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This review delivers a summary of the recent advances in polyaniline based electrocatalyst for direct methanol fuel cell applications. Today’s world is urging for global energy due to the fossil fuel diminution and ecological contamination which is overthrown by the direct methanol fuel cell. Amongst the conducting polymers, polyaniline has a significant role in the direct methanol fuel cell. Due to the high conductivity, unique redox properties, high flexibility, better solubility, reasonable stability, ease synthesis, and low cost. The nanocomposite of polyaniline with other electrochemically active materials such as metallic compounds and carbonaceous materials as well as nitrogen-doped carbon materials derived from PANI based nanocomposite were in detailly discussed in this review.

Amine-functionalized silica sorbents have been widely investigated for post-combustion CO2 capture at low temperature. In previous studies, amine-functionalized silica sorbents were prepared using a synthetic hierarchically porous silica, which is not commercially available in large quantities, because porous silica support structures strongly influence CO2 capture performance. Here, we propose a feasible and facile fabrication method for amine-functionalized silica sorbents using 3-aminopropyltrimethoxy silane (APTS) and fumed silica (FS), where APTS serves as both an active material and a binder. The APTS-functionalized FS sorbents have large amounts of active amino groups and porous structures and demonstrate good multicycle stability with excellent CO2 capture performance. In addition, cetyltrimethylammonium bromide was found to improve the diffusion pathway of CO2, leading to enhanced CO2 capture capacity because of the suppression of excessive condensation during preparation. Therefore, the APTS-functionalized FS sorbents could be cost- and energy-efficiently prepared using a novel one-pot synthesis method; the resulting sorbents exhibit excellent CO2 capture performance.

Amperometric sensor of polydiphenylamine (PDPA)/phosphotungstic acid (PTA)/zinc oxide (ZnO) on glassy carbon (GC) nanohybrid composite electrode (GC/PDPA/PTA/ZnO) fabricated via facile electrochemical deposition method. The structural geometry and surface morphology were recorded by X-ray diffraction spectrometer (XRD) and scanning electron microscopy (SEM). Electro-catalytic properties and performances of nanohybrid composite were recorded by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) methods. PTA-assisted PDPA/ZnO-ME shows linear steady-state response towards glucose with superior sensitivity of 20.30 μA μM−1 cm−2, lowest detection limit 0.1 μM, and rapid response less than 2 s. The improved electro-catalytic performance towards glucose by GC/PDPA/PTA/ZnO is due to the combined existence of diphenoquinone diamine (DPDI2+) and phosphotungstic acid anion which provides a higher electro-catalytic active spots leads to more electron transport pathway for the oxidation of glucose. Interference analyses confirm the prepared nanohybrid sensor is best apt for glucose detection claims its practical biomedical application.

An amperometric urea biosensor was fabricated using Indium tin oxide (ITO) coated Polydiphenylamine (PDPA)/ Phosphotungstic acid (PTA)/Graphene (Gra) hybrid nanocomposites modified electrode (ITO/PDPA/PTA/Gra-ME) by an electrochemical-deposition technique. Scanning Electron Microscopy (SEM) and Atomic Force microscopy (AFM) techniques were used to capture the surface morphology and surface coating thickness of nanocomposite sandwiched electrodes. Electro-catalytic performances of modified hybrid electrodes were examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) techniques. ITO/PDPA/PTA/Gra-ME exhibits a good linear response to urea concentration over the range of 1–13 μM along with a correlation coefficient of 0.999, good sensitivity (1.085 μA/μM cm2) and at a low response time (5 s). The enhanced electro-catalytic activity of ITO/PDPA/PTA/Gra-sandwich towards urea was owing to the synergistic contribution of tungsten atoms (phosphotungstic acid anion), diphenoquinone diamine (DPDI2+) form of PDPA/Graphene that enhances the fast electron transfer rate. Also, interfering analytes were studied to ensure the fabricated sensor is best suitable for practical applications.

Electrochemical-deposition method was engaged to prepare Fluorine doped Tin oxide (FTO) modified Polydiphenylamine (PDPA)/Phosphotungstic acid (PTA)/Manganese dioxide (MnO2) nanohybrid (FTO/PDPA/PTA/MnO2-ME) Electrode. Nanocomposites structural analysis, morphology, and molecular vibrational studies were characterized through X-ray diffractometer (XRD), Scanning Electron Microscope (SEM) and Fourier Transform Infra read Spectroscopy (FTIR). Recorded XRD and FTIR pattern authenticates the existence of PDPA, PTA, and MnO2 structures. Cyclic voltammetry (CV) studies performed using electrochemical workstation shows very high specific capacitance value of 514.77 Fg−1 at 5 mVs−1 for the modified hybrid electrode system. The superior capacitive performance, cyclic stability of FTO/PDPA/PTA/MnO2 electrode was attributed due to the existence and fast reversible multi‐electron redox response of tungsten atoms in PTA along with PDPA-MnO2 synergistic interaction that augments the electron transfer processes.

