The invention relates to an electrode suitable for electrolytic treatments of dilute solutions of sodium chloride even at low temperatures. The electrode can be used in the generation of active chlorine-based biocidal agents in ballast water for marine applications. The electrode has a titanium substrate, an inner catalytic coating containing oxides of tantalum, ruthenium and iridium, and an outer catalytic coating containing oxides of titanium, ruthenium and of at least one of nickel, iron and cobalt.