GB1400948A - Electrodes having a delafossite surface - Google Patents

Abstract

1400948 Coated electrodes P P G INDUSTRIES INC 3 Feb 1973 5471/73 Heading B2E [Also in Divisions C7 and H1] An electrode comprises a conductive base and a surface thereon comprising a delafossite selected from Pt Co, Pd Co, Pd Cr, Pd Rh, Pd Ru, Pd Pb, PdY, Pd lanthanide, Ag Co, Ag Gd, Ag Sc, Ag Tl, Ag In, Cu Co or Cu Fe delafossite of formula A x B x O 2 where x, y is 0.7 to 1. Other metals, e.g. Sc, Ti, V, Cr, Mn, Fe, Co, Ni may be present in a Pt delafossite. The delafossite surface may have a further exterior electrocatalytic coating, such as a spinel as described in Specification 1346794, perovskite (bronze) as described in Specification 1391625, ruthenate, ruthenite, rhodite, rhodate, RuO 2 or TiO 2 A material more ionductive than the delafossite or more resistant to electrolyte than the base may be interposed between the delafossite and the base; e.g. TiO 2 , Al 2 O 3 or oxide of V, Ta, W, Nb, Hf, Zr or SiO 2 , or Pt group metal or alloy or oxide or mixture thereof. Materials may be admixed with the delafossite, e.g. in a slurry of particles, such as perovskites (bronzes), Pt group metals or oxides, or borides, carbides, nitrides or oxides of Si, Ti, Zr, Hf, V, Nb, Ta, Mo or W; oxides may be formed in situ to bind the delafossite particles. The substrate may be graphite, valve metal (Ti, Ta, Nb, Hf, W, Al, Zr, V) or alloy, or Ti hydride; and may be in the form of perforate sheet or expanded mesh, or fine wires or rods. A slurry of delafossite may be prepared in a solvent such as ethanol, butanol, benzyl alcohol, phenol, benzene, polyene or cumene, and brushed onto an etched Ti base and heated to volatilise the solvent.