scholarly journals Catalytic and thermal characterisations of nanosized PdPt / Al<sub>2</sub>O<sub>3</sub> for hydrogen detection

2014 ◽  
Vol 3 (2) ◽  
pp. 273-280 ◽  
Author(s):  
T. Mazingue ◽  
M. Lomello-Tafin ◽  
M. Passard ◽  
C. Hernandez-Rodriguez ◽  
L. Goujon ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Hydrogen Oxidation ◽  
Thermal Response ◽  
High Conversion ◽  
Hydrogen Sensors ◽  
Flat Substrate ◽  
Sensing Material ◽  
High Conversion Rate ◽  
Very High

Abstract. Palladium platinum (PdPt) has been intensively studied these last decades due to high conversion rate in hydrogen oxidation at room temperature with significant exothermic effects. These remarkable properties have been studied by measuring the temperature variations of alumina (Al2O3) supported nanosized PdPt nanoparticles exposed to different hydrogen concentrations in dry air. This catalyst is expected to be used as a sensing material for stable and reversible ultrasensitive hydrogen sensors working at room temperature (low power consumption). Structural and gas sensing characterisations and catalytic activity of PdPt / Al2O3 systems synthesised by co-impregnation will be presented. Catalytic characterisations show that the system is already active at room temperature and that this activity sharply increases with rise in temperature. Moreover, the increase of the PdPt proportion in the co-impregnation process improves the activity, and very high conversion can be reached even at room temperature. The thermal response (about 3 °C) of only 1 mg of PdPt / Al2O3 is reversible, and the time response is about 5 s. The integration of PdPt / Al2O3 powder on a flat substrate has been realised by the deposition onto the powder of a thin porous hydrophobic layer of parylene. The possibility of using PdPt in gas sensors will be discussed.

Synthesis of NiO@CuO nanocomposite as high-performance gas sensing material for NO 2 at room temperature

2017 ◽  
Vol 412 ◽  
pp. 230-237 ◽  
Author(s):  
He Xu ◽  
Jiawei Zhang ◽  
Afrasiab Ur Rehman ◽  
Lihong Gong ◽  
Kan Kan ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Gas Sensing ◽  
Sensing Material

Highly Sensitive Room Temperature Hydrogen Sensors Based on Photochemically Deposited SnO2

2014 ◽  
Vol 787 ◽  
pp. 378-382 ◽  
Author(s):  
Masaya Ichimura ◽  
Dengbaoleer Ao
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Uv Light ◽  
High Sensitivity ◽  
Sensor Response ◽  
Hydrogen Sensors ◽  
Highly Sensitive ◽  
Initial Resistance ◽  
Very High ◽  
Higher Sensitivity

Highly sensitive room temperature hydrogen sensors based on undoped and Fe-doped SnO2 films were fabricated. The SnO2 films were deposited by the photochemical deposition using an aqueous solution containing SnSO4. For deposition of doped and undoped SnO2 films, a small amount of an aqueous solution was dropped on a glass substrate and irradiated by UV light. The sensors annealed at 200oC showed extremely high sensitivity to hydrogen, but the initial resistance was very high. The sensors annealed at 400oC had a much lower resistance, and thus the sensor response was able to be measured even by a pocket multimeter. The Fe-doped sample showed higher sensitivity compared with the undoped sample.

scholarly journals Berlin Green Framework-Based Gas Sensor for Room-Temperature and High-Selectivity Detection of Ammonia

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Tingqiang Yang ◽  
Lingfeng Gao ◽  
Wenxuan Wang ◽  
Jianlong Kang ◽  
Guanghui Zhao ◽  
...  
Keyword(s):  
High Resistance ◽  
Active Sites ◽  
Density Functional ◽  
Room Temperature ◽  
High Selectivity ◽  
Gas Sensing ◽  
Response Recovery ◽  
Sensing Material ◽  
Agriculture Industry ◽  
Ammonia Detection

