Synthesis And Properties Of Porous ZnO Micro-nanospheres

Zinc oxide, as an significant semiconductor metallic oxide material with a directband gap (3.37eV), has received much attention for its potential application in catalysis,optoelectronics, biology and chemical sensors and so on. Porous ZnO nanostructurespossess large surface area and unique porous structure. In this paper, we studiedsynthesis and properties of porous ZnO nanostructure. Different methods (etching,irradiating and solvothermal) were applied to prepare several kinds of porous ZnOmaterials. The microstructures of the materials were characterized by scanning electronmicroscope, transmission electron microscope, X-ray diffraction and nitrogenadsorption-desorption. gas sensor property of hydrogen sulfide, sulfur dioxide, ethanoland acetone were studied. And sensor mechanisms were also discussed. The maincontents are as follows:(1) Porous ZnO nanospheres with500nm in diameter were synthesized by acationic surfactant assisted selective etching strategy. The gas-sensing propertiesshowed that the as-obtained nanomaterials has a high and fast response to acetone, Thematerials sensor can detect acetone concentration down to1ppm with the sensitivityabout2.6. The excellent property derived to high surface area and grain sizes.Meanwhile, the photocatalytic degradation experiments revealed that the materialsexhibit high photocatalytic activity for the degradation of methyl orange with adegradation rate of96.2%by50min.(2) Ag2O doped ZnO materials for organic dye solution degradation under visiblelight was prepared. ZnO porous materials possess an average diameter of500nm, andAg2O nanoparticles coating on the surface of ZnO sphere possess the diameter of20nm.Ag2O/ZnO materials exhibited the highest photocatalytic activity for the degradation ofMB. It cost just40min to reach96%degradation.(3) Well-defined porous ZnO hollow microspheres (PZHM) were successfullysynthesized through a simple decomposition method. Zinc acetate and1,2-propyleneglycol was used as zinc source and solvent, respectively. The material can be used as anexcellent sensor for acetone detection (The PZHM sensor can detect acetone concentration down to1ppm with the sensitivity about1.65).The results indicate that the structure and morphology of the material plays asignificant role in the gas sensing performance. High surface area and small particle sizeof the materials can improve their gas sensitivity. The gas sensor test results show thatthe material has the best selectivity to acetone. These porous ZnO nanomaterials havepotential application on catalysis and adsorption field.