High energy-efficiency decomplexation of metal-complexes by H*-mediated electro-reduction on hydroxyphenyl Co-porphyrin catalysts.

Electrochemical reduction of metal-organic complex pollutants has been recognized as an environmental benign method that operates at mild condition. However, the selective reduction of metal complexes and energy consumption in cathodic process are still a big challenge. Herein, we found that hydroxyphenyl Co-porphyrin catalyst (CoTH@NG) realizes the highly selective decomplexation of metal-organic complexes by H* -mediated reduction, and simultaneously the impressive recovery efficiency of metal ions. Density functional theory (DFT) confirms the generation and capturing ability of H* on CoTH@NG, verifying the dominant role of H* -mediated reduction in the selective decomplexation of Cu-EDTA. CoTH@NG realizes the superior energy efficiency for Cu-EDTA removal (279.3 g kWh-1 of EEOCu-EDTA) and Cu recovery (48.6 g kWh-1 of EEOCu), which are remarkably 3.3 × 102 and 9.7 × 102 times higher than traditional carbon cloth electrode. Moreover, the recovered Cu0(s) nanowires on the electrode surface can be efficiently regenerated in HCOOH by a galvanic reaction through the electron channel of CoTH@NG, regenerating catalytic electrode. This is one of the pioneer studies on H* -mediated electro-reduction decomplexation of metal-complexes, metal recovery, and electrode regeneration on CoTH@NG, which providing a technical strategy for developing efficient electrocatalytic system for pollution control. Environmental Implication Metal complexes is a dramatic increase in the electroplating and mining industries, and seriously affect both public health and environmental sustainability. Our work reported a new hydroxyphenyl Co-porphyrin catalyst (CoTH@NG) which achieves the selective decomplexation of metal-organic complexes, and simultaneously the recovery of metal ions. CoTH@NG realizes the superior energy efficiency for Cu-EDTA removal (279.3 g kWh-1) and Cu0(s) recovery (48.6 g kWh-1), which are remarkably 3.3 × 102 and 9.7 × 102 times higher than traditional carbon cloth electrode. Moreover, the recovered Cu0(s) can be efficiently regenerated in HCOOH by a galvanic reaction through the electron channel of CoTH@NG, regenerating catalytic electrode.

Porphyrin-based covalent organic frameworks from design, synthesis to biological applications.

Covalent organic frameworks (COFs) constitute a class of highly functional porous materials composed of lightweight elements interconnected by covalent bonds, characterized by structural order, high crystallinity, and large specific surface area. The integration of naturally occurring porphyrin molecules, renowned for their inherent rigidity and conjugate planarity, as building blocks in COFs has garnered significant attention. This strategic incorporation addresses the limitations associated with free-standing porphyrins, resulting in the creation of well-organized porous crystal structures with molecular-level directional arrangements. The unique optical, electrical, and biochemical properties inherent to porphyrin molecules endow these COFs with diversified applications, particularly in the realm of biology. This review comprehensively explores the synthesis and modulation strategies employed in the development of porphyrin-based COFs and delves into their multifaceted applications in biological contexts. A chronological depiction of the evolution from design to application is presented, accompanied by an analysis of the existing challenges. Furthermore, this review offers directional guidance for the structural design of porphyrin-based COFs and underscores their promising prospects in the field of biology.

Perspective into ion storage of pristine metal-organic frameworks in capacitive deionization.

Metal-organic frameworks (MOFs), featuring tunable conductivity, tailored pore/structure and high surface area, have emerged as promising electrode nanomaterials for ion storage in capacitive deionization (CDI) and garnered tremendous attention in recent years. Despite the many advantages, the perspective from which MOFs should be designed and prepared for use as CDI electrode materials still faces various challenges that hinder their practical application. This summary proposes design principles for the pore size, pore environment, structure and dimensions of MOFs to precisely tailor the surface area, selectivity, conductivity, and Faradaic activity of electrode materials based on the ion storage mechanism in the CDI process. The account provides a new perspective to deepen the understanding of the fundamental issues of MOFs electrode materials to further meet the practical applications of CDI.

Soft-hard interface design in super-elastic conductive polymer hydrogel containing Prussian blue analogues to enable highly efficient electrochemical deionization.

