Polyaniline Research Articles

Disposable electrochemical sensors based on reduced graphene oxide/polyaniline/poly(alizarin red S)-modified integrated carbon electrodes for the detection of ciprofloxacin in milk.

Anelectrochemical sensor based on an electroactive nanocomposite was designedfor the first timeconsisting of electrochemically reduced graphene oxide (ERGO), polyaniline (PANI), and poly(alizarin red S) (PARS) for ciprofloxacin (CIPF) detection. The ERGO/PANI/PARS-modified screen-printed carbon electrode (SPCE) was constructed through a three-step electrochemical protocol and characterized using FTIR, UV-visible spectroscopy, FESEM, CV, LSV, and EIS. The new electrochemical CIPF sensor demonstrated a low detection limit of 0.0021μM, a broad linear range of 0.01 to 69.8μM, a high sensitivity of 5.09 μA/μM/cm2, and reasonable selectivity and reproducibility. Moreover, the ERGO/PANI/PARS/SPCE was successfully utilized to determine CIPF in milk with good recoveries and relative standard deviation (< 5%), which were close to those with HPLC analysis.

Synthesis of reduced graphene oxide (rGO)/polyaniline (PANI) composite electrode for energy storage: Aqueous asymmetric supercapacitor

Composite materials have gained significant interest for energy storage applications due to their possible synergistic effects. This work describes the synthesis of reduced graphene oxide (rGO)/polyaniline (PANI) composite thin films using chemical bath deposition (CBD) method. A field-emission scanning electron microscope revealed that PANI spikes coated on rGO sheets in rGO/PANI composite. The electrochemical studies of a rGO/PANI composite electrode showed a specific capacitance (Cs) of 1130F/g Cs at a scan rate of 5 mV/s in 1 M H2SO4 electrolyte. The combined effect of rGO with PANI, a aqueous asymmetric supercapacitor device (ASC) with configuration of rGO/PANI/H2SO4/WO3 produced 97F/g Cs at a 5 mV/s scan rate and retained 82 % capacitance after 5,000 galvanostatic charge–discharge cycles. The ASC achieved a high specific energy of 23 Wh kg−1 at a specific power of 732 W kg−1. The electrochemical properties of rGO/PANI composite indicate a feasible method for creating asymmetric supercapacitors.

Synergism in the electrocatalytic properties of cobalt phthalocyanine-carbon nanotube-polymeric electrospun nanofibers immobilized on a gold electrode for the detection of lead(II) ions

Core-shelled electrospun nanofibers (ENFs) comprising of a polyvinyl acetate (PVA) shell encapsulating a composite of polyaniline (PANI), tetra-4-(3-oxyflavonephthalocyaninato)cobalt(II) (CoPc-flav), carboxylic acid functionalized multiwalled carbon nanotubes (f-MWCNTs) and an annealed conductive top layer of Nafion (Nf) were used to fabricated a chemically modified gold electrode (Au|ENFs-1-Nf) via the adsorption method. The electrocatalytic sensing capabilities of the Au|ENFs-1-Nf electrode towards Pb(II) ions were evaluated. In comparison to the bare gold electrode and other chemically modified electrodes (CMEs), the Au|ENFs-1-Nf electrode was less prone to fouling showing more stable analyte signal and less compromised background electrolyte currents. The Au|ENFs-1-Nf electrode could detect the Pb(II) cations in a reproducible manner ranging from 8 to 125 μM where limits of detection and quantification of 0.51 and 1.55 μM were obtained, respectively. The analytical performance of the aforementioned CME rendered a comparable percentage recovery (103 %) with that of Inductively coupled plasma-optical emission spectroscopy (ICP-OES) (115 %).

Probing Electrocatalytic Synergy in Graphene/MoS2/Nickel Networks for Water Splitting through a Combined Experimental and Theoretical Lens.

