Morphology-driven gas sensing by fabricated fractals: A review

• Vishal Kamathe and
• Rupali Nagar

Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88

• macroscale, where the properties change with the length scales involved. This aspect has been addressed in the present review with focus on gas-sensing properties. While chemical or physical properties of the material may or may not remain the same, a change in geometry and architecture, especially as

• was reprinted from [67], Sensors and Actuators B: Chemical, vol. 255, by Y. Zhang; D. Li; L. Qin; P. Zhao; F. Liu; X. Chuai; P. Sun; X. Liang; Y. Gao; Y. Sun, “Preparation and gas sensing properties of hierarchical leaf-like SnO2 materials”, pages no. 2944–2951, Copyright (2018), with permission from

• ], Materials Letters, vol. 105, by J.-H. Jeun; D.-H. Kim; S.-H. Hong, “SnO2/CuO nano-hybrid foams synthesized by electrochemical deposition and their gas sensing properties”, pages no. 58–61, Copyright (2013), with permission from Elsevier. This content is not subject to CC BY 4.0. TiO2 fractals. (a) Top-view

A Au/CuNiCoS₄/p-Si photodiode: electrical and morphological characterization

• Adem Koçyiğit,
• Adem Sarılmaz,
• Teoman Öztürk,
• Faruk Ozel and
• Murat Yıldırım

Beilstein J. Nanotechnol. 2021, 12, 984–994, doi:10.3762/bjnano.12.74

• great attention due their unique electronic, magnetic, optical, and gas sensing properties. Spinel compounds can be employed in data storage applications, lithium-ion batteries, gas sensors, and medical diagnostics [1][2]. Spinels have a cubic crystal structure with the general chemical formula AB2X4

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• Micrograph software from at least 50 individual particles. Gas sensing properties of the sensor elements were characterized using a custom-designed flow-type sensing measurement system inside a corundum chamber with precisely controlled temperature and atmosphere. Calibrated according to STB ISO 9001-2009, a

Gas-sensing features of nanostructured tellurium thin films

• Dumitru Tsiulyanu

Beilstein J. Nanotechnol. 2020, 11, 1010–1018, doi:10.3762/bjnano.11.85

• Dumitru Tsiulyanu CIMAN Research Centre of Department of Physics, Technical University, bul. Dacia 41, MD-2060 Chisinau, Moldova 10.3762/bjnano.11.85 Abstract Nanocrystalline and amorphous nanostructured tellurium (Te) thin films were grown and their gas-sensing properties were investigated at

• were interpreted in terms of an increase in disorder (amorphization), leading to an increase in the surface chemical activity of chalcogenides, as well as an increase in the active surface area due to substrate porosity. Keywords: gas-sensing properties; NO2; tellurium thin films; nanocrystalline

• NO2 when in contact with microcrystalline, nanocrystalline or amorphous nanostructured Te-based films. Since that review was dedicated to exploring only the fabrication and investigation of gas-sensing properties of nanocrystalline Te films, it was only superficially mentioned that the amorphous films

Synthesis and acetone sensing properties of ZnFe₂O₄/rGO gas sensors

• Kaidi Wu,
• Yifan Luo,
• Ying Li and
• Chao Zhang

Beilstein J. Nanotechnol. 2019, 10, 2516–2526, doi:10.3762/bjnano.10.242

• effects in the heterostructures. This will enable corresponding gas sensors to accurately detect and monitor acetone vapor in real-time. In this view, compounding with certain organic or inorganic material could improve the gas sensing properties of ZnFe2O4 [18][19]. As a novel 2D carbon-based material

• ][25][26][27][28]. An optimum ratio of the composition and the fine nanostructure will contribute to obtaining better gas-sensing properties. A gas sensor with 3 wt % reduced graphene oxide (rGO) incorporated into In2O3 showed a rapid response, an improved stability and a low limit of detection of NO2

