Multilayer Spiral Tantalum Tungstate Nanotube Composites for Detection of Ascorbic acid and uric acid

Novel multilayer spiral tantalum tungstate nanotube composites were synthesized by guest-guest ion exchange insertion of a polyfluorinated cationic azobenzene derivative (C₃F₇-Azo⁺) into LiTaWO₆ host material. The C₃F₇-Azo⁺-TaWO₆ nanotube composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), thermogravimetric/differential thermal analysis (TG/DTA) and Fourier transform infrared spectroscopy (FTIR). TEM revealed spiral nanotubes with 4.2 nm basal spacing, consistent with a 4.13 nm basal spacing observed by XRD. FTIR, UV Spectral and XRD data indicated the azobenzene molecules were inserted between the tantalum tungstate layers. Electrochemical tests showed that the C₃F₇-Azo⁺-TaWO₆ nanotube composite modified on a glassy carbon electrode (C₃F₇-Azo⁺-TaWO₆/GCE) has faster electron transfer capability, larger effective contact area, excellent electrical conductivity, good stability and anti-interference ability. This enables C₃F₇-Azo⁺-TaWO₆/GCE to simultaneously detect ascorbic acid (AA) and uric acid (UA) without interfering with each other in the ranges of 0.03–0.25 mM and 0.01–0.13 mM, with detection limits of 2.3 µM and 1.4 µM, respectively. These multilayer spiral tantalum tungstate nanotube composites show promise for electrochemical sensing applications.