Towards scaling up the sonochemical synthesis of Pt-nanocatalysts.

Large scale production of electrocatalysts for electrochemical energy conversion devices such as proton exchange membrane fuel cells must be developed to reduce their cost. The current chemical reduction methods used for this synthesis suffer from problems with achieving similar particle properties such as particle size and catalytic activity when scaling up the volume or the precursor concentration. The continuous production of reducing agents through the sonochemical synthesis method could help maintain the reducing conditions (and also the particle properties) upon increasing the reactor volume.

Optimum scavenger concentrations for sonochemical nanoparticle synthesis.

Maintaining nanoparticle properties when scaling up a chemical synthesis is challenging due to the complex interplay between reducing agents and precursors. A sonochemical synthesis route does not require the addition of reducing agents as they are instead being continuously generated in-situ by ultrasonic cavitation throughout the reactor volume. To optimize the sonochemical synthesis of nanoparticles, understanding the role of radical scavengers is paramount.

Sonochemical Synthesis of Cu@Pt Bimetallic Nanoparticles.

Reducing the amount of noble metals in catalysts for electrochemical conversion devices is paramount if these devices are to be commercialized. Taking advantage of the high degree of particle property control displayed by the sonochemical method, we set out to synthesize Cu@Pt bimetallic nanocatalysts in an effort to improve the mass activity towards the hydrogen evolution reaction. At least 17 times higher mass activity was found for the carbon supported Cu@Pt bimetallic nanocatalyst (737 mA mg−1, E = −20 mV) compared to carbon supported Pt nanocatalysts prepared with the same ultrasound conditions (44 mA mg−1, E = −20 mV).

Synthetic Efforts to Investigate the Effect of Planarizing the Triarylamine Geometry in Dyes for Dye-Sensitized Solar Cells.

The geometry of a dye for dye-sensitized solar cells (DSSCs) has a major impact on its optical and electronic properties. The dye structure also dictates the packing properties and how well the dye insulates the metal-oxide surface from oxidants in the electrolyte. The aim of this work is to investigate the effect of planarizing the geometry of the common triarylamine donor, frequently used in dyes for DSSC.

Adamantyl Side Chains as Anti-Aggregating Moieties in Dyes for Dye-Sensitized Solar Cells.

Designing and evaluating novel dye concepts is crucial for the development of the field of dye-sensitized solar cells (DSSCs). In our recent report, the novel concept of tethering the anti-aggregation additive chenodeoxycholic acid (CDCA) to dyes for DSSC was introduced. Based on the performance improvements seen for this modification, the aim of this study is to see if a simplified anti-aggregation unit could achieve similar results.

Frequency controlled agglomeration of pt-nanoparticles in sonochemical synthesis.

Optimizing the surface area of nanoparticles is key to achieving high catalytic activities for electrochemical energy conversion devices. In this work, the frequency range (200 kHz-500 kHz) for maximum sonochemical radical formation was investigated for the sonochemical synthesis of Pt-nanoparticles to assess whether an optimum frequency exists or if the entire range provides reproducible particle properties. Through physical and electrochemical characterization, it was found that the frequency dependent mechanical effects of ultrasound resulted in smaller, more open agglomerates at lower frequencies with agglomerate sizes of (238 ± 4) nm at 210 kHz compared to (274 ± 2) nm at 326 kHz, and electrochemical surface areas of (12.

How do dissolved gases affect the sonochemical process of hydrogen production? An overview of thermodynamic and mechanistic effects - On the "hot spot theory".

Although most of researchers agree on the elementary reactions behind the sonolytic formation of molecular hydrogen (H) from water, namely the radical attack of HO and HO and the free radicals recombination, several recent papers ignore the intervention of the dissolved gas molecules in the kinetic pathways of free radicals, and hence may wrongly assess the effect of dissolved gases on the sonochemical production of hydrogen. One may fairly ask to which extent is it acceptable to ignore the role of the dissolved gas and its eventual decomposition inside the acoustic cavitation bubble? The present opinion paper discusses numerically the ways in which the nature of dissolved gas, i.e.

Optimization of Probabilistic Shaping for Nonlinear Fiber Channels with Non-Gaussian Noise.

Probabilistic constellation shaping is investigated in the context of nonlinear fiber optic communication channels. Based on a general framework, different link types are considered-1. dispersion-managed channels, 2.