Direct Growth of Bismuth Vanadate Thin Film Arrays on FTO via Galvanic Deposition Mediated by BiOI Nanosheets for Fabrication of Photoelectrochemical Non-Enzymatic Dopamine Sensing Platform

Abstract

Development of a photoelectrochemical (PEC) sensor utilizing the energy of photon for the detection of bioanalytes is a challenging task. We hereby propose the easiest development of PEC sensor based on bismuth vanadate (BiVO4) photoanode on fluorine doped tin dioxide (FTO) electrode for sensing of bioanalytes. The fabrication of BiVO4/FTO electrode was performed by an extremely simple and energy efficient method called galvanic deposition. This was achieved in a two-step process viz. development of bismuth oxyiodide (BiOI) on FTO-glass electrode by galvanic deposition (BiOI/FTO) followed by moderate temperature annealing of BiOI/FTO in presence of Vanadyl (IV) acetyl acetonate to form the final electrode. The BiOI/FTO and BiVO4/FTO were thoroughly characterized by physicochemical and electrochemical means. The resultant structure revealed formation of a monoclinic scheelite BiVO4 (ms-BiVO4) structure which has the highest photocatalytic response compared to the other phases of BiVO4. One of the photoelectrochemical applications of ms-BiVO4 in the detection of bioanalyte was performed through the sensing of dopamine (DA). The BiVO4/FTO electrode exhibited high sensitivity (0.257 nA μM−1 cm−2), good linear range of concentration (102–106 μM) and a low limit of detection (0.154 μM) as a sensor for DA. The BiVO4/FTO electrode showed high reproducibility (RSD <4% under optimal condition), good stability, and high resistance against the polydopamine (PDA) fouling. The electrode was successfully demonstrated to perform the detection of DA including in real serum samples.