The poor cycling stability of faradaic materials owing to volume expansion and stress concentration during faradaic processes limits their use in large-scale electrochemical deionization (ECDI) applications. Herein, we developed a "soft-hard" interface by introducing conducting polymer hydrogels (CPHs), that is, polyvinyl alcohol/polypyrrole (PVA/PPy), to support the uniform distribution of Prussian blue analogues (e.g., copper hexacyanoferrate (CuHCF)). In this design, the soft buffer layer of the hydrogel effectively alleviates the stress concentration of CuHCF during the ion-intercalation process, and the conductive skeleton of the hydrogel provides charge-transfer pathways for the electrochemical process. Notably, the engineered CuHCF@PVA/PPy demonstrates an excellent salt-adsorption capacity of 22.7 mg g-1 at 10 mA g-1, fast salt-removal rate of 1.68 mg g-1 min-1 at 100 mA g-1, and low energy consumption of 0.49 kW h kg-1. More importantly, the material could maintain cycling stability with 90% capacity retention after 100 cycles, which is in good agreement with in situ X-ray diffraction tests and finite element simulations. This study provides a simple strategy to construct three-dimensional conductive polymer hydrogel structures to improve the desalination capacity and cycling stability of faradaic materials with universality and scalability, which promotes the development of high-performance electrodes for ECDI.

Hormetic dose-response of halogenated organic pollutants on Microcystis aeruginosa: Joint toxic action and mechanism.

Quinolones (QNs), dechloranes (DECs), and chlorinated paraffins (CPs) are three kinds of new halogenated organic pollutants (HOPs), which originate from the use of flame retardants, lubricants and pesticides. Since QNs, DECs, and CPs are frequently detected in waters and sediments, it is necessary to investigate the toxic effects of these HOPs with dwelling phytoplankton, especially for cyanobacteria, to explore their potential hormetic effects and contributions to algal blooms. In the present study, we investigate single and joint toxicity of QNs, DECs and CPs on Microcystis aeruginosa (M. aeruginosa), a cyanobacterium that is frequently implicated with algal blooms. The results indicate single QNs and DECs induce marked hormetic effects on the proliferation of M. aeruginosa but CPs do not. The stimulatory effect of hormesis is linked with accelerated replication of DNA, which is considered to stem from the moderate rise in intracellular reactive oxygen species (ROS). Joint toxicity tests reveal that both QNs & CPs mixtures and DECs & CPs mixtures show hormetic effects on M. aeruginosa, but QNs & DECs mixtures show no hormetic effect. QNs & DECs mixtures exhibit synergistic toxic actions, which may be caused by a sharp rise in intracellular ROS simultaneously produced by the agents. Joint toxic actions of both QNs & CPs, and DECs & CPs shift from addition to antagonism as concentration increases, and this shift may mainly depend on the influence of CPs on cell membrane hydrophobicity of M. aeruginosa. This study provides data and toxic mechanisms for the hormetic phenomenon of single and joint HOPs on M. aeruginosa. The hormetic effects of HOPs may benefit the proliferation of M. aeruginosa in the aquatic environment, aggravating the formation of algal blooms. This study also reflects the important role of hormesis in environmental risk assessment of pollutants.

Purely Organic Room-Temperature Phosphorescence Endowing Fast Intersystem Crossing from Through-Space Spin-Orbit Coupling.

Purely organic room-temperature phosphorescence endowing very fast intersystem crossing from through-space systems has not been well investigated. Here we report three space-confined bridged phosphors, where phenothiazine is linked with dibenzothiophene, dibenzofuran, and carbazole by a 9,9-dimethylxanthene bridge. Nearly pure phosphorescence is observed in the crystals at room temperature. Interestingly, phosphorescence comes solely from the phenothiazine segment. Experimental results indicate that bridged counterparts of dibenzothiophene, dibenzofuran, and carbazole contribute as close-lying triplet states with locally excited (LE) character. The through-space spin-orbit coupling principle is proposed in these bridged systems, as their 1LE and 3LE states have intrinsic spatial overlap, degenerate energy levels, and tilting face-to-face alignment. The resulting effective through-space spin-orbit coupling leads to efficient intersystem crossing a with rate constant as high as 109 s-1 and an overwhelming triplet decay channel of the singlet excited state.

Investigations on the influence of energy source on time-dependent hormesis: A case study of sulfadoxine to Aliivibrio fischeri in different cultivation systems.

