The chemically prepared pristine and graphene-doped polyaniline (PANI) samples are utilized for the fabrication of room temperature methanol sensors. For the fabrication of PANI/graphene-based sensing devices, four samples of PANI/graphene composites were prepared with four different concentrations of graphene (2, 4, 6 and 8 wt%). The surface morphology of the prepared composites was analyzed under field emission scanning electron microscopy (FE-SEM), which revealed the agglomerated structures of PANI/graphene composites. X-Ray diffraction studies carried out on these samples revealed the semi-crystalline nature of the samples, whereas, Raman studies confirmed the growth of PANI with the presence of all fundamental bands of PANI in the pristine as well as in its doped state. The prepared PANI/graphene composites devices were tested for alcohol detection at two different concentrations (50 and 100 ppm) of methanol. The change in electric current with the change in environment has been recorded as a sensing parameter and is employed to determine other sensor parameters such as percentage response, response time and recovery time. The sensing response of the prepared samples is found to increase with graphene doping concentration as well as methanol ppm level. The PANI/graphene composite with 8 wt% doping of graphene has shown the highest response (~ 61.5% at 100 ppm) and the lowest response time (55 s). The mechanism of gas sensing has also been discussed in details with the possible theoretical analogy with the adsorption and desorption of gas molecules in accordance with Langmuir kinetic theory.

中文翻译：

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基于聚苯胺/石墨烯微/纳米复合材料的高效室温甲醇传感器

化学制备的原始和石墨烯掺杂的聚苯胺（PANI）样品用于制造室温甲醇传感器。为了制造基于PANI /石墨烯的传感设备，制备了四个PANI /石墨烯复合材料样品，其中包含四种不同浓度的石墨烯（2、4、6和8 wt％）。在场发射扫描电子显微镜（FE-SEM）下分析了所制备复合材料的表面形态，揭示了聚苯胺/石墨烯复合材料的团聚结构。在这些样品上进行的X射线衍射研究揭示了样品的半结晶性质，而拉曼研究证实了PANI的生长，因为PANI的所有基本谱带都处于原始状态以及处于掺杂状态。测试了所制备的PANI /石墨烯复合材料装置在两种不同浓度（50和100 ppm）甲醇下的酒精检测。电流随环境变化的变化已记录为传感参数，并用于确定其他传感器参数，例如百分比响应，响应时间和恢复时间。发现所制备样品的感测响应随石墨烯掺杂浓度以及甲醇ppm水平而增加。掺杂了8 wt％石墨烯的PANI /石墨烯复合材料显示出最高的响应速度（在100 ppm时约为61.5％）和最低的响应时间（55 s）。还根据朗缪尔动力学理论，以可能的理论类比与气体分子的吸附和解吸对气体传感机理进行了详细讨论。