Composite body comprising a porous layer of a hydrogenation catalyst

摘要

Hydrogen is purified, or hydrogen and deuterium are separated, by use of a composite body comprising a compact pore-free base of a metal or alloy permeable to hydrogen in contact with a porous layer of a hydrogenation catalyst other than a hydride of Ti, Zr, Th, Ce or U. Suitable catalysts include e.g. finely divided Pt, Ni, Co, Fe, Cu and alloys thereof, and certain semi-conductor materials, e.g. N-type Si. Preferred metals for the base include Pd and its alloys, e.g. T with Ag; Ta and its alloys, e.g. with W; and Ti. In specific examples:-(1) a hydrogen electrode (Fig. 3) for a fuel cell has an open-ended nickel-silver tube 1 to one end of which Pd foil 2 is soldered. In the tube is placed a layer 3 of Raney Ni, and a weight or wire mesh is pressed thereon to assure intimate contact between layer 3 and foil 2. The electrode is immersed in 6N NaOH solution 6. The counter-electrode is an iron sheet. Instead of Raney Ni, Raney Fe, Co or Cu may be used. Alternatively, (2) a Raney copper layer may be used with a Pd/Ag alloy foil, and this electrode may also be used to prepare pure H2. (3) A 1:1 H2/D2 gaseous mixture is fed into a Pd/Ag alloy tube 9 (Fig. 4) containing a powdered Raney Co liner which causes the H2 to be readily absorbed by tube 9, from which the H2 is removed either electrolytically or by reduced pressure at the outer wall of the tube which may also be coated with Raney Co. A D2-enriched mixture emerges from the end of the tube. The systems of Fig. 4 may be used in known cascading or counter-current arrangements. (4) Pure H2 may be obtained by feeding at 14 (Fig. 5) a gaseous mixture containing hydrogen into 13 which contains Pd/Ag alloy tube 11 closed at one end lined inside and outside with Cu powder layer 12. The gas in 13 is at about 20 atmospheres and in 11 is at 1 atmosphere. H2 is selectively adsorbed and dissolved in 11 and 12 and pure H2 will emerge from the tube while the remainder of the mixture leaves at 15. Blades 16 cause a turbulence in the inflowing mixture so that all the H2 is brought in contact with the tube. Specification 956,292 is referred to.ALSO:A hydrogen electrode comprises a compact pore-free base of a metal or alloy permeable to hydrogen in contact with a porous layer of a hydrogenation catalyst other than a hydride of Ti, Zr, Th, Ce, or U. Suitable catalysts include, e.g., Pt, Ni, Co, Fe, Cu, and alloys thereof, and certain semi-conductor materials, e.g. n-type Si. Preferred metals for the base include Pd and its alloys, e.g. with Ag; Ta and its alloys, e.g. with W ; and Ti. In specific examples, (1) a 1:1 hydrogen-deuterium gaseous mixture is fed into a Pd/Ag alloy tube 9, Fig. 4, containing a powdered Raney Co liner which causes the hydrogen to be readily absorbed by tube 9 from which the hydrogen is removed electrolytically while a deuterium-enriched mixture emerges from the tube; and (2) pure hydrogen is produced by electrolysis of 6N caustic soda solution using a cathode comprising a tube of Pd-Ag alloy or Pd closed at one end and packed with Pd black. Specification 956,292 is referred to.