Abstract In this work, the reduced graphene oxide (rGO) was introduced into SnO2 nanospheres to form the rGO-SnO2 nanocomposites, which were used for designing a high-performance NO2 gas sensor. The rGO-SnO2 nanocomposites were synthesized by a simple hydrothermal method, with the GO consumption from 0.1 wt% to 0.6 wt%. The synthesized samples were characterized by XRD, SEM, AFM, TEM, FTIR, and XPS. Microstructural characterization indicates that both pure SnO2 and SnO2 nanospheres in rGO-SnO2 nanocomposites have a tetragonal cassiterite structure. Pure SnO2 is a series of microspheres with the diameter of 1–2 μm assembled by a lot of nanoplates. While the SnO2 nanospheres with the diameter of 40–60 nm uniformly distribute on the rGO sheets. The pure rGO based sensor, pure SnO2 based sensor and rGO-SnO2 nanocomposite based sensor were investigated in their gas sensing performance at the operating temperature of 75–175 °C. The 0.2 wt% rGO-SnO2 nanocomposites show a higher response of 53.57 and faster response/recovery time of 16 s/63 s to 3 ppm NO2 at 125 °C than pure rGO and pure SnO2. The test results indicate that the introduction of rGO into SnO2 improves its sensing performance. Moreover, the rGO-SnO2 nanocomposites exhibit a high selectivity and good reproducibility to NO2.

中文翻译：

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用于 NO2 监测的高响应性和选择性 rGO-SnO2 纳米复合材料的设计与应用

摘要 在这项工作中，将还原氧化石墨烯 (rGO) 引入 SnO2 纳米球中形成 rGO-SnO2 纳米复合材料，用于设计高性能的 NO2 气体传感器。rGO-SnO2 纳米复合材料是通过简单的水热法合成的，GO 消耗量为 0.1 wt% 至 0.6 wt%。合成的样品通过 XRD、SEM、AFM、TEM、FTIR 和 XPS 进行表征。微观结构表征表明，rGO-SnO2 纳米复合材料中的纯 SnO2 和 SnO2 纳米球都具有四方锡石结构。纯 SnO2 是由大量纳米片组装而成的一系列直径为 1-2 μm 的微球。而直径为 40-60 nm 的 SnO2 纳米球均匀分布在 rGO 片上。基于纯 rGO 的传感器，研究了基于纯 SnO2 的传感器和基于 rGO-SnO2 纳米复合材料的传感器在 75-175°C 的工作温度下的气敏性能。与纯 rGO 和纯 SnO2 相比，0.2 wt% rGO-SnO2 纳米复合材料在 125 °C 下对 3 ppm NO2 显示出更高的响应（53.57）和更快的响应/恢复时间（16 秒/63 秒）。测试结果表明，将 rGO 引入 SnO2 提高了其传感性能。此外，rGO-SnO2 纳米复合材料对 NO2 表现出高选择性和良好的重现性。测试结果表明，将 rGO 引入 SnO2 提高了其传感性能。此外，rGO-SnO2 纳米复合材料对 NO2 表现出高选择性和良好的重现性。测试结果表明，将 rGO 引入 SnO2 提高了其传感性能。此外，rGO-SnO2 纳米复合材料对 NO2 表现出高选择性和良好的重现性。