Nanodiamonds for device applications: An investigation of the properties of boron-doped detonation nanodiamonds

© 2018 The Author(s). The inclusion of boron within nanodiamonds to create semiconducting properties would create a new class of applications in the field of nanodiamond electronics. Theoretical studies have differed in their conclusions as to whether nm-scale NDs would support a stable substitutional boron state, or whether such a state would be unstable, with boron instead aggregating or attaching to edge structures. In the present study detonation-derived NDs with purposefully added boron during the detonation process have been studied with a wide range of experimental techniques. The DNDs are of ~4 nm in size, and have been studied with CL, PL, Raman and IR spectroscopies, AFM and HR-TEM and electrically measured with impedance spectroscopy; it is apparent that the B-DNDs studied here do indeed support substitutional boron species and hence will be acting as semiconducting diamond nanoparticles. Evidence for moderate doping levels in some particles (∼10 17 B cm -3 ), is found alongside the observation that some particles are heavily doped (∼10 20 B cm -3 ) and likely to be quasi-metallic in character. The current study has therefore shown that substitutional boron doping in nm NDs is in fact possible, opening-up the path to a whole host of new applications for this interesting class of nano-particles

Electrochemical characterisation of gallium-aluminium amalgams

The electrochemical behaviour of aluminium recovered by a film of liquid gallium and gallium-aluminium amalgams in chloride and acetic acid solutions and in distilled water has been investigated using electrochemical and surface analytical techniques. The development of a very reactive interface is described. It is proposed that, besides gallium losses, the deposition of corrosion products on the electrode surface also contributes to passivation. The influence of electrode configuration and electrolyte composition on the development of the active interface as well as on its posterior deactivation is discussed.Fil: Flamini, Daniel Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Cunci, L.. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; ArgentinaFil: Saidman, Silvana Beatriz. Universidad Nacional del Sur. Departamento de Ingeniería Química. Instituto de Ingeniería Electroquímica y Corrosión; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentin

Graphene-Supported Pt, Ir, and Pt-Ir Nanoparticles as Electrocatalysts for the Oxidation of Ammonia

Graphene oxide nanosheets are used as a support to anchor metal ions and produce graphene-metal nanoparticle hybrids in a sol-gel method. The influence of experimental conditions on the features of graphene-supported Pt, Ir, and Pt-Ir alloy nanoparticles is studied using transmission electron microscopy. Good dispersion of metal nanoparticles on the graphene sheets are observed for the catalysts heat-treated under exposure to N-2 gas. The existence of metal species with zero oxidation state in the prepared catalysts is evident from the X-ray photoelectron spectroscopy. The characteristic X-ray diffraction peaks of Pt are observed for the graphene-supported Pt and Pt-Ir catalysts. Electrochemical activity of the finely dispersed catalysts toward ammonia oxidation is investigated using cyclic voltammetry. The performance increased in the order Ir < Pt a parts per thousand Pt-Ir

Platinum Electrodeposition at Unsupported Electrochemically Reduced Nanographene Oxide for Enhanced Ammonia Oxidation

[Image: see text] The electrochemical reduction of highly oxidized unsupported graphene oxide nanosheets and its platinum electrodeposition was done by the rotating disk slurry electrode technique. Avoiding the use of a solid electrode, graphene oxide was electrochemically reduced in a slurry solution with a scalable process without the use of a reducing agent. Graphene oxide nanosheets were synthesized from carbon platelet nanofibers to obtain highly hydrophilic layers of less than 250 nm in width. The graphene oxide and electrochemically reduced graphene oxide/Pt (erGOx/Pt) hybrid materials were characterized through different spectroscopy and microscopy techniques. Pt nanoparticles with 100 facets, clusters, and atoms at erGOx were identified by high resolution transmission electron microscopy (HRTEM). Cyclic voltammetry was used to characterize the electrocatalytic activity of the highly dispersed erGOx/Pt hybrid material toward the oxidation of ammonia, which showed a 5-fold current density increase when compared with commercially available Vulcan/Pt 20%. This is in agreement with having Pt (100) facets present in the HRTEM images of the erGOx/Pt material