Hormesis is a biphasic dose-response relationship featured by low-dose stimulation and high-dose inhibition. Although the hormetic phenomenon has been extensively studied over the past decades, there is little information regarding the influence of energy source on the occurrence of hormesis, especially the time-dependent one. In this study, to explore the role of cultivation system's energy source in time-dependent hormesis, the toxic dose-responses of Aliivibrio fischeri (A. fischeri) bioluminescence to Sulfadoxine (SDX) during 24 h were determined in four cultivation systems with different energy source conditions. The results indicated that the time-dependent hormetic effects were induced by SDX in all cultivation systems: SDX triggered hormetic phenomenon on the bioluminescence at each growth stage over 24 h in the cultivation systems with sufficient and insufficient energy source; due to the diauxic growth of A. fischeri under multiple energy source conditions, the hormetic effects of SDX gradually disappeared after the preferred energy source was used up. It was speculated that the inhibitory action of SDX was derived from its interaction with DHPS to impede the synthesis of proteins, and SDX bound with AC to upregulate the quorum sensing (QS) system to exhibit the stimulatory action. Comparing the time-dependent hormesis in each cultivation system, it was obtained that the energy source could impact the hourly maximum stimulatory rate, the EC50 of SDX, and the time point that hormesis occurred, which might result from the influence of energy source on the stimulatory and inhibitory actions of SDX through regulating the metabolic system (individual level) and QS system (group level) of bacteria. This study clarifies the importance of energy source for hormesis occurrence, which may further promote the development of hormesis.

Highly emissive phenylene-expanded [5]radialene.

A pentagonal macrocycle (MC5-PER) with radialene topology was facilely synthesized through a selective one-pot Suzuki-Miyaura cross-coupling reaction. The resulting product is endowed with a pentagonal architecture as revealed by its single crystal structure, which affords the smallest ring strain and the best conjugation. As tetraphenylethene subunits are embedded, MC5-PER is highly emissive in the solid state due to the aggregation-induced emission effect. Because of the flexible structure and preferable fibre-like self-assembly, the aggregate of MC5-PER displays interesting polymorphism-dependent emission and acts as a sensitive fluorescence sensor for explosives detection.

Synthesis of poly(1,5-diaminonaphthalene) microparticles with abundant amino and imino groups as strong adsorbers for heavy metal ions.

Poly(1,5-diaminonaphthalene) microparticles with abundant reactive amino and imino groups on their surface were synthesized by one-step oxidative polymerization of 1,5-diaminonaphthalene using ammonium persulfate as the oxidant. The molecular, supramolecular, and morphological structures of the microparticles were systematically characterized by IR and UV-vis spectroscopies, elementary analysis, wide-angle X-ray diffractometry, and transmission electron microscopy. The microparticles demonstrate electrical semiconductivity and high resistance to strong acid and alkali, and strong adsorption capability for lead(II), mercury(II), and silver(I) ions. The experimental conditions for adsorption of Pb(II) were optimized by varying the persulfate/monomer ratio, adsorption time, sorbent concentration, and pH value of the Pb(II) solution. The maximum adsorption capacity is 241 mg·g-1 for particles after a 24 h-exposure to a solution at an initial Pb(II) concentration of 29 mM. The adsorption data fit a Langmuir isotherm and follow a pseudo-second-order reaction kinetics. This indicates a chemical adsorption that is typical for a chelation interaction between Pb(II) and amino/imino groups on the sorbent. Graphical abstract Poly(1,5-diaminonaphthalene) microparticles with abundant functional amino and imino groups have been synthesized by one-step direct polymerization of non-volatile 1,5-diaminonaphthalene in aqueous medium for sustainable preparation of high-performance adsorbents to strongly adsorb lead(II), mercury(II), and silver(I) ions.

[Hydrochemical Characteristics and the Dissolved Inorganic Carbon Flux in Liuzhou Section of Liujiang Basin].

