Improving the ammonia sensing of reduced graphene oxide film by using metal nano-materials

Gas sensing is one of the most promising applications for reduced graphene oxide (rGO). High surface-to-volume ratio in conjunction with remaining reactive oxygen functional groups translates into sensitivity to molecular on the rGO surface. The response of the rGO based devices can be further improved by functionalizing its surface with metal nano-materials. In this paper, we report the ammonia (NH3) sensing behavior of rGO based sensors functionalized with nano-structured metal: silver (Ag) or platinum (Pt) or gold (Au) in air at room temperature and atmospheric pressure. The gas response is detected by the monitoring changes in electrical resistance of the rGO/metal hybrids due to NH3 gas adsorption. Compared to bare rGO, significantly improved NH3 sensitivity is observed with the addition of nano-structured metals. These materials are applied to play the small bridges role connecting many graphene islands together to improve electrical conduction of hybrids while maintaining the inherent advantage of rGO for NH3 gas sensitivity.

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Mesoporous titanosilicate/reduced graphene oxide composites: layered structure, high surface-to-volume ratio, doping effect and application in dye removal from water

Journal of Materials Chemistry ◽

10.1039/c2jm33309k ◽

2012 ◽

Vol 22 (38) ◽

pp. 20504 ◽

Cited By ~ 20

Author(s):

Thuy-Duong Nguyen-Phan ◽

Eun Woo Shin ◽

Viet Hung Pham ◽

Hyukmin Kweon ◽

Sunwook Kim ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Layered Structure ◽

Dye Removal ◽

High Surface ◽

Volume Ratio ◽

Doping Effect ◽

Reduced Graphene ◽

Oxide Composites

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N-doped reduced graphene oxide for room-temperature NO gas sensors

Scientific Reports ◽

10.1038/s41598-021-99883-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yu-Sung Chang ◽

Feng-Kuan Chen ◽

Du-Cheng Tsai ◽

Bing-Hau Kuo ◽

Fuh-Sheng Shieu

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Room Temperature ◽

Gas Sensing ◽

Ambient Conditions ◽

Gas Sensitivity ◽

Nitrogen Doped ◽

Low Concentrations ◽

Reduced Graphene ◽

P Type

AbstractIn this study, we use nitrogen-doped to improving the gas-sensing properties of reduced graphene oxide. Graphene oxide was prepared according to a modified Hummers’ method and then nitrogen-doped reduced graphene oxide (N-rGO) was synthesized by a hydrothermal method using graphene oxide and NH4OH as precursors. The rGO is flat and smooth with a sheet-like morphology while the N-rGO exhibits folded morphology. This type of folding of the surface morphology can increase the gas sensitivity. The N-rGO and the rGO sensors showed n-type and p-type semiconducting behaviors in ambient conditions, respectively, and were responsive to low concentrations of NO gases (< 1000 ppb) at room temperature. The gas-sensing results showed that the N-rGO sensors could detect NO gas at concentrations as low as 400 ppb. The sensitivity of the N-rGO sensor to 1000 ppb NO (1.7) is much better than that of the rGO sensor (0.012). Compared with pure rGO, N-rGO exhibited a higher sensitivity and excellent reproducibility.

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Reduced Graphene Oxide Screen Printed Thick Film as NO2 Gas Sensor at Low Temperature

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1167.43 ◽

2021 ◽

Vol 1167 ◽

pp. 43-55

Author(s):

Anil Patil ◽

Umesh Tupe ◽

Arun V. Patil

Keyword(s):

Graphene Oxide ◽

Thick Film ◽

Reduced Graphene Oxide ◽

Gas Sensing ◽

Thick Films ◽

Research Work ◽

Fast Response ◽

Gas Sensitivity ◽

Reduced Graphene ◽

Sensitivity And Selectivity

Most of the recent reduced graphene oxide (rGO) based sensors shows gas sensitivity above 50o to 150°C. The present investigation deals with the gas sensing at 50°C temperature. In the present research work, thick film sensors of rGO were developed on glass substrate by using standard screen-printing technique. The silver paste of rGO was used to make electrodes for contact on thick films for the electrical and gas sensing system. The electrical properties of rGO thick films such as resistivity, activation energy and temperature coefficient were studied. The resistivity of rGO thick films was found to be 84.84 Ω/m. The morphological, elemental and structural properties of rGO thick films were analyzed by SEM, EDS and XRD techniques respectively. The crystallite size of rGO thick films was found as 28.42 nm by using Scherer’s formula. The rGO thick films were prepared and exposed to Ethanol, NH3, NO2 and LPG gases to determine sensitivity and selectivity. The sensitivity of NO2 has been found to be maximum among other exposed gases. The maximum sensitivity of NO2 gas was 92.55 % at 50 °C found with fast response (~ 11 sec) and recovery (~ 19 sec) time.

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Synthesis of transition metal sulfide and reduced graphene oxide hybrids as efficient electrocatalysts for oxygen evolution reactions

Royal Society Open Science ◽

10.1098/rsos.180927 ◽

2018 ◽

Vol 5 (9) ◽

pp. 180927 ◽

Cited By ~ 3

Author(s):

Yu-Rim Hong ◽

Sungwook Mhin ◽

Jiseok Kwon ◽

Won-Sik Han ◽

Taeseup Song ◽

...

Keyword(s):

Graphene Oxide ◽

Catalytic Activity ◽

Transition Metal ◽

Reduced Graphene Oxide ◽

Oxygen Evolution ◽

Chemical Interaction ◽

High Surface ◽

Metal Sulfide ◽

Volume Ratio ◽

Reduced Graphene

The development of electrochemical devices for renewable energy depends to a large extent on fundamental improvements in catalysts for oxygen evolution reactions (OERs). OER activity of transition metal sulfides (TMSs) can be improved by compositing with highly conductive supports possessing a high surface-to-volume ratio, such as reduced graphene oxide (rGO). Herein we report on the relationship between synthetic conditions and the OER catalytic properties of TMSs and rGO (TMS–rGO) hybrids. Starting materials, reaction temperature and reaction time were controlled to synergistically boost the OER catalytic activity of TMS–rGO hybrids. Our results showed that (i) compared with sulfides, hydroxides are favourable as starting materials to produce the desired TMS–rGO hybrid nanostructure and (ii) high reaction temperatures and longer reaction times can increase physico-chemical interaction between TMSs and rGO supports, resulting in highly efficient OER catalytic activity.

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