Although many reports have been reported on the rGO sensing devices, it is still a great challenge to develop chemiresistive sensors based on rGO with miniature, low-cost, and portable characteristics. In order to fabricate
chemiresistive sensors based on nanomaterial, there are generally two main methods. One is to deposit nanomaterial on substrates followed by patterning electrodes on top of sensing materials [34]. However, the process is complicated and requires exquisite skills. The other fascinating method is to drop-cast nanomaterial solution onto the pre-patterned electrode surfaces [29, 35]. This technique is facile, less expensive with higher yields, since it can be operated in solution, which benefits for the large-scale fabrication of the sensing devices. However, drop-casting method is very hard to ensure the reproducibility of the fabricated devices, which needs to be improved and applied in the realistic detection fields. Herein, we report Selleck HDAC inhibitor a facile and controllable self-assembly technique to fabricate rGO sensors, which could be
used as an excellent NH3 gas sensing device. Negative GO sheets with large sizes (>10 μm) can be easily electrostatically attracted onto positive Au electrodes modified C188-9 in vivo with cysteamine hydrochloride in aqueous solution. The assembled GO sheets on Au electrodes can be directly reduced into rGO sheets by hadrazine or pyrrole vapor and consequently provide the sensing devices based on self-assembled rGO sheets. In addition, pyrrole-vapor-reduced rGO-based sensor exhibits excellent response to NH3. We expect the easy, reproducible, green, and scalable fabrication of the sensors based on rGO reduced by pyrrole, with excellent performance, miniature,
low-cost, and portable characteristics, can pave a new avenue for the application of assembled rGO devices in gas sensing field. Methods Materials The natural graphite (32 meshes) used in this study was obtained from Qingdao Jinrilai Co. Ltd, Qingdao, China. Pyrrole was obtained from Shanghai Chemical Reagents Co. Ltd. (Shanghai, China) and purified by distillation. Pre-determined NH3 gas (1 ppm) mixed with air was purchased from Beijing Beiyang Special Gases Institute Co. Ltd. (Beijing, China). Concentrated ammonia solution (25 wt.%) and all of other chemicals (analytical reagent grade) Urocanase were purchased from Shanghai Chemical Reagents Co. Ltd. (Shanghai, China) and were used without further purification. All of organic solvents were purified by distillation. Self-assembly of GO sheets on Au electrodes GO sheets with large sizes were prepared Selleckchem Q VD Oph similar to the method reported by Zhao et al. [36]. Large-size GO aqueous solution with the concentration at 2.5 mg/mL was prepared by mild sonication (80 W for 5 min) and stored for the further self-assembly process. The standard microfabrication procedures were exploited to obtain the Au electrodes according to the method illustrated by us before [37].
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