Gold-based carbon-supported bimetallic catalysts for energy storage and biomedical applications

In this study, the controlled synthesis of highly reactive gold palladium bimetallic nanostructured catalyst, using polyvinyl pyrrolidone stabiliser, has been proposed. In order to determine the morphology, biocompatibility and to explore the chemistry of the produced Au0.8Pd0.2-C samples, microscopic examinations, cell viability and Raman spectroscopy technique were performed. The XRD pattern displayed a well-defined fcc crystalline structure for the Au0.8Pd0.2-C and PdC catalysts. The presence of Au in Au0.8Pd0.2-C electrodes promotes a positive effect, which was confirmed by the appearance of a broad peak in the region of H2 adsorption/desorption, suggesting that the H2 adsorption/desorption processes on the surface of catalyst were favored. Standard MTT assay performed on the Au0.8Pd0.2-C samples displayed a decreased cellular response with respect to the control group; however, cell confluency throughout the tissue culture plate suggested biocompatibility of the given sample. Moreover, when the Au0.8Pd0.2-C catalyst was chemically tested by Raman spectroscopy, the presence of Au and Pd ions was confirmed

Rechargeable Nickel-Iron Batteries for large-scale Energy storage

This manuscript reports the effect of bismuth sulphide and copper composites on the electrochemical performance of NiFe batteries. Nickel stripes were coated with an iron-rich electroactive paste and were cycled against commercial nickel electrodes. The electrodes thus produced were characterized by using galvanostatic charge/discharge, cyclic voltammetry and X-ray diffraction (XRD), atomic force microscopy (AFM) techniques. Our experimental results would indicate that the addition of iron sulphide and copper (II) sulphate significantly enhances the performance of the battery. Our in-house made iron-based electrodes exhibit good performance, and so they have a potential to store grid amounts of energy

Control of ferromagnetic properties of Ni80Fe20 thin films by voltage-induced oxidation

We demonstrate large voltage-induced changes of magnetic properties in thin films of Ni80Fe20(permalloy) when gated using an ionic liquid medium [1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIMTFSI)]. The coercivity and magnetic moment of 5 nm thick permalloy films could be reduced by 75% and 35%, respectively, by using applied voltages. These changes were partially restored by reversing the potential polarity. Electrochemical, time-course magnetometry and surface analysis measurements suggest that the voltage-induced changes are due to changes in the oxidation state at the surface of the film, causing a thinning of the permalloy layer. The control of soft magnetic properties with low voltages may be of use in tuneable devices

A new synthesis route for sustainable gold copper utilization in direct formic acid fuel cells

In the efforts to develop a more sustainable energy mix there is an urgent need to develop new materials for environmentally friendly processes. Developing low metal loading anode catalyst with high electrocatalytic activity for liquid fuel cells remains a great challenge. Polyvinylpyrrolodoneprotected AuCu-C core-shell was fabricated by a facile one-pot modified chemical reduction method. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM) analyses. XRD analysis indicates the preferential orientation of catalytically active (111) planes in AuCu-C core-shell nanoparticles. The inclusion of Cu in the AuCuC catalysts increased catalytic activities, which can be attributed to the increases lattice parameters. Comparative results show that AuCu-C catalyst exhibited much better electrocatalytic activity and stabilization compared to commercial Au nanoparticle on carbon support catalyst. The high performance of AuCu-C catalyst may be attributed to the electronic coupling or synergistic interaction between Cu core structure, and the Au shell makes it a promising for DFAFCs application