Polyaniline Layer Research Articles

Rapid-response electrochromic devices with self-wrinkling polyaniline for enhanced infrared emissivity modulation

Electrochromic devices (ECDs) based on polyaniline (PANI) can alter their optical properties reversely by varying applied voltages, showing great potential in infrared (IR) information concealment. However, the traditional ECD with a flat PANI layer tends to perform unsatisfactorily in IR emissivity regulation and response time, resulting in risks of information leakage and low transfer efficiency. To address these challenges, a wrinkled microstructure is incorporated into the PANI layer (PANI-W) of the ECD (ECD-W) through a self-wrinkling method. Theoretic simulations combined with experimental results verify that the PANI-W endows an enhanced antireflection effect and a more complete redox degree. As a result, the ECD-W exhibits an exceptional IR emissivity modulation (0.375) and a short response time (1.8 s/2.6 s), allowing it to realize a temperature modulation of 8.9 °C. Moreover, various patterned and anti-patterned ECDs-W are feasibly prepared without masks, and more complicated patterns can be realized by erasing the unnecessary part of PANI-W on the ECDs-W. Two encryption/decryption strategies based on these ECDs-W are presented to provide more secure ways for IR information concealment. This research offers guidance to achieve high-performance ECDs with more effective spectrum regulation and faster responses, showing great potential in thermal regulation and IR information protection.

N, S-Codoped 3D Carbon Protected Nanoporous MnS With Record High Sodium Ion Storage Performance for Potential Industry Applications.

With a high theoretical capacity, the MnS anode, however, exhibits a rather complex sodium diffusion kinetics and poor mechanical stability that hinder its application in sodium-ion batteries (SIBs). In this work, a simple, economical, and scalable strategy is developed to inherently coat nanoporous MnS with a 3D N, S co-doped thin carbon layer by using commercially available MnCO3 as precursors. Specifically, the strategy involves a two-step annealing process, which converts the MnCO3 microparticles into nanoporous Mn2O3 and MnS step by step. The 3D N, S codoped carbon layer is in situ formed during the second annealing process by first coating the nanoporous Mn2O3 with a polyaniline layer. Due to the inherent 3D carbon protection and the strong electronic interaction between N, S dopants and MnS, the N, S codoped carbon protected MnS obtained at 900 °C (NS-C@MnS-900) anode displays a high specific capacity of 845mAhg-1 at 0.1Ag-1, which is higher than all reported MnS-based SIB anodes. It also shows an outstanding cyclability and rate performance, maintaining a stable capacity of ≈493mAhg-1 after 1300 cycles at 10Ag-1, which is also the best according to knowledge. These exceptional electrochemical performances and the scalable/simple/low-cost synthesis make the NS-C@MnS-900 attractive for industry application.

Conductive single enzyme nanocomposites prepared by in-situ growth of nanoscale polyaniline for high performance enzymatic bioelectrode

Enzyme-based electrochemical biosensors hold great promise for applications in health/disease monitoring, drug discovery, and environmental monitoring. However, inherently non-conductive nature of proteinaceous enzymes often hampers effective electron transfer at enzyme-electrode interface, limiting biosensor performance of enzyme bioelectrodes. To address this problem, we present an approach to synthesize polyaniline (PAN)-based conductive single enzyme nanocomposites of glucose oxidase (GOx) (denoted as PAN-GOx). To prevent multimerization of enzymes during nanocomposite synthesis and enable single enzyme wrapping, we activate GOx surface with phenylamine groups based on the programmed diffusion of reactants in the reaction solution. Subsequent in-situ polymerization enables the synthesis of nanoscale conductive PAN layer (∼2.7 nm thickness) grafted from individual GOx molecule. PAN-GOx retains 83% and 74% of its specific activity and catalytic efficiency, respectively, compared to free GOx, while demonstrating a ∼500% improved conductivity. Furthermore, PAN-GOx-based glucose biosensors show an approximately 16- and 3-fold higher sensitivity compared to biosensors prepared by using free GOx and a mixture of PAN and GOx, respectively. This study provides a facile method to fabricate conductive single enzyme nanocomposites with enhanced electron transfer, which can potentially be further modified and/or compounded with conductive materials for demonstrating high performance enzymatic bioelectrodes.

Construction of Solution Processable NUS-8/PANI Nanosheets via Template-Directed Polymerization for Ultratrace Gas Sensing.

