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

• comparably good gas-sensing performance [21][22]. However, due to their high affinity toward HCs and low thermal stability, they are sometimes unstable and exhibit poor sensitivity [23][24]. In this context, metal oxides (MOx) have been proposed as promising active sensing layers because of their

• advantageous properties such as good sensitivity under ambient conditions and easy preparation [25]. The fundamental process of the gas-sensing mechanism, holding the MOx-based sensing material at elevated temperatures above 300 °C, is the reaction of the surrounding gases with the oxygen of the MOx layer

• but lower the activation energy. The sensing response of ZnO towards most of the toxic gases in general, and towards HC gases in particular, can be improved by surface deposition of noble metals. Sivapunniyam et al. [39] have reported the improvement of ZnO-nanorod-based HC gas sensing by doping the

Diffusion of dilute gas in arrays of randomly distributed, vertically aligned, high-aspect-ratio cylinders

• Wojciech Szmyt,
• Carlos Guerra and
• Ivo Utke

Beilstein J. Nanotechnol. 2017, 8, 64–73, doi:10.3762/bjnano.8.7

• nanocylinder arrays in solar cells and energy storage applications. Furthermore, gas sensing devices with high-aspect-ratio nanocylinder arrays and the growth of vertically aligned carbon nanotubes need the fundamental understanding and precise modelling of gas transport to optimise such processes. Keywords

• ALD [14]. Arrays of nanocylinders are also used in gas sensing systems [15][16]. The increasing interest in surface functionalisation via gas phase techniques as well as gas sensing applications with high-aspect-ratio nanocylinder arrays has raised the need for the fundamental understanding and

• of a great assistance in understanding quantitatively the process of gas transport in arrays of vertically aligned cylinders, such as nanotubes or nanowires of various materials. This is crucial for the optimisation of gas-based surface-functionalisation processes of such arrays as well as of the gas

Nanostructured SnO₂–ZnO composite gas sensors for selective detection of carbon monoxide

• Paul Chesler,
• Cristian Hornoiu,
• Susana Mihaiu,
• Cristina Vladut,
• Jose Maria Calderon Moreno,
• Mihai Anastasescu,
• Carmen Moldovan,
• Bogdan Firtat,
• Costin Brasoveanu,
• George Muscalu,
• Ion Stan and
• Mariuca Gartner

Beilstein J. Nanotechnol. 2016, 7, 2045–2056, doi:10.3762/bjnano.7.195

• . Highly toxic and flammable gases (CO, CO2, CH4, and C3H8) were tested under lab conditions (carrier gas was dry air) using a special gas sensing cell developed by our research group. The gas concentrations varied between 5 and 2000 ppm and the optimum working temperatures were in the range of 210–300 °C

• (chemometrics) and advanced sensor operation techniques, such as temperature modulation [1]. In the past few years the use of composite sensors has yielded a lot of published work in the gas sensing domain [1][3][5][7][8][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33

• program developed by Park Systems was used for displaying the images and subsequent statistical data analysis. Gas sensing measurements The gas sensing measurements were performed under lab conditions (carrier gas, dry air) using a custom built sensing system (see Figure 5). The cell includes a heating

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

Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra

• Oriol Gonzalez,
• Sergio Roso,
• Xavier Vilanova and
• Eduard Llobet

Beilstein J. Nanotechnol. 2016, 7, 1507–1518, doi:10.3762/bjnano.7.144

• light, which convey important information for the quantitative analysis of nitrogen dioxide. Keywords: dynamic gas sensing; indium oxide; nitrogen dioxide; pulsed UV light; UV-activated metal oxide; Introduction Technological barriers related to sensor performance and power consumption are currently

• (XRD). As shown in Figure 2, the as-grown samples show the typical features of cubic In2O3. The XRD pattern for a commercially available, cubic phase indium oxide has been added for comparison. No peaks belonging to other materials or impurities were found. Gas sensing analysis Static sensor operation

A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors

• Vardan Galstyan,
• Elisabetta Comini,
• Iskandar Kholmanov,
• Andrea Ponzoni,
• Veronica Sberveglieri,
• Nicola Poli,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2016, 7, 1421–1427, doi:10.3762/bjnano.7.133