• (10 ppb) [29]. ZnO1−x/rGO composites with 2 wt % rGO had enhanced gas sensing properties compared with pure ZnO, as indicated by an enhanced sensitivity and an improved response/recovery speed [30]. It has been proved that coupling or compounding metal oxides with graphene enhances the electronic

High-temperature resistive gas sensors based on ZnO/SiC nanocomposites

• Vadim B. Platonov,
• Marina N. Rumyantseva,
• Alexander S. Frolov,
• Alexey D. Yapryntsev and
• Alexander M. Gaskov

Beilstein J. Nanotechnol. 2019, 10, 1537–1547, doi:10.3762/bjnano.10.151

• (XPS). The electrophysical and gas sensing properties of the materials were investigated by in situ conductivity measurements in the presence of the reducing gases CO and NH3 (20 ppm), in dry conditions (relative humidity at 25 °C RH25 = 0) and in humid air (RH25 = 30%) in the temperature range 400–550

Selective gas detection using Mn₃O₄/WO₃ composites as a sensing layer

• Yongjiao Sun,
• Zhichao Yu,
• Wenda Wang,
• Pengwei Li,
• Gang Li,
• Wendong Zhang,
• Lin Chen,
• Serge Zhuivkov and
• Jie Hu

Beilstein J. Nanotechnol. 2019, 10, 1423–1433, doi:10.3762/bjnano.10.140

• , the peaks at a binding energy of 641.1 eV and 653 eV are attributed to Mn 2p3/2 and Mn 2p1/2 with a splitting of 11.9 eV, which matches well with Mn3O4 [16][19][20]. The XPS results confirm the existence of crystalline Mn3O4. Gas sensing properties Since the electron mobility in the conduction band is

• composites, the improved gas sensing properties can be ascribed to the following two reasons. Firstly, Mn3+ in the Mn3O4/WO3 composites results in more defects on the surface of the WO3 matrix, which promotes the adsorption of the oxygen species [34]. More adsorbed oxygen means a broader electron depletion

• atom % Mn3O4/WO3 composites have the best ammonia sensing performance. Conclusion In summary, WO3 and Mn3O4/WO3 composites with different concentrations of Mn were prepared and characterized. Their selective gas sensing properties were investigated, and the measurement results show that the gas sensors

Gas sensing properties of individual SnO₂ nanowires and SnO₂ sol–gel nanocomposites

• Alexey V. Shaposhnik,
• Dmitry A. Shaposhnik,
• Sergey Yu. Turishchev,
• Olga A. Chuvenkova,
• Stanislav V. Ryabtsev,
• Alexey A. Vasiliev,
• Xavier Vilanova,
• Francisco Hernandez-Ramirez and
• Joan R. Morante

Beilstein J. Nanotechnol. 2019, 10, 1380–1390, doi:10.3762/bjnano.10.136

• selectivity to target gases. The aim of this work is the comparison of gas sensing properties of tin dioxide in the form of individual nanowires and nanopowders obtained by sol–gel synthesis. This comparison is necessary because the traditional synthesis procedures of small particle, metal oxide materials

• noticeable density of oxygen vacancies inside the powder particles and at the surface of wire-like crystals. Gas sensing properties During the characterization of the sensing properties of the devices, the following conditions were used: the sensors were exposed to air for one hour, then air was replaced by

Hydrophilicity and carbon chain length effects on the gas sensing properties of chemoresistive, self-assembled monolayer carbon nanotube sensors

• Juan Casanova-Cháfer,
• Carla Bittencourt and
• Eduard Llobet

Beilstein J. Nanotechnol. 2019, 10, 565–577, doi:10.3762/bjnano.10.58

• chain and its hydrophilicity on the gas sensing properties of SAMs formed on carbon nanotubes are studied, and additionally, the gas sensing mechanisms are discussed. Four thiols differing in the length of the carbon chain and in the hydrophobic or hydrophilic nature of the head functional group are