The advancement of wireless gas sensing signifies a substantial leap forward in gas detection and intelligent monitoring technologies. This necessitates stringent design criteria for gas sensitive materials with good solution processability, conductivity, and porosity, whose design and synthesis remain challenging yet highly sought-after. Herein, the fabrication of NUS-8/polyaniline (PANI) nanosheets is presented with excellent solution processability, high porosity, triboelectric property, and superior electrical conductivity via a template-directed polymerization strategy. Solution processable NUS-8 nanosheets, synthesized directly by a "one-pot" approach, serve as templates to enhance the "on-site" polymerization of aniline, resulting in the formation of PANI layer on NUS-8 nanosheets with a thickness of 7nm. The resultant NUS-8/PANI nanosheets exhibit outstanding solution processability, and a film conductivity of 8.6 Sm-1. The solution processability enables the facile fabrication of homogeneous and compact NUS-8/PANI films and thus their integration onto electronic devices targeted for multifunctional sensing. The NUS-8/PANI coated sensors demonstrate sensitive and selective detection at room temperature toward ultratrace ammonia with a detection limit of 120 ppb. A wireless sensing system based on the NUS-8/PANI-coated sensor is capable to monitor the spoilage process of meat. This study paves novel avenues for designing and synthesizing gas-sensitive materials for practical applications.

Molecularly Imprinted Polymers Electrochemical Sensing: The Effect of Inhomogeneous Binding Sites on the Measurements. A Comparison between Imprinted Polyaniline versus nanoMIP-Doped Polyaniline Electrodes for the EIS Detection of 17β-Estradiol.

Molecularly imprinted polymers (MIPs) are synthetic receptors made by template-assisted synthesis. MIPs might be ideal receptors for sensing devices, given the possibility to custom-design selectivity and affinity toward a targeted analyte and their robustness and ability to withstand harsh conditions. However, the synthesis of MIP is an inherently random process that produces a statistical distribution of binding sites, characterized by a variety of affinities. This is verified both for bulk MIP materials and for MIP's thin layers. In the present work, we aimed at assessing the effects of inhomogeneous versus homogeneous imprinted binding sites on electrochemical sensing measurements, and the possible implications on the sensor's performance. In the example of an Electrochemical Impedance Spectroscopy (EIS) sensor for the 17β-estradiol (E2) hormone, the scenario of inhomogeneous binding sites was studied by modifying electrodes with an E2-MIP polyaniline (PANI) thin layer, called the "Imprinted PANI layer". In contrast, the condition of discrete and uniform binding sites was epitomized by electrodes modified with a thin PANI layer purposedly doped with E2-MIP nanoparticles (nanoMIPs), which were referred to as "nanoMIP-doped PANI". The behaviors of the two EIS sensors were compared. Interestingly, the sensitivity of the nanoMIP-doped PANI was almost twice with respect to that of the imprinted PANI layer, strongly suggesting that the homogeneity of the binding sites has a fundamental role in the sensor's development. The nanoMIP-doped PANI sensor, which showed a response for E2 in the range 36.7 pM-36.7 nM and had a limit of detection of 2.86 pg/mL, was used to determine E2 in wastewater.

In Situ Surface Polymerization of PANI/SWCNT Bilayer Film: Effective Composite for Improving Seebeck Coefficient and Power Factor

AbstractFlexible thermoelectric composites are promising in harvesting low‐temperature energies and have a wide range of applications in wearable devices. However, the uncontrollable interfaces between the components significantly scatter the transport of electrons leading to a reduced thermoelectric performance. In this research, hydrochloride acid doped polyaniline (PANI) is directly prepared on the surface of a single‐walled carbon nanotube (SWCNT) film to form a bilayer structure in controlling the interfacial filtering effect and preserve the high conductivity. Under optimal conditions, a PANI/SWCNT bilayer composite exhibits a Seebeck coefficient of 26 µVK−1 at near room temperature, and a high electrical conductivity of 1320 S cm−1 is maintained. The Seebeck coefficient is a twofold increase compared to a pure SWCNT film, while the power factor is three times the value from a pure SWCNT film and 500 times that from a solution‐mixed PANI/SWCNT composite. The enhanced thermoelectric performance is attributed to SWCNT‐assisted growth through π–π interaction promoting the formation of an oriented and compacted PANI layer, and the bilayer structure can also maximally maintain the electrical conductivity of the composite. The bilayer composite has then been investigated as an energy harvester and a temperature sensor, indicating its reliable performance in wearable applications.

