scholarly journals Ag Nanoparticles Sensitized In2O3 Nanograin for the Ultrasensitive HCHO Detection at Room Temperature

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Shiqiang Zhou ◽  
Mingpeng Chen ◽  
Qingjie Lu ◽  
Yumin Zhang ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Indoor Air ◽  
Ag Nanoparticles ◽  
Room Temperature ◽  
Unsolved Problem ◽  
Air Pollutant ◽  
Ag Nps ◽  
Performance Targets ◽  
Fabrication Cost ◽  
Low Concentrations ◽  
Stringent Performance

AbstractFormaldehyde (HCHO) is the main source of indoor air pollutant. HCHO sensors are therefore of paramount importance for timely detection in daily life. However, existing sensors do not meet the stringent performance targets, while deactivation due to sensing detection at room temperature, for example, at extremely low concentration of formaldehyde (especially lower than 0.08 ppm), is a widely unsolved problem. Herein, we present the Ag nanoparticles (Ag NPs) sensitized dispersed In2O3 nanograin via a low-fabrication-cost hydrothermal strategy, where the Ag NPs reduces the apparent activation energy for HCHO transporting into and out of the In2O3 nanoparticles, while low concentrations detection at low working temperature is realized. The pristine In2O3 exhibits a sluggish response (Ra/Rg = 4.14 to 10 ppm) with incomplete recovery to HCHO gas. After Ag functionalization, the 5%Ag-In2O3 sensor shows a dramatically enhanced response (135) with a short response time (102 s) and recovery time (157 s) to 1 ppm HCHO gas at 30 °C, which benefits from the Ag NPs that electronically and chemically sensitize the crystal In2O3 nanograin, greatly enhancing the selectivity and sensitivity.

Photocatalytic Degradation of Gaseous Formaldehyde by Modified Hierarchical TiO2 Nanotubes at Room Temperature

2016 ◽  
Vol 69 (3) ◽  
pp. 343 ◽  
Author(s):  
Di Gu ◽  
Baohui Wang ◽  
Yanji Zhu ◽  
Hongjun Wu
Keyword(s):  
Indoor Air ◽  
Room Temperature ◽  
Air Pollutant ◽  
Noble Metal Nanoparticles ◽  
Reaction Rate Constants ◽  
Volatile Organic ◽  
Major Process ◽  
Formaldehyde Degradation ◽  
Tio2 Nts ◽  
Gaseous Formaldehyde

As a major indoor air pollutant, formaldehyde released from building and furnishing materials is one of the main volatile organic compounds (VOCs). Hierarchical TiO2 nanotube arrays (TiO2 NTs) prepared via a facile two-step anodization showed excellent photocatalytic (PC) degradation of formaldehyde at room temperature. Modification with noble metal nanoparticles (NMNs) could further improve the PC activity of TiO2 NTs. The final products of formaldehyde degradation were detected to be CO2 and H2O, which indicated that the mineralization of formaldehyde was the major process in this PC reaction. The reaction rate constants (k) determined for the three catalysts were in the order kTiO2 NTs < kAu/TiO2 NTs < kPt/TiO2 NTs (Pt/TiO2 NTs had the highest PC ability). The significant enhancement of PC performance can be ascribed to the formation of a Schottky junction between the NMNs and TiO2 NTs.

SnS2/MXene derived TiO2 hybrid for ultra-fast room temperature NO2 gas sensing

2021 ◽  
Author(s):  
Tianding CHEN ◽  
Wenhao YAN ◽  
Ying WANG ◽  
Jinli Li ◽  
Haibo Hu ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Human Health ◽  
Room Temperature ◽  
Gas Sensing ◽  
Air Pollutant

Nitrogen dioxide (NO2) is a prominent air pollutant that is harmful to both the environment and human health. Conventional NO2 sensors that are designed to operate at room temperature often...

scholarly journals Non-Destructive Detection of Pentachlorophenol Residues in Historical Wooden Objects

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1052
Author(s):  
Ida Kraševec ◽  
Nataša Nemeček ◽  
Maja Lozar Štamcar ◽  
Irena Kralj Cigić ◽  
Helena Prosen
Keyword(s):  
Indoor Air ◽  
Room Temperature ◽  
Quantitative Methods ◽  
Solid Phase ◽  
Contact Mode ◽  
Solvent Extraction Method ◽  
Museum Objects ◽  
Wooden Furniture ◽  
Non Destructive ◽  
Heritage Collections

