One-step electrodeposition of carbon–silicate sponge assisted by a three-phase junction for efficient bioelectrocatalysis

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. A 1625 ± 140 nm thick, sponge-like, nanoparticulate stripe of CNPs embedded in a silicate matrix is formed at the electrode surface close to the three-phase junction. The obtained material is an excellent support for enzyme adsorption exhibiting mediatorless bioelectrocatalysis of dioxygen reduction.