An important aspect of the current global change research is using river chemical composition to reveal the chemical weathering process and its effect of carbon sink. In this study, water samples were collected and analyzed 2 ~3 times per month from January to December in 2013. The hydrochemistry belonged to HCO3-Ca type. Ca+ and HCO3- were the main cation and anion, which reflected that the hydrochemical characteristics of river were mainly affected by the dissolution of carbonate rock. The concentration of main ions varied with the seasons, which reflected that the crest value occurred in winter, followed by those in autumn and spring, and the lowest value was observed in summer. Due to the interaction of effect of dilution and effect of C2, the seasonal variation of Ca2+ and HCO3- showed that the highest value was in autumn and the lowest value was in summer. The seasonal variation law of other ions should be attributed to the effect of dilution or agricultural activities or combined action of them. Both carbonic acid and sulfuric acid took part in the chemical weathering of carbonate rocks as evidenced by stoichiometric analysis. Besides, the δ34S of sulfate ion of the river waters (δ34S: from 7. 65 per thousand to 8. 55 per thousand) showed that SO2- was originated mainly from oxidation of sulfide minerals in ore deposits and acid rain. Chemical mass balance method was applied to estimate the proportion of HCO- coming from carbonate weathering by sulfuric acid. The result was 28. 26% . On this basis, the total carbon flux of carbon ( by CO2 calculation) in Liuzhou section calculated month by month was about 8. 95 x 10(5) t . a-1. What's more, the carbon flux showed a positive correlation with flow, which implied that the discharge of catchment was the main influencing factor of carbon flux rather than the HCO3- concentration.

Efficient synthesis of oligofluoranthene nanorods with tunable functionalities.

Strongly fluorescence-emitting oligofluoranthene (OFA) nanorods are readily synthesized by a direct template-free chemical oxidative oligomerization of fluoranthene in nitromethane containing ferric chloride as an oxidant. The OFAs likely consist of five fluoranthene units containing cyclic pentamers with crystalline order and tunable electrical conductivity across 12 orders of magnitude. The OFA nanorods are heat-resistant materials and efficient precursors for macroporous carbon materials with high carbon yield in argon at 1100 °C. In particular, the optimal ring-like pentamer shows 12.2 times stronger cyan fluorescence-emission than recognized highly fluorescent fluoranthene under the same conditions, which makes the OFAs into ideal strong fluorescent emitters, tunable conductors, and high carbon-yield precursors for the preparation of sensors and carbon materials. These findings demonstrate an advance in the direct synthesis of oligomers from fused-ring aromatic hydrocarbons and provide a potential direction to optimize the synthesis and functionalities of wholly aromatic nanomaterials.

Interfacial chemical oxidative synthesis of multifunctional polyfluoranthene.

A novel polyfluoranthene (PFA) exhibiting strong visual fluorescence emission, a highly amplified quenching effect, and widely controllable electrical conductivity is synthesized by the direct cationic oxidative polymerization of fluoranthene in a dynamic interface between n-hexane and nitromethane containing fluoranthene and FeCl3, respectively. A full characterization of the molecular structure signifies that the PFAs have a degree of polymerization from 22-50 depending on the polymerization conditions. A polymerization mechanism at the interface of the hexane/nitromethane biphasic system is proposed. The conductivity of the PFA is tunable from 6.4 × 10-6 to 0.074 S cm-1 by doping with HCl or iodine. The conductivity can be significantly enhanced to 150 S cm-1 by heat treatment at 1100 °C in argon. A PFA-based chemosensor shows a highly selective sensitivity for Fe3+ detection which is unaffected by other common metal ions. The detection of Fe3+ likely involves the synergistic effect of well-distributed π-conjugated electrons throughout the PFA helical chains that function as both the fluorophore and the receptor units.

Synthesis of semiconducting polymer microparticles as solid ionophore with abundant complexing sites for long-life Pb(II) sensors.

Intrinsically electrically semiconducting microparticles of semiladder poly(m-phenylenediamine-co-2-hydroxy-5-sulfonic aniline) structures containing abundant functional groups, like -NH-, -N=, -NH2, -OH, -SO3H as complexation sites, were efficiently synthesized by chemical oxidative copolymerization of m-phenylenediamine and 2-hydroxy-5-sulfonic aniline. The obtained copolymers were found to be nonporous spherical microparticles that were able to achieve greater π-conjugated structure, smaller particle aggregate size, and stronger interaction with Pb(II) ions than poly(m-phenylenediamine) containing only -NH-, -N=, and -NH2. A potentiometric Pb(II) sensor was fabricated on the basis of the copolymer microparticles as a crucial solid ionophore component within plasticized PVC. The sensor exhibited a Nernstian response to Pb(II) ions over a wide concentration range, together with a fast response, a wide pH range capability, a long lifetime of up to 5 months, and good selectivity over a wide variety of other ions and redox species. The process for synthesizing the microparticles and fabricating the Pb(II)-sensor can be facilely scaled-up for use in the straightforward long-term online monitoring of Pb(II) ions in heavily polluted wastewaters. This study develops an understanding of the facile synthesis of conducting microparticles bearing many functional groups and their structures governing the potentiometric susceptibility toward interaction between Pb(II) ions and the microparticles for fabricating robust long-lived Pb(II)-sensor, signifying the potential suitability of such novel materials for inexpensive sensitive detection of Pb(II) ions.

