The enhanced NO2 sensing properties of SnO2 nanoparticles/reduced graphene oxide composite

Zhang

Adv Materials Technologies

et al. 2020

The detection of ultralow NO2 for practical applications remains a significant challenge because the two critical characteristics of high sensitivity and good robustness are considerably unsatisfactory. Inspired by the classification of stimuli‐receiving and signal‐conveying for a stimuli‐responsive procedure of a neuron in organisms, an internal micro‐Schottky junction introduced into a chemiresistor is constructed as an efficient transduction strategy to boost the less concerned transducing stage for a further improvement in NO2 sensing performance. The SnO2 nanoflowers/reduced graphene oxide‐based chemiresistor achieves a response of 10.5 toward 10 ppt NO2, with a record‐breaking limit of detection of 0.73 ppt at room temperature as well as fast response and recovery times of 59 and 9 s at 10 ppt. Surprisingly, the sensor exhibits good robustness, including higher selectivity, long‐term stability, and process stability. A comprehensive analysis of the electrical properties and energy band of inorganic materials reveals that the ultrahigh sensitivity and faster response/recovery are primarily related to the efficient transducing ability arising from the rapid electron transport and signal‐amplifying effect contributed by micro‐Schottky junctions. The concept of affiliating the sensing material modulation to the recepting and transducing stages and considering comprehensively provides a novel insight into the enhancement of gas sensing performance.

Section: Resultsmentioning

confidence: 85%

Micro‐Schottky Junction‐Boosted Efficient Charge Transducing for Ultrasensitive NO₂ Sensing

Zhang

Adv Materials Technologies

et al. 2020

“…The same is not true for removing oxygen from the surface and edge. Oxygen can be completely removed using hydrazine [8]. The UV radiation can break the OH bond to graphene at the surface only.…”

Section: Theorymentioning

confidence: 99%

“…The large surface area of graphene is one of the important features that give graphene superiority in gas sensing operations. This superiority is also kept even after the mixture of graphene with other materials since the mixed materials are dispersed on graphene surfaces or edges that prevent agglomeration [8,9]. Graphene oxide can be activated using materials that remove oxygencontaining functional groups on the surfaces of graphene oxide.…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity of SnO2 nanoparticles/reduced graphene oxide hybrid to NO2 gas: A DFT study

Abdulridha

Abdulsattar²,

Hussein

2022

Preprint

The sensitivity of SnO2 nanoparticles/reduced graphene oxide hybrid to NO2 gas is discussed in the present work using density functional theory (DFT). The SnO2 nanoparticles shapes are taken as pyramids, as proved by experiments. The reduced graphene oxide (rGO) edges have oxygen or oxygen-containing functional groups. However, the upper and lower surfaces of rGO are clean, as expected from the oxide reduction procedure. Results show that SnO2 particles are connected at the edges of rGO, making a p-n heterojunction with a reduced agglomeration of SnO2 particles and high gas sensitivity. The DFT results are in good agreement with the experimental characterization of both SnO2 and rGO using energy gap and XPS values. Gibbs free energy, enthalpy, and entropy of the various considered reactions are calculated. Results show that the sensitivity of the rGO/SnO2 hybrid to NO2 gas is the result of the interplay of the dissociation and oxidation reactions of NO2 gas.

“…Tungsten oxide-loaded graphene has been found useful at detecting alcohols [ 29 ], triethylamine [ 30 ], and aniline [ 31 ]. Tin oxide-loaded graphene has been reported for the detection of, mainly, nitrogen dioxide [ 32 , 33 , 34 , 35 , 36 ], but also of formaldehyde [ 37 , 38 ], acethylene [ 39 ], and acetone [ 40 ].…”

Section: Introductionmentioning

confidence: 99%

Metal Oxide Nanoparticle-Decorated Few Layer Graphene Nanoflake Chemoresistors for the Detection of Aromatic Volatile Organic Compounds

Behi

Bohli

Casanova-Cháfer

et al. 2020

Sensors

Benzene, toluene, and xylene, commonly known as BTX, are hazardous aromatic organic vapors with high toxicity towards living organisms. Many techniques are being developed to provide the community with portable, cost effective, and high performance BTX sensing devices in order to effectively monitor the quality of air. In this paper, we study the effect of decorating graphene with tin oxide (SnO2) or tungsten oxide (WO3) nanoparticles on its performance as a chemoresistive material for detecting BTX vapors. Transmission electron microscopy and environmental scanning electron microscopy are used as morphological characterization techniques. SnO2-decorated graphene displayed high sensitivity towards benzene, toluene, and xylene with the lowest tested concentrations of 2 ppm, 1.5 ppm, and 0.2 ppm, respectively. In addition, we found that, by employing these nanomaterials, the observed response could provide a unique double signal confirmation to identify the presence of benzene vapors for monitoring occupational exposure in the textiles, painting, and adhesives industries or in fuel stations.