Crystalline growth of tungsten trioxide (WO3) nanorods and their development as an electrochemical sensor for selective detection of vitamin C

Abstract

Tungstate nanorods (WO3 -NRs) were synthesized by a facile hydrothermal method using sodium tungstate as a precursor while sodium sulfate and hydrochloric acid were used as stabilizing agents. Scanning electron microscopy (SEM) images showed outstanding growth of WO3-NRs with uniform surface morphology. The X-ray diffraction (XRD) analysis confirmed the purity and crystalline nature of the synthesized material. The material was further characterized by different tools such as TEM, EDX, FTIR, XPS, BET, and Raman spectroscopy. For the electrochemical response of WO3-NRs, cyclic voltammetry measurements were performed for the detection of vitamin C (ascorbic acid). The designed sensor shows a limit of detection of 0.56 µM and higher selectivity in the presence of its structural and functional analogs such as uric acid and lauric acid. Improved sensing properties of WO3-NRs are attributed to the synergistic effects involving the quantum effect, high surface area, fast electron transfer, and highly ordered 1-D nanostructure. Among them, the highly arranged 1-D growth of WO3 nanorods has a greater impact on the efficiency of the biosensor. These results provide a new insight for the synthesis of 1-D nanostructures of transition metal oxides for contributions in sensor devices, solar cells, and capacitor applications.