Combinatorial screening of potentiometric Pb(II) sensors from polysulfoaminoanthraquinone solid ionophore.

A potentiometric Pb(II)-selective sensor was fabricated by a combinatorial screening of electrically conducting polysulfoaminoanthraquinone (PSA) nanoparticles as a solid ionophore, ion exchangers (oleic acid (OA) and NaTPB), plasticizers in a polyvinyl chloride (PVC) matrix, membrane thickness, inner filling ion species, and concentration. The membrane sensor with the composition of PSA/PVC/DOP (dioctyl phthalate)/OA (1.0:33:61:5.0) exhibited the best performance, including a slope of 29.3 mV decade(-1) in the concentration range 10(-6.3)-10(-1.6) M, detection limit of 1.6 × 10(-7) M, response time of 16 s, lifetime of five months, and good response reversibility. The proposed sensor has demonstrated good selectivity for Pb(II) over other monovalent, divalent and trivalent interfering ions, and could be used in a pH range of 3.62-5.22. The Pb(II) sensor has been successfully applied for the determination of Pb(II) concentration in real-world samples and also as an indicator electrode for potentiometric titration of lead ions.

Lead-ion potentiometric sensor based on electrically conducting microparticles of sulfonic phenylenediamine copolymer.

A potentiometric sensor to detect lead ions using newly synthesized conducting copolymer microparticles as an ionophore in self-supporting poly(vinyl chloride) membrane matrix plasticized with dioctyl phthalate was developed. The copolymer microparticles containing many ligating functional groups including amino, imino and sulfonic groups were synthesized by a chemical oxidative copolymerization of m-phenylenediamine (mPD) and p-sulfonic-m-phenylenediamine (SPD) in pure water. Due to the presence of -NH-, -N=, -NH2, and -SO3H ligating groups on the microparticles, a linear Nernstian response is obtained within a Pb(II) activity range from 1.00 × 10(-6) M to 1.00 × 10(-3) M. The Pb(II)-sensor containing the mPD/SPD (95/5) copolymer microparticles with the maximal electrical conductivity demonstrates a superior detection limit down to 1.26 × 10(-7) M, short response time to 14 s, and long lifetime of up to 4 months. The Pb(II)-sensor also exhibits a selective response to Pb(II) over 9 other metal ions and a pH independent plateau between 2.7 and 5.0. These advantages could make for a robust sensor performing credible analysis of Pb(II) concentration in real-world samples at trace levels.

Carbon nanotube-templated polyaniline nanofibers: synthesis, flash welding and ultrafiltration membranes.

Electro-active switchable ultrafiltration membranes are of great interest due to the possibility of external control over permeability, selectivity, anti-fouling and cleaning. Here, we report on hybrid single-walled carbon nanotube (SWCNT)-polyaniline (PANi) nanofibers synthesized by in situ polymerization of aniline in the presence of oxidized SWCNTs. The composite nanofibers exhibit unique morphology of core-shell (SWCNT-PANi) structures with average total diameters of 60 nm with 10 to 30 nm thick PANi coatings. The composite nanofibers are easily dispersed in polar aprotic solvents and cast into asymmetric membranes via a nonsolvent induced phase separation. The hybrid SWCNT-PANi membranes are electrically conductive at neutral pH and exhibit ultrafiltration-like permeability and selectivity when filtering aqueous suspensions of 6 nm diameter bovine serum albumin and 48 nm diameter silica particles. A novel flash welding technique is utilized to tune the morphology, porosity, conductivity, permeability and nanoparticle rejection of the SWCNT-PANi composite ultrafiltration membranes. Upon flash welding, both conductivity and pure water permeability of the membranes improves by nearly a factor of 10, while maintaining silica nanoparticle rejection levels above 90%. Flash welding of SWCNT-PANi composite membranes holds promise for formation of electrochemically tunable membranes.

Interfacial synthesis and functionality of self-stabilized polydiaminonaphthalene nanoparticles.

