An electrochemical cell with Gortex-based electrodes capable of extracting pure hydrogen from highly dilute hydrogen-methane mixtures

In this work we report a novel liquid-acid electrochemical cell containing Gortex-based gas diffusion electrodes, layered with suitable catalysts and current collectors, that is capable of sustainably extractin g pure hydrogen from methane mixtures containing as little as 5% hydrogen. The origin of its efficiency appears to derive from the solid-liquid interface between the solid Gortex electrodes and the liquid electrolyte, as well as the high proton conductivity of the electrolyte. This interface and electrolyte exhibit an efficiency for reaction that greatly exceeds that achieved by the comparable solid-solid interface and proton conductor in Proton Exchange Membrane Fuel Cell (PEMFC) technology. We report hydrogen yields and recovery by the cell from a range of methane-hydrogen mixtures. Electrochemical impedance spectroscopy has been used to characterise the cell and to illuminate the system limitations

Alkaline Fuel Cells with Novel Gortex-Based Electrodes are Powered Remarkably Efficiently by Methane Containing 5% Hydrogen

Numerous electric and gas utilities are actively pursuing power-to-gas technology, which involves using unwanted, excess renewable energy to manufacture hydrogen gas (H 2 ) that is then injected into the existing natural gas pipeline network in 5-10% by volume. This work reports an alkaline fuel cell that has the potential to harness such gas mixtures for downstream generation of electric power. The fuel cell, which employs novel Gortex-based electrodes layered with Pd/Pt catalysts, generates electricity remarkably efficiently when fuelled with methane (CH 4 ) containing 5% hydrogen. Methane constitutes the major component of natural gas. The fuel cell has been studied over a range of hydrogen to methane ratios using Tafel plots and electrochemical impedance spectroscopy. These show that, in terms of fundamental operation, there is, astonishingly, almost no difference between using pure hydrogen and 5% hydrogen in methane, as the fuel. The Gortex electrodes and alkaline electrolyte are clearly able to utilize the dilute hydrogen as a fuel with remarkable efficiency. The methane acts as an inert carrier gas and is not consumed

Antitumor Activity of Gold(I), Silver(I) and Copper(I) Complexes Containing Chiral Tertiary Phosphines

The in vitro cytotoxicities of a number of gold(I), silver(I) and copper(I) complexes containing chiral tertiary phosphine ligands have been examined against the mouse tumour cell lines P815 mastocytoma, B16 melanoma [gold(I) and silver(I) compounds] and P388 leukaemia [gold(I) complexes only] with many of the complexes having IC50 values comparable to that of the reference compounds cis-diamminedichloroplatinum(ll), cisplatin, and bis[1,2-bis(diphenylphosphino) ethane]gold(I) iodide. The chiral tertiary phosphine ligands used in this study include (R)-(2-aminophenyl)methylphenylphosphine; (R,R)-, (S,S)- and (R*,R*)-1,2-phenylenebis(methylphenylphosphine); and (R,R)-, (S,S)- and (R*,R*)-bis{(2-diphenylphosphinoethyl)phenylphosphino}ethane. The in vitro cytotoxicities of gold(I) and silver(I) complexes containing the optically active forms of the tetra(tertiary phosphine) have also been examined against the human ovarian carcinoma cell lines 41M and CH1, and the cisplatin resistant 41McisR, CH1cisR and SKOV-3 tumour models. IC50 values in the range 0.01 - 0.04 μM were determined for the most active compounds, silver(I) complexes of the tetra(tertiary phosphine). Furthermore, the chirality of the ligand appeared to have little effect on the overall activity of the complexes: similar IC50 data were obtained for complexes of a particular metal ion with each of the stereoisomeric forms of a specific ligand

Towards hydrogen energy: progress on catalysts for water splitting

This article reviews some of the recent work by fellows and associates of the Australian Research Council Centre of Excellence for Electromaterials Science (ACES) at Monash University and the University of Wollongong, as well as their collaborators, in the field of water oxidation and reduction catalysts. This work is focussed on the production of hydrogen for a hydrogen-based energy technology. Topics include: (1) the role and apparent relevance of the cubane-like structure of the Photosystem II Water Oxidation Complex (PSII-WOC) in non-biological homogeneous and heterogeneous water oxidation catalysts, (2) light-activated conducting polymer catalysts for both water oxidation and reduction, and (3) porphyrin-based light harvesters and catalysts

A method for monitoring ink homogeneity

An important concern when developing new inks containing novel, bulk, solid-state additives is to ensure consistency during the printing process. In particular, the additives should not build up on the rollers, blankets or plates during printing. In this work we describe a method for detecting such events and quantitatively monitoring, in real time, the consistency of developmental inks during commercial printing processes. The technique employs a two-component mixture of emissive nanoparticles whose ratio becomes variable in a non-homogeneous environment. Even tiny variations in the ratio can be readily and dynamically detected in real time using a fibre-optic equipped fluorescence microspectrometer. © 2010 VSP

