Catalyst coating and method for its production

Wet-chemically producing catalyst coating on an electrically conductive carrier for electrodes for chloralkali- or hydrochloric acid electrolysis, comprises producing a coating solution or a coating dispersion comprising a precursor compound of a noble metal and/or a metal oxide of a noble metal, optionally a tin- and/or valve metal compound and a solvent or a dispersant; applying the coating solution or the coating dispersion on the conductive carrier; removing the solvent or the dispersant from the applied layer by drying; and subjecting the obtained dried layer to a thermal treatment. Wet-chemically producing catalyst coating on an electrically conductive carrier for electrodes for chloralkali- or hydrochloric acid electrolysis, having electrocatalytically active components based on at least one noble metal oxide and/or noble metal of transition group VIIIa, preferably ruthenium, rhodium, palladium, osmium, iridium or platinum, preferably ruthenium oxide and/or iridium oxide, and optionally at least one valve metal oxide, preferably titanium oxide, comprises (a) producing a coating solution or a coating dispersion comprising a precursor compound of a noble metal and/or a metal oxide of a noble metal, preferably ruthenium and/or iridium, optionally a tin- and/or valve metal compound, preferably a titanium compound, and a solvent or a dispersant, and adding at least one acid to the coating solution or the coating dispersion, (b) applying the coating solution or the coating dispersion on the conductive carrier, (c) removing the solvent or the dispersant from the applied layer by drying, and (d) subjecting the obtained dried layer to a thermal treatment at a temperature of at least 300[deg] C and optionally in presence of oxygen-containing gases, to form the catalyst coating. The molar ratio of total amount of acid present in the coating solution or the coating dispersion and total amount of metals of the metal-containing components present in the coating solution or the coating dispersion is at least 2:1, preferably at least 4:1. An independent claim is also included for an electrode having the catalyst coating obtained by the above method.