The development of low-cost and active electrocatalysts signifies an important effort toward accelerating economical water electrolysis and overcoming the sluggish hydrogen or oxygen evolution reaction (HER or OER) kinetics. Herein, we report a scalable and rapid synthesis of inexpensive Ni and MoS2 electrocatalysts on N-doped graphene/carbon cloth substrate to address these challenges. Mesoporous N-doped graphene is synthesized by using electrochemical polymerization of polyaniline (PANI), followed by a rapid one-step photothermal pyrolysis process. The N-doped graphene/carbon cloth substrate improves the interconnection between the electrocatalyst and substrate. Consequently, Ni species deposited on an N-doped graphene OER electrocatalyst shows a low Tafel slope value of 35 mV/decade at an overpotential of 130 mV at 10 mA/cm2 current density in 1 M KOH electrolytes. In addition, Ni-doped MoS2 on N-doped graphene HER electrocatalyst shows Tafel slopes of 37 and 42 mV/decade and overpotentials of 159 and 175 mV, respectively, in acidic and alkaline electrolytes at 10 mA/cm2 current density. Both these values are lower than recently reported nonplatinum-group-metal-based OER and HER electrocatalysts. These excellent electrochemical performances are due to the high electrochemical surface area, a porous structure that improves the charge transfer between electrode and electrolytes, and the synergistic effect between the substrate and electrocatalyst. Raman spectroscopy, X-ray photoelectron spectroscopy, and density functional theory (DFT) calculations demonstrate that the Ni hydroxide species and Ni-doped MoS2 edge sites serve as active sites for OER and HER, respectively. Finally, we also evaluate the performance of the HER electrocatalyst in commercial alkaline electrolyzers.

Melamine foam scaffolded 3D porous polyaniline/reduced graphene oxide composite electrode for flexible supercapacitor

Graphene composite foam with enhanced mechanical and electrochemical properties holds great promise for flexible supercapacitors. This work developed a cost-effective method for massive production of three-dimensional (3D) porous graphene composite using melamine foam (MF) as a flexible scaffold. The MF was coated reduced graphene oxide (RGO) to form an interconnected conductive layer by dip-coating and vapor reduction, and loaded with polyaniline (PANI) by in-situ polymerization. The resulted PANI/RGO/MF, as self-supporting electrode, exhibits extraordinary mechanical flexibility and a high specific capacitance of 806.2 mF cm−2 at 0.5 mA cm−2. Furthermore, the assembled solid-state supercapacitor exhibits an outstanding capacity of 299.1 mF cm−2 at 0.5 mA cm−2, a high energy density of 26.6 μWh cm−2 at 200 μW cm−2, nearly 100 % capacitance retention at 0°–180°, and good cycling stability. This study provides a scalable strategy for fabricating graphene composite foam suitable for flexible energy storage application.

High‐performance supercapacitors using nanostructured polyaniline‐based carbon: Effect of electrolytes

AbstractDeveloping high‐performance materials for electrochemical energy storage devices such as batteries, and supercapacitors is a significant topic in material chemistry‐based research. The high consumption and limited availability of numerous materials used in energy devices lead to the development of alternative, effective, and cost‐effective materials exhibiting superior electrochemical chemical performance. A porous activated carbon, derived from polyaniline (PANI) synthesized through chemical oxidative polymerization, can be considered a viable solution in this context. In this study, the electrochemical window of the nitrogen‐doped porous activated carbon was enhanced through a combined synthesis process involving the carbonization and activation of PANI nanotubes with KOH. Moreover, alternations in surface area and porosity were evaluated using BET analysis for the samples having PANI to KOH ratios 1:0.5, 1:1, and 1:2. The results revealed a significant improvement in surface area and pore volume, increasing from 18 to 3535 m2/g from pure PANI to chemically treated samples. Among those materials, the PANI to KOH ratio of 1:1 exhibited the highest surface area of 3535 m2/g and the highest pore volume of 0.7131 cm3/g. Subsequently, the electrochemical performance of all materials was evaluated using a three‐electrode cell system and a symmetrical coin‐cell device. Electrodes fabricated with PANI to KOH ratio of 1:1 by weight showed better electrochemical performance in an aqueous electrolyte (6 M KOH) in both systems. This material exhibited the highest capacitance of 378 F/g (at 0.5 A/g) in the three‐electrode system and 143 F/g (at 0.5 A/g) in the SCCD. The SCCD achieved a maximum energy density of 23 Wh/kg with a power density of 544 W/kg. Additionally, these supercapacitors provided a good Coulombic efficiency of about 99% with capacitance retention of 97% at 7 A/g current density after 10 000 charge–discharge cycles. Further, this study expanded by investigating variations of electrochemical performance across various electrolytes, including aqueous, organic, and ionic liquids in coin‐cell supercapacitors. The findings reveal promising results, suggesting potential commercial applications for this facile approach to synthesize nitrogen‐doped activated carbon, especially for supercapacitors with aqueous electrolytes.