• on the gas sensing properties of SAMs supported on CNTs. The response towards two gases, nitrogen dioxide and ethanol, was investigated. On the one hand, the detection of nitrogen dioxide has attracted great interest because of its adverse consequences for the environment and health risks associated

• better assess the effect of the thiol SAMs on the gas sensing properties of nanomaterials. Gas measurements were performed under dry air. It is well known that the triple bond in molecular nitrogen makes it chemically inert, however, oxygen presents high electronegativity (3.44 in Pauling scale) making

Wet chemistry route for the decoration of carbon nanotubes with iron oxide nanoparticles for gas sensing

• Hussam M. Elnabawy,
• Juan Casanova-Chafer,
• Badawi Anis,
• Mostafa Fedawy,
• Mattia Scardamaglia,
• Carla Bittencourt,
• Ahmed S. G. Khalil,
• Eduard Llobet and
• Xavier Vilanova

Beilstein J. Nanotechnol. 2019, 10, 105–118, doi:10.3762/bjnano.10.10

• by selecting the appropriate ratio of carbon nanotubes/iron salt, while nanoparticle size can be modulated by controlling the calcination period. Pristine and iron-decorated carbon nanotubes were deposited on silicon substrates to investigate their gas sensing properties. It was found that loading

• study of the gas sensing properties of the different hybrid nanomaterials was conducted in an effort to determine the optimal functionalization parameters to maximize sensor response. The selectivity of the resulting layer for potential interfering gases such as CO and benzene has also been investigated

• s in a continuous scanning mode. Fabrication and testing of gas sensors In order to check the effect of the different decorations on the gas sensing properties of modified CNTs, simple sensing devices were fabricated. For that purpose, small rectangular pieces of a silicon wafer, previously oxidized

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

• parameter in gas sensing properties. Less connected particles in Cr2O3 and Co3O4 nanofibers show a reduced gas sensing response [113]. Sensors calcined at 750 °C (grain size 36 ± 4 nm) showed 10–25% and 25–65% more sensitivity toward CO and NO2, respectively, than those calcined at 450 °C (grain size 17 ± 2

• at lower temperature (240 °C) with shorter response and recovery times (1 s and 10 s), respectively. Rare earth metals and their oxides significantly improve gas sensing properties of semiconducting metal oxide materials by substitution in their lattice structure. For example, 3 wt % Eu2O3-doped

Free-radical gases on two-dimensional transition-metal disulfides (XS₂, X = Mo/W): robust half-metallicity for efficient nitrogen oxide sensors

• Chunmei Zhang,
• Yalong Jiao,
• Fengxian Ma,
• Sri Kasi Matta,
• Steven Bottle and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1641–1646, doi:10.3762/bjnano.9.156

• ]. Besides, the corresponding binding position and energy of NO adsorbed on single-layer MoS2 [23] and WS2 [28] were analyzed from a theoretical point of view. Even though the gas-sensing properties involving NO and NO2 are well studied, few studies [29] have been carried out to explore the difference in

Surface-plasmon-enhanced ultraviolet emission of Au-decorated ZnO structures for gas sensing and photocatalytic devices

• T. Anh Thu Do,
• Truong Giang Ho,
• Thu Hoai Bui,
• Quang Ngan Pham,
• Hong Thai Giang,
• Thi Thu Do,
• Duc Van Nguyen and
• Dai Lam Tran

Beilstein J. Nanotechnol. 2018, 9, 771–779, doi:10.3762/bjnano.9.70

• NPs to interact directly with the adsorbed oxygen species and target gases [40][41]. As a result, the gas-sensing properties of Au NP/ZnO sensors are crucial to maintain the high sensitivity and fast response–recovery characteristics. The strong electronic interaction between gold and the defect sites

• photomultiplier tube (MCP-PMT). The full-width at half-maximum (FWHM) of the total instrument response function (IRF) was less than 130 ps. Gas sensing characteristics Gas sensing properties of the as-deposited ZnO and Au NP/ZnO samples were evaluated by measuring the resistance change of the corresponding

