scholarly journals Semiconductor Metal Oxides as Chemoresistive Sensors for Detecting Volatile Organic Compounds

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 233 ◽  
Author(s):  
Tingting Lin ◽  
Xin Lv ◽  
Zhineng Hu ◽  
Aoshu Xu ◽  
Caihui Feng
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Gas Sensors ◽  
Low Cost ◽  
Environmental Safety ◽  
Oil Refining ◽  
Detection Methods ◽  
Special Importance ◽  
Vehicle Exhaust ◽  
Volatile Organic

Volatile organic compounds (VOCs), which originate from painting, oil refining and vehicle exhaust emissions, are hazardous gases that have significant effects on air quality and human health. The detection of VOCs is of special importance to environmental safety. Among the various detection methods, chemoresistive semiconductor metal oxide gas sensors are considered to be the most promising technique due to their easy production, low cost and good portability. Sensitivity is an important parameter of gas sensors and is greatly affected by the microstructure, defects, catalyst, heterojunction and humidity. By adjusting the aforementioned factors, the sensitivity of gas sensors can be improved further. In this review, attention will be focused on how to improve the sensitivity of chemoresistive gas sensors towards certain common VOCs with respect to the five factors mentioned above.

scholarly journals Silver Enhances Hematite Nanoparticles Based Ethanol Sensor Response and Selectivity at Room Temperature

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 440
Author(s):  
Daniel Garcia-Osorio ◽  
Pilar Hidalgo-Falla ◽  
Henrique E. M. Peres ◽  
Josue M. Gonçalves ◽  
Koiti Araki ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Ethanol Vapor ◽  
Oxide Semiconductor ◽  
Charge Carrier Density ◽  
Ethanol Sensor ◽  
Volatile Organic

Gas sensors are fundamental for continuous online monitoring of volatile organic compounds. Gas sensors based on semiconductor materials have demonstrated to be highly competitive, but are generally made of expensive materials and operate at high temperatures, which are drawbacks of these technologies. Herein is described a novel ethanol sensor for room temperature (25 °C) measurements based on hematite (α‑Fe2O3)/silver nanoparticles. The AgNPs were shown to increase the oxide semiconductor charge carrier density, but especially to enhance the ethanol adsorption rate boosting the selectivity and sensitivity, thus allowing quantification of ethanol vapor in 2–35 mg L−1 range with an excellent linear relationship. In addition, the α-Fe2O3/Ag 3.0 wt% nanocomposite is cheap, and easy to make and process, imparting high perspectives for real applications in breath analyzers and/or sensors in food and beverage industries. This work contributes to the advance of gas sensing at ambient temperature as a competitive alternative for quantification of conventional volatile organic compounds.

scholarly journals Comparison of primary aerosol emission and secondary aerosol formation from gasoline direct injection and port fuel injection vehicles

2018 ◽  
Vol 18 (12) ◽  
pp. 9011-9023 ◽  
Author(s):  
Zhuofei Du ◽  
Min Hu ◽  
Jianfei Peng ◽  
Wenbin Zhang ◽  
Jing Zheng ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Fuel Injection ◽  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Vehicle Exhaust ◽  
Port Fuel Injection ◽  
Gasoline Vehicles ◽  
Volatile Organic ◽  
The Impact

Abstract. Gasoline vehicles significantly contribute to urban particulate matter (PM) pollution. Gasoline direct injection (GDI) engines, known for their higher fuel efficiency than that of port fuel injection (PFI) engines, have been increasingly employed in new gasoline vehicles. However, the impact of this trend on air quality is still poorly understood. Here, we investigated both primary emissions and secondary organic aerosol (SOA) formation from a GDI and a PFI vehicle under an urban-like driving condition, using combined approaches involving chassis dynamometer measurements and an environmental chamber simulation. The PFI vehicle emits slightly more volatile organic compounds, e.g., benzene and toluene, whereas the GDI vehicle emits more particulate components, e.g., total PM, elemental carbon, primary organic aerosols and polycyclic aromatic hydrocarbons. Strikingly, we found a much higher SOA production (by a factor of approximately 2.7) from the exhaust of the GDI vehicle than that of the PFI vehicle under the same conditions. More importantly, the higher SOA production found in the GDI vehicle exhaust occurs concurrently with lower concentrations of traditional SOA precursors, e.g., benzene and toluene, indicating a greater contribution of intermediate volatility organic compounds and semi-volatile organic compounds in the GDI vehicle exhaust to the SOA formation. Our results highlight the considerable potential contribution of GDI vehicles to urban air pollution in the future.

