Oxidation of Cr³⁺-Ions at the Composite ТіО_х/РtО_у Electrode

Abstract

Electrochemical properties of composite ТіОх/РtОу electrodes havebeen studied. The temperature of preparation was shown to affectthe catalytic activity through the surface morphology and thechemical composition. Composite ТіОх/РtОу-electrodes werefound to be n-type semiconductors. Increase in treatmenttemperature leads to thermal diffusion of Pt into substrate bulk andresults in shift of flatband potential to positive values and increasein donor concentrations. Peak of reduction of Pt phase oxides onthe cathodic branch of voltammograms characterizes quantity ofelectrochemically active platinum on electrode surface and couldbe correlated with electrocatalytic activity of thermally treated ТіОх/РtОу-electrodes.

Anodes Based on Pt Doped Titanium Sub-Oxides

“…1a). Morphology of platinized Ebonex ® strongly depends on amount of electrodeposited Pt that typical for platinized electrodes obtained by elecrodeposition (10,11,13). Coatings containing low amount of Pt (2 mg/cm 2 ) are nonuniform and look like islands of Pt on substrate (Fig.…”

“…Specifically, electrodeposition of chromium coatings from a trivalent bath comes to an end when concentration of Cr(VI)species exceeds 200 mg/L (9). Most of materials don't obey these requirements (9)(10)(11)18). As was shown in (11) platinum anode is characterized by high rate of Cr(VI)-species generation.…”

“…For example, choice of an appropriate anode for a trivalent chromium bath is complicated by the strict anode requirements. Taking into account that composition changes and accumulation of Cr(VI)-species in trivalent chromium bath lead to technological parameters deterioration (9)(10)(11) an anode material must be characterized by low activity towards electrolyte components oxidation reactions and high selectivity towards oxygen evolution reaction. In addition anode material mustn't lose activity in time and should have long service life.…”