Pt-decorated nanoporous gold for glucose electrooxidation in neutral and alkaline solutions

Exploiting electrocatalysts with high activity for glucose oxidation is of central importance for practical applications such as glucose fuel cell. Pt-decorated nanoporous gold (NPG-Pt), created by depositing a thin layer of Pt on NPG surface, was proposed as an active electrode for glucose electrooxidation in neutral and alkaline solutions. The structure and surface properties of NPG-Pt were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and cyclic voltammetry (CV). The electrocatalytic activity toward glucose oxidation in neutral and alkaline solutions was evaluated, which was found to depend strongly on the surface structure of NPG-Pt. A direct glucose fuel cell (DGFC) was performed based on the novel membrane electrode materials. With a low precious metal load of less than 0.3 mg cm-2 Au and 60 μg cm-2 Pt in anode and commercial Pt/C in cathode, the performance of DGFC in alkaline is much better than that in neutral condition

Golden single-atomic-site platinum electrocatalysts

Bimetallic nanoparticles with tailored structures constitute a desirable model system for catalysts, as crucial factors such as geometric and electronic effects can be readily controlled by tailoring the structure and alloy bonding of the catalytic site. Here we report a facile colloidal method to prepare a series of platinum–gold (PtAu) nanoparticles with tailored surface structures and particle diameters on the order of 7 nm. Samples with low Pt content, particularly Pt 4 Au 96 , exhibited unprecedented electrocatalytic activity for the oxidation of formic acid. A high forward current density of 3.77 A mg Pt −1 was observed for Pt 4 Au 96 , a value two orders of magnitude greater than those observed for core–shell structured Pt 78 Au 22 and a commercial Pt nanocatalyst. Extensive structural characterization and theoretical density functional theory simulations of the best-performing catalysts revealed densely packed single-atom Pt surface sites surrounded by Au atoms, which suggests that their superior catalytic activity and selectivity could be attributed to the unique structural and alloy-bonding properties of these single-atomic-site catalysts

Enhanced HER and ORR behavior on photodeposited Pt nanoparticles onto oxide-carbon composite

International audienceThe photodeposition process under ultraviolet domain for platinum nanoparticles was explored. The concomitant presence of different mechanisms during the photodeposition of Pt nanoparticles onto TiO2 in the presence of water and alcohol is evidenced. According to the process, one can devise various complex mechanisms. The presence of nanoparticulated oxide anatase phase enhances the photodeposition process of metal nanoparticles via the so-called heterogeneous photocatalysis. A description and the effect of mixing of various chemicals in the reactor reveal interesting information, which allows controlling the size of nanoparticles by the photodeposition process. This study also paves the way to decrease the amount of precious metals used in material composition used as catalysts towards hydrogen evolution reaction and oxygen reduction reaction for fuel cell technologies

The Functionalizing Effect of Increasingly Graphitic Carbon Supports on Carbon-Supported and TiO2-Carbon Composite-Supported Pt Nanoparticles.

International audienceStrong interaction between Pt nanoparticles and graphitic carbon in carbon-based and oxide–carbon composite substrates is demonstrated using electrochemical CO stripping experiments. A correlation between the in-plane crystallite size of the carbon supports and the oxidation charge of CO stripping wave was made. It appears that π-system of graphitized carbon anchors platinum particles in a way that strongly modifies the electronic properties of the Pt valence band. The effects of graphitized carbon on platinum are even observable on TiO2–carbon composite-supported Pt, where a well-known strong metal–support interaction between Pt and TiO2 is already present, demonstrating the significant extent of the interaction between Pt and graphite. Finally, a preliminary proof of the role played by the interfacial Pt–Ti nanoalloy on oxide–carbon composite is given

Towards Understanding the Essential Role Played by the Platinum-Support Interaction on Electrocatalytic Activity

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Mixed-oxide Ti1−xWxO2 as support for (photo)-electrochemical processes

Abstract In this study, mixed-oxides of Ti1−xWxO2 (0 ≤ x ≤ 0.3) nanomaterials have been synthesized via a multistep sol–gel process. The effect of W doping on the anatase structure and on the electrical conductivity of the material was investigated. Photo-electrochemical action spectra and UV–vis spectroscopy were used to determine the bang-gap energy of the mixed-oxides. The electrochemical stability of these materials was also investigated before they were tested as substrate for platinum nanocatalysts for oxygen reduction reaction. The metal was deposited onto the support either via the chemical route (carbonyl method) or via UV-irradiation