scholarly journals Fabrication of Transition-metal (Zn, Mn, Cu)-based MOFs as Efficient Sensor Materials for Detection of H2 Gas by Clad Modified Fiber Optic Gas Sensor Technique

2021 ◽  
Author(s):  
M Nagoor Meeran ◽  
S.P. Saravanan ◽  
H.H Hegazy
Keyword(s):  
Transition Metal ◽  
Fiber Optic ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Long Term Stability ◽  
Sensing Material ◽  
Sensor Technique ◽  
Recent Developments ◽  
Metal Organic ◽  
Elevated Surface

Abstract Recent research demonstrate that promising gas sensing materials are called metal-organic structures (MOFs) and their products due to their tunable form, elevated surface area, and extremely porous structure and physisorption towards gases with relatively low temperature.In this report, recent developments in transition-metal (Zn, Mn, Cu)-based MOFs and their derivatives are synthesized as sensing materials. The sensors samples were analyzed by XRD, SEM, TEM, BET and XPS in order to know the textural, structural and electronic state of the samples. Fiber optic clad modified sensors were fabricated and tested gas sensing properties towards H2 gas with various concentrations (0-1000 ppm). Among the three sensing material, Zn doped MOFs sensor showed outstanding selectivity with high sensitivity (115 counts/kpa) towards H2 gas. Moreover, it has shown high response (20 s) and recovery time (27 s) as well as long term stability. The designed sensors may be required to apply to the production of an outstanding sensor for H2 for commercial uses.

Schottky diodes based on 2D materials for environmental gas monitoring: a review on emerging trends, recent developments and future perspectives

2021 ◽  
Author(s):  
Minu Mathew ◽  
Chandra Sekhar Rout
Keyword(s):  
Gas Sensing ◽  
2D Materials ◽  
Schottky Diodes ◽  
High Sensitivity ◽  
Future Perspectives ◽  
Working Temperature ◽  
Emerging Trends ◽  
Gas Sensing Properties ◽  
Recent Developments ◽  
Sensitivity And Selectivity

This review details the fundamentals, working principles and recent developments of Schottky junctions based on 2D materials to emphasize their improved gas sensing properties including low working temperature, high sensitivity, and selectivity.

A metal-organic framework featuring highly sensitive fluorescence sensing for Al3+ ion

CrystEngComm ◽  
2021 ◽  
Author(s):  
Yang Qiao ◽  
Zeqi Li ◽  
Mei-Hui Yu ◽  
Ze Chang ◽  
Xian-He Bu
Keyword(s):  
Metal Ions ◽  
Human Health ◽  
Metal Organic Framework ◽  
High Sensitivity ◽  
Fluorescence Sensing ◽  
Sensing Material ◽  
Highly Sensitive ◽  
Sensitivity And Selectivity ◽  
Metal Organic ◽  
Organic Framework

High sensitivity and selectivity for detection of metal ions are very important to protect human health. Fluorescent metal-organic framework (MOF) as a new sensing material has attracted more and more...

Ethanol Sensing with Cu-BTC Metal Organic Framework: Mass Sensitive, Work Function Based and IR Investigations

2014 ◽  
Vol 605 ◽  
pp. 87-90 ◽  
Author(s):  
Polina Davydovskaya ◽  
Angelika Tawil ◽  
Roland Pohle
Keyword(s):  
Work Function ◽  
Gas Sensing ◽  
Metal Organic Framework ◽  
Good Thermal Stability ◽  
Sensing Material ◽  
Metal Organic ◽  
Experimental Approaches ◽  
Ethanol Sensing ◽  
Diffuse Reflectance Infrared ◽  
Unsaturated Metal Sites

Cu-BTC, also known as H-KUST 1, belongs to Metal Organic Frameworks (MOFs). Nanoporosity, relatively good thermal stability and unsaturated metal sites are some of its properties that make this MOF promising for application as a gas sensing material. In this work we chose different experimental approaches to examine trace gas sensing (5 to 50 ppm) of ethanol with Cu-BTC. Measurements with mass sensitive, as well as work function based readout, were successfully performed in dry synthetic air at room temperature. Strong, fast and concentration dependent response to ethanol was observed. In-situ measurements with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were additionally applied to visualize the adsorption of ethanol molecules on the Cu-BTC sensing layer.

