Electrode for obtaining chlorine through electrolysis

摘要

Electrode comprises at least an electrically conductive substrate based on a valve metal, preferably titanium-, tantalum or niobium or its alloys. The main component of the valve metal and an electrocatalytically active coating comprises: a noble metal oxide and/or a noble metal oxide mixture; and titanium oxide. The coating exhibits a minimum proportion of oxides with an anatase structure, which is determined by a ratio of a signal height of intensive anatase reflexes (101) in a X-ray diffraction pattern after allowing a linear substrate to a signal height of intensive rutile reflexes (110). Electrode comprises at least one electrically conductive substrate based on a valve metal, preferably titanium-, tantalum or niobium metal or its alloys, where the main component of titanium, tantalum or niobium and an electrocatalytically active coating comprises (in mole-%): a noble metal oxide and/or a noble metal oxide mixture (50); and titanium oxide (at least 50). The coating exhibits a minimum proportion of oxides with an anatase structure, which is determined by a ratio of at least 0.6, preferably at least 1 of a signal height of intensive anatase reflexes (101) in a X-ray diffraction pattern (copper (K-alpha ) radiation) after allowing a linear substrate to a signal height of intensive rutile reflexes (110) in the same diffraction pattern. An independent claim is also included for producing the electrode with the electrocatalytically active coating on the electrically conductive substrate, comprising: dissolving noble metal salts in an organic solvent; adding a soluble titanium compound, preferably titanium isopropoxide in an organic- and/or an aqueous solution; mixing the solution; hydrolyzing the salts in water and/or an aqueous acid, preferably acetic acid, propionic acid, hydrochloric acid or nitric acid; applying the solution on the electrically conductive substrate in at least one stage; removing the solvent; thermally post-treating the formed layer at a temperature of not > 250[deg] C, preferably 100-250[deg] C and a pressure of 10-100 bar in the presence of water vapor and optionally lower alcohols; and subsequently calcining the formed layer in the presence of oxygen-containing gases at a temperature of more than 300[deg] C, preferably 450-550[deg] C.