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Results for “POTASSIUM HYDROXIDE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Oxygen reduction of several gold alloys in 1-molar potassium hydroxide

With rotated disk-and-ring equipment, polarograms and other electrochemical measurements were made of oxygen reduction in 1-molar potassium hydroxide on an equiatomic gold-copper (Au-Cu) alloy and a Au-Cu alloy doped with either indium (In) or cobalt (Co) and on Au doped with either nickel (Ni) or platinum (Pt). The results were compared with those for pure Au and pure Pt. The two-electron reaction dominated on all Au alloys as it did on Au. The polarographic results at lower polarization potentials were compared, assuming exclusively a two-step reduction. A qualified ranking of cathodic electrocatalytic activity on the freshly polished reduced disks was indicated: anodized Au Au-Cu-In Au-Cu Au-Cu-Co is equivalent or equal to Au-Pt Au-Ni. Aging in distilled water improved the electrocatalytic efficiency of Au-Cu-Co, Au-Cu, and (to a lesser extent) Au-Cu-In.

Miller, R. O.↗
NASA NTRS1979

Electron impact study of potassium hydroxide

An attempt is made to measure the sum of the elastic, rotational and vibrational scattering of electrons by KOH at low impact energies (5 to 20 eV) at angles from 10 to 120 deg. Energy loss spectra taken in the 0 to 18 eV range using an electron impact spectrometer are used to identify the species contributing to electric scattering. At temperatures between 300 and 500 C, only inelastic spectral features belonging to water are detected, while at temperatures from 500 to 800 C strong atomic K lines, indicative of molecular dissociation, and H2 energy loss features become prominent. No features attributable to KOH, the KOH dimer, O2 or potassium oxides were observed, due to the effects of the dissociation products, and it is concluded that another technique will have to be developed in order to measure electron scattering by KOH.

Vuskovic, L.↗
NASA NTRS1970

Film breakers prevent migration of aqueous potassium hydroxide in fuel cells

Electrolyte film breakers made from polytetrafluoroethylene are installed in the reactant and water vapor removal outlets of each cell and sealed by elastomers. Use of these devices in the water vapor removal cavity outlets prevents loss of KOH solution through film migration during water removal.

Hess, P. D.↗
NASA NTRS1972

Cadmium poisoning of oxygen reduction on platinum electrode in potassium hydroxide

Experiment with a rotating disk and ring apparatus showed no poisoning by cadmium in 8.5 M KOH, alone or with Cl(-) or CO3(=). Poisoning does not occur either in 0.1 M KOH supernatant at CdO, but a partially reversible poisoning results from .0001 M CdCl2 and traces of fatty acid are present. Evidence indicates that the catastrophic poisoning affects the four-electron O2 reduction more than it does the one-electron H3O(+) discharge.

Miller, R. O.↗
NASA NTRS1979

Three methods for in situ cross-linking of polyvinyl alcohol films for application as ion-conducting membranes in potassium hydroxide electrolyte

Three methods of in situ cross-linking polyvinyl alcohol films are presented. They are: (1) acetalization with a dialdehyde such as glutaraldehyde, (2) acetalization with aldehyde groups formed by selective oxidative cleaving of the few percent of 1,2 diol units present in polyvinyl alcohol, and (3) cross-linking by hydrogen abstraction by reaction with hydrogen atoms and hydroxyl radicals from irradiated water. For the third method, improvement in film conductivity in KOH solution at the expense of mechanical strength is obtained by the presence of polyacrylic acid in the polyvinyl alcohol films. Resistivities in 45 percent KOH are given for in situ cross-linked films prepared by each of the three methods.

Philipp, W. H.↗
NASA NTRS1978

Determination of the zincate diffusion coefficient and its application to alkaline battery problems

The diffusion coefficient for the zincate ion at 24 C was found to be 9.9 X 10 to the minus 7th power squared cm per sec + or - 30 percent in 45 percent potassium hydroxide and 1.4 x 10 to the minus 7 squared cm per sec + or - 25 percent in 40 percent sodium hydroxide. Comparison of these values with literature values at different potassium hydroxide concentrations show that the Stokes-Einstein equation is obeyed. The diffusion coefficient is characteristic of the zincate ion (not the cation) and independent of its concentration. Calculations with the measured value of the diffusion coefficient show that the zinc concentration in an alkaline zincate half cell becomes uniform throughout in tens of hours by diffusion alone. Diffusion equations are derived which are applicable to finite size chambers. Details and discussion of the experimental method are also given.

May, C. E.↗
NASA NTRS1978

Determination of the zincate diffusion coefficient and its application to alkaline battery problems

The diffusion coefficient for the zincate ion at 24 C was found to be 9.9 x 10 to the -7th power sq cm/sec + or - 30% in 45% potassium hydroxide and 1.4 x 10 to the -7th power sq cm/sec + or - 25% in 40% sodium hydroxide. Comparison of these values with literature values at different potassium hydroxide concentrations show that the Stokes-Einstein equation is obeyed. The diffusion coefficient is characteristic of the zincate ion (not the cation) and independent of its concentration. Calculations with the measured value of the diffusion coefficient show that the zinc concentration in an alkaline zincate half-cell becomes uniform throughout in tens of hours by diffusion alone. Diffusion equations are derived which are applicable to finite-size chambers. Details and discussion of the experimental method are also given.

