Study On Preparation And Gas-sensing Properties Of Low-dimensional And Hierarchical Vanadium Oxide Nanostructures

With the development of modern society, security issues have becomeincreasingly prominent, and the requirements of reliability gas detection are alsoincreasing, Ethanol gas sensors with high sensitivity, stability, selectivity, andportability are used in the biological, chemical, medical and food industries. Gassensor based on the semiconductor oxide nanowires has great potential applicationswith the environment and our health. In this article, the ultra-dispersed V2O5nanowires and nanorods were studied, and gas sensors based on V2O5hierarchicalnanostructured were be able to evaluate the ethanol gas sensing properties.Gas sensors based on V2O5hierarchical nanostructured networks were formedthrough a direct seed-induced hydrothermal growth of nanostructured V2O5on thesubstrate attached a pair of patterned Pt electrodes by controlling precursor (NH4VO3)concentrations, Porous flower-or honeycomb-like V2O5hierarchical nanostructuresare synthesized on the substrate, especially the flower-like network with radiallyoriented ultrathin nanoneedles and nanoribbons and the overlaped nanowires asconstituents, show the continuous nanostructured networks of porous feature.The ethanol gas sensing properties of V2O5network-structured sensors showsdual working temperature characteristic. The gas sensor shows perfect sensitivity,good selectivity, high response value and fast response-recovery characteristic toethanol gas at room temperature (20℃) and250℃. Gas sensor based on the V2O5nano-flowers hierarchical nanostructured networks can detect ethanol concentrationsas low as25ppm and5ppm during the dual working temperature, which showedtemperature-dependent p-to n-type response characteristic reversal with thetemperature increasing. Analyzed and discussed its anomalous p-type conductivity atroom temperature and the physical mechanism of conductive p-n transition.With the aid of P123as template directing agent, the ultra-dispersed V2O5nanorods and nanowires have been successfully prepared on the alumina substrate bya simple thermal metavanadate precursor layer, a single nanowires with diameters of50-100nm and lengths of10-20μm. Ultra-dispersion nanowire/rod for thetransplantation of single nanowire/rod and nano-device based on single nanowire/rodprovides great applications.