Preliminary Study of WO3 Nanostructures Produced via Facile Hydrothermal Synthesis Process for CO2 Sensing

2013 ◽  
Vol 431 ◽  
pp. 37-41 ◽  
Author(s):  
Amirul Abd Rashid ◽  
Nor Hayati Saad ◽  
Chia Sheng Daniel Bien ◽  
Wai Yee Lee ◽  
M.A.S.M. Haniff
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Hydrothermal Reaction ◽  
Hydrothermal Process ◽  
Single Step ◽  
Synthesis Process ◽  
Sensor Element ◽  
Response Measurement ◽  
Sensor Fabrication ◽  
Preliminary Study

Tungsten trioxide (WO3) nanostructure with aspect ratio of 20 (length/diameter) have been successfully synthesized by single step hydrothermal reaction at moderate temperature of 180 °C. The crystal structure and morphology evolution are characterized by SEM and Raman while the carbon dioxide (CO2) sensing capability was tested by simple sensor fabrication .It was observed that the nanorods were initially coalesce in bundles before breaking up loosely towards the end of the hydrothermal process. A response measurement reveals that the sensor was able to detect CO2 at room temperature with the sensitivity around 13ohm/100 ppm. The detection performance of such nanostructure provides a positive indication that it can be a competitive sensor element candidate not only for CO2 applications in particular but can be expanded to other gas sensing application such as O2, C2H4 and NO2.

scholarly journals ZnO/RGO Heterojunction Based near Room Temperature Alcohol SENSOR with Improved Efficiency

2021 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Sanghamitra Ghosal ◽  
Partha Bhattacharyya
Keyword(s):  
Active Sites ◽  
Room Temperature ◽  
Surface Engineering ◽  
Gas Sensing ◽  
Energy Band Diagram ◽  
Future Generation ◽  
High Yield ◽  
Synthesis Process ◽  
Ethanol Sensor ◽  
Vapor Sensing

The systematic optimization of surface engineering (dimensionality) indeed plays a crucial role in achieving efficient vapor-sensing performance. Among various semiconducting metal oxides, owing to some of its unique features and advantages, ZnO has attracted researchers on a global scale due to its application in various fields, including chemical sensors. The concomitant optimization of the surface attributes (varying different dimensions) of ZnO have become a sensation for the entire research community. Moreover, the small thickness and extremely large surface of exfoliated 2D nanosheets render the gas sensing material an ideal candidate for achieving strong coupling with different gas molecules. However, temperature is a crucial factor in the field of chemical sensing. Recently, graphene-based gas sensors have attracted attention due to their variety of structures, unique sensing performances and room temperature working conditions. In this work, a highly sensitive and fast responsive low temperature (60 °C)-based ethanol sensor, based on RGO/2D ZnO nanosheets hybrid structure, is reported. After detailed characterizations, the vapor sensing potentiality of this sensor was tested for the detection of ethanol. The ethanol sensor offered the response magnitude of 89% (100 ppm concentration) with response and recovery time of 12 s/29 s, respectively. Due to excessively high number of active sites for VOC interaction, with high yield synthesis process and appreciably high carrier mobility, this has paved the way for developing future generation, miniaturized and flexible (wearable) vapor sensor devices, meeting the multidimensional requirements for traditional and upcoming (health/medical sector) applications. The underlying mechanistic framework for vapor sensing, using this hybrid junction, is explained with the Energy Band Diagram.

scholarly journals New Design of ZnO Nanorod- and Nanowire-Based NO2 Room-Temperature Sensors Prepared by Hydrothermal Method

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Vo Thanh Duoc ◽  
Dang Thi Thanh Le ◽  
Nguyen Duc Hoa ◽  
Nguyen Van Duy ◽  
Chu Manh Hung ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Room Temperature ◽  
Gas Sensing ◽  
Local Heating ◽  
Zno Nanorods ◽  
Hydrothermal Process ◽  
Maximal Response ◽  
Sensor Applications ◽  
Sensing Characteristics ◽  
Sensing Performance

