Estudo do sinergismo de nanocristais de dióxido de titânio dopados com níquel com óxido de grafeno e sua aplicação em sensores para detecção de ácido ascórbico

Abstract

Ascorbic acid, known as vitamin C, plays a crucial role in human health, and it is necessary to develop sensitive and selective sensors for its detection in complex samples. In order to enhance electrical responses and interaction with biomolecules, nanomaterials are incorporated into the surface of sensors. Titanium dioxide (T iO2) and graphene oxide (GO) nanocrystals have interesting properties, such as high surface area, catalytic activity and ability to amplify electrical signals, being excellent candidates for electrochemical sensors. Thus, their synergism can enhance these properties. Therefore, this work investigated the synergism between nanocrystals of T iO2 doped with nickel (Ni) and GO and its application in the detection of ascorbic acid. The optical, structural and vibrational properties of the samples were investigated using optical absorption spectroscopy (AO), X-ray diffraction (XRD), Raman spectroscopy and cyclic voltammetry (VC). In the AO spectra, it confirmed the absorption in the ultraviolet of the T iO2 nanocrystals and that with the doping it altered the band gap. XRD and Raman data confirmed the presence of the anatase phase of the T iO2 nanocrystals, the lattice distortions with doping and the formation of GO. In the results of voltammetry and application in sensors for detection of ascorbic acid, it confirmed that nanocrystals of T iO2 doped with Ni and GO presented a high sensitivity and selectivity in the detection of ascorbic acid, with linear response in the concentration range, enhancing the sensitivity of the sensor . The synergistic effect of the two nanomaterials further enhanced the detection signal. Therefore, these results contribute to the advancement of knowledge in the field of nanomaterials and their application in sensitive and selective detection systems of bioactive compounds, such as ascorbic acid.