Wood is a natural polymeric material that is an important constituent of many heritage collections. Because of its susceptibility to biodegradation, it is often chemically treated with substances that can be harmful to human health. One of the most widely used wood preservatives was pentachlorophenol (PCP), which is still present in museum objects today, although its use has been restricted for about forty years. The development of non-destructive methods for its determination, suitable for the analysis of valuable objects, is therefore of great importance. In this work, two non-destructive solid-phase microextraction (SPME) methods were developed and optimized, using either headspace or contact mode. They were compared with a destructive solvent extraction method and found to be suitable for quantification in the range of 7.5 to 75 mg PCP/kg wood at room temperature. The developed semi-quantitative methods were applied in the wooden furniture depot of National Museum of Slovenia. PCP was detected inside two furniture objects using headspace mode. The pesticide lindane was also detected in one object. The indoor air of the depot with furniture was also sampled with HS SPME, and traces of PCP were found. According to the results, SPME methods are suitable for the detection of PCP residues in museum objects and in the environment.

Characterization of particle composition, organic vapor constituents, and mutagenicity of indoor air pollutant emissions

1986 ◽  
Vol 12 (1-4) ◽  
pp. 351-362 ◽  
Author(s):  
Ken Sexton ◽  
Lurance M. Webber ◽  
Steven B. Hayward ◽  
Richard G. Sextro
Keyword(s):  
Indoor Air ◽  
Air Pollutant ◽  
Pollutant Emissions ◽  
Particle Composition ◽  
Organic Vapor

scholarly journals Porous silica spheres as indoor air pollutant scavengers

2010 ◽  
Vol 12 (12) ◽  
pp. 2244 ◽  
Author(s):  
Paul Delaney ◽  
Robert M. Healy ◽  
John P. Hanrahan ◽  
Lorraine T. Gibson ◽  
John C. Wenger ◽  
...  
Keyword(s):  
Indoor Air ◽  
Porous Silica ◽  
Air Pollutant ◽  
Silica Spheres

scholarly journals Metallicity and Superconductivity in Doped Strontium Titanate

2019 ◽  
Vol 10 (1) ◽  
pp. 25-44 ◽  
Author(s):  
Clément Collignon ◽  
Xiao Lin ◽  
Carl Willem Rischau ◽  
Benoît Fauqué ◽  
Kamran Behnia
Keyword(s):  
Liquid Helium ◽  
Free Path ◽  
Coulomb Interaction ◽  
Strontium Titanate ◽  
Room Temperature ◽  
Mean Free Path ◽  
Helium Temperature ◽  
Ongoing Research ◽  
Low Concentrations ◽  
Wide Gap

Strontium titanate is a wide-gap semiconductor avoiding a ferroelectric instability thanks to quantum fluctuations. This proximity leads to strong screening of static Coulomb interaction and paves the way for the emergence of a very dilute metal with extremely mobile carriers at liquid-helium temperature. Upon warming, mobility decreases by several orders of magnitude. Yet, metallicity persists above room temperature even when the apparent mean free path falls below the electron wavelength. The superconducting instability survives at exceptionally low concentrations and beyond the boundaries of Migdal–Eliashberg approximation. An intimate connection between dilute superconductivity and aborted ferroelectricity is widely suspected. In this review, we give a brief account of ongoing research on bulk strontium titanate as an insulator, a metal, and a superconductor.

scholarly journals First steps in the development of a possible measurement method to estimate the radon concentration as an indicator of the indoor air quality

2014 ◽  
Vol 29 (suppl.) ◽  
pp. 52-58
Author(s):  
Franz Roessler ◽  
Jai Azzam ◽  
Volker Grimm ◽  
Hans Hingmann ◽  
Tina Orovwighose ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Primary Energy ◽  
Air Pollutant ◽  
Daily Routine ◽  
Air Exchange Rate ◽  
Pollutant Concentrations ◽  
Air Exchange