Room-temperature gas sensors are attracting attention because of their low power consumption, safe operation, and long-term stability. Herein, ZnO nanorods (NRs) and nanowires (NWs) were on-chip grown via a facile hydrothermal method and used for room-temperature NO2 gas sensor applications. The ZnO NRs were obtained by a one-step hydrothermal process, whereas the NWs were obtained by a two-step hydrothermal process. To obtain ZnO NW sensor, the length of NRs was controlled short enough so that none of the nanorod-nanorod junction was made. Thereafter, the NWs were grown from the tips of no-contact NRs to form nanowire-nanowire junctions. The gas-sensing characteristics of ZnO NRs and NWs were tested against NO2 gas at room temperature for comparison. The gas-sensing characteristics of the sensors were also tested at different applied voltages to evaluate the effect of the self-activated gas-sensing performance. Results show that the diameter of ZnO NRs and NWs is the dominant parameter of their NO2 gas-sensing performance at room temperature. In addition, self-activation by local heating occurred for both sensors, but because the NWs were smaller and sparser than the NRs, local heating thus required a lower applied voltage with maximal response compared with the NRs.

scholarly journals Effect of Phosphate Addition and Exposure of Micro Waves on Comparatives Ca/F in Gipsum Waste: Preliminary Study of Hydroxyappatite Synthesis (HAp) from Ceramics Gypsum Industry Waste

2018 ◽  
Vol 21 (4) ◽  
pp. 218-223
Author(s):  
Dewantoro Dewantoro ◽  
Margareta Novian Cahyanti ◽  
Sri Hartini
Keyword(s):  
Time Variation ◽  
Hydrothermal Process ◽  
Initial Study ◽  
Synthesis Process ◽  
30Th Minute ◽  
Industry Waste ◽  
Preliminary Study ◽  
Phosphate Addition

This study aims to conduct an initial study of hydroxyapatite synthesis from ceramic gypsum waste. The parameters of the synthesis process carried out were variations in the time of the hydrothermal process namely 10, 20, 30, 40 and 50 minutes. The time variation was studied to study the effect of time on the hydroxyapatite character of gypsum waste. The initial synthesis process was conducted by looking at the comparison of Phosphate and Calcium levels in gypsum. In this study the results of the highest Phosphate levels obtained were 0.607% in the 10th  minute, while the largest Calcium levels were obtained in the 30th minute which was 0.171%. The treatment in the 30th minute gave the most optimal difference in effect which was 0.413. FTIR results showed the emergence of hydroxyapatite peaks namely –OH, PO43- and Ca-O, as well as the increase in the intensity of the peak of gypsum powder before treatment and after treatment. While the XRD results strengthened the presence of hydroxyapatite in gypsum with the presence of high peaks at 2θ = 31.08°; 32.14° and 33.45° respectively which indicated the presence of hydroxyapatite. While the main impurities in the synthesized hydroxyapatite are carbonates identified from FTIR results.

Ethanol Gas Sensor Fabrication Based on ZnO Flower Like Nanorods

2020 ◽  
Vol 38 (3B) ◽  
pp. 85-97
Author(s):  
Abdulqader D. Faisal ◽  
Mofeed A. Jaleel ◽  
Fahad Z. Kamal
Keyword(s):  
Gas Sensor ◽  
Seed Layer ◽  
Room Temperature ◽  
Gas Sensing ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Sensor Fabrication ◽  
Synthesized Materials

Zinc oxide flower-like nanorods (ZnO NRs) was successfully synthesized via the hydrothermal method. The growth process was conducted with seed layer concentrations of 20mM. The as-synthesized nanostructures were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), and ultraviolet-visible (UV-VIS) spectrophotometer. The analysis results revealed a pure Wurtzite ZnO hexagonal nanostructures with preferred orientation (002) along the c-direction. The calculated band gap of average crystallite size is 3.2eV and 25 nm respectively. New designed, constructed and successfully calibrated for ethanol gas sensing was found. The ethanol gas sensor was fabricated at room temperature based on the ZnO NRs film. The synthesized materials proved to be a good candidate for the ethanol gas sensor. The optimum results of the gas sensor measurements of the synthesized gas sensor are as follows, the sensitivity, response time, and recovery time at 25 °C are 60%, 80 Seconds and 80 seconds respectively, and at 200 °C are 70%, 60 seconds and 50 seconds respectively.

scholarly journals Selective and self-validating breath-level detection of hydrogen sulfide in humid air by gold nanoparticle-functionalized nanotube arrays

Nano Research ◽  
2021 ◽  
Author(s):  
Luis Antonio Panes-Ruiz ◽  
Leif Riemenschneider ◽  
Mohamad Moner Al Chawa ◽  
Markus Löffler ◽  
Bernd Rellinghaus ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Room Temperature ◽  
Sensor Array ◽  
High Selectivity ◽  
Electrochemical Sensors ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Electrical Characteristics ◽  
Sensor Fabrication ◽  
Walled Carbon Nanotubes