Graphene-enhanced manganese dioxide functional ink infused with polyaniline for high-performance screen-printed micro supercapacitor

In the world of miniature advancements in technology, a current champion has emerged: the micro supercapacitors. In order to fabricate these micro-supercapacitors, we have developed a promising and user-friendly approach for printing a conductive functional ink containing a ternary composite of manganese dioxide (MnO2) nanoparticles, Graphene, and polyaniline (PANI) as a dopant. Screen-printing technique was employed to fabricate micro-supercapacitors using the nanocomposite conductive ink. The performance of the energy storage device was examined using flexible symmetric and asymmetric, with an aqueous 1 M KOH electrolyte. According to this strategy, the characterisation and electrochemical study results revealed that doping PANI into both symmetric and asymmetric devices significantly increased the material’s capacitive performance of areal capacitance 167 mFcm−2 for MnO2/Graphene/PANI-5 composite (MGP-5) and 292.5 mFcm−2 for asymmetric supercapacitor (ASSC) at 5 mVs−1. Furthermore, the asymmetric supercapacitor displayed outstanding cyclic stability, retaining 93.6% of its capacitance after 10000 cycles. This underscores the possibility of incorporating polyaniline (PANI) into MnO2 and graphene matrices as efficient blueprints for the development of superior electrode materials. The improvement represents a significant step forward, opening avenues for the future development of novel devices and their integration into top-of-the-line flexible energy storage systems.

Exfoliated 2D Nanosheet-Based Conjugated Polymer Composites with P-N Heterojunction Interfaces for Highly Efficient Electrocatalytic Hydrogen Evolution.

We have achieved a significant breakthrough in the preparation and development of two-dimensional nanocomposites with P-N heterojunction interfaces as efficient cathode catalysts for electrochemical hydrogen evolution reaction (HER) and iodide oxidation reaction (IOR). P-type acid-doped polyaniline (PANI) and N-type exfoliated molybdenum disulfide (MoS2) nanosheets can form structurally stable composites due to formation of P-N heterojunction structures at their interfaces. These P-N heterojunctions facilitate charge transfer from PANI to MoS2 structures and thus significantly enhance the catalytic efficiency of MoS2 in the HER and IOR. Herein, by combining efficient sodium-functionalized chitosan-assisted MoS2 exfoliation, electropolymerization of PANI on nickel foam (NF) substrate, and electrochemical activation, controllable and scalable Na-Chitosan/MoS2/PANI/NF electrodes are successfully constructed as non-noble metal-based electrochemical catalysts. Compared to a commercial platinum/carbon (Pt/C) catalyst, the Na-Chitosan/MoS2/PANI/NF electrode exhibits significantly lower resistance and overpotential, a similar Tafel slope, and excellent catalytic stability at high current densities, demonstrating excellent catalytic performance in the HER under acidic conditions. More importantly, results obtained from proton exchange membrane fuel cell devices confirm the Na-Chitosan/MoS2/PANI/NF electrode exhibits a low turn-on voltage, high current density, and stable operation at 2 V. Thus, this system holds potential as a replacement for Pt/C with feasibility for applications in energy-related fields.

Polyaniline-Coated Na3V2(PO4)2F3 Cathode Enables Fast Sodium Ion Diffusion and Structural Stability in Rechargeable Batteries.

