Abstract NO2 and H2 gas sensing by few-layer graphene (FLG) were studied in dependence on the annealing and decoration of graphene by palladium nanoparticles (NPs). Graphene was deposited onto SiO2 (500 nm)/Si substrates by a modified Langmuir-Schaefer technique. A solution of FLG flakes in 1-methyl-2-pyrrolidone was obtained by a mild sonication of the expanded milled graphite. FLG films were characterized by atomic force microscopy, X-ray diffraction, Raman spectroscopy, and the Brunnauer-Emmett-Teller method. Average FLG flake thickness and lateral dimension were 5 nm and 300 nm, respectively. Drop casting of Pd NP (6–7 nm) solution onto FLG film was applied to decorate graphene by Pd. The room temperature (RT) resistance of the samples was stabilized at 15 kΩ by vacuum annealing. Heating cycles of FLG film revealed its semiconducting character. The gas sensing was tested in the mixtures of dry air with H2 gas (10 to 10 000 ppm) and NO2 gas (2 to 200 ppm) between RT and 200 °C. The response of 26 % to H2 was achieved by FLG with Pd decoration at 70 °C and 10 000 ppm of H2 in the mixture. Pure FLG film did not show any response to H2. The response of FLG with Pd to 6 ppm of NO2 at RT was ≥ 23 %. It is 2 times larger than that of the pure FLG sample. Long term stability of sensors was studied.

中文翻译：

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用于 NO2 和 H2 气体传感器的 Pd 纳米颗粒装饰的石墨烯 Langmuir-Schaefer 薄膜

摘要 基于钯纳米颗粒 (NPs) 对石墨烯的退火和装饰，研究了少层石墨烯 (FLG) 对 NO2 和 H2 气体的传感。通过改进的 Langmuir-Schaefer 技术将石墨烯沉积在 SiO2 (500 nm)/Si 衬底上。FLG 薄片在 1-甲基-2-吡咯烷酮中的溶液通过膨胀研磨石墨的温和超声处理获得。FLG 薄膜通过原子力显微镜、X 射线衍射、拉曼光谱和 Brunnauer-Emmett-Teller 方法进行表征。平均 FLG 薄片厚度和横向尺寸分别为 5 nm 和 300 nm。将 Pd NP（6-7 nm）溶液滴铸到 FLG 膜上，用 Pd 装饰石墨烯。通过真空退火，样品的室温 (RT) 电阻稳定在 15 kΩ。FLG 薄膜的加热循环揭示了其半导体特性。在室温和 200 °C 之间，在干燥空气与 H2 气体（10 至 10 000 ppm）和 NO2 气体（2 至 200 ppm）的混合物中测试了气体传感。26% 对 H2 的响应是通过 FLG 在 70°C 和 10000 ppm 的 H2 混合物中使用 Pd 装饰实现的。纯 FLG 薄膜对 H2 没有任何反应。在室温下，含 Pd 的 FLG 对 6 ppm NO2 的响应≥ 23 %。比纯 FLG 样品大 2 倍。研究了传感器的长期稳定性。比纯 FLG 样品大 2 倍。研究了传感器的长期稳定性。比纯 FLG 样品大 2 倍。研究了传感器的长期稳定性。