For three-dimensional hydrogel functionalized graphene high performance gas detection, both 3D and green synthetic!

Nitrogen dioxide (NO 2 ) and other gases has become today\’s environment pollution and health field solved, develop accurate, rapid and sensitive detection of low concentration of the gas is important gas sensor. Reduced graphene oxide (of RGO) having a potential in the preparation of high-performance, low-cost gas sensors aspect, but there are three problems limit its practical application: 1) the graphene gas sensor response to various gases are poor selectivity; 2) the graphene sheets are stacked prone to agglomeration, leading to reduction in the gas molecules adsorption sites alkenyl graphite surface; 3) GO reduced to RGO, the conventional reducing agents (such as hydroquinone, hydrazine, etc.) having some toxicity bring problems of environmental pollution and safety operations. Based on this, Sun Yat-sen Professor Wu Jinfu team by a simple self-assembly method to the human body-friendly vitamin C (VC) as a reducing agent in relatively mild conditions (95 ℃ , atmospheric pressure), synthesized the the VC-dimensional graphene modified hydrogel (V-RGOH), and used to prepare a chemical gas sensor impedance . VC nontoxic, on the one hand as a reducing agent to achieve the RGOH generated, on the other hand were a function modification RGO, significantly improve the performance of the sensor. Three-dimensional porous structures significantly increase the surface area, provides a large amount of gas adsorption sites, it is conducive to improve the sensitivity of the sensor. Moreover, this work also explored the use of implanted micro heater device performance dependence on temperature.

用于高性能气体检测的三维功能化石墨烯水凝胶,兼具三维和绿色合成!
FIG 1. V-RGOH sensor SEM photograph and schematic diagram preparation

obtained in comparison with RGOH hydrothermal method, the V-RGOH sensor detection sensitivity NO 2 and NH higher 3 , the lower limit of detection and faster response / recovery rate . For example, RGOH and V-RGOH detection sensitivity NH3 were 0.03 ppm -1 and 0.39 ppm -1 . Meanwhile, V-RGOH detection limit as low as 0.42 ppm, is better than 6.4 ppm RGOH. Dimensional porous structure that provides a large amount of gas adsorption sites; Meanwhile, VC pointsA hydroxyl group on the sub-hydrogen bond may be formed with gas molecules, so that the interaction of V-RGOH gas has been enhanced to improve the binding energy, the promotion of the gas adsorption. Further, the carrier may also be hopping through the nanopore, facilitate the transmission carriers.

用于高性能气体检测的三维功能化石墨烯水凝胶,兼具三维和绿色合成!
FIG. 2. V-RGOH IV characteristics of the sensor response characteristics of NH3
用于高性能气体检测的三维功能化石墨烯水凝胶,兼具三维和绿色合成!
Figure 3. The V-RGOH sensor response of NO2 characteristics

Further, the other surface of the sensor substrate of the integrated micro-heater, in situ by changing the operating temperature of the device, gas-sensitive behavior change investigated. It found that the temperature rise weakened sensitivity, but can play a significant role in promoting the recovery process. For example, the detection of 80 ppm NH2 3 , the temperature was raised from 22 ° C to 57 ° C, V-RGOH response decreased from 22.7 to 4.13 percent, but the signal recovery percentage increase from 75.2% to 100%.

用于高性能气体检测的三维功能化石墨烯水凝胶,兼具三维和绿色合成!
FIG. 4. V-RGOH NH3 gas sensing sensor responses at different temperatures

In addition to the above properties, V-RGOH sensor further exhibit good linearity, select and a wider detection range. This work uses green synthetic route, the functionalized chemically combining the three-dimensional structural control, reveal its advantages in terms of making highperformance gas sensor.

用于高性能气体检测的三维功能化石墨烯水凝胶,兼具三维和绿色合成!
FIG. 5. V-RGOH selective sensors

In the above-mentioned results of \”Green Synthesis of 3DChemically Functionalized Graphene Hydrogel for High-Performance NH3and NO2 Detection at Room Temperature\” was published in the \”ACS Applied Materials & Interfaces\” journals, first author and corresponding author for the Sun Yat-sen Professor Wu Jinfu . This work was supported by StateNatural Science Foundation-funded home, Guangdong Natural Science Foundation and other projects. Article link:

https://doi.org/10.1021/acsami.0c00578

related links the three-dimensional graphene gas sensor:

https://pubs.acs.org/doi/10.1021/ acsami.9b18098https: //doi.org/10.1039/C6TA01426Ghttps: //doi.org/10.1002/advs.201600319

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