Design Strategies for Alkaline Exchange Membrane-Electrode Assemblies: Optimization for Fuel Cells and Electrolyzers.

Production of hydrocarbon-based, alkaline exchange, membrane-electrode assemblies (MEA's) for fuel cells and electrolyzers is examined via catalyst-coated membrane (CCM) and gas-diffusion electrode (GDE) fabrication routes. The inability effectively to hot-press hydrocarbon-based ion-exchange polymers (ionomers) risks performance limitations due to poor interfacial contact, especially between GDE and membrane. The addition of an ionomeric interlayer is shown greatly to improve the intimacy of contact between GDE and membrane, as determined by ex situ through-plane MEA impedance measurements, indicated by a strong decrease in the frequency of the high-frequency zero phase angle of the complex impedance, and confirmed in situ with device performance tests.

A low-loading Ru-rich anode catalyst for high-power anion exchange membrane fuel cells.

Herein, we report a Ru-rich anode catalyst for alkaline exchange membrane fuel cells. The fuel cell with such a RuPdIr/C anode and Ag-based cathode attained a peak power density close to 1 W cm-2 with only 0.2 mg cm-2 anode precious group metal loading, reaching the highest mass activity reported for this technology.

A Pd/C-CeO2 Anode Catalyst for High-Performance Platinum-Free Anion Exchange Membrane Fuel Cells.

One of the biggest obstacles to the dissemination of fuel cells is their cost, a large part of which is due to platinum (Pt) electrocatalysts. Complete removal of Pt is a difficult if not impossible task for proton exchange membrane fuel cells (PEM-FCs). The anion exchange membrane fuel cell (AEM-FC) has long been proposed as a solution as non-Pt metals may be employed.

Influence of the structure and composition of mono- and dialkyl phosphate mixtures on aluminum complex organogels.

The rheological properties and structure of organogels formed by the in situ complexation and self-assembly of aluminum isopropoxide and didodecyl phosphate surfactant in decane are investigated as mono-n-dodecyl phosphoric acid and bis(2-ethylhexyl) phosphoric acid complexing agents are added. At low loadings, the bulky bis(2-ethylhexyl) additive disrupts the physical gel structure by changing the packing around the aluminum centers, weakening the transition from viscoelastic fluid to physical network of branched cylinders, and completely suppresses gelation at high loadings. Monododecyl phosphate affects coordination at the Al center.

Osmotic pressure and phase boundary determination of multiphase systems by analytical ultracentrifugation.

We show that analytical ultracentrifugation can be applied to derive full equations of state of colloids in a single sedimentation equilibrium experiment, by determination of single-phase boundaries as well as of osmotic pressure versus concentration at fixed temperatures. A continuous dependence of the osmotic pressure, over orders of magnitude between at least approximately 10(1) and 10(4) Pa, and a wide concentration range, are determined in agreement with standard theoretical considerations. Two model experimental colloidal systems are investigated: For a well-known synthetic clay system (laponite), it is shown that two regimes-counter-ion ideal gas and interacting double layers-can easily be identified in the equation of state, whereas metastable glass- or microphase-separated gel states previously encountered in osmotic stress measurements of laponite are circumvented.

Competitive surface adsorption of solvent molecules and compactness of agglomeration in calcium hydroxide nanoparticles.

Calcium hydroxide forms unstable reactive nanoparticles that are stabilized when they are dispersed in ethylene glycol or 2-propanol. The aggregation behavior of these particles was investigated by contrast-variation small-angle neutron scattering (SANS), combined with small-angle X-ray scattering (SAXS). Nanoparticles on the order of 100 nm were found to aggregate into mass-fractal superstructures in 2-propanol, while forming more compact agglomerated aggregates with surface fractal behavior in ethylene glycol.