New Methods to Produce Electrocatalytic Lead (Ⅳ) Dioxide Coatings on Titanium and Stainless Steel

摘要

Catalytic lead (Ⅳ) dioxide coatings have been produced on titanium and stainless steel 316 and 316L anodes. Good adherence of the lead (Ⅳ) dioxide coatings was obtained by depositing thin intermediate tin and nickel layers on titanium and steel respectively; this was achieved by procedures which have not been previously reported. On both the pretreated titanium and stainless steel substrates, the formation of α-lead (Ⅳ) dioxide (orthorhombic) and β-lead (Ⅳ) dioxide (tetragonal) takes place, the β form being the most abundant. Catalytic surfaces were produced at different current densities on both substrates. The lead (Ⅳ) dioxide surface stability was good in all cases. Anode performance was tested by means of the cyanide to cyanate oxidation reaction. The oxidation efficiency for the steel substrate anodes was better than the efficiency exhibited by titanium substrate anodes.%Mit verschiedenen Vorbehandlungsmethoden durchgeführte Versuchsreihen ergaben, daß gutanhaftende Blei(Ⅳ)dioxid-Überzüge auf Titan- bzw. rostfreien Stahlanoden mittels Zwischenschichten aus Zinn bzw. Nickel hergestellt werden können. Die Abscheidung erfolgt bevorzugt in Form von β-Blei(Ⅳ)-, aber auch als α-Blei(Ⅳ)dioxid. Die Überprüfung des katalytischen Verhaltens der Überzüge bei der Oxidation von Cyanid zu Cyanat ergab, daß Stahlsubstrat-Anoden effektiver den Stoffumsatz beeinflussen als Titananoden.