The energy conservation regulation provides upper limits for the annual primary energy requirements for new buildings and old building renovation. The actions required could accompany a reduction of the air exchange rate and cause a degradation of the indoor air quality. In addition to climate and building specific aspects, the air exchange rate is essentially affected by the residents. Present methods for the estimation of the indoor air quality can only be effected under test conditions, whereby the influence of the residents cannot be considered and so an estimation under daily routine cannot be ensured. In the context of this contribution first steps of a method are presented, that allows an estimation of the progression of the air exchange rate under favourable conditions by using radon as an indicator. Therefore mathematical connections are established that could be affirmed practically in an experimental set-up. So this method could provide a tool that allows the estimation of the progression of the air exchange rate and in a later step the estimation of a correlating progression of air pollutant concentrations without limitations of using the dwelling.

scholarly journals Structural and Optical Analysis of Ag Nanoparticles assisted Vertically Aligned TiO2 Nanowires based photoanode for Dye-sensitized Solar Cells Application

2021 ◽  
Author(s):  
Biraj Shougaijam ◽  
Salam Surjit Singh
Keyword(s):  
Solar Cells ◽  
Ag Nanoparticles ◽  
Dye Sensitized Solar Cells ◽  
Visible Region ◽  
Ag Nps ◽  
Dye Sensitized ◽  
Vertically Aligned ◽  
Glad Technique ◽  
Sensitized Solar Cells ◽  
Pet Substrate

Abstract In this work, vertically aligned TiO 2 -Nanowires (TiO 2 -NWs) and Ag Nanoparticles assisted TiO 2 Nanowires (TAT-NWs) were deposited on glass and flexible PET substrates using the Glancing Angle Deposition (GLAD) technique. The morphology and structural analysis of the samples manifest the successful deposition of vertically aligned TiO 2 -NWs and TAT-NWs. The HR-TEM image of TiO 2 -NWs shows the polycrystalline nature. Further, the XRD result confirms the polycrystalline nature of both the TiO 2 -NWs and TAT-NWs samples. Besides, the HR-TEM image confirms the presence of small crystal grains of Ag Nanoparticles (Ag-NPs) at the mid of the annealed TAT-NWs. It is evident from the Selective Area Electron Diffraction (SAED) analysis of the TiO 2 -NWs and annealed TAT-NWs that the crystallinity of TiO 2 present in the annealed TAT-NWs improves after annealing. The absorption spectrum analysis of TAT-NWs deposited on glass substrate shows enhance absorption peak in the visible region with a maximum peak at ~463 nm wavelength compare to the TiO 2 -NWs, which may be attributed to the Surface Plasmon Resonance (SPR) effect of Ag-NPs. Further, it is interesting to observe that the TAT-NWs deposited on PET substrate show further absorption enhancement in the UV and visible region. In addition, the Photoluminescence analysis reveals that the bandgap of the TiO 2 -NWs is ~3.12 eV, which supports the bandgap extracted from the Tauc plot. Therefore, the proposed method of fabricating TAT-NWs on glass and flexible ITO coated PET substrate using the GLAD technique may be applicable for developing novel photoanode for Dye-sensitized Solar Cells (DSSCs) and other optoelectronic applications.

scholarly journals Effect of GNWs/NiO-WO3/GNWs Heterostructure for NO2 Gas Sensing at Room Temperature

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 626
Author(s):  
Seokhun Kwon ◽  
Seokwon Lee ◽  
Joouk Kim ◽  
Chulmin Park ◽  
Hosung Jung ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Room Temperature ◽  
Microwave Plasma ◽  
Gas Sensing ◽  
Chemical Vapor ◽  
Gas Concentration ◽  
Negative Change ◽  
Low Concentrations ◽  
Detection Characteristics ◽  
No2 Detection

Recently, as air pollution and particulate matter worsen, the importance of a platform that can monitor the air environment is emerging. Especially, among air pollutants, nitrogen dioxide (NO2) is a toxic gas that can not only generate secondary particulate matter, but can also derive numerous toxic gases. To detect such NO2 gas at low concentration, we fabricated a GNWs/NiO-WO3/GNWs heterostructure-based gas sensor using microwave plasma-enhanced chemical vapor deposition (MPECVD) and sputter, and we confirmed the NO2 detection characteristics between 10 and 50 ppm at room temperature. The morphology and carbon lattice characteristics of the sensing layer were investigated using field emission scanning electron microscopy (FESEM) and Raman spectroscopy. In the gas detection measurement, the resistance negative change according to the NO2 gas concentration was recorded. Moreover, it reacted even at low concentrations such as 5–7 ppm, and showed excellent recovery characteristics of more than 98%. Furthermore, it also showed a change in which the reactivity decreased with respect to humidity of 33% and 66%.

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