Sensing behavior of flower-shaped MoS₂ nanoflakes: case study with methanol and xylene

• Maryam Barzegar,
• Masoud Berahman and
• Azam Iraji zad

Beilstein J. Nanotechnol. 2018, 9, 608–615, doi:10.3762/bjnano.9.57

• process is known as one of the scalable methods to synthesize MoS2 nanostructures. In this study, the gas sensing properties of flower-shaped MoS2 nanoflakes, which were prepared from molybdenum trioxide (MoO3) by a facile hydrothermal method, have been studied. Material characterization was performed

• the most suitable candidates to use in gas sensing devices [14][15]. There are few reports on gas sensing properties of MoS2. Cantalini et al. [8] reported the response of few layer MoS2 films to NO2 at sub-ppm concentrations and reasonable sensitivity to 1 ppm NO2 with fast and reversible response at

• electro-activity of MoS2 nanosheets. Furthermore, sulfur vacancies contribute significantly to the electronic properties of MoS2 [36][37]. Hence, such sulfur vacancy is desirable for the gas sensing properties of MoS2. To study the application of the flower-shaped MoS2 for gas sensing, the Brunauer–Emmett

Gas-sensing behaviour of ZnO/diamond nanostructures

• Marina Davydova,
• Alexandr Laposa,
• Jiri Smarhak,
• Alexander Kromka,
• Neda Neykova,
• Josef Nahlik,
• Jiri Kroutil,
• Jan Drahokoupil and
• Jan Voves

Beilstein J. Nanotechnol. 2018, 9, 22–29, doi:10.3762/bjnano.9.4

• electron microscopy, X-ray diffraction measurements and Raman spectroscopy. The gas sensing properties of the sensors based on i) NCD films, ii) ZnO nanorods, and iii) hybrid ZnO NRs/NCD structures were evaluated with respect to oxidizing (i.e., NO2, CO2) and reducing (i.e., NH3) gases at 150 °C. The

• , materials with hybrid components have become more popular in the field of sensing because the hybridization and synergic effect of organic or inorganic materials could enhance the gas sensing properties. For example, Wang et al. fabricated a ring-like PdO–NiO composite with a lamellar structure and showed a

• ) in order to investigate their gas sensing properties for nitrogen dioxide (NO2), ammonia (NH3) and carbon dioxide (CO2) at different concentration ranges of 25–100 ppm or 1250–5000 ppm. For this purpose we developed three different gas sensor devices based on i) NCD thin films, ii) ZnO nanorods, and

Gas sensing properties of MWCNT layers electrochemically decorated with Au and Pd nanoparticles

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Riccardo Rossi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 592–603, doi:10.3762/bjnano.8.64

• interplay between the surface chemical composition and gas sensing properties of hybrid gas sensors, sensing mechanisms have been proposed. The electrophoretic process is herein shown to be a versatile and simple method to deposit various pre-synthesized colloidal metal NPs, specifically Au and Pd NPs, on

• covers MWCNT sidewalls as shown in Figure 4E. In the following section, the effect of the nature and loading of the deposited catalytic metal NPs on the gas sensing properties of MWCNTs is discussed. Gas sensing properties The effect of the working temperature in the range 45–200 °C on NO2 detection is

Graphene functionalised by laser-ablated V₂O₅ for a highly sensitive NH₃ sensor

• Margus Kodu,
• Artjom Berholts,
• Tauno Kahro,
• Mati Kook,
• Peeter Ritslaid,
• Helina Seemen,
• Tea Avarmaa,
• Harry Alles and
• Raivo Jaaniso

Beilstein J. Nanotechnol. 2017, 8, 571–578, doi:10.3762/bjnano.8.61

• structures was investigated using Raman spectroscopy. Based on the electrical conductivity modulation, the room temperature gas sensing properties of the manufactured sensor structure towards ammonia (NH3) and (for comparison) nitrogen dioxide (NO2) gases were investigated. Results Figure 1a shows a typical