Na3V2(PO4)2F3 (NVPF), a typical sodium superionic conductor (NASICON) type structure, has attracted much interest as a potential positive electrode in sodium-ion battery. However, the inherently poor electronic conductivity of phosphates compromises the electrochemical properties of this material. Here, we develop a general strategy to improve the electrochemical performance by preparing a new composite material "polyaniline (PANI)@NVPF" using a Pickering emulsion method. The X-ray diffraction and Raman results indicated a successful PANI coating without affecting the NASICON-type structure of NVPF, and they enhanced the interfacial bonding between the two components. Also, thermogravimetric analysis and scanning electron microscopy analyses revealed that the PANI content influenced the thermal stability and morphology of the nanocomposites. As a result, the sodium test cells exhibited multielectron reactions and a better rate performance for PANI@NVPF nanocomposites as compared to NVPF. Specifically, 2%PANI@NVPF maintained 70% of its initial capacity at 5C. Ex-situ electron paramagnetic resonance revealed the existence of mixed valence states of vanadium (V4+/V3+) in both discharge and charge processes. Consequently, the successful PANI coating into the sodium superionic conductor framework improved the sodium diffusion channels with a measurable increase of diffusion coefficients with cycling (ca. 3.25 × 10-11 cm2 s-1). Therefore, PANI@NVPF nanocomposites are promising cathode candidates for high-rate sodium-ion battery applications.

Polyaniline-modified amorphous tin-based Prussian blue analogue as cathodes for long-life aqueous zinc ion batteries

Prussian blue analogs (PBAs) have emerged in the field of aqueous zinc ion batteries (AZIBs) owing to their simple synthesis method and three-dimensional open framework structure. Although PBAs have high redox potentials, the unsatisfactory specific capacity and poor electrical conductivity limit their development to some extent. In this work, amorphous tin hexacyanoferrate (SnHCF) and polyaniline (PANI) were combined to form SnHCF/PANI composite. The synergistic effect of the amorphous structure of SnHCF and PANI with good conductivity makes the SnHCF/PANI electrode exhibit excellent redox activity and achieve rapid ion/electron transfer. When used as a cathode in AZIBs, the SnHCF/PANI provides a high specific capacity (136.8 mAh g−1 at 0.5 A g−1) and excellent cycling stability (a discharge specific capacity of 54.3 mAh g−1 after 2500 cycles at 2 A g−1). This work offers a new idea for the development of PBAs-based composites as cathode materials for AZIBs.

Enhancing interfacial electron transfer through PANI electron bridge for tailoring dynamic reconstruction and achieving high-performance water oxidation

Tailoring the dynamic reconstruction of transition metal compounds into highly active oxyhydroxides through surface electron state modification is crucial for advancing water oxidation, yet remains a formidable challenge. In this study, a unique polyaniline (PANI) electron bridge was integrated into the metal–organic frameworks (MOFs)/layer double hydroxides (LDHs) heterojunction to expedite electron transfer from MOFs to LDHs, facilitating electron accumulation at the metal sites within MOF and electron-deficient LDHs. This configuration promotes the surface dynamic reconstruction of LDHs into highly active oxyhydroxides while safeguarding the MOF from corrosion in harsh environments over extended periods. The optimized electronic structure modification of both MOFs and LDHs enhances reaction kinetics. The superior MIL-88B(Fe)@PANI@NiCo LDH catalyst achieved 10 mA∙cm−2 at an overpotential of 202 mV and demonstrated stable operation for 120 h at this current density. This research introduces an innovative approach for guiding electron transfer and dynamic catalyst reconstruction by constructing a PANI electron bridge, potentially paving the way for more efficient catalytic systems.

Waste-derived carbon quantum dots for improving the photostability of perovskite solar cells to > 1,000 h

Power conversion efficiency (PCE) of perovskite solar cells (PSCs) has reached 26.1%, but PSC devices are plagued by poor stability when exposed to light (especially ultraviolet (UV) radiation), heat, and moisture. UV stability remains a significant challenge to overcome. Luminescent down-shifting (LDS) filters have shown significant enhancement in photostability and efficiency for PSCs. However, most explored LDS materials are costly, non-biodegradable, and the resulting photostability is limited to ∼100 h. In this report, as-obtained waste filtrate from the polyaniline (PANI) synthesis is used to synthesize fluorescent PANI carbon quantum dots (PANI-CQDs) using a facile hydrothermal method. Here we report, for the first time, the use of waste-derived PANI-CQDs to fabricate UV filters that are low-cost, bio-degradable, and room-temperature processible and, importantly, impart high UV and photostability to the PSCs. PSCs with these filters retained 90% and 100% of their initial performance when exposed to UV light and AM 1.5 solar radiation, respectively, for more than 900 h, while PSCs without filters degraded to 14 and 70% of their initial performance under the same conditions. Hence, we clearly show that using a waste-derived LDS filter improves the UV stability of PSCs by six times and photostability beyond 1,000 h.

