Fabrication of CoTiO₃-TiO₂ composite films from a heterobimetallic single source precursor for electrochemical sensing of dopamine

Cobalt titanate-titania composite oxide films have been grown on FTO-coated glass substrates using a single-source heterometallic complex [Co₂Ti₄(μ-O)₆(TFA)₈(THF)₆]·THF (1) which was obtained in quantitative yield from the reaction of diacetatocobalt(ii) tetrahydrate, tetraisopropoxytitanium(iv), and trifluoroacetic acid from a tetrahydrofuran solution. Physicochemical investigations of complex 1 have been carried out by melting point, FT-IR, thermogravimetric and single-crystal X-ray diffraction analyses. CoTiO₃-TiO₂ films composed of spherical objects of various sizes have been grown from 1 by aerosol-assisted chemical vapor deposition at different temperatures of 500, 550 and 600 °C. Thin films characterized by XRD, Raman and X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis have been explored for electrochemical detection of dopamine (DA). The cyclic voltammetry with the CoTiO₃-TiO₂ electrode showed a DA oxidation peak at +0.215 V while linear sweep voltammetry displayed a detection limit (LoD) of 0.083 μM and a linear concentration range of 20-300 μM for DA. Thus, the CoTiO₃-TiO₂ electrode is a potential candidate for the sensitive and selective detection of DA.