Hybrid hexacyanoferrate films of copper and cobalt (CuCoHCF) were electrodeposited on a platinum electrode by cyclic voltammetry from 0. 0 V to + 1.0 V (vs. SCE) at 50 mV/s in a solution mixture containing 0. 25 mol/L KNO_3, 1.25 * 10~(-4) mol/L CuSO_4, 1.25 * 10~(-4) mol/L Co (NO_3)_2 and 2.5 * 10~(-4) mol/L K_3Fe-(CN)_6, and characterized with electrochemistry, XRD and XPS. The results demonstrate that CuCoHCF is not a simple mixture of copper hexacyanoferrate and cobalt hexacyanoferrate, but a new compound with cyano moiety bridge between two adjacent lattice sites, Cu~(2+) and Co~(2+) coordinated to nitrogen atom and Fe~(2+) to carbon atom. With the increase of Cu~(2+) concentration in the deposition solution, Cu~(2+) content in the films increased, while the lattice constant of the films decreased gradually. Typical properties were obtained for the films electrodeposited from a solution mixture with content ratio of Cu~(2+), Co~(2+) and Fe~(3+) being 1:1:2. The CuCoHCF modified platinum electrode exhibited stable electrochemical response in pH range 4 ～ 10 and permeability for monovalent cations in the order of K~+ > Li~+ > Na~+ > NH_4~+, all of which were different from that of the respective single component hexacyanoferrates. XPS reveals that the iron atom exists in the form of Fe(III) in oxidized films, which is reduced to Fe~(2+) during X-ray scanning.

Key words: FERRATE, CHEMICAL MODIFIED ELECTRODE, XRD, XPS