Amorphous titanium dioxide and polyaniline dual modifying silicon for highly enhanced lithium-ion storage

Silicon (Si) anode material is promising in the next generation of lithium-ion batteries (LIBs) with high energy densities for its much higher capacity (4200 mAh/g) than that of commercial graphite (372 mAh/g). However, silicon anode material with low electronic conductivity suffers a huge volume variation and accompanies side reactions during alloyed and de-alloyed process. Here, we design an inner amorphous titanium dioxide (TiO2) and an outer flexible conductive polyaniline (PANI) network dual modified Si@TiO2@PANI material for LIBs, where the TiO2 avoids the side reactions and the PANI network layer buffers the volume expansion and increases the electronic conductivity. The as-prepared Si@TiO2@PANI exhibits a high initial discharge capacity of 3050 mAh/g and maintains 1583 mAh/g after 200 cycles at 0.5 A/g. It even delivers the discharge capacity of 1002 mAh/g after 600 cycles at 1 A/g, as well as an excellent rate ability with discharge capacity of 1890, 1260 and 432 mAh/g at the high current density of 1, 2 and 5 A/g, respectively. Our strategy shows that the innovative design of double buffer layers on Si can synergistically promote stability and accelerate kinetics of Li+ transport, offering novel resolution strategy to enhance the performance of Si-based anodes for LIBs.

Flexible Hybrid Supercapacitor Achieving 2.2V with NiCo2S4/Polyaniline/MnO2 and N, S-Co-Doped Carbon Nanofibers for Ultra-High Energy Density.

Flexible all-solid-state asymmetric supercapacitors (FAASC) represent a highly promising power sources for wearable electronics. However, their energy density is relatively less as compared to the conventional batteries. Herein, a novel ultra-high energy density FAASC is developed using nickel-cobalt sulfide (NiCo2S4)/polyaniline (PANI)/manganese dioxide (MnO2) ternary composite on carbon fiber felt (CF) as positive and N, S-co-doped carbon nanofibers (CNF)/CF as negative electrode, respectively. Initially, porous δ-MnO2 nanoworm-like network is decorated on CF using potentiodynamic method. Subsequently, interconnected PANI nanostructures is grown on the MnO2 via a facile in situ chemical polymerization, followed by the electrodeposition of highly porous NiCo2S4 nanowalls. Benefiting from 3D porous structure of conductive CF and redox active properties of NiCo2S4, PANI and MnO2, FAASC achieved a superior energy storage capacity. Later, high-performance N, S-co-doped CNF/CF negative electrode is synthesized using electropolymerization of PANI nanofibers on CF, followed by the carbonization process. The assembled FAASC exhibits a wide voltage window of 2.2V and remarkable specific capacitance of 143 F g-1 at a current density of 1 A g-1. The cell further delivers a superb energy density of 71.6Wh kg-1 at a power density of 492.7W kg-1, supreme cycle life and remarkable electrochemical stability under mechanical bending.

Polyaniline-based bovine serum albumin imprinted electrochemical sensor for ultra-trace-level detection in clinical and food safety applications

Monitoring bovine serum albumin (BSA) at ultra-low levels is crucial for clinical and food safety applications, as it plays a significant role in identifying various health conditions and potential risks, necessitating fast, trace-level detection of BSA. This study proposes an approach to address these challenges by employing molecularly imprinted polymer (MIP) to develop an ultra-trace-level and cost-effective BSA sensing platform. The MIP electrochemical sensor was developed using polyaniline (PANI) combined with the protein crosslinker glutaraldehyde (GA) to optimize BSA surface imprinting in the MIP. As a result, the sensor achieves a sensitivity of 1.24 μA/log(pg/mL), with a picomolar detectable limit of 2.3 pg/mL (0.035 pM) and a wide detection range from 20 pg/mL to 200,000 pg/mL (0.303 pM to 3030 pM), making it suitable for clinical and food safety applications. Additionally, the study explores the interaction between an acidic surfactant protein eluent (acetic acid with sodium dodecyl sulfate, AcOH-SDS) and BSA vacant sites, enhancing recognition and re-binding. The PANI-based MIP sensor demonstrates initial feasibility and practicality in commercial milk and real human serum, opening avenues for early disease detection and ensuring food safety in BSA-related immune responses.

