Preparation and characterization of CePtCl6 films and their electrocatalytic properties with NAD+, l-cystine and sulfur oxoanions

Cerium hexachloroplatinate (CePtCl6) films have been prepared by mixing Ce3+ and PtCl62- ions in an aqueous KCl pH 3.0 solutions. The deposition of a cerium hexachloroplatinate film occurred when PtIVCl62- was electrochemically reduced to PtIICl64- and Ce4+ to Ce3+. The electrochemical quartz crystal microbalance (EQCM), UV–visible absorption spectroscopy, stopped-flow kinetic method, amperometry and cyclic voltammetry techniques were used to study the deposition and growth mechanism of the cerium hexachloroplatinate films. The electrochemical properties of this film indicated a single redox process which was corresponding to reduction of PtIVCl62- to PtIICl64- immobilized cerium hexachloroplatinate films. In the aqueous KCl pH 3.0 solution, PtIVCl62- was electrochemically reduced to PtIICl64- and the Ce3+ reacted with the film to maintain the electrochemical neutrality. The reversibility of the cerium (III) hexachloroplatinate film during cycling and with changing frequency has been found good, and the Ce3+ ion exchange obviously occurred in the redox couples. The electrocatalytic reduction properties of (β-nicotinamide adenine dinucleotide) NAD+, l-cystine, SO52- and S4O62- were determined using the cerium hexachloroplatinate films. The electrocatalysis and electrochemical reactions of NAD+ with cerium hexachloroplatinate film were measured by amperometry using the rotating disk electrodes.