A simple and effective template-free synthesis method for nanosized conducting polymers with self-stability and functionality is a main challenge. Herein, a strategy is reported for the facile synthesis of poly(1,5-diaminonaphthalene) nanospherical particles by an interfacial miniemulsion oxidative polymerization of 1,5-diaminonaphthalene at mobile microinterfaces between a stirred biphase without external emulsifiers. The size of the nanospheres was carefully optimized by controlling the polymerization conditions. Formation and self-stabilization mechanisms of the nanoparticles are proposed. The constantly movable and refreshed microinterface is a key to successful synthesis of the nanospheres, for significantly suppressing secondary growth leading to agglomerated particles because vigorous stirring makes as-formed self-stabilized nanospheres instantly leave the microinterfaces. The resulting nanospheres possess several advantages: clean surface, self-stability, redispersibility, semiconductivity, electroactivity, and fluorescence emission. The fluorescence emission can be quenched by specific quenchers, thus enabling low-cost, high-performance chemosensors to be obtained for the sensitive detection of Zn(II) ions in a wide linear concentration range of more than five orders of magnitude with a superior detection limit down to 1 nM.

Ultrasensitive Pb(II) potentiometric sensor based on copolyaniline nanoparticles in a plasticizer-free membrane with a long lifetime.

A newly designed Pb(II) potentiometric sensor based on intrinsically conducting nanoparticles of solid poly(aniline-co-2-hydroxy-5-sulfonic aniline) possessing many ligating functional groups like -NH-, -N=, -OH, -SO(3)H, -NH(2) as ionophores in plasticizer-free vinyl resin solid membranes has been fabricated. A linear Nernstian response is obtained within a wide Pb(II) activity range from 1.0 × 10(-3) to 1.0 × 10(-10) M with a detection limit as low as 2.2 × 10(-11) M. The pH independent plateau ranges between 3.5 and 7.0. After 15 months' usage, the sensor maintains 95% performance parameters. Its anti-interference ability to Cu(II), Cd(II), Ag(I), and Hg(II) is much stronger than other sensors with a detection limit at (sub)nanomolar level. Electrochemical impedance spectroscopy reveals that the solid sensing membrane has a diffusion coefficient of around 5 × 10(-14) to 1 × 10(-13) cm(2) s(-1). The much lower diffusion coefficient for Pb(II) is highly beneficial for the elimination of Pb(II) flux across the membrane. The wide detection concentration range, low detection limit, high selectivity, extensive pH window, and long lifetime make for a robust sensor giving reliable measurement of Pb(II) content with potential application in real-world samples at trace levels.

Lead ion-selective electrodes based on polyphenylenediamine as unique solid ionophores.

A novel membrane electrode for Pb(II) ion detection based on semi-conducting poly(m-phenylenediamine) microparticles as a unique solid ionophore was fabricated. The electrode exhibited significantly enhanced response towards Pb(II) over the concentration range from 3.16×10(-6) to 0.0316 M at pH 3.0-5.0 with a low detection limit of 6.31×10(-7) M, a high sensitivity displaying a near-Nernstian slope of 29.8 mV decade(-1) for Pb(II). The electrode showed a long lifetime of 5 months and a short response time of 14s. A systematical investigation on the effect of anion excluder and various foreign ions on the selectivity of the electrode by a fixed interference method suggests that all other metal ions hardly ever interfere with the determination of Pb(II) except high concentration Hg(II). The electrode was successfully used as an indicator electrode in the potentiometric titration of Pb(II) with EDTA. Furthermore, the electrode has been used to satisfactorily analyze four types of real-world samples like spiked human urine, spiked tap water, and river water containing interfering ions like Na(I), Ca(II), Mg(II), Zn(II), Pd(II), Fe(III), K(I), Cu(II) and Hg(II) up to 8.04×10(-4) M, demonstrating fast response, high selectivity, good recovery (96.6-121.4%), good repeatability (RSD 0.31-6.45%), and small relative error (5.0%).

Carbon nanotube/polyaniline composite nanofibers: facile synthesis and chemosensors.

An initiator is applied to synthesize single-walled carbon nanotube/polyaniline composite nanofibers for use as high-performance chemosensors. The composite nanofibers possess widely tunable conductivities (10(-4) to 10(2) S/cm) with up to 5.0 wt % single-walled carbon nanotube (SWCNT) loadings. Chemosensors fabricated from the composite nanofibers synthesized with a 1.0 wt % SWCNT loading respond much more rapidly to low concentrations (100 ppb) of HCl and NH(3) vapors compared to polyaniline nanofibers alone (120 s vs 1000 s). These nanofibrillar SWCNT/polyaniline composite nanostructures are promising materials for use as low-cost disposable sensors and as electrodes due to their widely tunable conductivities.