Structure and Characteristics of Electrospun ZnO Nanofibers for Gas Sensing

2020 ◽  
Vol 16 (2) ◽  
pp. 187-195
Author(s):  
Tang-Yu Lai ◽  
Te-Hua Fang ◽  
Yu-Jen Hsiao ◽  
En-Yu Kuo
Keyword(s):  
Gas Sensor ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Oxide Semiconductor ◽  
Woven Fabric ◽  
Membrane Thickness ◽  
One Dimensional ◽  
Sensing Mechanism ◽  
Sensing Material

Background:: A sensing material of zinc oxide (ZnO) was investigated for its use in the electrospun nanofibers for gas sensing. The metal oxide semiconductor gas sensor response is caused by the oxygen that undergoes a chemical reaction on the surface of an oxide, resulting in a change in the measured resistance. Objective:: One-dimensional nanofibers gas sensor have high sensitivity and diverse selectivity. Methods:: One-dimensional nanofiber by an electrospinning method was collected and a sensing membrane was formed. In addition, the gas sensing mechanism was discussed and verified by X-ray photoelectron spectroscopy (XPS). Results:: The ZnO nanofiber membrane had an optimum crystalline phase with a lattice spacing of 0.245 nm and a non-woven fabric structure at a calcination temperature of 500°C, whereas the nanofiber diameter and membrane thickness were about 100 nm and 8 μm, respectively. At an operating temperature of 200°C, the sensing material exhibited good recovery and reproducibility in response to Carbon monoxide (CO), and the concentration was also highly discernible. In addition, the reduction in the peak of OIII at 531.5 to 532.5 eV according to the analysis of XPS was consistent with the description of the sensing mechanism. Conclusion:: The gas sensor of ZnO nanofiber membranes has high sensitivity and diverse selectivity, which can be widely applied in potential applications in various sensors and devices.

Fabrication and Morphological Control of a Palladium Film with a Three-Dimensional Nano-Network Structure as a Hydrogen Gas Sensing Material using Organic Acid Chelation

MRS Advances ◽  
2019 ◽  
Vol 4 (5-6) ◽  
pp. 319-324
Author(s):  
Takuji Ube ◽  
Akizumi Kawamoto ◽  
Tomoya Nishi ◽  
Takashi Ishiguro
Keyword(s):  
Organic Acid ◽  
Network Structure ◽  
Gas Sensing ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Strong Acid ◽  
Alloy Film ◽  
Hydrogen Gas ◽  
Sensing Material ◽  
Sensitivity And Selectivity

ABSTRACTNano-porous palladium (Pd) thin films could potentially be applied to hydrogen gas sensing materials with high sensitivity and selectivity. In our previous study, a nano-porous Pd film was fabricated with a three-dimensional network structure from an AlPd mother alloy film by a dealloying method using the chelating ability of an organic acid. This process was simple and environmentally friendly because it only required organic acid in a ppm concentration, and did not exhaust a strong acid waste solution, including heavy metal ions. This method was modified to improve the Pd purity of the dealloyed specimen, reaction rate, and morphology control. In this study, the existence of a composition undulation pattern was shown in the AlPd mother alloy film, and its effects on the morphology of the dealloyed specimen were evaluated. Furthermore, this pattern could be controlled by N2 gas addition to the Ar sputtering gas during the preparation of the AlPd mother alloy film.