AbstractWe demonstrate the selective detection of hydrogen sulfide at breath concentration levels under humid airflow, using a self-validating 64-channel sensor array based on semiconducting single-walled carbon nanotubes (sc-SWCNTs). The reproducible sensor fabrication process is based on a multiplexed and controlled dielectrophoretic deposition of sc-SWCNTs. The sensing area is functionalized with gold nanoparticles to address the detection at room temperature by exploiting the affinity between gold and sulfur atoms of the gas. Sensing devices functionalized with an optimized distribution of nanoparticles show a sensitivity of 0.122%/part per billion (ppb) and a calculated limit of detection (LOD) of 3 ppb. Beyond the self-validation, our sensors show increased stability and higher response levels compared to some commercially available electrochemical sensors. The cross-sensitivity to breath gases NH3 and NO is addressed demonstrating the high selectivity to H2S. Finally, mathematical models of sensors’ electrical characteristics and sensing responses are developed to enhance the differentiation capabilities of the platform to be used in breath analysis applications.

Preparation and investigation of co-doped VO2 powders

2019 ◽  
Vol 12 (02) ◽  
pp. 1950015 ◽  
Author(s):  
Lingna Liu ◽  
Yi Hou ◽  
Xiuzhao Yin ◽  
Fang Zhang ◽  
Zifei Peng
Keyword(s):  
Phase Transition ◽  
Vanadium Dioxide ◽  
Room Temperature ◽  
Hydrothermal Reaction ◽  
Raw Materials ◽  
Sodium Molybdate ◽  
Tungstic Acid ◽  
Ft Ir ◽  
Preliminary Study ◽  
Co Doped

In this paper, tungsten-and molybdenum-doped vanadium dioxide (VO[Formula: see text] powders were prepared by hydrothermal reaction using vanadium pentoxide (V2O[Formula: see text], H2O2, white tungstic acid (WPTA) and sodium molybdate (Na2MoO[Formula: see text] as raw materials. The microstructure and composition of VO2 powders were characterized by means of XRD, XPS, DSC and FT-IR. We made a preliminary study on the thermal-induced phase transition properties of powders. The experimental results show that the co-doped samples are monoclinic rutile. Tungsten and molybdenum atoms exist in the lattice at the positive six valence. When the W and M W were 3% and 2%, respectively, the transition temperature of co-doped samples were close to room temperature can reach 25.5∘C.

Room-temperature SO2 gas-sensing properties based on a metal-doped MoS2 nanoflower: an experimental and density functional theory investigation

2017 ◽  
Vol 5 (39) ◽  
pp. 20666-20677 ◽  
Author(s):  
Dongzhi Zhang ◽  
Junfeng Wu ◽  
Peng Li ◽  
Yuhua Cao
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Room Temperature ◽  
Gas Sensing ◽  
Single Step ◽  
Hydrothermal Route ◽  
Functional Theory ◽  
Gas Sensing Properties ◽  
Metal Doped ◽  
So2 Gas

This paper demonstrates a sulfur dioxide (SO2) gas sensor based on a transition-metal-doped molybdenum disulfide (MoS2) nanocomposite synthesized via a facile single-step hydrothermal route.

Preparation of Polyaniline/Cu-BTC Composite and its Sensing Application for Ammonia

2017 ◽  
Vol 748 ◽  
pp. 353-357
Author(s):  
Yong Jin Zou ◽  
Ying Yin ◽  
Hai Tao Zhang ◽  
Fen Xu ◽  
Li Xian Sun
Keyword(s):  
Surface Area ◽  
Room Temperature ◽  
Gas Sensing ◽  
High Surface ◽  
Hydrothermal Process ◽  
High Surface Area ◽  
High Sensitivity ◽  
Pani Composite ◽  
Sensing Application ◽  
Sensing Performance

In this study, a newly materials based on copper–benzene-1,3,5-tricarboxylate/polyaniline (PANI/Cu-BTC) composite was investigated for NH3 sensing. Cu-BTC was grown on the PANI a hydrothermal process. The sensing performance of as-grown product was studied for different concentrations of NH3 at room temperature. The results reveal that Cu-BTC/PANI composite exhibit high sensitivity toward NH3. The good sensing performance of the composite was attributed to high surface area and good affinity of Cu-BTC for NH3, which can act like preconcentrator for the NH3 gas sensing.

