title: Synthesis of self-supporting gold microstructures with three-dimensional morphologies by direct replication of diatom templates.
abstract: Diatoms (unicellular algae) form porous silica walls (frustule) with intricate, hierarchically organized three-dimensional (3D) structures with micro- to nanoscale dimensions. This paper presents the fabrication of self-supporting gold microstructures with complex 3D morphologies by using electroless gold deposition onto a diatom silica substrate, followed by the substrate removal by acid dissolution. It was demonstrated that gold diatom replicas with distinct micro- to nanoscale structures can be created by a simple and scalable process based on electroless gold deposition. Excellent catalytic properties (catalytic rate constant k = 23.5 +/- 1 x 10(-2) min(-1)) of prepared gold replica catalysts were confirmed for the reduction process of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) in the presence of NaBH(4) as the reductant. This synthetic approach is general and flexible, and it is envisaged that it can be applied for the preparation of a wide range of different metals (Pt, Pd, Ag, Ni, etc.) offering more efficient catalytic, optical, or magnetic properties.
authors.affiliation: Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, 5095 SA, Australia.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.forename: Jonas
authors.initials: J
authors.lastname: Addai-Mensah
authors.forename: Dusan
authors.initials: D
authors.lastname: Losic
mesh_terms: D000627:Aminophenols / Q000138:chemical synthesis / Q000737:chemistry; D001894:Borohydrides / Q000737:chemistry; D002384:Catalysis; D017377:Diatoms / Q000737:chemistry* / Q000302:isolation & purification; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D009596:Nitrophenols / Q000737:chemistry; D010084:Oxidation-Reduction; D010316:Particle Size; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000627:Aminophenols; D001894:Borohydrides; D009596:Nitrophenols; D006046:Gold; D012822:Silicon Dioxide; C025364:sodium borohydride; C026729:4-aminophenol; C024836:4-nitrophenol