(ZA8509529-A)      A galvanically prepd. electrode for electrochemical processes comprises an electroconductive support having an electrocatalytic coating of (i) metal (alloy) contg. dispersed electrocatalytic material; or (ii) metal (alloy) contg. Pt-gp. metal(s) as a homogeneous phase. The electrode is prepd. by galvanically depositing the coating onto the support from a plating bath contg. (i) suspended particles of the electrocatalytic material; or (ii) dissolved soluble salt(s) of Pt gp. metal(s); and 0.005-2000 ppm cpd. of elements IB, IIB, IIIA, IVA, VA, VB, VIA((i) only), VIB or VIII.    Pref. for (i) the additive is a cpd. of Ag, Cd, Hg, Tl, Pb, As, V, S, Mo, Pt or Pd. The suspended electrocatalytic material is Ti, Zr, Nb, Hf, Ta, Pt gp. metals, Ni, Co, Sn, Mn as metals, alloys, oxides, borides, nitrides, carbides or sulphides, pref. Ru oxide. For (ii) the additive is a cpd. of Au, Cd, Tl, Pb, Sn, As, V, Mo, Pt or Pd. The soluble salt of a Pt-gp. metal is RuCl3. For either embodiment, the galvanic plating bath is an Ni, Cu or Ag plating bath.    USE/ADVANTAGE -   The electrode is used as a cathode in an electrolytic cell for electrolysis of alkali metal halides (claimed), pref. as H evolution cathode in ion exchange membrane or permeable diaphragm cells. The coatings are practically immune to poisoning by Fe and Hg, avoiding a rise in H overvoltage with operating time when used with impure alkali solns.    (JP62501219-W)      A galvanically prepd. electrode for electrochemical processes comprises an electroconductive support having an electrocatalytic coating of (i) metal (alloy) contg. dispersed electrocatalytic material; or (ii) metal (alloy) contg. Pt-gp. metal(s) as a homogeneous phase. The electrode is prepd. by galvanically depositing the coating onto the support from a plating bath contg. (i) suspended particles of the electrocatalytic material; or (ii) dissolved soluble salt(s) of Pt gp. metal(s); and 0.005-2000 ppm cpd. of elements IB, IIB, IIIA, IVA, VA, VB, VIA((i) only), VIB or VIII.    Pref. for (i) the additive is a cpd. of Ag, Cd, Hg, Tl, Pb, As, V, S, Mo, Pt or Pd. The suspended electrocatalytic material is Ti, Zr, Nb, Hf, Ta, Pt gp. metals, Ni, Co, Sn, Mn as metals, alloys, oxides, borides, nitrides, carbides or sulphides, pref. Ru oxide. For (ii) the additive is a cpd. of Au, Cd, Tl, Pb, Sn, As, V, Mo, Pt or Pd. The soluble salt of a Pt-gp. metal is RuCl3. For either embodiment, the galvanic plating bath is an Ni, Cu or Ag plating bath.    USE/ADVANTAGE -   The electrode is used as a cathode in an electrolytic cell for electrolysis of alkali metal halides (claimed), pref. as H evolution cathode in ion exchange membrane or permeable diaphragm cells. The coatings are practically immune to poisoning by Fe and Hg, avoiding a rise in H overvoltage with operating time when used with impure alkali solns.    (US4724052-A)      Allcali metal chloride soln. is electrolysed using an electrolytic cell contg. anode and cathode sepd. by an ion exchange membrane impermeable to electrolyte flow, by passing an electric current from anode to cathode. Cathode comprises (a) an electroconductive support; and (b) an electro-catalytic coating of metal (alloy) with particles of electrocatlytic materials dispersed in it. Prepn. comprises depositing coating by galvanic deposition onto (a) from a galvanic plating bath contg. suspended particles of electrocatalytic materials and small amt. of 1or more Gp. IB, IIB, IIIA, IVA, VA, VB, VIA, VIB and/or VIII cpd. to inhibit poisoning of cathode by metal impurities in an alkali metal hydroxide catholyte soln.    ADVANTAGE -   Exhibits low hydrogen overvoltages, is constant with time, and is immune to poisoning by Fe-, Hg- or other metal impurities. (7pp)p    (US4938851-A)      Modified cathode for the electrolysis of alkali chloride in membrane or diaphragm cells comprises a conducting core (e.g. Fe, steel, Ni or Cu, or corresp. alloys) coated with a Pt gp. metal by cathodic deposition; such that the electrolyte also contains one or more cpds. of metals from Gps. IIB, IIIA, IVA and VA, (e.g. 0.005-2,000 ppm Cd, Tl, Pb, As, Sb or Bi), which are codeposited and serve to inhibit the poisoning effects of traces of Fe or Hg in the alkali chloride cells.    