Single-step electrodeposition of nanocomposite silicate materials based on hydrophilic carbon nanoparticles (CNPs) and a hydrophobic sol-gel precursor with the help of an electrode|organic-phase|aqueous-electrolyte three-phase junction is presented. A tin-doped indium oxide electrode is immersed into a cell filled with two immiscible liquids. The upper aqueous phase contains dispersed carbon nanoparticles in electrolyte and the bottom organic phase consists of sol-gel precursor in nitrobenzene. Applying a positive potential to the electrode results in generation of protons which act as catalyst for the sol-gel process [1,2]. This method leads to the formation of a narrow, sponge-like carbon–silicate stripe at the electrode surface close to the three-phase junction. To increase the active surface area several parallel stripes were deposited, however this resulted in the formation of a compact film between the stripes. The morphology and structure of the nanocomposites were thoroughly investigated by AFM, SEM, optical and infrared mapping. The electrodes were examined as a support for bilirubin oxidase — an enzyme showing bioelectrocatalytic activity towards dioxygen reduction.
 M.M. Collinson, Acc. Chem. Res. 40 (2007) 777-783.
 J. Niedziolka, M. Opallo, Electrochem. Commun. 10 (2008) 1445-1447.