Cobalt improves nickel hydroxide electrodes for batteries

Positive nickel hydroxide electrodes containing 20 mole percent of cobalt hydroxide are more efficient than when impregnated to the same degree by weight with nickel hydroxide alone. Charge-acceptance and oxygen-evolution tests indicate cobalt electrodes are more efficient than plain positive nickel hydroxide electrodes at all rates of charge

Modeling electrolyte composition effects on anion-exchange membrane water electrolyzer performance

Anion-exchange membrane (AEM) water electrolysis could allow inexpensive and greener hydrogen production than other alternatives, such as steam methane reforming. To increase performance, hydroxide salts are often added to the water feed, with the tradeoff of corrosivity and complexity. Recently, carbonate salts that are less corrosive have shown promise, but their specific functionality remains unknown. In this paper, we use a mathematical model to compare an AEM electrolyzer with added potassium carbonate to an AEM electrolyzer with added potassium hydroxide. We show that the conductivity of the carbonate-form membrane has little impact on the performance of the device, but that carbonate ions replace hydroxide in the ionomer, which creates a Nernstian voltage difference across the membrane. The replacement of hydroxide anions with carbonate also reduces utilization of the catalyst in the anode, resulting in an additional voltage loss

In-situ X-ray spectroscopy of the electric double layer around TiO2 nanoparticles dispersed in aqueous solution: Implications for H2 generation

We report an experimental observation of a significant amount of hydroxide (OH–) created upon water dissociation and subsequently trapped around TiO2 nanoparticles dispersed in NH4OH aqueous solution. The hydroxide species is identified and quantified by a combination of photoemission and photon emission X-ray spectroscopies conducted on liquid samples using a liquid microjet. Unlike previous X-ray studies that observed only a few monolayers of water coverage on TiO2 surfaces and found maximally submonolayer of OH–, the true aqueous environment adopted in this study enables ion mobility and the separation of the water dissociation products H+/OH–. This facilitates the formation of OH– diffused multilayer in which the trapped OH– ions are discovered to coordinate with three water molecules to form a tetrahedral hydration configuration. The negatively charged diffuse layers, together with the positive NH4+ Stern layers, constitute >0.8 nm thick electric double layers around the TiO2 nanoparticles. The large observed amount of hydroxide indicates a high efficiency of water dissociation for the TiO2 catalyst, a promising result for H2 generation in true aqueous environments

Control of Bactrocera oleae and Ceratitis capitata in Organic Orchards: Use of Clays and Copper Products.

Tests on the effect of clays (kaolin and bentonite) and copper products (hydroxide and oxychloride) in the control of olive fruit fly, Bactrocera oleae (Rossi), and Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were carried out from 2003 to 2006 in olive groves and in organic citrus orchards (satsuma, clementine, ‘Navelina’ orange). Results demonstrate an efficacy of kaolin products in reducing attacks of B. oleae on olives and those of C. capitata on citrus fruits; in olive groves the clays gave similar or better results than copper hydroxide. Bentonite AG/8W showed a significant reduction in punctures by C. capitata. Bentonite products and BPLK kaolin are washed off by rainfall more easily than Surround WP kaolin. In contrast to the effect of copper hydroxide on B. oleae in olive groves, no tested copper product showed a significant reduction in C. capitata punctures on citrus fruits. Clays are very useful tools to control tephritid and other insects and are also environmentally friendly, but currently, they are not permitted as products for plant protection in European and Swiss organic farming

Recrystallized parylene as a mask for silicon chemical etching

This paper presents the first use of recrystallized parylene as masking material for silicon chemical etch. Recrystallized parylene was obtained by melting parylene C at 350°C for 2 hours. The masking ability of recrystallized parylene was tested in HNA (hydrofluoric acid, nitric acid and acetic acid) solution of various ratios, KOH (potassium hydroxide) solution and TMAH (tetramethylammonium hydroxide) at different temperatures and concentrations. It is found that interface between parylene and the substrate can be attacked, which results in undercuts. Otherwise, recrystallized parylene exhibited good adhesion to silicon, complete protection of unexposed silicon and silicon etching rates comparable to literature data

Positive electrodes of nickel-cadmium batteries

Ni hydroxide sintered electrodes which are filled electrochemically are superior to chemically treated electrodes. In the electrochemical process, the hydroxide grows on the Ni grains and possesses a well-defined porous structure. Diffusion and conducting mechanisms are therefore facilitated

Effect of fibre treatments on interfacial shear strength of hemp fibre reinforced polylactide and unsaturated polyester composites

Surface treatment of hemp fibres was investigated as a means of improving interfacial shear strength (IFSS) of hemp fibre reinforced polylactide (PLA) and unsaturated polyester (UPE) composites. Fibres were treated with sodium hydroxide, acetic anhydride, maleic anhydride and silane. A combined treatment using sodium hydroxide and silane was also carried out. IFSS of PLA/hemp fibre samples increased after treatment, except in the case of maleic anhydride treatment. Increased IFSS could be explained by better bonding of PLA with treated fibres and increased PLA transcrystallinity. The highest IFSS was 11.4 MPa which was obtained for the PLA/alkali treated fibre samples. IFSS of UPE/hemp fibre samples increased for all treated fibres. This is believed to be due to the improvement of chemical bonding between the treated fibres and the UPE as supported by FT-IR results. The highest IFSS (20.3 MPa) was found for the combined sodium hydroxide and silane treatment fibre/UPE samples

Nickel hydroxide electrode. 3: Thermogravimetric investigations of nickel (II) hydroxides

Water contained in Ni hydroxide influences its electrochemical reactivity. The water content of alpha and beta Ni hydroxides is different with respect to the amount and bond strength. Thermogravimetric experiments show that the water of the beta Ni hydroxides exceeding the stoichiometric composition is completely removed at 160 deg. The water contained in the interlayers of the beta hydroxide, however, is removed only at higher temperatures, together with the water originating from the decomposition of the hydroxide. These differences are attributed to the formation of II bonds within the interlayers and between interlayers and adjacent main layers. An attempt is made to explain the relations between water content and the oxidizability of the Ni hydroxides

The effect of crystal orientation on the cryogenic strength of hydroxide catalysis bonded sapphire

Hydroxide catalysis bonding has been used in gravitational wave detectors to precisely and securely join components of quasi-monolithic silica suspensions. Plans to operate future detectors at cryogenic temperatures has created the need for a change in the test mass and suspension material. Mono-crystalline sapphire is one candidate material for use at cryogenic temperatures and is being investigated for use in the KAGRA detector. The crystalline structure of sapphire may influence the properties of the hydroxide catalysis bond formed. Here, results are presented of studies of the potential influence of the crystal orientation of sapphire on the shear strength of the hydroxide catalysis bonds formed between sapphire samples. The strength was tested at approximately 8 K; this is the first measurement of the strength of such bonds between sapphire at such reduced temperatures. Our results suggest that all orientation combinations investigated produce bonds of sufficient strength for use in typical mirror suspension designs, with average strengths >23 MPa