May, C. E.↗
NASA NTRS1972

Fuel cell technology program

A fuel cell technology program was established to advance the state-of-the art of hydrogen oxygen fuel cells using low temperature, potassium hydroxide electrolyte technology as the base. Cell and component testing confirmed that low temperature, potassium hydroxide electrolyte technology is compatible with the requirements of the space shuttle Phase B contractors. Testing of the DM-1 powerplant demonstrated all of the important requirements of the shuttle except operating life. Testing also identified DM-1 powerplant life limiting mechanisms; hydrogen pump gear wear and pressurization of the cell stack over its design limits.

Source record↗
NASA NTRS2004

Treated Carbon Nanofibers for Storing Energy in Aqueous KOH

A surface treatment has been found to enhance the performances of carbon nanofibers as electrode materials for electrochemical capacitors in which aqueous solutions of potassium hydroxide are used as the electrolytes. In the treatment, sulfonic acid groups are attached to edge plane sites on carbon atoms. The treatment is applicable to a variety of carbon nanofibers, including fibrils and both single- and multiple-wall nanotubes. The reason for choosing nanofibers over powders and other forms of carbon is that nanofibers offer greater power features. In previous research, it was found that the surface treatment of carbon nanofibers increased energy-storage densities in the presence of acid electrolytes. Now, it has been found that the same treatment increases energy-storage densities of carbon nanofibers in the presence of alkaline electrolytes when the carbon is paired with a NiOOH electrode. This beneficial effect varies depending on the variety of carbon substrate to which it is applied. It has been conjectured that the sulfonic acid groups, which exist in a deprotonated state in aqueous KOH solutions, undergo reversible electro-chemical reactions that are responsible for the observed increases in energystorage capacities. The increases can be considerable: For example, in one case, nanofibers exhibited a specific capacitance of 34 Farads per gram before treatment and 172 Farads per gram (an increase of about 400 percent) after treatment. The most promising application of this development appears to lie in hybrid capacitors, which are devices designed primarily for storing energy. These devices are designed to be capable of (1) discharge at rates greater than those of batteries and (2) storing energy at densities approaching those of batteries. A hybrid capacitor includes one electrode like that of a battery and one electrode like that of an electrochemical capacitor. For example, a hybrid capacitor could contain a potassium hydroxide solution as the electrolyte, a carbon capacitor electrode, and a nickel hydroxide battery electrode. By making the capacitor electrode of treated carbon nanofibers instead of another carbon material, one could obtain greater energy-storage capacity.

Firsich, David W.↗
NASA NTRS1989

Pilot Plant Makes Oxygen Difluoride

Pilot plant makes oxygen difluoride highly-energetic, space-storable oxidizer not made commercially. Designed to handle reactants, product, and byproduct, most of which highly reactive, corrosive, and toxic. Oxygen difluoride evolves continuously from reactor containing potassium hydroxide in water at 10 degree C. Collection tanks alternated; one filled while other drained to storage cylinder. Excess OF2 and F2 dissipated in combustion of charcoal in burn barrel. Toxic byproduct, potassium fluoride, reacted with calcium hydroxide to form nontoxic calcium fluoride and to regenerate potassium hydroxide. Equipment processes toxic, difficult-to-make substance efficiently and safely.

Humphrey, Marshall F.↗
NASA NTRS1966

Argentic oxysalt electrodes

Silver ions with plus three oxidation states investigated as cathode electrodes in potassium hydroxide with zinc as anodes

SILVER↗
NASA NTRS1994

Investigation of new hypergol scrubber technology

The ultimate goal of this work is to minimize the liquid waste generated from the scrubbing of hypergolic vent gases. In particular, nitrogen tetroxide, a strong oxidizer used in hypergolic propellant systems, is currently scrubbed with a sodium hydroxide solution resulting in a hazardous liquid waste. This study investigated the use of a solution of potassium hydroxide and hydrogen peroxide for the nitrogen textroxide vent scrubber system. The potassium nitrate formed would be potentially usable as a fertilizer. The hydrogen peroxide is added to convert the potassium nitrite that is formed into more potassium nitrate. Smallscale laboratory tests were conducted to establish the stability of hydrogen peroxide in the proposed scrubbing solution and to evaluate the effectiveness of hydrogen peroxide in converting nitrite to nitrate.

Glasscock, Barbara H.↗
NASA NTRS1974

The synthesis of higher oxides of alkali and alkaline earth metals in an electric discharge: Theoretical and experimental studies

Potassium hydroxide was subjected to the products of an electrical discharge sustained in oxygen and produced both potassium peroxide and superoxide. The conversion to higher oxides was shown to strongly depend upon the particle size of KOH, the position of KOH in the discharge zone, and the operating conditions of the discharge. Similar experiments were performed with hydroxides of lithium and calcium which do not form superoxides, but are converted to peroxides. The yields of peroxides were shown to strongly depend upon the operating conditions of the discharge. The absence of superoxides and the presence of peroxides of lithium and calcium was explained from the consideration of relative thermodynamic stability of the oxides of lithium and calcium. Thermogravimetric analysis was shown to provide a more accurate means for determining the amount of KO2 than previous methods.

Bell, A. T.↗