Electrochemical synthesis of a novel platinum nanostructure on a glassy carbon electrode, and its application to the electrooxidation of methanol

Direct Quinone Fuel Cells

The increasing interest and need to shift to sustainable energy give rise to the utilization of fuel cell technologies in various applications. The challenging task of hydrogen storage and transport led to the development of liquid hydrogen carriers (LHCs) as fuels for direct LHC fuel cells, such as methanol in direct methanol fuel cells (DMFCs). Although simpler to handle, most direct LHC fuel cells suffer from durability and price issues derived from high catalysts' loadings and byproducts of the oxidation reaction of the fuel. Herein, we report on the development of direct hydroquinone fuel cells (DQFCs) based on anthraquinone-2,7-disulfonic acid (AQDS) as an LHC. We have shown that DQFC can operate with a continuous flow of quinone as a hydrogen carrier, outperforming the incumbent state-of-the-art DMFC by a factor of 3 in peak power density while completely removing the need for any catalyst at the anode. In addition, we demonstrate that quinone can be charged with protons in the same system, making it a reversible fuel cell system. We optimized the operating conditions and discussed the governing conditions to reach the best performance.

Synthesis and Catalytic Properties of Modified Electrodes by Pulsed Electrodeposition of Pt/PANI Nanocomposite

In this study, the modification of glassy carbon electrodes by potentiostatic pulsed deposition of platinum nanoparticles and potentiostatic pulsed polymerization of polyaniline nanofibers was investigated. During the preparation of the nano-composite materials, the control of the potentiostatic pulsed deposition and potentiostatic pulsed polymerization parameters, such as pulse potential, pulse width time, duty cycle, and platinum precursor concentration allowed the optimization of the size, shape, and distribution of the deposited Pt nanoparticles. It is noteworthy that the polymerization method, cyclic voltammetry method, or potentiostatic pulsed polymerization method show an important effect in the morphology of the deposited polyaniline (PANI) film. The obtained modified electrodes, with highly uniform and well dispersed platinum nanoparticles, exhibit good electrocatalytic properties towards methanol oxidation.

Facile synthesis of 3D flower-like Pt nanostructures on polypyrrole nanowire matrix for enhanced methanol oxidation

Here we report the simple and rapid synthesis of three-dimension Pt flower-like nanostructures (PtNFs) on a polypyrrole nanowires (PPyNWs) matrix. Both PtNFs and PPyNWs are prepared by an electrochemical approach without using any seed, template or surfactant. The morphology and chemical composition of the resulting PtNF/PPyNWs hybrids are characterized by scanning electron microscopy and by X-ray photoelectron spectroscopy, respectively. Taking methanol oxidation as a model catalysis reaction, the electrocatalytic performance of the as-prepared PtNF/PPyNWs system has been evaluated by cyclic voltammetry and chronoamperometry, evidencing that these 3D materials exhibit excellent electrocatalytic activity and high level of poisoning tolerance to the carbonaceous oxidative intermediates. Such electrocatalytic performances can be ascribed to the combined effect of the flower-like structure promoting the exposure of more sites and the polymer nanowires matrix endorsing high dispersion of PtNF on a high electrochemically active surface area, besides the removal of sub-products from electrocatalytic sites.

Detection of Methanol with Fast Response by Monodispersed Indium Tungsten Oxide Ellipsoidal Nanospheres

Indium tungsten oxide ellipsoidal nanospheres were prepared with different In/W ratios by using a simple hydrothermal method without any surfactant for the first time. Sensors based on different In/W ratios samples were fabricated, and one of the samples exhibited better response to methanol compared with others. High content of defective oxygen (Ov) and proper output proportion of In to W might be the main reasons for the better gas sensing properties. The length of the nanosphere was about 150-200 nm, and the width was about 100 nm. Various techniques were applied to investigate the nanospheres. Sensing characteristics toward methanol were investigated. Significantly, the sensor exhibited ultrafast response to methanol. The response time to 400 ppm methanol was no more than 2 s and the recovery time was 9 s at 312 °C. Most importantly, the humidity almost had no effect on the response of the sensor fabricated here, which is hard to achieve in gas-sensing applications.