VO_2(B)/ZnO异质复合纳米棒结构的室温NH_3敏感性能研究

Room-temperature NH_3 Gas Sensing Property of VO_2(B)/ZnO Hierarchical Heterogeneous Composite with Nanorod Structure

以VO_2(B)纳米棒为内核,利用液相生长法制备了VO_2(B)/ZnO异质复合纳米棒,研究了ZnO生长溶液浓度对复合结构微观形貌和气敏性能的影响规律。采用扫描电子显微镜和X射线衍射仪对复合结构样品的微观形貌和结晶取向进行表征,并测试了复合结构对NH_3的敏感性能。实验结果表明,随着ZnO种子液浓度的增大,ZnO逐渐由纳米颗粒生长为纳米棒结构,当ZnO种子液浓度为0.01 mol/L时,ZnO呈棒状沿径向发散生长在VO_2(B)纳米棒表面,形成树枝状VO_2(B)/ZnO异质复合纳米棒结构,这一结构在室温下表现出对NH_3的高灵敏度和突出的选择性,其灵敏度最大可达5.6,对NH_3的响应时间最短仅为2 s。在室温下表现出的优良NH_3敏感性能,主要与高密度的VO_2(B)/ZnO异质结和树枝状结构有关。研究结果为低功耗高灵敏度NH_3气敏传感器的研制提供了重要依据。

VO2 (B)/ZnO nanorods hierarchical heterogeneous composite was synthesized by solution growth method on VO2 (B) nanorods surface. Effects of ZnO seeds’ solution concentration on microstructure and NH3 gas sensing properties of composite structures were investigated. X-ray diffractometer and scanning electron microscopy were used to characterize the crystal structure and surface morphology of the samples. NH 3 gas sensing properties of the composite was measured by the gas testing system at different temperatures and gas concentrations. The results show that ZnO grows on VO 2 (B) surface and changes its shape from nanoparticle to nanorod as the ZnO seeds’ solution concentration increasing from 0.002 mol/L to 0.03 mol/L. ZnO nanorods radially grows on the VO2 (B) nanorod surface and branch-shaped hierarchical heterogeneous VO2 (B)/ZnO composite structures are formed when the solution concentration is 0.01 mol/L. The composite exhibits high gas response and outstanding selectivity at room temperature. The response value reaches 5.6 while the response time is reduced to 2s at room temperature. This excellent NH3 gas sensing performance is related to the highly dense VO 2 (B)/ZnO hetero-junction and hierarchical structure. The present results may provide more information for design and fabrication of low power and high sensitive NH3 gas sensors at room temperature.