Three-dimensional mesoporous graphene aerogel-supported SnO2 nanocrystals for high-performance NO2 gas sensing at low temperature

Two-dimensional layered nanomaterials for gas-sensing applications

In this critical review, we mainly focus on the current developments of gas sensors based on typical 2D layered nanomaterials, including graphene, MoS₂, MoSe₂, WS₂, SnS₂, VS₂, black phosphorus (BP), h-BN, and g-C₃N₄.

High efficiency room temperature detection of NO2gas based on ultrathin metal/graphene devices

High efficiency detection of NO₂by ultrathin metal decorated graphene sensors at room temperature.

Improved Selectivity and Sensitivity of Gas Sensing Using a 3D Reduced Graphene Oxide Hydrogel with an Integrated Microheater

Low-cost, one-step, and hydrothermal synthesized 3D reduced graphene oxide hydrogel (RGOH) is exploited to fabricate a high performance NO2 and NH3 sensor with an integrated microheater. The sensor can experimentally detect NO2 and NH3 at low concentrations of 200 ppb and 20 ppm, respectively, at room temperature. In addition to accelerating the signal recovery rate by elevating the local silicon substrate temperature, the microheater is exploited for the first time to improve the selectivity of NO2 sensing. Specifically, the sensor response from NH3 can be effectively suppressed by a locally increased temperature, while the sensitivity of detecting NO2 is not significantly affected. This leads to good discrimination between NO2 and NH3. This strategy paves a new avenue to improve the selectivity of gas sensing by using the microheater to raise substrate temperature.

Graphene Hybrid Materials in Gas Sensing Applications

Graphene, a two dimensional structure of carbon atoms, has been widely used as a material for gas sensing applications because of its large surface area, excellent conductivity, and ease of functionalization. This article reviews the most recent advances in graphene hybrid materials developed for gas sensing applications. In this review, synthetic approaches to fabricate graphene sensors, the nano structures of hybrid materials, and their sensing mechanism are presented. Future perspectives of this rapidly growing field are also discussed.

SnO2 quantum dots decorated on RGO: a superior sensitive, selective and reproducible performance for a H2 and LPG sensor

We report the H2 and LPG gas sensing behavior of RGO/SnO2 QDs synthesized by a surfactant assisted hydrothermal method. The RGO/SnO2 QD based sensor shows a high response of ∼89.3% to H2 and ∼92.4% to LPG for 500 ppm test gas concentration at operating temperatures of 200 °C and 250 °C, respectively. Further, the RGO/SnO2 QD based sensor shows good selectivity for H2 and LPG in the presence of other interfering gases such as ammonia, chloroform, toluene, benzene, acetone, n-butylacetate, acetic acid and formic acid. We observed that the gas response to H2 is 29.8 times higher than that to acetic acid whereas the gas response to LPG is 17.8 times higher than that to formic acid. Long-term analyses have also been performed to demonstrate the reproducible nature of the RGO/SnO2 QD based sensor over passing time which shows excellent reproducibility.

Fabrication of SnO2-SnO nanocomposites with p-n heterojunctions for the low-temperature sensing of NO2 gas

In this report, the fabrication of a novel SnO2-SnO nanostructure with p-n heterojunctions has been achieved through a facile one-pot and low-cost hydrothermal process. The structure and properties of the nanocomposite were analyzed with X-ray techniques and electron microscopy. HRTEM characterization showed that the p-n heterojunctions were formed with small n-type SnO2 nanocrystals dispersed on the surface of large p-type SnO crystals. Compared to the single SnO2-based material, a gas sensor fabricated from the SnO2-SnO composite exhibited an enhanced sensing performance for NO2 gas detection, with a limit of detection and sensitivity of 0.1 ppm and 0.26 ppm(-1), respectively, at a relatively low operating temperature (50 °C). Moreover, the p-n heterojunctions exhibited high sensing selectivity for NO2. Such a high sensing sensitivity and a low operating temperature make the SnO2-SnO p-n nanomaterial a promising gas sensor for practical NO2 gas detection. The improved sensing response characteristics of the hybrid material could be attributed to the p-n junctions formed through the in situ growth of SnO2 nanocrystals on SnO nanoplates. The present study is helpful for the design of novel gas sensing materials and the development of NO2 gas sensors.

Gas sensors based on ultrathin porous Co3O4 nanosheets to detect acetone at low temperature

Gas sensors based on ultrathin porous Co₃O₄ nanosheets to detect acetone for diagnosing diabetes at a low operating temperature.

Fabrication of a high density graphene aerogel–gold nanostar hybrid and its application for the electrochemical detection of hydroquinone and o-dihydroxybenzene

We report the first synthesis of a high density graphene aerogel–gold nanostar hybrid with excellent mechanical and electrical properties and its application in the electrochemical detection of hydroquinone and o-dihydroxybenzene.