Multiresonator-based Chipless RFID System for Low-Cost Item Tracking

A fully passive printable chipless RFID system is presented. The chipless tag uses the amplitude and phase of the spectral signature of a multiresonator circuit and provides I : 1 correspondence of data bits. The tag comprises of a microstrip spiral multiresonator and cross-polarized transmitting and receiving microstrip ultra-wideband disc loaded monopole antennas. The reader antenna is a log periodic dipole antenna with average 5.5-dBi gain. Firstly, a 6-bit chipless tag is designed to encode 000000 and 010101 IDs. Finally, a 35-bit chipless tag based on the same principle is presented. The tag has potentials for low-cost item tagging such as banknotes and secured documents

Introduction: the concept of biomimicry and bioinspiration in chemistry

The idea of looking to Nature to solve problems is undoubtedly as old as humanity itself. Observations of Nature, particularly of its biological face, have impacted the development of every facet of human society, from basic survival tactics to art, and from fashion to philosophy. Indeed, as a part of the biosphere ourselves, we cannot help but frame our conceptual understanding of ourselves and our environment in terms of biology. Bioinspiration and biomimicry, then, are ancient processes that take advantage of millions of years of evolutionary experimentation to help us address the many challenges that affect human well-being

Comparative evaluation of the structural and other features governing photo-electrochemical oxygen evolution by Ca/Mn oxides

Mn-Based oxides, particularly CaMn oxides, have recently attracted significant practical interest as a new class of catalyst due to their elemental and structural similarity to the natural oxygen evolving cluster (OEC) in photosynthetic plant cells. However, their performance as oxygen-generating anodes in photoelectrochemical cells has not been studied in detail. In this work, ultra-fine particles of amorphous MnO2, crystalline MnO2 nanorods, Ca2Mn3O8, CaMn2O4 and CaMnO3 were synthesised using a green and scalable mechanochemical method. The particles were comparatively studied as water oxidation photocatalysts in a photo-electrochemical cell at near-neutral pH. The oxides were immobilized on the anode surface using an organic, conducting polymer that facilitated electron exchange and catalytic turnover in a manner similar to redox-active tyrosine in the OEC. The differences in their photocatalytic performances were evaluated in terms of: (1) structural similarities to the natural OEC, (2) Mn oxidation state, (3) crystal structure, (4) specific surface area, (5) electron energy state, and (6) the presence/absence of Ca. The results confirmed the importance of having a local structure that is as similar as possible to the natural OEC cluster, including the presence of Ca. However, it also indicated that it is simplistic to focus only on this feature. The other factors listed above may also play a critical role in performance. Future design of biomimetic catalysts for solar fuel production needs to consider and concurrently optimize all of the relevant influences

Kinematic molecular manufacturing machines

The principles of kinematic manufacturing machines of the type widely used since the industrial revolution are reviewed. Consideration is then given to how the principles of kinematics (\u27the geometry of motion\u27) may manifest in molecular catalysts. Actions of this type involve synchronized, regular, repeated and rapid conformational flexing along geometrically optimum pathways that define a single degree of freedom. The proposition that many of the catalysts of biology, enzymes, may generally exploit a kinematic action is discussed. Thereafter, in the major portion of this work, representative abiological molecular catalysts whose actions display the characteristic features of kinematic manufacturing processes, are reviewed. In accordance with the principles of kinematics, molecular catalytic actions of this type are shown to be capable of transforming unremarkable chemical species into powerful catalysts with high activities, selectivities, and durabilities

Molecular Water Oxidation Catalysts for Photoelectrochemical Cells

Photoelectrochemical cells that efficiently split water into oxygen and hydrogen, the fuel of the future , need to combine robust water oxidation catalysts at the anode (2H(2)O -\u3e O-2 + 4H(+) + 4e(-)) with hydrogen reduction catalysts at the cathode (2H(+) + 2e(-) -\u3e H-2). Both sets of catalysts will, ideally, operate at low overpotentials and employ light-driven or light-assisted processes. In this Perspective article, we focus on significant efforts to develop solid state materials and molecular coordination complexes as catalyst for water oxidation. We briefly review the field with emphasis on the various molecular catalysts that have been developed and then examine the activity of molecular catalysts in water oxidation following their attachment to conducting electrodes. For such molecular species to be useful in a solar water-splitting device it is preferable that they are securely and durably affixed to an electrode surface. We also consider recent developments aimed at combining the action of molecular catalysts with light absorption so that light driven water oxidation may be achieved