This work reports the synthesis, characterization, and antimicrobial activity of polyaniline/polyvinyl alcohol (PANI/PVA) and polydiphenylamine/polyvinyl alcohol (PDPA/PVA) co-polymer nanocomposite films. Initially, chemical oxidative polymerization was employed to synthesis PANI and PDPA by oxidizing aniline (AN) and diphenylamine (DPA) in the presence of ammonium peroxydisulfate (APS) as an oxidant. A trace amount of prepared PANI and PDPA were used to prepare nanocomposite films by solution casting technique, using PVA as a stabilizer. Surface morphological studies reveal the impregnated amorphous structure of PANI and PDPA size in the range of ~ 50–150 nm. Fourier transform infrared (FTIR) examines to confirm the presence of PANI, PDPA, and PVA in nanocomposite film. Disk diffusion approach was adopted to study the antimicrobial activity of PANI/PVA and PDPA/PVA nanocomposite films.

Herein, a novel Poly (melamine) have been successively electrodeposited on glassy carbon electrode and decorated by Pd nanoparticles (Pd NPs) subsequently to fabricate Poly (melamine) – Pd nanocomposite. Structural geometry, morphological view, and elemental composition analysis were ensured by X-ray diffractogram, scanning electron microscope, and X-ray photoelectron spectroscopy. The electrodeposited Poly (melamine) (PME) material depicts an interconnected nano rod (50 nm) morphology leads to a nano exploder (~150 nm) arrangement. Spherical shaped Pd decorated PME morphology was obtained for GC\PME-Pd NPs composite (150 nm). The electrocatalytic activity of the fabricated anode electrocatalyst was examined by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry methods. The modified GC\PME-Pd NPs composite electrode validates superior electrocatalytic behaviour towards methanol and ethanol oxidation in alkaline background. Besides, the electrochemical surface area and electrocatalytic behaviour make it a greater anode catalyst towards methanol and ethanol oxidation. The synergic effects amid the Poly (melamine)-Pd NPs composite enhances the catalytic activity, mechanical stability on the electrocatalysis of methanol and ethanol oxidation reaction superior than modified Poly (melamine) electrode. Hence, the fabricated anode electrocatalyst is proficient to get realistic approach towards the progression in the direct alcohol (methanol and ethanol) oxidation reaction in direct alcohol fuel cells (DAFCs) applications.

The search for novel nanostructures towards multifunctional applications is the main objective of numerous researches in progress. This review article mainly centres the recent research updates in the synthesis, properties, advantages and applications of polyaniline (PANI) nanofibers (NFs) based on electrospinning technique. Among various nano structured conducting polymers (CPs) based NF architecture, PANI is in spotlight drawing too much attention among the scientific communities owing to the exceptional and enhanced characteristic features. This PANI based NFs were attained from the precursor polymer solution by engaging electrospinning technique has been notorious as a direct and facile route via the utilization of strong electrostatic field. Owing to its excellent physicochemical and electrochemical properties, E-spinning NFs based on polyaniline (PANI) becomes the most important novel material towards the emerging advancements such as NF based supercapacitor, sensor devices, scaffold materials and conductive tissue engineering, water filtration and purification, solar cells and so on. Though, the processability of PANI is quite tough in comparison with other CPs, mostly due to its firm structure of backbone with high conjugation level. To meet the demanding specifications towards the applications, the challenges in the E-spinning of PANI NF were explored and led to the progress in the electrospun based nanocomposites or hybrids and their blends. Thus, to explore more and to ignite the state-of-the-art progress, this review manuscript highlights a short review and understanding on the recent research efforts and escalation in the applications of E-spun PANI NFs in various fields such as supercapacitor, sensor, biomedical, and corrosion applications along with the fundamentals, theory, general working principle, and future prospects and challenges ahead of E-spinning.

