BiVO4-based coatings for non-enzymatic photoelectrochemical glucose determination

BiVO4 is known as a promising material for the design of analytical systems dedicated for non-enzymatic photoelectrochemical (PEC) glucose determination. In this work BiVO4 coatings were deposited on fluoride-doped tin oxide substrate by simple sol-gel method. The influence of different stabilizers, such as polyethylene glycol, urea, citric acid and polyvinyl alcohol (PVA) on the morphology and photoelectrochemical activity of the BiVO4 coatings was investigated. X-ray diffraction, scanning electron microscopy, UV–vis optical absorbance and photoluminescence techniques were used to evaluate structural and optical properties of BiVO4 films. PEC performance was characterized by means of voltammetry, electrochemical impedance spectroscopy and chronoamperometry. It is shown that the combination of urea and polyvinyl alcohol leads to the formation of BiVO4 coatings with lower charge transfer resistance as well as higher affinity towards adsorption of glucose, resulting in higher sensitivity of these photoelectrodes in glucose sensing. Sensitivity of BiVO4 coatings synthesized with urea (Bi_Urea) or with urea and PVA (Bi_Urea_PVA) towards glucose was 0.0033 mA cm−2 mM−1 and 0.0056 mA cm−2 mM−1, respectively. The limit of detection was estimated to be 7.94 μM for Bi_Urea and 6.87 μM for Bi_Urea_PVA.