AbstractAmmonia detection possesses great potential in atmosphere environmental protection, agriculture, industry, and rapid medical diagnosis. However, it still remains a great challenge to balance the sensitivity, selectivity, working temperature, and response/recovery speed. In this work, Berlin green (BG) framework is demonstrated as a highly promising sensing material for ammonia detection by both density functional theory simulation and experimental gas sensing investigation. Vacancy in BG framework offers abundant active sites for ammonia absorption, and the absorbed ammonia transfers sufficient electron to BG, arousing remarkable enhancement of resistance. Pristine BG framework shows remarkable response to ammonia at 50–110 °C with the highest response at 80 °C, which is jointly influenced by ammonia's absorption onto BG surface and insertion into BG lattice. The sensing performance of BG can hardly be achieved at room temperature due to its high resistance. Introduction of conductive Ti3CN MXene overcomes the high resistance of pure BG framework, and the simply prepared BG/Ti3CN mixture shows high selectivity to ammonia at room temperature with satisfying response/recovery speed.

scholarly journals Graphene-enhanced metal oxide gas sensors at room temperature: a review

2018 ◽  
Vol 9 ◽  
pp. 2832-2844 ◽  
Author(s):  
Dongjin Sun ◽  
Yifan Luo ◽  
Marc Debliquy ◽  
Chao Zhang
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Metal Oxide Semiconductors ◽  
Oxide Semiconductors ◽  
Sensing Material ◽  
Metal Oxide Gas Sensors ◽  
Low Sensitivity ◽  
Sensing Performance

Owing to the excellent sensitivity to gases, metal-oxide semiconductors (MOS) are widely used as materials for gas sensing. Usually, MOS gas sensors have some common shortages, such as relatively poor selectivity and high operating temperature. Graphene has drawn much attention as a gas sensing material in recent years because it can even work at room temperature, which reduces power consumption. However, the low sensitivity and long recovery time of the graphene-based sensors limit its further development. The combination of metal-oxide semiconductors and graphene may significantly improve the sensing performance, especially the selectivity and response/recovery rate at room temperature. In this review, we have summarized the latest progress of graphene/metal-oxide gas sensors for the detection of NO2, NH3, CO and some volatile organic compounds (VOCs) at room temperature. Meanwhile, the sensing performance and sensing mechanism of the sensors are discussed. The improved experimental schemes are raised and the critical research directions of graphene/metal-oxide sensors in the future are proposed.

scholarly journals Investigation of Pristine Graphite Oxide as Room-Temperature Chemiresistive Ammonia Gas Sensing Material

Sensors ◽  
2017 ◽  
Vol 17 (2) ◽  
pp. 320 ◽  
Author(s):  
Alexander Bannov ◽  
Jan Prášek ◽  
Ondřej Jašek ◽  
Lenka Zajíčková
Keyword(s):  
Graphite Oxide ◽  
Room Temperature ◽  
Gas Sensing ◽  
Ammonia Gas ◽  
Sensing Material

scholarly journals A Room-Temperature CNT/Fe3O4 Based Passive Wireless Gas Sensor

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3542 ◽  
Author(s):  
Tao Guo ◽  
Tianhao Zhou ◽  
Qiulin Tan ◽  
Qianqian Guo ◽  
Fengxiang Lu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Fast Response ◽  
Sensing Material ◽  
Recovery Times ◽  
Response And Recovery ◽  
Good Repeatability

A carbon nanotube/Fe3O4 thin film-based wireless passive gas sensor with better performance is proposed. The sensitive test mechanism of LC (Inductance and capacitance resonant) wireless sensors is analyzed and the reason for choosing Fe3O4 as a gas sensing material is explained. The design and fabrication process of the sensor and the testing method are introduced. Experimental results reveal that the proposed carbon nanotube (CNT)/Fe3O4 based sensor performs well on sensing ammonia (NH3) at room temperature. The sensor exhibits not only an excellent response, good selectivity, and fast response and recovery times at room temperature, but is also characterized by good repeatability and low cost. The results for the wireless gas sensor’s performance for different NH3 gas concentrations are presented. The developed device is promising for the establishment of wireless gas sensors in harsh environments.

scholarly journals Hexanal Gas Detection Using Chitosan Biopolymer as Sensing Material at Room Temperature

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Devi Shantini ◽  
Irwana Nainggolan ◽  
Tulus Ikhsan Nasution ◽  
Mohd Nazree Derman ◽  
Roshida Mustaffa ◽  
...  
Keyword(s):  
Dairy Products ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Chitosan Film ◽  
Gas Detection ◽  
Film Sensor ◽  
Sensing Material ◽  
Good Repeatability ◽  
Chitosan Biopolymer