Polyaniline (PANI) is one of the important materials in conducting polymers (CPs) for significant applications in devices due to its unique properties such as high electrical conductivity, flexibility, and economical price. In this work, novel and eco-friendly green synthesis of polyaniline Nanorod (PANI-NR) were developed by solar irradiation approach in acidic medium without the aid of any surfactant and template. As characterized by morphology studies, the average diameter of PANI-NR is approximately 200–250 nm and length is 2–2.5 µm. The elemental analysis and structural geometry of PANI-NR are examined through EDX, Mapping, and XRD studies. The electrochemical properties were investigated using CV, GCD, and EIS techniques. The electrochemical performance of Cyclic voltammetry analysis shows the redox peaks which confirms the PANI-NR has excellent electrical conductivity. A specific capacitance of 25 F/g at 10 mV/s scan rate by CV studies and 106 F/g at 1 A/g current density by GCD studies is observed for One-Dimensional (1D) PANI-NR as an electrode material for supercapacitor. Also, it shows remarkable cyclic retention and stability. These results indicate that PANI-NR is expected to have better electrochemical performance in energy storage applications.

We report for the first time a rapid electrochemical synthesis of one-dimensional poly(2,5-dimethoxyaniline) nanorods (PDMA-NR) in the presence of surfactant. FE-SEM and TEM images confirm the PDMA-NR formation and the average diameter of single rod sizes in the range of ∼200–300 nm. An enzymatic glucose biosensor was fabricated through immobilizing glucose oxidase (GOx) into PDMA-NR matrix. The amperometric current response of PDMA-NR/GOx to glucose is linear in the concentration range between 1 and 10 μM with a detection limit of 0.5 μM (S/N = 3). The PDMA-NR/GOx electrode possesses high sensitivity (5.03 μA/μM), selectivity, stability, and reproducibility toward glucose.

In this work, a copolymer (polyaniline(PANI)-copolymer(co)-polydiphenylamine (PDPA)) hybrid impregnated on graphene (Gra) nanosheets was examined. At first, graphene was synthesized by the oxidation of natural graphite employing modified Hummer’s method and subsequently reduced using hydrazine monohydrate. Then, interfacial chemical oxidative polymerization was engaged to synthesize PANI, PDPA, and copolymer (PANI/PDPA) along with graphene nanosheets in liquid–liquid (CHCl3/HCl) interface individually. During the polymerization process, PANI and PDPA chain grown well and dispersed homogeneously on the graphene nanosheets. Morphological and molecular vibrational analyses were confirmed by field emission scanning electron microscopy (FESEM) and Fourier transform infra red spectroscopy (FTIR). In addition, the electrochemically modified Gra-PDPA, Gra-PANI, and Gra-copolymer hybrids show good electrical conductivity ensured via cyclic voltammetry (CV). The enhanced electro-catalytic activity of Gra-PANI-co-PDPA-ME towards glucose with superior sensitivity 0.51 μ A/ μ M at 5 s was achieved. The combined existence and synergistic interaction amid of graphene, aniline and diphenoquinone diamine (DPDI 2 + ) provides enhanced electron transfer for the glucose oxidation. Also, Interference studies ensure that the fabricated sensor is best suitable for glucose sensing performance.

We report on the synthesis of an electrically conductive chitosan nanofibrous scaffold (NFS) by a “simple template free self-assembly method” from biopolymer chitosan in the presence of inorganic acids as dopants and ammonium persulphate (APS) as an initiator. The morphology of the chitosan nanofibers scaffold (CS-NFS) was examined by field emission scanning electron microscopy (FE-SEM). Physiochemical characterizations of the CSNFS were analyzed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. It is found that the morphology and structure of the CS-NFS strongly depend on the kinds of dopant used. Cyclic voltammogram measurement reveals that CS nanofibers have high electrocatalytic activity compared to chitosan powder. The CS nanofibers are expected to be useful in electrical, optical, and electrochemical devices. Open image in new window

To simultaneously remove hydrogen sulfide and ammonia from hot coal gases, the ammonia decomposition abilities of various metal oxide catalysts were tested in the absence/presence of hydrogen sulfide, at 650 °C. Cobalt oxide, molybdenum oxide, and nickel oxide have high ammonia decomposition abilities (>95%) in the absence of hydrogen sulfide, but such abilities rapidly decreased during the reaction in the presence of hydrogen sulfide. To improve the simultaneous removal abilities of metal oxides, Zn-based catal sorbents were prepared via impregnation with various metals, such as cobalt, nickel, and molybdenum, on zinc oxide. The CZ-30 (promoted with 30 wt% cobalt oxide on zinc oxide) and NZ-30 (promoted with 30 wt% nickel oxide on zinc oxide) catal sorbents showed excellent sulfur removal capacities, which, calculated until the breakthrough point, were 0.35 and 0.39 g S/g catal sorbent, respectively, while MZ-30 promoted with molybdenum showed a low sulfur removal capacity of 0.08 g S/g catal sorbent. The ammonia decomposition ability of CZ-30, however, increased more than 18 times compared with Co3O4, whose ammonia decomposition ability was more than 95% until 465 min, even though the ammonia decomposition ability of NZ-30 sharply decreased after 30 min. The CZ catal sorbent is a good candidate for the simultaneous removal of ammonia and hydrogen sulfide.

