MBE Grown Vanadium Oxide Thin Films for Enhanced Non‐Enzymatic Glucose Sensing

In the search for non-enzymatic alternatives to glucose oxidase, reliable and microchip-compatible approaches to catalyst development are highly desirable. Herein, the electrochemical behavior of thin films of VOx deposited by molecular beam epitaxy (MBE) on glassy carbon electrodes is reported. A process of partial etching during polarization is observed. Thereafter, highly active and stable traces of VOx act as catalytic centers for glucose electrooxidation. A mechanistic description of the electrochemical process is proposed based on evidence provided by voltammetric measurements. The sensors are calibrated both with potentiometric and amperometric techniques, the former showing a wide linear range (1–10 mM), good sensitivity (14.93 ± 0.39 µA cm⁻² × mM^–1) and a limit of detection (0.32 m-M). Unlike most metal oxides, it is shown that VOx on glassy carbon is capable of successfully oxidizing glucose at −0.4 V. Such a one-of-kind behavior can have important ramifications for energy-efficient integrated electrochemical sensors and non-enzymatic glucose sensing as a whole.