Pyrrole as a multi-functional additive to concurrently stabilize Zn anode and cathode via interphase regulation towards advanced aqueous zinc-ion battery

The advancement of aqueous zinc-ion batteries (AZIBs) is impeded by challenges encompassing cathodic and anodic aspects, such as limited capacity and dendrite formation, constraining their broader utilization. Herein, pyrrole, an economically viable and readily accessible compound, is proposed as a versatile electrolyte additive to address these challenges. Experiments and DFT calculations reveal that pyrrole and its derivatives preferentially adsorb onto zinc foil, facilitating the formation of a pyrrole-based solid electrolyte interphase (SEI), which effectively guides uniform Zn2+ deposition through strong attraction force and suppresses hydrogen evolution reactions and parasitic reactions. On the cathode side, the additive promotes the formation of a durable cathode electrolyte interphase (CEI) enriched with poly-pyrrole (Ppy) analogues. Such layer significantly contributes to extra capacity of both polyaniline (PANI) and MnO2 cathodes by leveraging the electrochemical reactivity of Ppy towards Zn2+ and improves their cyclic stability. Consequently, a dendrite-free Zn anode is realized with an extended cyclic lifespan surpassing 6000 h in Zn//Zn cell, coupled with an average Coulombic efficiency of 99.7 % in Cu//Zn cell. Moreover, the PANI//Zn and MnO2//Zn full cells demonstrate enhanced capacities along with improved cycling stability. This work provides a new additive strategy towards concurrent stabilization of cathode and Zn anode in AZIBs.

Energy-safety balanced composites of attractive cyclic nitramines with polyaniline

Composite microcrystals of the cyclic nitramines 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (ε-CL-20), 1,3,5-trinitro-1,3,5-triazinane(RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (β-HMX), and cis-1,3,4,6-tetranitrooctahydroimidazo-[4,5-d]imidazole (BCHMX) with polyaniline (PANi) have been prepared and thoroughly characterized in terms of morphology and phase purity. PANi outperformed other conducting polymers in terms of selectivity towards NAs due to its better interaction with NAs, low production cost, and ease of preparation. The bonding of nitramines with the polymeric PANi chain has been examined by means of Fourier transform infrared (FTIR), Raman spectroscopy methods, and fluorescence quenching; the Raman spectrum has shown the laser sensitivity of these microcrystals. Powder X-ray diffraction results have shown changes in polymorph modifications in CL20 (from ɛ to β) and HMX (from β to α) during the preparation of the composites, which have also been confirmed by spectral and differential thermal analysis techniques. The structural orientations found in these composites significantly stabilize nitramines against impact; their detonation properties have slightly deteriorated, but the PANi electrical conductivity has strongly increased their electric-spark sensitivity. The above properties of the prepared composites determine their potential use mainly as parts of the electric or laser impulse initiators, having “a green character”, for various charges.

Label-Free Electrochemical Dopamine Biosensor Based on Electrospun Nanofibers of Polyaniline/Carbon Nanotube Composites.