• used to quantify the elemental composition of the obtained materials. GO platelets were deposited onto Si substrates and characterized by Raman spectroscopy (WITec Micro-Raman Spectrometer Alpha 300, λ = 532 nm, 100× objective). To perform gas sensing measurements, the platinum electrodes and the

• heater were deposited on the front and rear sides of the alumina substrate, respectively. During gas sensing tests, the conductance of the samples was monitored by means of the volt-amperometric technique and the applied voltage during the measurements was 1 V. We recorded the resistance of the

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

• of these materials towards NH3 vapor (100 to 1000 ppm) were measured at room temperature. The results revealed that the gas sensing abilities of In2O3/PANI composite nanofibers were better than pure PANI. In addition, the mass ratio of In2O3 to aniline and the p–n heterostructure between In2O3 and

• to aniline (0, 1:1, 1:2 and 1:4) were prepared. Correspondingly, the four sensors were denoted as PANI sensor, In2O3/PANI-1 nanofibers sensor, In2O3/PANI-2 nanofibers sensor and In2O3/PANI-3 nanofibers sensor. Structural characterization and gas sensing test The crystal structure of In2O3 nanofibers

NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography

• Li-Yang Hong and
• Heh-Nan Lin

Beilstein J. Nanotechnol. 2016, 7, 1044–1051, doi:10.3762/bjnano.7.97

• Li-Yang Hong Heh-Nan Lin Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan 10.3762/bjnano.7.97 Abstract In this work, the fabrication of single titanium oxide nanodot (ND) resistive sensors for NO gas sensing at room temperature is reported. Two

• atomic force microscopy nanolithography methods, nanomachining and nano-oxidation, are employed. A single titanium nanowire (NW) is created first along with contact electrodes and a single titanium oxide ND is subsequently produced in the NW. Gas sensing is realized by the photo-activation and the photo

• potential application of single metal oxide NDs for gas sensing with a performance that is comparable with that of metal oxide nanowire gas sensors. Keywords: atomic force microscopy nanolithography; photo-activation; photo-recovery; resistive NO gas sensor; titanium oxide nanodot sensor; Introduction In

Bacteriorhodopsin–ZnO hybrid as a potential sensing element for low-temperature detection of ethanol vapour

• Saurav Kumar,
• Sudeshna Bagchi,
• Senthil Prasad,
• Anupma Sharma,
• Ritesh Kumar,
• Rishemjit Kaur,
• Jagvir Singh and
• Amol P. Bhondekar

Beilstein J. Nanotechnol. 2016, 7, 501–510, doi:10.3762/bjnano.7.44

• , nanomaterial–biomolecule hybrid gas sensors. Keywords: amphipol; bacteriorhodopsin; bio-hybrid; gas sensing; ITO; ZnO nanostructure; Introduction Nanomaterial–biomolecule conjugates have emerged into one of the most rapidly developing and sought after areas in modern biomolecular device fabrication and

• , SiO2) and polymers (e.g., PVA, gelatine) have been explored for photo–energy conversion, energy storage devices and gas sensing based on photo-conductive activity [12][14][20][21][22]. In parallel, ZnO and its hybrids have evolved as promising structures for sensing and semiconductor applications [23

• sensing material [28]. Further, the advancement in concepts and techniques in nanotechnology resulted in the demonstration of the gas sensing capabilities of ZnO-based nanostructures [29][30]. Recently, researchers have explored innovative hybrid nanostructures based on the interaction of organic and

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

• , respectively. The pristine ZnO and Au@ZnO nanocomposites are proposed as active layer in chemiresistive gas sensors for low-cost processing. Gas-sensing measurements towards NO2 were collected at 300 °C, evaluating not only the Au-doping effect, but also the influence of the different ZnO nanostructures on the

• 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

• active layer in low-cost chemiresistive gas sensors, due to their high sensitivity to gaseous analytes and easy production. The gas-sensing mechanism of MOS-based gas sensors is based on receptor and transducer functions [3]. Specifically, the first regards the recognition of a gaseous analyte by an

Nanostructures for sensors, electronics, energy and environment II

• Nunzio Motta

Beilstein J. Nanotechnol. 2015, 6, 1937–1938, doi:10.3762/bjnano.6.197

• be exploited in room temperature gas sensing devices. The plasmonic effect, generated by the inclusion of metallic nanoparticles, can be used to overcome certain limitations of the carbon materials, especially in organic solar cells [5]. The optical properties of nanomaterials can also be exploited

