Si or Pt substrate through the boron-doped diamond matrix, and they were electroactive for the UPD of hydrogen and the oxidation of methanol. The dispersed Pt particles are extremely stable as no loss in the activity was observed after 1000 potential cycles between the oxygen and hydrogen evolution regimes in 0.1 M HClO_4. The films were fully characterized by scanning electron microscopy, energy dispersive x-ray analysis, atomic force microscopy, auger electron spectroscopy, Raman spectroscopy, powder x-ray diffraction, secondary ion mass spectrometry and cyclic voltammetry.