Preparation of gold nanoparticles by heat treatment of sputter deposited gold on boron-doped diamond film electrode

A novel two-step method was developed to synthesize gold nanoparticles on boron-doped diamond (BDD) electrode. It consisted of sputter deposition of maximum 15 equivalent monolayers of gold, followed by a heat treatment at 400-600 °C in air. The as-sputtered gold deposits were highly dispersed (estimated particle size of 2-7 nm) but also unstable, a continuous potential cycling in the stability region of sulfuric acid leading to complete loss of the deposited gold. Subsequent heat treatment of as-sputtered deposits resulted in formation of a stable population of nanosized gold particles characterized by scanning electron microscopy and cyclic voltammetry. Gold nanoparticles with an average size of 15-35 nm could be prepared by this method on polycrystalline BDD film electrode, the particle size being dependent of the deposited amount. The invariant voltammetric response of the heat-treated gold deposits confirmed their applicability for electrocatalysis.