A modified electrode was fabricated by grafting poly(2,5-dimethoxyaniline) (PDMA) onto multiwalled carbon nanotubes (MWNTs) and used for the electrocatalytic oxidation of ascorbic acid (AA). Cyclic voltammetry was used to fabricate the modified electrode and demonstrate the electroactivity of MWNT-g-PDMA-ME towards AA. Field emission scanning electron microscopy (FESEM) of MWNT-g-PDMA-ME revealed the combined presence of MWNT and PDMA. The MWNT-g-PDMA-ME exhibited excellent performance for AA at 320 mV with a high sensitivity (12.78 μA/mM) and linear concentration range of 1 to 5 mM (correlation coefficient of 0.9991). Differential pulse voltammetry (DPVs) showed that MWNT-g-PDMA-ME experiences negligible interference from other electro-active components.

Conducting hybrid submicrostructures composed of chitosan (CS and silica-based conducting poly[N-(3-trimethoxysilylpropyl)aniline] (PTMSPA were prepared by graft copolymerization. The spherical and fibrous morphologies of the CS-PTMSPA hybrid submicrostructures could be observed by optical and field emission electron microscopy. Under room temperature conditions, the CS-PTMSPA graft copolymers possessed the uniformly distributed spherical submicroparticles with diameters in the range of ca. 400–1,000 nm. On the other hand, under ice cold conditions (5 °C), CS-PTMSPA showed the development of randomly oriented fiber bundles. The diameter of a single fiber was in the range of ca. 100–500 nm. These CS-PTMSPA fibers were obtained by a temperature-driven template-free self-assembly pathway. Spectroscopic and thermal evaluations confirmed that CS-PTMSPA graft copolymer had been prepared by an oxidative polymerization method. The electrochemical performance of the CS-PTMSPA submicrostructures were compared with CS and PTMSPA by cyclic voltammetry with the Fe(CN)63−/4− system as a redox marker. The CS-PTMSPA submicrostructures showed high electrical conductivity (difference between the anodic and cathodic peaks = 0.24 and 0.29 V for CS-PTMSPA sphere and fiber, respectively compared to those of CS (0.14 V and PTMSPA (0.20 V), which was ascribed to the relatively high surface-to-volume ratios of these submicrostructures. Open image in new window

A new regenerable alumina-modified sorbent was developed for CO2 capture at temperatures below 200 °C. The CO2 capture capacity of a potassium-based sorbent containing Al2O3 (KAlI) decreased during multiple CO2 sorption (60 °C) and regeneration (200 °C) tests due to the formation of the KAl(CO3)(OH)2 phase, which could be converted into the original K2CO3 phase above 300 °C. However, the new regenerable potassium-based sorbent (Re-KAl(I)) maintained its CO2 capture capacity during multiple tests even at a regeneration temperature of 130 °C. In particular, the CO2 capture capacity of the Re-KAl(I)60 sorbent which was prepared by the impregnation of Al2O3 with 60 wt.% K2CO3 was about 128 mg CO2/g sorbent. This excellent CO2 capture capacity and regeneration property were due to the characteristics of the Re-KAl(I) sorbent producing only a KHCO3 phase during CO2 sorption, unlike the KAlI30 sorbent which formed the KHCO3 and KAl(CO3)(OH)2 phases even at 60 °C. This result was explained through the structural effect of the support containing the KAl(CO3)(OH)2 phase which was prepared by impregnation of Al2O3 with K2CO3 in the presence of CO2.