New Potential Biologically Active Compounds: Synthesis and Characterization of Urea and Thiourea Derivativpes Bearing 1,2,4-oxadiazole Ring

2020 ◽  
Vol 17 (7) ◽  
pp. 525-534 ◽  
Author(s):  
Nevin Arıkan Ölmez ◽  
Faryal Waseer
Keyword(s):  
Microwave Irradiation ◽  
Room Temperature ◽  
Antimicrobial Activities ◽  
Phenyl Isocyanate ◽  
Single Step ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Active Compounds ◽  
Thiourea Derivatives ◽  
Acyl Chlorides

Background: Urea, thiourea, and 1,2,4-oxadiazole compounds are of great interest due to their different activities such as anti-inflammatory, antiviral, analgesic, fungicidal, herbicidal, diuretic, antihelminthic and antitumor along with antimicrobial activities. Objective: In this work, we provide a new series of potential biologically active compounds containing both 1,2,4-oxadiazole and urea/thiouprea moiety. Materials and Methods: Firstly, 5-chloromethyl-3-aryl-1,2,4-oxadiazoles (3a-j) were synthesized from the reaction of different substituted amidoximes (2a-j) and chloroacetyl chloride in the presence of pyridine by conventional and microwave-assisted methods. In the conventional method, 1,2,4-oxadiazoles were obtained in two steps. O-acylamidoximes obtained in the first step at room temperature were heated in toluene for an average of one hour to obtain 1,2,4-oxadiazoles. The yields varied from 70 to 96 %. 1,2,4-oxadiazoles were obtained under microwave irradiation in a single step in a 90-98 % yield at 160 °C in five minutes. 5-aminomethyl-3-aryl-1,2,4- oxadiazoles (5a-j) were obtained by Gabriel amine synthesis in two steps from corresponding 5-chloromethyl-3- aryl-1,2,4-oxadiazoles. Finally, twenty new urea (6a-j) and thiourea (7a-j) compounds bearing oxadiazole ring were synthesized by reacting 5-aminomethyl-3-aryl-1,2,4-oxadiazoles with phenyl isocyanate and isothiocyanate in tetrahydrofuran (THF) at room temperature with average yields (40-70%). Results and Discussions: An efficient and rapid method for the synthesis of 1,2,4-oxadiazoles from the reaction of amidoximes and acyl halides without using any coupling reagent under microwave irradiation has been developed, and twenty new urea/thiourea compounds bearing 1,2,4-oxadiazole ring have been synthesized and characterized. Conclusion: We have synthesized a new series of urea/thiourea derivatives bearing 1,2,4-oxadiazole ring. Also facile synthesis of 3,5-disubstituted 1,2,4-oxadiazoles from amidoximes and acyl chlorides under microwave irradiation was reported. The compounds were characterized using FTIR, 1H NMR, 13C NMR, and elemental analysis techniques.

scholarly journals Preparation and Gas Sensing Properties of PANI/SnO2 Hybrid Material

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1360
Author(s):  
Qiaohua Feng ◽  
Huanhuan Zhang ◽  
Yunbo Shi ◽  
Xiaoyu Yu ◽  
Guangdong Lan
Keyword(s):  
Hybrid Material ◽  
Room Temperature ◽  
Tin Dioxide ◽  
Gas Adsorption ◽  
Gas Sensing ◽  
Oxidative Polymerization ◽  
Environmental Pollutants ◽  
Decomposition Temperature ◽  
Benzene Vapor ◽  
Thermo Gravimetric Analyzer

A sensor operating at room temperature has low power consumption and is beneficial for the detection of environmental pollutants such as ammonia and benzene vapor. In this study, polyaniline (PANI) is made from aniline under acidic conditions by chemical oxidative polymerization and doped with tin dioxide (SnO2) at a specific percentage. The PANI/SnO2 hybrid material obtained is then ground at room temperature. The results of scanning electron microscopy show that the prepared powder comprises nanoscale particles and has good dispersibility, which is conducive to gas adsorption. The thermal decomposition temperature of the powder and its stability are measured using a differential thermo gravimetric analyzer. At 20 °C, the ammonia gas and benzene vapor gas sensing of the PANI/SnO2 hybrid material was tested at concentrations of between 1 and 7 ppm of ammonia and between 0.4 and 90 ppm of benzene vapor. The tests show that the response sensitivities to ammonia and benzene vapor are essentially linear. The sensing mechanisms of the PANI/SnO2 hybrid material to ammonia and benzene vapors were analyzed. The results demonstrate that doped SnO2 significantly affects the sensitivity, response time, and recovery time of the PANI material.

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