中文摘要：

利用聚乙烯吡咯烷酮（PVP）作为表面活性剂，将四氯化锡（SnCl4）溶解在甲醇溶液中，再通过溶剂热法，制备了多孔氧化锡（SnO2）纳米球。采用X射线衍射（XRD）仪和扫描电子显微镜（SEM）对合成材料的结构和形貌进行了表征。结果表明，SnO2纳米球为分布均匀的多孔球。同时，采用旁热式气敏元件结构对样品进行氢气（H2）敏感性能研究，测试结果证明制作的气体传感器对氢气表现出良好的气敏特性，在最佳工作温度250℃下对体积分数10^-4氢气的响应可达到6，最低体积分数检测极限为5×10^-6，并且响应时间和恢复时间分别为2s和4S。

英文摘要：

The porous SnO2 nanospheres were synthesized via a solvothermal method by using polyvinyl pyrrolidone （PVP） as the surfactant and dissolving SnCl4 in the methanol solution. The structure and morphology of the synthetic materials were characterized by the X-ray diffrac- tion （XRD） and scanning electron microscope （SEM）. The experimental results show that the SnO2 nanospheres are porous and uniformly distributed. Meanwhile, the gas sensing properties of the indirectly heated type gas sensors based on SnO2 nanospheres were investigated for hydrogen （H2） detection. The test results indicate that the fabricated gas sensor has good gas sensing properties to hydrogen. At the optimum working temperature of 250 ℃, the response to hydro- gen with the volume fraction of 10^-4 can reach 6 and the minimal detection limit of the volume fraction is as low as 5 × 10^-6. Besides, the response time and recovery time are 2 s and 4 s, respectively.