Doped ZnO Nanostructured Sensor in Electronic Nose for Detection of Ammonia, Hydrogen and Liquefied Petroleum Gas

In this experimental work, a nanostructured ZnO like nano flowers doped with different elements, X = Pd, Pt, Co, Mn, Ni, Sn are synthesized. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) are used for characterization of the materials and surface morphology. The materials were synthesized from pyrolysis of Zn(NO3)(2) solution with triethanolamine (TEA) with adequate dopant. After complete dehydration of the precursor solution, a black, carbonaceous, mesoporous fluffy mass is obtained, which after calcinations produces the desired nanocrystalline materials. Formation of hexagonal single phase ZnO nanoparticle is confirmed by the careful analysis of XRD data. It follows from non oriented growth for undoped nanostructure to strongly (002) oriented, at intermediate (similar to 1at. %) doping level. The materials are also characterized through transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis to obtain the shape, size, morphology and elemental compositions. Average crystallite size and particle size are observed to be between 24 and 33 nm, which are analyzed through XRD and transmission electron microscope, respectively. Electrical as well as gas sensing properties of the synthesized materials have been studied by dc measurement.