Ag-Functionalized macro-/mesoporous AZO synthesized by solution combustion for VOCs gas sensing application

RSC Advances ◽  
2016 ◽  
Vol 6 (103) ◽  
pp. 101304-101312 ◽  
Author(s):  
Xinxin Xing ◽  
Yuxiu Li ◽  
Dongyang Deng ◽  
Nan Chen ◽  
Xu Liu ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Solution Combustion ◽  
Highly Sensitive ◽  
Volatile Organic ◽  
Sensing Application

The aim of this paper is to develop easily manufactured and highly sensitive gas sensors for VOCs (volatile organic compounds) detection.

scholarly journals Formaldehyde and Total VOC (TVOC) Commercial Low-Cost Monitoring Devices: From an Evaluation in Controlled Conditions to a Use Case Application in a Real Building

Chemosensors ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 8 ◽  
Author(s):  
Valérie Goletto ◽  
Geneviève Mialon ◽  
Timothé Faivre ◽  
Ying Wang ◽  
Isabelle Lesieur ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
General Public ◽  
Low Cost ◽  
Qualitative Evaluation ◽  
Experimental Methodology ◽  
Portable Devices ◽  
Test Case ◽  
Controlled Conditions ◽  
Volatile Organic

Formaldehyde and volatile organic compounds (VOCs) are major indoor pollutants with multiple origins. Standard methods exist to measure them that require analytical expertise and provide, at best, an average value of their concentrations. There is a need to monitor them continuously during periods of several days, weeks, or even months. Recently, portable devices have become available. Two categories of portable devices are considered in this research paper: connected objects for the general public (price <500 €) and monitoring portable devices for professional users (price in the range >500 to 5000 €). The ISO method (ISO 16000-29) describes the standard for VOC detector qualification. It is quite complex and is not well adapted for a first qualitative evaluation of these low-cost devices. In this paper, we present an experimental methodology used to evaluate commercial devices that monitor formaldehyde and/or total volatile organic compounds (TVOC) under controlled conditions (23 °C, 50–65% relative humidity (RH)). We conclude that none of the connected objects dedicated to the general public can provide reliable data in the conditions tested, not even for a qualitative evaluation. For formaldehyde monitoring, we obtained some promising results with a portable device dedicated to professional users. In this paper, we illustrate, with a real test case in an office building, how this device was used for a comparative analysis.

Detection and discrimination of volatile organic compounds by noble metal nanoparticle functionalized MoS2 coated biodegradable paper sensors

2020 ◽  
Vol 44 (38) ◽  
pp. 16613-16625
Author(s):  
Radha Bhardwaj ◽  
Venkatarao Selamneni ◽  
Uttam Narendra Thakur ◽  
Parikshit Sahatiya ◽  
Arnab Hazra
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Noble Metal ◽  
Low Cost ◽  
Metal Nanoparticle ◽  
Selective Detection ◽  
Low Concentrations ◽  
Volatile Organic

In the current study, noble metal nanoparticle functionalized MoS2 coated biodegradable low-cost paper sensors were fabricated for the selective detection of low concentrations of volatile organic compounds (VOCs).

Progress in Research of the Combined Adsorption-Photocatalysis for the Removal of Volatile Organic Compounds

2014 ◽  
Vol 1015 ◽  
pp. 540-543
Author(s):  
Bo Tao Lin ◽  
Dong Mei Shi ◽  
Tao Li ◽  
Sen Kuan Meng
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Low Cost ◽  
Photocatalytic Efficiency ◽  
Toxic Chemical ◽  
Air Treatment ◽  
The Past ◽  
Photocatalytic Effect ◽  
Volatile Organic ◽  
Visible Light Photocatalytic

TiO2photocatalytic technology was developed in the past two decades in air treatment because of good photocatalytic effect, non-toxic, chemical stability, low cost, reusable features, the effect use of solar energy. A new composite materials of visible light photocatalytic degradation of low concentration of volatile organic compounds were produced by use of combining the adsorbent with TiO2photocatalytic technology.The adsorbent can enrich concentrations of volatile organic compounds on the surface of the TiO2photocatalyst. In this paper,the mechanism of the combined adsorption-photocatalysis for the removal of volatile organic compounds and immobilization methods、principle、craft were reviewed.The characteristic of the immobilization methods was analysed.It laid the foundation for the optimizing of the immobilization methods and the improving of the photocatalytic efficiency.

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