The DSK System of Fuel Cell Electrodes

Abstract

Double skeleton catalyst (DSK) electrodes combine the high catalytic activity of Raney powder catalysts with the mechanical rigidity and electrical conductivity of bulk metals. They consist of a supporting macroskeleton pressed and sintered of metal grains of uniform size and Raney catalyst grains embedded in its pores. The authors have prepared more than 3000 different samples and investigated the following parameters: composition and particle size of both catalyst and macroskeleton, blending ratio of these two components, mixing process, pressing and sintering conditions, and a special potentiostatic process to leach the inactive component (Al or Zn) by KOH . This “controlled activation” provides extremely high activity and uniform pore sizes, avoiding too narrow and too large pores. Such “homeoporous” electrodes offer some 10−2 pores with three phase boundaries, each contributing several microamperes to the total current density. Detailed recipes are given for the production of hydrogen DSK electrodes containing Raney Ni catalyst in a Ni macroskeleton and generating up to 750 ma/cm2 at 40 mv polarization at 85°C. Oxygen DSK electrodes contain a new brittle Ag Raney alloy in a supporting Ni macroskeleton. The open‐cell polarization φ‐U 0 at 85°C is 100 mv only and the maximum current density about 500 ma/cm2. Such electrodes with fine pore coating layers are absolutely gas tight and show nearly 100% Faraday efficiency. Although the oxygen DSK electrodes contain but 0.05 g Ag/cm2 they reach the ideal process H2+½O2=H2O delivering 4 electrons per O2 molecule instead of the Berl process with 2 electrons. A battery with such electrodes fed with impure H2 and O2 in uninterrupted service one year showed no deterioration. Therefore the lifetime of DSK cells is estimated to be at least 103, perhaps some 104 amphr/cm2. Different types of DSK electrodes such as economy electrodes used for the dissolved fuel fuel cell, and valve electrodes for the electrochemical storage of energy are described. They also act as electrolytic compressors without moving parts and can control catalytic reactions automatically. DSK electrodes may be used for light storage batteries. Mo‐ and W‐DSK electrodes offer the possibility of the electrochemical oxidation of CO. DSK electrodes belong to the most promising systems disclosed hitherto and are capable of further improvement.

Some Preliminary Considerations of A Molten-Salt Extraction Process to Remove Tritium from Liquid Lithium Fusion Reactor Blankets

“…Several methods have been developed for the collection of electrolyfically evolved gases. In particular, double -5 -' skeleton catalyst electrodes 17 have been used to evolve and collect H2 in aqueous electrolytic media. Another effective approach to gas collection at electrodes in molten salt media is the porous valve electrode described by Swinkels.…”

Seed-mediated synthesis of silver with skeleton structures

“…In the scanning electron microscopy (SEM) image of Raney nickel given in the literature [19], it is shown that Raney nickel is composed of pores arranged in a crisscross pattern with a supporting skeleton. Raney nickel, as a porous material, has found widespread application as a catalyst of hydrogenation of organic compounds [19] and especially as an anode in liquid fuel cell [20]. Xiao et al [21] have used Raney nickel as a template to prepare palladium and silver dendritic nanostructures with the assistance of ultrasonic waves.…”

Kameralismus als paradoxe Konzeption der gleichzeitigen Stärkung von Markt und Staat. Komplexe Theorielagen im deutschen 18. Jahrhundert

“…17 Doch bleibt die ganze Anstrengung der Produktivitätsförderung an das allmäch-tige und moralische Wohlfahrtskriterium gebunden, die "Glückseligkeit" aller Staatsbürger herzustellen. 18 Indem die Menschen, insbesondere die "Armen", "zum Dienst des gemeinen Wesens, <…> auch zu vielen Tugenden größtentheils (als) unfä-hig" 19 angesehen werden, tritt der Staat paternalistisch als Promotor ihrer Lebensziele und Bedürfnisse auf, die sie unterstelltermaßen selbst, in ihrer Unvollkommenheit, zu erlangen nicht in der Lage sind. In diesem Sinne kann bei Justi von einem "sozialwirtschaftlichen" Systementwurf die Rede sein, der eine Tradition entwirft, die in der "Socialoekonomie" des 19.…”

“…Jahrhundert modernisiert wird. Im Unterschied zur Nationalökonomie des 19 25 ist, werden die Menschen, die sich zu einem Staat zusammenschließen, bestrebt sein, damit einen sozialen Raum zu etablieren, der dem Einzelnen möglichst wenige Handlungsbeschränkungen auferlegt. Ferner will sich der einzelne Mensch natürlicherweise selbst erhalten, vermag sich jedoch im Stand der natürlichen Freiheit vor Übergriffen durch Andere nicht ausreichend zu schützen; eine der Erwartungen, die er mit der Staatsbildung verbindet, bezieht sich dementsprechend auf die Produktion des Gutes Sicherheit.…”