A novel amperometric cholesterol biosensor was fabricated by the immobilization of ChOx (cholesterol oxidase) onto the chitosan nanofibers/gold nanoparticles (designated as CSNFs/AuNPs) composite network (NW). The fabrication involves preparation of chitosan nanofibers (CSNFs) and subsequent electrochemical loading of gold nanoparticles (AuNPs). Field emission scanning electron microscopy (FE-SEM) was used to investigate the morphology of CSNFs (sizes in the range of ∼50–100 nm) and spherical AuNPs. Cyclic voltammetry, hydrodynamic voltammetry and amperometry were used to examine the performance of CSNF–AuNPs/ChOx biosensor. The CSNF–AuNPs/ChOx biosensor exhibited a wide linear response to cholesterol (concentration range of 1–45 μM), good sensitivity (1.02 μA/μM), low response time (∼5 s) and excellent long term stability. The combined existence of AuNPs within CSNFs NW provides the excellent performance of the biosensor towards the electrochemical detection of cholesterol.

Synthesis of nine Task Specific Ionic liquids (TSILs), their characterization using1H NMR spectral studies and other physical properties and potential applications in the removal of certain heavy metals such as Nickel, Iron, Zinc, Copper and Lead has been studied. The removal of these heavy metals from the industrial effluents / contaminated water bodies using these ionic liquids has been proved to be more successful than conventional methods such as precipitation, cementation, reverse osmosis, ion exchange and adsorption.

The preparation and characterization results of a new nanocomposite, polyaniline (PANI) grafted multiwalled carbon nanotube (MWNT) loaded Nafion-silica, (designated as Nafion-silica/MWNT-g-PANI), are reported in this paper. The preparation involves the formation of a silica network in a Nafion membrane and the subsequent loading of polyaniline-grafted multiwalled carbon nanotubes (MWNT-g-PANI) onto the Nafion-silica nanocomposite. The new nanocomposite, Nafion-silica/ MWNT-g-PANI, was characterized as to its morphology, structure and properties. The conductivity and methanol permeability of the nanocomposite membranes were evaluated.

A glucose biosensor was fabricated with loading of glucose oxidase (GOx) into a new organic-inorganic hybrid nanocomposite. The preparation involves formation of silica network into a Nafion (perfluorosulfonate ionomer) and subsequent loading of polyaniline grafted multiwalled carbon nanotubes (MWNT-g-PANI) onto Nafion-silica nanocomposite. Field emission scanning electron microscopy (FE-SEM) of Nafion-silica/MWNT-g-PANI composite reveals the presence of spherical silica particles (sizes in the range 250 nm-1 microm) and tubular MWNT-g-PANI particles. Chronoamperometry and cyclic voltammetry were used to evaluate the performance of biosensor towards glucose. The Nafion-silica/MWCNT-g-PANI/GOx biosensor exhibited a linear response to glucose in the concentration range of 1-10 mm with a correlation coefficient of 0.9972, good sensitivity (5.01 microA/mm), a low response time (approximately 6s), repeatability (R.S.D value of 2.2%) and along-term stability. The presence of silica network within Nafion and MWNT-g-PANI synergistically contributes to the performance of the biosensor towards the electrochemical detection of glucose.

Kinetics of Pd (core)–Au (shell) nanoparticles (NPs) catalyzed transformation of dihydronicotinamide adenine dinucleotide (NADH) to NAD + was monitored by UV–vis spectroscopy. Pd (core)–Au (shell) NPs were prepared by microwave irradiation method. High resolution transmission electron microscopy image reveals the core–shell morphology. X-ray diffraction pattern shows the presence of distinct crystalline domains for Pd and Au. The changes in absorbances at 340 nm were followed for various time intervals. Rates of conversion of NADH to NAD + were determined for different conditions. The conversion of NADH to NAD + was to be first order with respect to NADH at lower concentrations (upto 0.04 mM) and pseudo-first-order beyond 0.04 mM. Rate constants for the Pd (core) Au–(shell) NPs catalyzed transformation of NADH to NAD + were deduced.

A layer-by-layer (LbL) film assembly was constructed that comprises alternative layers of poly(diphenylamine) (PDPA) and phosphotungstic acid (PTA). First, a layer of oxidized PDPA (referred to as PDPA(+)) was deposited by electropolymerization. Then, a layer of negatively charged PTA was deposited on the PDPA(+) layer . This processes was repeated several times to obtain multilayer LbL film (PDPA/PTA)n, where n is the number of double layers. The LbLs were characterized by UV-Vis spectroscopy, FT-IR spectroscopy and X- ray diffraction spectroscopy. The process of formation of the LbL assembly was monitored by electrochemical methods. Electrochemical studies revealed that this LbL film possesses a remarkable electrocatalytic activity towards oxidation of ascorbic acid in neutral aqueous medium. The enhanced electrocatalytic activity of (PDPA/PTA)n LbL film is attributed to the existence of tungsten atoms in the interlayers of PDPA.