• distribution of the system [37]. V2O5 is known for its catalytic properties and as a good NH3 adsorber [7][8]. The good NH3 gas sensing properties of V2O5 thin films and nanofibers have been demonstrated by Huotari et al. [12] and Modafferi et al. [38]. Two strongly bound adsorption species are typically

Sensitive detection of hydrocarbon gases using electrochemically Pd-modified ZnO chemiresistors

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 82–90, doi:10.3762/bjnano.8.9

• , in which each sensor system is selective in the detection of a specific gas. Conclusion The successful electrochemical functionalization of ZnO NRs by Pd NPs is reported. The gas sensing properties of pristine and Pd-modified rod-like ZnO-based chemiresistor revealed that the presence of catalytic Pd

Nanostructured TiO₂-based gas sensors with enhanced sensitivity to reducing gases

• Wojciech Maziarz,
• Anna Kusior and
• Anita Trenczek-Zajac

Beilstein J. Nanotechnol. 2016, 7, 1718–1726, doi:10.3762/bjnano.7.164

• . Mickiewicza 30, Krakow 30-059, Poland 10.3762/bjnano.7.164 Abstract 2D TiO2 thin films and 3D flower-like TiO2-based nanostructures, also decorated with SnO2, were prepared by chemical and thermal oxidation of Ti substrates, respectively. The crystal structure, morphology and gas sensing properties of the

• as H2 [7], NO2 [8], NOx [9], CO [10], NH3 [11], H2S [12], and VOCs (i.e., methanol, ethanol, propanol [13], and acetone [14]). The influence of effective surface area on the gas sensing properties of TiO2 thin films is also frequently observed and investigated [15]. TiO2 is a wide-band gap

• sensitive material, and hence the higher the concentration of active surface oxygen adsorption centers. As a result, enhanced gas selectivity and sensitivity can be obtained. Since gas sensing properties depend on the method of synthesis and conditions applied in the preparation process, it is of crucial

Ammonia gas sensors based on In₂O₃/PANI hetero-nanofibers operating at room temperature

• Qingxin Nie,
• Zengyuan Pang,
• Hangyi Lu,
• Yibing Cai and
• Qufu Wei

Beilstein J. Nanotechnol. 2016, 7, 1312–1321, doi:10.3762/bjnano.7.122

• morphology of In(NO3)3/PVP, In2O3/PANI composite nanofibers and pure PANI were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and current–voltage (I–V) measurements. The gas sensing properties

• form a typical ohmic system [31]. Thus, it can be confirmed that a p–n junction between PANI and In2O3 had been formed. Gas sensing properties To study the ammonia sensing behavior of the sensors with different ratios of In2O3 to aniline, the dynamic response of the sensors based on pure PANI and In2O3

Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2016, 7, 22–31, doi:10.3762/bjnano.7.3

• gas-sensing properties. Keywords: Au-doped ZnO; chemiresistive gas sensor; electrosynthesis; NO2 gas sensor; ZnO nanostructures; Introduction Today the use of low-cost portable gas sensors is essential to detect and to monitor toxic, polluting and combustible gases for the environmental protection

• ]. Moreover, it has been demonstrated that a careful control of the MOS nanostructures, used as active layers in gas sensors, permits to improve their gas-sensing properties [10][11]. Specifically, the smaller grain size influences the material resistivity, so that the conductive properties of the material

• affected by this drawback, improving the stability of gas sensors [9][15][16]. Additionally, also the use of one-dimensional nanostructures (e.g., nanorods, nanowires, and nanobelts), with high surface to volume ratio, improves the gas-sensing properties [9][17]. Among different MOS, ZnO has been widely

Radiation losses in the microwave K_u band in magneto-electric nanocomposites

• Talwinder Kaur,
• Sachin Kumar,
• Jyoti Sharma and
• A. K. Srivastava

Beilstein J. Nanotechnol. 2015, 6, 1700–1707, doi:10.3762/bjnano.6.173

• interesting material with variable properties and a large anisotropy field having a magnetic resonance in the range of 2–52 GHz. Also, at the nano-scale, its optical properties [19], magnetic properties [20][21], piezo-electric properties [22], photocatalytic properties [23], gas-sensing properties [24

