Titania (TiO2)/silica (SiO2) nanospheres or NSs amalgamated on a pencil graphite electrode to sense l-ascorbic acid electrochemically and augmented NSs for antimicrobial behaviour

Abstract

An electrochemical sensing electrode based on titania (anatase) and silica nanospheres (TiO₂@SiO₂ NSs) loaded on a pencil graphite electrode (TiO₂@SiO₂NSs/PGE) was fabricated and scrutinized for L-ascorbic acid detection. The PGE surface was designed by coating the nanospheres using the drop casting method. NSs and modified electrodes were investigated structurally, optically and morphologically using various characterization techniques. An electrochemical study was performed via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). Further, the designed electrode performance was optimized by varying pH, potential and scan rates. The TiO₂@SiO₂NS/PGE-modified electrode showed a high sensitivity of 2696.9 μA mM⁻¹ cm⁻² and a lower detection limit for ascorbic acid. The modified electrode also revealed a linear range of 50–2500 μM with a regression coefficient of R² = 0.9932. Additionally, the electrode exhibited high stability and good anti-interference capability. Similarly, the modified electrode performed well in real samples for ascorbic acid detection. Furthermore, TiO₂@SiO₂ NSs performed very effectively against harmful microbes including Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Shigella flexneri bacteria with good inhibition.