The development of conducting polymer incorporated with carbon materials-based electrochemical biosensors has been intensively studied due to their excellent electrical, optical, thermal, physical and chemical properties. In this work, a label-free electrochemical dopamine (DA) biosensor based on polyaniline (PANI) and its aminated derivative, i.e., poly(3-aminobenzylamine) (PABA), composited with functionalized multi-walled carbon nanotubes (f-CNTs), was developed to utilize a conducting polymer as a transducing material. The electrospun nanofibers of the composites were fabricated on the surface of fluorine-doped tin oxide (FTO)-coated glass substrate under the optimized condition. The PANI/f-CNTs and PABA/f-CNTs electrospun nanofibers were characterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which confirmed the existence of f-CNTs in the composites. The electroactivity of the electrospun nanofibers was investigated in phosphate buffer saline solution using cyclic voltammetry (CV) before being employed for label-free electrochemical detection of DA using differential pulse voltammetry (DPV). The sensing performances including sensitivity, selectivity, stability, repeatability and reproducibility of the fabricated electrospun nanofiber films were also electrochemically evaluated. The electrochemical DA biosensor based on PANI/f-CNTs and PABA/f-CNTs electrospun nanofibers exhibited a sensitivity of 6.88 µA·cm-2·µM-1 and 7.27 µA·cm-2·µM-1 in the linear range of 50-500 nM (R2 = 0.98) with a limit of detection (LOD) of 0.0974 µM and 0.1554 µM, respectively. The obtained DA biosensor showed great stability, repeatability and reproducibility with precious selectivity under the common interferences, i.e., glucose, ascorbic acid and uric acid. Moreover, the developed electrochemical DA biosensor also showed the good reliability under detection of DA in artificial urine.

Facile dual-functionalization of PEN nanofibrous membranes with solar evaporation and photocatalysis for efficient dye wastewater purification

Purification of dye wastewater by combining photocatalytic degradation with solar energy-driven interfacial water evaporation has emerged as a promising approach to address water pollution in recent years. In this work, a high-performance polymer, polyarylene ether nitrile (PEN), was electrostatically spun to construct a robust nanofibrous substrate, then dual-functionalized using polyaniline (PANI) and titanium dioxide (TiO2) via a facile polydopamine (PDA)-assisted vacuum self-assembly method. Moreover, the CA of the PEN membrane after PDA and PANI@TiO2 treatment changes from 20° to 0° within 0.4 s, showing superhydrophilic properties and providing rapid water supply for water evaporation. PANI and TiO2 were employed as the photo-thermal conversion component and photocatalytic component, respectively. The fabricated dual-functionalized PANI@TiO2/PEN composite nanofibrous membrane exhibited a high water evaporation rate of up to 3.23 kg m−2 h−1 under a simulated solar illumination of 1 KW m−2. Owing to the reduction in the photoelectron-hole recombination rate promoted by PANI, the composite nanofibrous membrane demonstrated a favorable dye removal rate of 92.18% in 6 h for methylene blue (MB). Furthermore, the robust PEN nanofibrous skeleton conferred the composite membrane with thermal resistance and corrosion resistance properties, ensuring long-term performance in harsh environments. The facile fabricated PANI@TiO2/PEN membrane achieved comprehensive performance, offering a promising strategy by combining solar-driven interfacial water evaporation and photocatalytic degradation for water purification.

All-Organic Piezo-Photocatalytic Film with Highly Efficient Catalysis, Weak-Force Excitation, and Recyclability.

Polyaniline (PANI), a typical organic photocatalyst, has an adjustable structure and good stability, can be easily synthesized on a large scale, and is economical. PANI is doped with ions to regulate its internal structure and improve its photocatalytic performance. However, its photocatalytic performance is limited by the doping concentration and its intrinsic properties, hindering its further application. Herein, PANI films with a piezo-photocatalytic function are fabricated to improve photocatalytic performance and explore their self-powered environmental purification property. PANI/poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) sandwich films, with PVDF-HFP as the interlayer, are prepared by introducing a piezoelectric field into PANI photocatalysts, thereby achieving excellent piezo-photocatalytic performance. The as-fabricated piezo-photocatalyst degrades methyl orange at a rate of 91.2% after 60min under magnetic stirring. Owing to the low Young's modulus of the all-organic catalyst, self-powered purification is realized using the PANI/PVDF-HFP film. Leaf surfaces are functionalized by loading the film in them for removing pollutants under sunlight and water flow. Thus, this study proposes a common strategy, wherein a piezoelectric interlayer is introduced to load the organic photocatalyst for preparing an all-organic piezo-photocatalyst. This piezo-photocatalyst can be easily recycled and responds to weak forces, realizing its application for self-powered environmental purification.