Pt- and Pd-decorated MWCNTs for vapour and gas detection at room temperature

• Hamdi Baccar,
• Atef Thamri,
• Pierrick Clément,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2015, 6, 919–927, doi:10.3762/bjnano.6.95

• Nanomatériaux (UR11ES30), Faculté des Sciences de Bizerte, Jarzouna, 7021, Tunisia MINOS-EMaS, Universitat Rovira i Virgili, Avda. Països Catalans 26, 43007 Tarragona, Spain 10.3762/bjnano.6.95 Abstract Here we report on the gas sensing properties of multiwalled carbon nanotubes decorated with sputtered Pt or

• /vapour response of carbon nanotubes, selectivity remains an important challenge that is still far from being achieved. In the quest to improve selectivity, in this paper, we report on the gas sensing properties of carbon nanotubes decorated with sputtered Pt or Pd nanoparticles. Sputtering is an

• evaporation onto carbon nanotubes and this sensor was also somewhat responsive to aromatic VOCs. Conclusion In this paper, we have reported on the gas sensing properties of carbon nanotubes decorated with Pt or Pd nanoparticles. Nanoparticles were formed by rf sputtering, which allowed an oxygen plasma

Gas sensing properties of nanocrystalline diamond at room temperature

• Marina Davydova,
• Pavel Kulha,
• Alexandr Laposa,
• Karel Hruska,
• Pavel Demo and
• Alexander Kromka

Beilstein J. Nanotechnol. 2014, 5, 2339–2345, doi:10.3762/bjnano.5.243

• Prague, Czech Republic 10.3762/bjnano.5.243 Abstract This study describes an integrated NH3 sensor based on a hydrogenated nanocrystalline diamond (NCD)-sensitive layer coated on an interdigitated electrode structure. The gas sensing properties of the sensor structure were examined using a reducing gas

• ) and a visible development of diamond nanocrystal faceting. Moreover, the NCD primarily grew on the IDEs as was previously found [9]. The gas-sensing properties of the hydrogenated NCD sensor with a sparse electrode arrangement of 200 µm were tested against a sequence of NH3 pulses (Figure 1b). These

• + IDEs with a separation of 50 µm) coated with the NCD layer after 40 min of nucleation time. The coating exhibited a continuous diamond layer with diamond grains up to 80 nm in size. The gas-sensing properties of the hydrogenated NCD sensor with a dense electrode arrangement of 50 µm was also tested

Room temperature, ppb-level NO₂ gas sensing of multiple-networked ZnSe nanowire sensors under UV illumination

• Sunghoon Park,
• Soohyun Kim,
• Wan In Lee,
• Kyoung-Kook Kim and
• Chongmu Lee

Beilstein J. Nanotechnol. 2014, 5, 1836–1841, doi:10.3762/bjnano.5.194

• Department of Nano-Optical Engineering, Korea Polytechnic University, 2121 Jeongwang-dong, Shiheung city, Gyeonggi-do, 429-793, Republic of Korea 10.3762/bjnano.5.194 Abstract Reports of the gas sensing properties of ZnSe are few, presumably because of the decomposition and oxidation of ZnSe at high

• diodes [5] and UV photodetectors [6]. On the other hand, there are almost no reports on the gas sensing properties of ZnSe. This might be due to the decomposition and oxidation of ZnSe at temperatures above 200 °C [7] and a lack of good sensing performance at room temperature. In recent years, one

• enhance the sensing performance of ZnSe, 1D nanostructure-based sensors at room temperature. In this study, multiple-networked ZnSe nanowire sensors were fabricated and examined for their room-temperature, NO2-gas sensing properties under UV illumination. Unlike individual 1D nanostructure sensors