Study On Preparation And Gas Sensing Property Of Sheetlike ZnO And Its Doped Products

Zinc oxide, as an n-type semiconductor material with wide band-gap, is anindispensable material in the areas of gas detection and clean energy, owing to itsexcellent optical, catalytic and gas sensing properties. Zinc oxide also has manyadvantages, such as simple preparation process, low-cost and non-toxic. Based onprevious studies, zinc oxide nanosheets and Fe, Al, Ce, Ag-doped products had beenprepared by hydrothermal method in this paper. Factors, such as the types of dopingelements and the doping amounts, having an effect on the crystal structure andmorphology of zinc oxide, were studied. We also studied the gas sensing property ofthe products. The main contents are as follows.First, we studied the gas sensing property of zinc oxide nanosheets and Fe, Al,Ce-doped products, which were prepared by solvothermal method from zinc acetateand urea, using ethylene glycol and water as solvent. The results showed that zincoxide with trace doping did not change its own crystal structure, Fe-doped zincoxide’s morphology became more uniform, a certain amount of doping effectivelyimproved the gas sensing property of zinc oxide, and Ce-doped zinc oxide’s gassensing enhancement was better than Al and Fe-doped ones.Multilayered zinc oxide nanosheets and Al-doped products were prepared byhydrothermal method, using zinc nitrate, urea and oleic acid as raw materials. Wetested its gas sensing and optical properties. We found that the pore on the nanosheetsof Al-doped zinc oxide became more uniform. Zinc oxide’s gas sensing propertyenhanced obviously when the doping amount of Al element was3%. The lightemitting regions of doped zinc oxide contained ultraviolet region (380-400nm) andblue region (460-490nm), and the intensity of blue-emitting enhanced.We studied the gas sensing and optical properties of the zinc oxide porousnanosheets and Ag-doped products. The samples were prepared by solvothermalmethod from zinc acetate, urea and PVP, using ethylene glycol and water as solvent.The results indicated that the doped samples had silver phase and zinc oxide phase,silver particles attached to the surface of zinc oxide nanosheets. The effect of the reaction temperature, reaction time and calcination temperature on the gas sensingproperty of zinc oxide were studied. We found that zinc oxide had a best gas sensingperformance when the hydrothermal reaction proceed21h at the temperature of140℃and the precursor was calcinated at the temperature of600℃. Ag-doped zincoxide had a best gas sensing property when the doping amount was1%. After westudied the optical property of undoped and doped zinc oxide, we found thatAg-doped zinc oxide’s band-gap became narrow and its emission intensity in thevisible region had been enhanced. The light emitting regions of zinc oxide containedultraviolet region (380-400nm) and blue region (460-490nm). There was a largeamount of oxygen vacancy (Vo) and zinc interstitial (Zni) on the surface of undopedand doped zinc oxide.