Metal-organic frameworks-derived porous ZnO/Ni0.9Zn0.1O double-shelled nanocages as gas sensing material for selective detection of xylene

2017 ◽  
Vol 252 ◽  
pp. 649-656 ◽  
Author(s):  
Fengdong Qu ◽  
Bingxue Zhang ◽  
Xinxin Zhou ◽  
Huifang Jiang ◽  
Chuanxi Wang ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Metal Organic Frameworks ◽  
Selective Detection ◽  
Sensing Material ◽  
Metal Organic

Nonlinear-Based Switch Triggered by Gas Using Electrostatically Actuated Microbeams

2016 ◽  
Author(s):  
Adam Bouchaala ◽  
Nizar Jaber ◽  
Omar Yassine ◽  
Osama Shekhah ◽  
Mohamed Eddaoudi ◽  
...  
Keyword(s):  
Nonlinear Response ◽  
Gas Sensing ◽  
Metal Organic Framework ◽  
Noise Analysis ◽  
High Sensitivity ◽  
Electrostatically Actuated ◽  
Mems Switch ◽  
Metal Organic ◽  
Clamped Beams ◽  
Nonlinear Behaviors

The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a Metal-Organic Framework (MOF), namely HKUST-1 to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

scholarly journals Hydrogen Gas Sensing Using Palladium-Graphene Nanocomposite Material Based on Surface Acoustic Wave

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Nguyen Hai Ha ◽  
Nguyen Hoang Nam ◽  
Dang Duc Dung ◽  
Nguyen Huy Phuong ◽  
Phan Duy Thach ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Gas Sensing ◽  
Specific Interaction ◽  
High Sensitivity ◽  
Fast Response ◽  
Hydrogen Gas ◽  
Chemical Route ◽  
Response Recovery ◽  
Sensing Material

We report the fabrication and characterization of surface acoustic wave (SAW) hydrogen sensors using palladium-graphene (Pd-Gr) nanocomposite as sensing material. The Pd-Gr nanocomposite as sensing layer was deposited onto SAW delay line sensor-based interdigitated electrodes (IDTs)/aluminum nitride (AlN)/silicon (Si) structure. The Pd-Gr nanocomposite was synthesized by a chemical route and deposited onto SAW sensors by air-brush spraying. The SAW H2 sensor using Pd-Gr nanocomposite as a sensing layer shows a frequency shift of 25 kHz in 0.5% H2 concentration at room temperature with good repeatability and stability. Moreover, the sensor showed good linearity and fast response/recovery within ten seconds with various H2 concentrations from 0.25 to 1%. The specific interaction between graphene and SAW transfer inside AlN/Si structures yields a high sensitivity and fast response/recovery of SAW H2 sensor based on Pd-Gr/AlN/Si structure.

scholarly journals NH3 Sensor Based on 3D Hierarchical Flower-Shaped n-ZnO/p-NiO Heterostructures Yields Outstanding Sensing Capabilities at ppb Level

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4754
Author(s):  
Zhenting Zhao ◽  
Haoyue Yang ◽  
Zihan Wei ◽  
Yan Xue ◽  
Yongjiao Sun ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Three Dimensional ◽  
Fast Response ◽  
Molar Ratios ◽  
Response Characteristics ◽  
Long Term Stability ◽  
Sensing Material ◽  
Nh3 Sensor ◽  
Phase Surface ◽  
Gas Response

Hierarchical three-dimensional (3D) flower-like n-ZnO/p-NiO heterostructures with various ZnxNiy molar ratios (Zn5Ni1, Zn2Ni1, Zn1Ni1, Zn1Ni2 and Zn1Ni5) were synthesized by a facile hydrothermal method. Their crystal phase, surface morphology, elemental composition and chemical state were comprehensively investigated by XRD, SEM, EDS, TEM and XPS techniques. Gas sensing measurements were conducted on all the as-developed ZnxNiy-based sensors toward ammonia (NH3) detection under various working temperatures from 160 to 340 °C. In particular, the as-prepared Zn1Ni2 sensor exhibited superior NH3 sensing performance under optimum working temperature (280 °C) including high response (25 toward 100 ppm), fast response/recovery time (16 s/7 s), low detection limit (50 ppb), good selectivity and long-term stability. The enhanced NH3 sensing capabilities of Zn1Ni2 sensor could be attributed to both the specific hierarchical structure which facilitates the adsorption of NH3 molecules and produces much more contact sites, and the improved gas response characteristics of p-n heterojunctions. The obtained results clear demonstrated that the optimum n-ZnO/p-NiO heterostructure is indeed very promising sensing material toward NH3 detection for different applications.

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