자연주의적 탐구조사(Naturalistic Inquiry)

Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

The Chemistry and Applications of Metal-Organic Frameworks

New materials hold the key to fundamental advances in energy conversion and storage, both of which are vital in order to meet the challenge of global warming and the finite nature of fossil fuels. Nanomaterials in particular offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. This review describes some recent developments in the discovery of nanoelectrolytes and nanoelectrodes for lithium batteries, fuel cells and supercapacitors. The advantages and disadvantages of the nanoscale in materials design for such devices are highlighted.

https://img62.chem17.com/1/20140715/635410323829886334962.pdf

Nanostructured materials for advanced energy conversion and storage devices

Li-ion batteries have transformed portable electronics and will play a key role in the electrification of transport. However, the highest energy storage possible for Li-ion batteries is insufficient for the long-term needs of society, for example, extended-range electric vehicles. To go beyond the horizon of Li-ion batteries is a formidable challenge; there are few options. Here we consider two: Li-air (O(2)) and Li-S. The energy that can be stored in Li-air (based on aqueous or non-aqueous electrolytes) and Li-S cells is compared with Li-ion; the operation of the cells is discussed, as are the significant hurdles that will have to be overcome if such batteries are to succeed. Fundamental scientific advances in understanding the reactions occurring in the cells as well as new materials are key to overcoming these obstacles. The potential benefits of Li-air and Li-S justify the continued research effort that will be needed.

Li-O2 and Li-S batteries with high energy storage.

Fuel cells convert chemical energy directly into electrical energy with high efficiency and low emission of pollutants. However, before fuel-cell technology can gain a significant share of the electrical power market, important issues have to be addressed. These issues include optimal choice of fuel, and the development of alternative materials in the fuel-cell stack. Present fuel-cell prototypes often use materials selected more than 25 years ago. Commercialization aspects, including cost and durability, have revealed inadequacies in some of these materials. Here we summarize recent progress in the search and development of innovative alternative materials.

Materials for fuel-cell technologies

Proton Conductivity and Operational Features Of PBI-Based Membranes


 It has been demonstrated that it is possible to produce methanol in one step in reasonable amounts by electrolysis of CO2 and H2O gasses dissolved under 28 bar and at 240°C in contact with an electrolyte consisting of solid CsH2PO4 with additions of polyvinyl butyral (PVB) acting as a binder. The cathode was designed as a sandwich with a layer of a copper methanol catalyst and a porous platinum electrode. The anode consisted of porous ruthenium metal covered by a layer of RuO2. The system was operated with current densities of up to ca. 100 mA/cm2 with a voltage of less than 2 Volts producing methanol with a Faradaic efficiency of up to ca. 7 %. There seems to be nothing against recirculating the rest of reactant gases to improve the conversion. The question is of course whether the present approach can compete with a more traditional conversion starting with electrochemical produced hydrogen.

/pdf/methanol-synthesis-from-co2-and-h2o-using-a-solid-phosphate-3kdf4cgg.pdf

Methanol Synthesis from CO2 and H2O Using a Solid Phosphate Electrolyzer at 240°C and 28 Bar

Potentiometric study of the systems kcl-alcl3 and kcl-alcl3-zncl2 at 300 grad, performed with a chlorine-chloride electrode

Lower oxidation states of selenium. 2. potentiometric study involving tetravalent selenium, tetraselenium(2+), octaselenium(2+), and three other low oxidation states of selenium in a chloroaluminate melt

The goal of the present study was to obtain a comprehensive knowledge about synthesis conditions, structure, thermal behavior and conductivity properties of neodymiumorthophosphates in order to analyzeof use this material in intermediate temperature fuel cells due to their thermal and chemical stability properties.The impedance spectroscopy technique (IS) was used to measure the conductivity. The conductivity of compositesobserved to be lower than conductivity of pure CsH2PO4 but had improvedsufficiently conductivity of pure NdPO4•nH2O.

Niels J. Bjerrum

Papers

Proton Conductivity and Operational Features Of PBI-Based Membranes

Methanol Synthesis from CO2 and H2O Using a Solid Phosphate Electrolyzer at 240°C and 28 Bar

Potentiometric study of the systems kcl-alcl3 and kcl-alcl3-zncl2 at 300 grad, performed with a chlorine-chloride electrode

Lower oxidation states of selenium. 2. potentiometric study involving tetravalent selenium, tetraselenium(2+), octaselenium(2+), and three other low oxidation states of selenium in a chloroaluminate melt

Conductivity of Composite Material Based on System NdPo4•nH2O- CsH2PO4