BiVO4-based coatings for non-enzymatic photoelectrochemical glucose determination

Abstract

• Non-enzymatic photoelectrochemical glucose sensors based on BiVO4 coatings were developed. • BiVO 4 coatings were deposited on fluoride-doped tin oxide (FTO) substrate by sol-gel method. • The effect of polyethylene glycol, urea, citric acid and PVA on photoelectrochemical activity was investigated. • Results revealed that morphology of BiVO 4 coatings plays critical role for sensitivity of sensor. • Sensitivity of some BiVO 4 coatings towards glucose was 0.0056 mA cm −2 mM −1 and limit of detection −6.87 μM. BiVO 4 is known as a promising material for the design of analytical systems dedicated for non-enzymatic photoelectrochemical (PEC) glucose determination. In this work BiVO 4 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 BiVO 4 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 BiVO 4 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 BiVO 4 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 BiVO 4 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.