Hexanal was identified as one of the major volatile gases which are produced in degraded dairy products and wood industries. Therefore, preliminary study on hexanal gas detection with the laboratory scale was carried out in this paper. Electrical testing with chitosan as a sensing material to sense hexanal gas in low concentration was carried out at room temperature. Chitosan sensor was fabricated by using electrochemical deposition technique to form active sensing layer. The response of the chitosan film sensor (CFS) towards hexanal was tested via electrical testing by exposing different hexanal concentrations ranging between 20 ppm, 100 ppm, 200 ppm, and 300 ppm using air as a carrier gas. Sensing properties of the CFS toward hexanal exposure including responsibility, recovery, repeatability, stability, and selectively were studied. Overall, our result suggested that hexanal sensor based on chitosan was able to perform well at room temperature demonstrated by good response, good recovery, good repeatability, good stability, and good selectively. This simple and low cost sensor has high potential to be utilized in early quality degradation detection in dairy products and can be used to monitor the level of hexanal exposure in wood industries.

Sulfur dioxide gas-sensitive materials based on zeolitic imidazolate framework-derived carbon nanotubes

2018 ◽  
Vol 6 (25) ◽  
pp. 12115-12124 ◽  
Author(s):  
Qun Li ◽  
Jiabin Wu ◽  
Liang Huang ◽  
Junfeng Gao ◽  
Haowen Zhou ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Sulfur Dioxide ◽  
Room Temperature ◽  
Gas Sensing ◽  
Zeolitic Imidazolate Framework ◽  
Sensing Material

An active and stable gas-sensing material for SO2 at room temperature is presented. The particles synthesized using zinc-doped ZIFs as the precursor exhibit a porous polyhedral morphology with abundant interconnecting carbon nanotubes on the surface and improved conductivity.

scholarly journals A Novel Type Room Temperature Surface Photovoltage Gas Sensor Device

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2919 ◽  
Author(s):  
Monika Kwoka ◽  
Michal Borysiewicz ◽  
Pawel Tomkiewicz ◽  
Anna Piotrowska ◽  
Jacek Szuber
Keyword(s):  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Signal To Noise Ratio ◽  
Fast Response ◽  
Surface Photovoltage ◽  
Kelvin Probe ◽  
Sensor Device ◽  
Sensing Material ◽  
Highly Sensitive

In this paper a novel type of a highly sensitive gas sensor device based on the surface photovoltage effect is described. It is based on the Kelvin probe approach. Porous ZnO nanostructured thin films deposited by the direct current (DC) reactive magnetron sputtering method are used as the active gas sensing electrode material. Crucially, the obtained gas sensing material exhibited a nanocoral surface morphology and surface Zn to O non-stoichiometry with respect to its bulk mass. Among other responses, the demonstrated SPV gas sensor device exhibits a high response to an NO2 concentration as low as 1 ppm, with a signal to noise ratio of about 50 and a fast response time of several seconds under room temperature conditions.

scholarly journals Enhanced Gas-Sensing Performance of GO/TiO2 Composite by Photocatalysis

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3334 ◽  
Author(s):  
Eunji Lee ◽  
Doohee Lee ◽  
Jaesik Yoon ◽  
Yilin Yin ◽  
You Lee ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Charge Carrier Density ◽  
Sensing Properties ◽  
Photocatalytic Effect ◽  
Sensing Material ◽  
Gas Sensing Properties ◽  
Before And After ◽  
Reducing Gases ◽  
Composite Sensor

Few studies have investigated the gas-sensing properties of graphene oxide/titanium dioxide (GO/TiO2) composite combined with photocatalytic effect. Room temperature gas-sensing properties of the GO/TiO2 composite were investigated towards various reducing gases. The composite sensor showed an enhanced gas response and a faster recovery time than a pure GO sensor due to the synergistic effect of the hybridization, such as creation of a hetero-junction at the interface and modulation of charge carrier density. However, the issue of long-term stability at room temperature still remains unsolved even after construction of a composite structure. To address this issue, the surface and hetero-junction of the GO/TiO2 composite were engineered via a UV process. A photocatalytic effect of TiO2 induced the reduction of the GO phase in the composite solution. The comparison of gas-sensing properties before and after the UV process clearly showed the transition from n-type to p-type gas-sensing behavior toward reducing gases. This transition revealed that the dominant sensing material is GO, and TiO2 enhanced the gas reaction by providing more reactive sites. With a UV-treated composite sensor, the function of identifying target gas was maintained over a one-month period, showing strong resistance to humidity.

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