ADVANTAGE -   The coated electrodes exhibit low hydrogen overvoltages even after running the cellse for long periods. @(7pp)    (DE3585621-G)      A galvanically prepd. electrode for electrochemical processes comprises an electroconductive support having an electrocatalytic coating of (i) metal (alloy) contg. dispersed electrocatalytic material; or (ii) metal (alloy) contg. Pt-gp. metal(s) as a homogeneous phase. The electrode is prepd. by galvanically depositing the coating onto the support from a plating bath contg. (i) suspended particles of the electrocatalytic material; or (ii) dissolved soluble salt(s) of Pt gp. metal(s); and 0.005-2000 ppm cpd. of elements IB, IIB, IIIA, IVA, VA, VB, VIA((i) only), VIB or VIII.    Pref. for (i) the additive is a cpd. of Ag, Cd, Hg, Tl, Pb, As, V, S, Mo, Pt or Pd. The suspended electrocatalytic material is Ti, Zr, Nb, Hf, Ta, Pt gp. metals, Ni, Co, Sn, Mn as metals, alloys, oxides, borides, nitrides, carbides or sulphides, pref. Ru oxide. For (ii) the additive is a cpd. of Au, Cd, Tl, Pb, Sn, As, V, Mo, Pt or Pd. The soluble salt of a Pt-gp. metal is RuCl3. For either embodiment, the galvanic plating bath is an Ni, Cu or Ag plating bath.    USE/ADVANTAGE -   The electrode is used as a cathode in an electrolytic cell for electrolysis of alkali metal halides (claimed), pref. as H evolution cathode in ion exchange membrane or permeable diaphragm cells. The coatings are practically immune to poisoning by Fe and Hg, avoiding a rise in H overvoltage with operating time when used with impure alkali solns.    (JP95013310-B2)      The galvanically prepd. electrode for electrochemical processes comprises an electroconductive support having an electrocatalytic coating of (i) metal (alloy) contg. dispersed electrocatalytic material; or (ii) metal (alloy) contg. Pt-gp. metal(s) as a homogeneous phase. The electrode is prepd. by galvanically depositing the coating onto the support from a plating bath contg. (i) suspended particles of the electrocatalytic material; or (ii) dissolved soluble salt(s) of Pt gp. metal(s); and 0.005-2000 ppm cpd. of elements IB, IIB, IIIA, IVA, VA, VB, VIA((i) only), VIB or VIII.    Pref. for (i) the additive is a cpd. of Ag, Cd, Hg, Tl, Pb, As, V, S, Mo, Pt or Pd. The suspended electrocatalytic material is pref. Ti, Zr, Nb, Hf, Ta, Pt gp. metals, Ni, Co, Sn, Mn as metals, alloys, oxides, borides, nitrides, carbides or sulphides, pref. Ru oxide. For (ii) the additive is pref. a cpd. of Au, Cd, Tl, Pb, Sn, As, V, Mo, Pt or Pd. The soluble salt of a Pt-gp. metal is pref. RuCl3.    USE/ADVANTAGE -   The electrode is used as a cathode in an electrolytic cell for electrolysis of alkali metal halides (claimed), pref. as H evolution cathode in ion exchange membrane or permeable diaphragm cells. The coatings are practically immune to poisoning by Fe and Hg, avoiding a rise in H overvoltage with operating time when used with impure alkali solns..    (RU2018543-C1)      A galvanically prepd. electrode for electrochemical processes comprises an electroconductive support having an electrocatalytic coating of (i) metal (alloy) contg. dispersed electrocatalytic material; or (ii) metal (alloy) contg. Pt-gp. metal(s) as a homogeneous phase. The electrode is prepd. by galvanically depositing the coating onto the support from a plating bath contg. (i) suspended particles of the electrocatalytic material; or (ii) dissolved soluble salt(s) of Pt gp. metal(s); and 0.005-2000 ppm cpd. of elements IB, IIB, IIIA, IVA, VA, VB, VIA((i) only), VIB or VIII.    Pref. for (i) the additive is a cpd. of Ag, Cd, Hg, Tl, Pb, As, V, S, Mo, Pt or Pd. The suspended electrocatalytic material is Ti, Zr, Nb, Hf, Ta, Pt gp. metals, Ni, Co, Sn, Mn as metals, alloys, oxides, borides, nitrides, carbides or sulphides, pref. Ru oxide. For (ii) the additive is a cpd. of Au, Cd, Tl, Pb, Sn, As, V, Mo, Pt or Pd. The soluble salt of a Pt-gp. metal is RuCl3. For either embodiment, the galvanic plating bath is an Ni, Cu or Ag plating bath.    USE/ADVANTAGE -   The electrode is used as a cathode in an electrolytic cell for electrolysis of alkali metal halides (claimed), pref. as H evolution cathode in ion exchange membrane or permeable diaphragm cells. The coatings are practically immune to poisoning by Fe and Hg, avoiding a rise in H overvoltage with operating time when used with impure alkali solns.