title: Controlled synthesis of ZnO from nanospheres to micro-rods and its gas sensing studies.
abstract: 1D ZnO rods are synthesized using less explored hydrazine method. Here we find, besides being combustible hydrazine can also be used as a structure-directing agent. The ratio of zinc nitrate (ZN) to hydrazine is found to control the morphology of ZnO. At lower concentration of ZN as compared with hydrazine the morphology of ZnO is found to be spherical. As we increase the hydrazine content the morphology changes from spherical (diameter approximately 100 nm) to the elongated structures including shapes like Y, T as well dumbbell (diameter approximately 40 nm and length approximately 150 nm). Interestingly for more than 50% of hydrazine ZnO micro-rods are formed. Such rods are of diameter approximately 120 nm having length of about 1 microm for ZN to hydrazine ratio of 1:9, isolated as well as bundle of rods are seen in scanning electron microscopy (SEM). The X-ray diffraction (XRD) reveals the phase formation with average particle size of 37 nm as calculated using Scherrer's formula. The high-resolution transmission electron microscopy (HRTEM) is also done to confirm the d-spacing in ZnO. Gas sensing study for these samples shows high efficiency and selectivity towards LPG at all operating temperatures. Photoluminescence (PL) study for these samples is performed at room temperature to find potential application as photoelectric material.
authors.affiliation: Physical and Materials Chemistry Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Shalaka C
authors.initials: SC
authors.lastname: Navale
authors.forename: S W
authors.initials: SW
authors.lastname: Gosavi
authors.forename: I S
authors.initials: IS
authors.lastname: Mulla
mesh_terms: D005740:Gases; D006834:Hydrazines / Q000737:chemistry; D054118:Nanospheres / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry*; D009566:Nitrates / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties; D013696:Temperature; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000737:chemistry; D015034:Zinc Oxide / Q000138:chemical synthesis*
chemical_list: D005740:Gases; D006834:Hydrazines; D009566:Nitrates; D017967:Zinc Compounds; C029424:hydrazine; C042103:zinc nitrate; D015034:Zinc Oxide