Atomic scale interface design and characterisation

• Carla Bittencourt,
• Chris Ewels and
• Arkady V. Krasheninnikov

Beilstein J. Nanotechnol. 2015, 6, 1708–1711, doi:10.3762/bjnano.6.174

• their properties [16][17]. Besides dealing with fundamental questions, contributions emphasize possible applications of the remarkable physical and chemical properties of this class of materials such as thermoelectrics [18], plasmonics [19] and gas sensing [20]. In the future, spatial control of doping

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

Transformations of PTCDA structures on rutile TiO₂ induced by thermal annealing and intermolecular forces

• Szymon Godlewski,
• Jakub S. Prauzner-Bechcicki,
• Thilo Glatzel,
• Ernst Meyer and
• Marek Szymoński

Beilstein J. Nanotechnol. 2015, 6, 1498–1507, doi:10.3762/bjnano.6.155

• example, titanium dioxide surfaces are exceptionally useful in various applications, including the catalysis, solar energy conversion, gas sensing and others [8][9][10][11][12][13][14][15]. Merging two classes of materials, i.e., metal oxide surfaces with organic molecules, seems to be one of the most

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

• used as reported in [40]. Gas sensing measurements The electrical characterisation under gas or vapour environment was performed employing an HP 4192A impedance analyzer [17]. Since all devices showed a resistive behavior at frequencies below 100 kHz, the resistance of the metal-decorated carbon

In situ scanning tunneling microscopy study of Ca-modified rutile TiO₂(110) in bulk water

• Giulia Serrano,
• Beatrice Bonanni,
• Tomasz Kosmala,
• Marco Di Giovannantonio,
• Ulrike Diebold,
• Klaus Wandelt and
• Claudio Goletti

Beilstein J. Nanotechnol. 2015, 6, 438–443, doi:10.3762/bjnano.6.44

• applications ranging from nanotechnology [7] to gas sensing [8], as well as catalysis [9] and biomedicine [10][11]. In particular, the high corrosion resistance of titanium to biological environments has stimulated the study of this metal and its oxide for in vivo or in vitro calcium phosphate ceramic growth

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

• several hours up to several days. Only thermal annealing of the sensor reduces the sensor recovery speed [1][2]. Recently, much attention has been given to solid-state integrating-type (i.e., accumulating- or dosimeter-type) gas sensing devices, which are able to overcome the aforementioned drawbacks [3

• ) 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

Advances in NO₂ sensing with individual single-walled carbon nanotube transistors

• Kiran Chikkadi,
• Matthias Muoth,
• Cosmin Roman,
• Miroslav Haluska and
• Christofer Hierold

Beilstein J. Nanotechnol. 2014, 5, 2179–2191, doi:10.3762/bjnano.5.227

• and forests have been shown to be effective for gas sensing, and can be fabricated efficiently on a large scale at low cost. However, the sensing behavior of nanotube networks is very complex due to the large variety of available adsorption sites, the presence of grooves and junctions between

• individual single-walled carbon nanotubes for NO2 sensing. Review Individual-nanotube transistors for gas sensing The typical individual-SWNT gas sensor is a 3-terminal device, in which the nanotube is contacted by a source and a drain electrode and a current flowing through it is measured. Depending on the

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

Experimental techniques for the characterization of carbon nanoparticles – a brief overview

• Wojciech Kempiński,
• Szymon Łoś,
• Mateusz Kempiński and
• Damian Markowski

Beilstein J. Nanotechnol. 2014, 5, 1760–1766, doi:10.3762/bjnano.5.186

• carrier transport within the systems of CNs by varying the temperature, adsorbed molecules and external electric field. Due to the significant changes in resistivity induced by the host–guest interactions, the systems of CNs might prove interesting in the fields of gas sensing, molecular electronics or

Effects of palladium on the optical and hydrogen sensing characteristics of Pd-doped ZnO nanoparticles

• Anh-Thu Thi Do,
• Hong Thai Giang,
• Thu Thi Do,
• Ngan Quang Pham and
• Giang Truong Ho

Beilstein J. Nanotechnol. 2014, 5, 1261–1267, doi:10.3762/bjnano.5.140

• the gas sensing response characteristics allows us to suggest that the dissociation of hydrogen takes place at PdZn-vacancies ([Pd 2+(4d9)]). The design of this sensor allows for a continuous monitoring in the range of 0–100% LEL H2 concentration with high sensitivity and selectivity. Keywords