A novel amperometric biosensor was fabricated based on the immobilization of cholesterol oxidase (ChOx) into a cross-linked matrix of chitosan (Chi)-room-temperature ionic liquid (IL) (1-butyl-3-methylimidazolium tetrafluoroborate). Initially, the surface of bare electrode (indium tin oxide coated glass) was modified with the electrodeposition of Au particles onto thiol (-SH) functionalized multi-walled carbon nanotubes (MWNTs). The biosensor electrode is designated as MWNT(SH)-Au/Chi-IL/ChOx. Scanning electron microscopy image of MWNT(SH)-Au/Chi-IL/ChOx reveals that Chi-IL exists as the interconnected wires covering the Au particles on the surface of MWNT(SH)-Au. Cyclic voltammetry and chronoamperometry were used for the electrochemical determination of cholesterol at the biosensor electrode, MWNT(SH)-Au/Chi-IL/ChOx. The presence of Au particles in the matrix of CNTs provides an environment for the enhanced electrocatalytic activities. The MWNT(SH)-Au/Chi-IL/ChOx biosensor exhibited a linear response to cholesterol in the concentration range of 0.5-5mM with a correlation coefficient of 0.998, good sensitivity (200 microAM(-1)), a low response time ( approximately 7s), repeatability (R.S.D value of 1.9%) and long term stability (20 days with a decrease of 5% response). The synergistic influence of MWNT(SH), Au particles, Chi and IL contributes to the excellent performance for the biosensor.

We report an ingenious approach for the fabrication of a promising glucose sensor, GOx/Au/CS–IL–MWNT(SH), that exploits the synergistic beneficial characteristics of multiwalled-carbon nanotubes (MWNTs), gold nanoparticles (AuNPs), chitosan (CS) and room temperature ionic liquid (RTIL). Direct electron transfer between glucose oxidase (GOx) and electrode was achieved. Scanning electron microscopy and atomic force microscopy images of GOx/Au/CS–IL–MWNT(SH) reveal that MWNTs and AuNPs are dispersed in CS–IL matrix. Cyclic voltammetry, impedance spectroscopy and chronoamperometry were used to evaluate the performance of biosensor. The GOx/Au/CS–IL–MWNT(SH) biosensor exhibits a linear current response to glucose concentration (1–10 mM) at a low potential of 0.10 V and precludes interferences from uric acid and ascorbic acid. The GOx/Au/CS–IL–MWNT(SH) biosensor has superior performances over GOx/CS–IL–MWNT(SH). Keywords: Direct electrochemistry, Chitosan, Glucose oxidase (GOx), Ionic liquid, Glucose sensor

A simple, rapid and efficient route to prepare polyaniline nanostructures (PANI-NS) by “one-step chemical oxidative polymerization” method is described. This method possesses advantages in terms of good yield, short reaction time, neat conditions and cost-effectiveness. The morphology of the PANI-NS was investigated by field-emission scanning electron microscopy (FE-SEM). The average diameter of single PANI-NS was calculated to be ∼376 nm. Results from UV–visible spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and cyclic voltammetry (CV) reveals the existence of PANI units present in the polymeric nanostructures. Also, electrical conducting property of the PANI-NS was analyzed using four-probe measurement method.

The effects of the SnO2 pore size and metal oxide promoters on the sensing properties of SnO2-based thick film gas sensors were investigated to improve the detection of very low H2S concentrations (

The sensing behavior of SnO(2)-based thick film gas sensors in a flow system in the presence of a very low concentration (ppb level) of chemical agent simulants such as acetonitrile, dipropylene glycol methyl ether (DPGME), dimethyl methylphosphonate (DMMP), and dichloromethane (DCM) was investigated. Commercial SnO(2) [SnO(2)(C)] and nano-SnO(2) prepared by the precipitation method [SnO(2)(P)] were used to prepare the SnO(2) sensor in this study. In the case of DCM and acetonitrile, the SnO(2)(P) sensor showed higher sensor response as compared with the SnO(2)(C) sensors. In the case of DMMP and DPGME, however, the SnO(2)(C) sensor showed higher responses than those of the SnO(2)(P) sensors. In particular, the response of the SnO(2)(P) sensor increased as the calcination temperature increased from 400 °C to 800 °C. These results can be explained by the fact that the response of the SnO(2)-based gas sensor depends on the textural properties of tin oxide and the molecular size of the chemical agent simulant in the detection of the simulant gases (0.1-0.5 ppm).