• hydrogen sensing [1][2][3][4][5][6]. The key features and availability of ZnO nanocrystals in distributed discrete gas sensing devices crucially depend on the growth conditions. These conditions strongly influence their size, uniformity and defects. Optical properties and gas sensing characteristics in ZnO

• ], compatibility with other nanodevices, and are potentially the best gas sensors. Oxides cannot easily distinguish between different types of gases, but the addition of certain noble metals as dopants can promote the gas-sensing performance [9][10][11]. Noble metal dopants in ZnO can modify the optical and

Highly NO₂ sensitive caesium doped graphene oxide conductometric sensors

• Carlo Piloto,
• Marco Notarianni,
• Mahnaz Shafiei,
• Elena Taran,
• Dilini Galpaya,
• Cheng Yan and
• Nunzio Motta

Beilstein J. Nanotechnol. 2014, 5, 1073–1081, doi:10.3762/bjnano.5.120

• and environmental monitoring [12]. Theoretical [13][14] and experimental [15][16][17][18][19] studies have revealed that functionalization of graphene can improve significantly its gas sensing performance [20]. The presence of dopants or defects in the graphene lattice can increase the adsorption

• groups can be easily controlled [28][34][35][36][37][38] making this process a good candidate for graphene functionalization. The oxygen groups of the resulting GO lead to the disruption of the graphitic structure, thus making the material electrically too much insulating for resistive gas sensing

• applications. However, the partial removal of oxygen groups, leading to reduced GO can be achieved by chemical [38][39], thermal [40][41] or ultraviolet-assisted process [42]. The conductivity and gas sensing performance of the reduced GO is comparable or superior to that of the pristine graphene [43], due to

Gas sensing with gold-decorated vertically aligned carbon nanotubes

• Prasantha R. Mudimela,
• Mattia Scardamaglia,
• Oriol González-León,
• Nicolas Reckinger,
• Rony Snyders,
• Eduard Llobet,
• Carla Bittencourt and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2014, 5, 910–918, doi:10.3762/bjnano.5.104

• , regardless of the nanotube length. Keywords: alignment; carbon nanotubes; decoration; gas sensors; metal nanoparticles; thermal CVD; Introduction The interest in gas sensing for reaching a widespread, continuous pollution detection and control has been growing steadily in the last decades due to the

• based on nanomaterials have been developed to fabricate small and inexpensive gas sensors with high sensitivity and able to work at room temperature [1]. Among the possible active materials in gas sensing devices, good candidates are carbon nanotubes (CNTs), thanks to their intrinsic properties such as

• room temperature), prompt response, short recovery time and reasonable reversibility and stability [2][3][4][6]. A further advance in the development of CNT gas sensing devices was the use of vertically aligned CNTs (VA-CNTs). In this case the sensing device benefits from the unidirectional electrical

In situ growth optimization in focused electron-beam induced deposition

• Paul M. Weirich,
• Marcel Winhold,
• Christian H. Schwalb and
• Michael Huth

Beilstein J. Nanotechnol. 2013, 4, 919–926, doi:10.3762/bjnano.4.103

• are used in highly miniaturized magnetic field [1][2], strain/force [3][4] and gas sensing [5] applications, as well as in micromagnetic studies on domain wall nucleation and propagation [6][7]. On the basis of the in situ, electron irradiation-induced tunability of metallic FEBID-structures

Plasmonics-based detection of H₂ and CO: discrimination between reducing gases facilitated by material control

• Gnanaprakash Dharmalingam,
• Nicholas A. Joy,
• Benjamin Grisafe and
• Michael A. Carpenter

Beilstein J. Nanotechnol. 2012, 3, 712–721, doi:10.3762/bjnano.3.81

• , and particularly for plasmonics-based gas sensing. The extremely high sensitivity of the plasmon resonance peak to changes in the free-electron density of gold nanoparticles or a change in the dielectric function of the metal-oxide host material due to adsorbate reactions on surfaces makes this a

• through studies using infra-red spectroscopy [26]. A significant difference between this previous study and practical studies of emission-gas sensing is that the measurements were not done in the presence of background oxygen. However, if H2 were to react in the presence of an oxygen background, (such as