Optimization of the polyaniline solid contact in potentiometric sensors for detection of paralytic shellfish toxins in mussels

The present study optimized the properties of the electropolymerized polyaniline (PANI) solid inner contact for a potentiometric chemical sensor by varying the thickness of the polymer layer. A potentiometric sensor for detecting one of the paralytic shellfish toxins, decarbamoyl saxitoxin (dcSTX), in mussel extracts was selected as a case study. The plasticized PVC membrane composition, developed in previous work for the detection of this toxin, was used. The structure and electrical properties of PANI layers of different thicknesses were studied using scanning electron microscopy and electrochemical impedance spectroscopy. The effect of PANI solid contact thickness on the characteristics of the potentiometric sensor, including sensitivity, detection limit, and selectivity to dcSTX in buffer solutions and mussel extracts, was evaluated. The formation of a water layer at the inner solid contact and PVC membrane interface was investigated using electrochemical impedance spectroscopy and a water test. PANI layer thickness 1.1 µm was found to be optimal for solid inner contact for potentiometric sensor with PVC membrane providing highest sensitivity and selectivity.

Sodium alginate supramolecular nanofibers in synergy with surface crack engineering to prepare tough and highly sensitive hydrogels

Soft and wet hydrogels often struggle to achieve both toughness and high sensitivity simultaneously, limiting their usefulness in flexible devices. To tackle this challenge, we devised a strategy that combines supramolecular sodium alginate nanofibers, utilizing Zr4+ as physical crosslinkers, with surface crack engineering via the micro-phase separation of polyaniline, to create a physically and chemically dual crosslinked polyacrylamide (PAM)/sodium alginate (SA)/polyaniline (PANI) hydrogel with exceptional toughness and high sensitivity. Owing to the supramolecular sodium alginate nanofibers, the dual crosslinked hydrogel exhibited a tensile strength of 0.391 MPa, an elongation at break of 568.9 %, and a toughness of 1.020 MJ/m3. The in-situ polymerized polyaniline layer, confined within the dense network, introduced micro-cracks onto the hydrogel surface, resulting in a high gauge factor of 11.4 for the fabricated hydrogel. Furthermore, integrating this hydrogel into a triboelectric nanogenerator transformed it into self-powered sensors capable of detecting external forces and generating various signals without power supply. These findings suggest that the developed hydrogel held great potential in diverse fields, including human motion detection, human-machine interaction, and wearable electronic devices.

Charge Photogeneration and Transfer in Polyaniline/Titanium Dioxide Heterostructure

The photoinduction process in a p-n heterogeneous structure should be in correlation with the electronic properties of its semiconductor components. Based on that assumption, a double layer made of polyaniline (PANi) and titanium dioxide (TiO2) on glass substrate is used to investigate the charge photogenerated and transferred in the structure. The PANi layer is made by in situ polymerization of aniline in HCl acidic aqueous medium, while the TiO2 layer is made by thermolysis of TiCl3 dilute solution. It has been found that the PANi/TiO2 double layer is a composition of a PANi emeraldine salt layer (p-type semiconductor) covered by a TiO2 rutile layer (n-type conductor), creating a p-n heterogeneous structure. Upon exposure to the excitation light, the light sensitivity of the PANi layer in the PANi/TiO2 structure reveals a response mode distinct from those of the neat PANi layer. The conductance of the PANi layer in the coupling structure shows two modes of response: (1) a negative mode, i.e., a decrease in conductance in response to the excitation light of wavelength 369, 396 and 447 nm, and (2) a positive mode, namely an increase in conductance, as with the excitation light of wavelength 667 nm. On the other hand, the neat PANi layer simply shows a single positive response to excitation light. Those response modes account for a modulation of the PANi/TiO2 depletion region that in turn depends upon the photoexcited electrons and holes in the heterostructure. The diffusion of excess photogenerated electrons and holes over the heterojunction results in an expansion or reduction of depletion width that gives rise to an increase or decrease of the PANi layer conductance, i.e., a positive or negative response, respectively. In addition, the negative mode in response to the excitation light of wavelength 447 nm (~2.8 eV) is assumed to be an impact of the PANi in extending the photoinduction of the TiO2 component into the vision range at the blue region.

Super-Elastic and Temperature-Tolerant Hydrogel Electrodes for Supercapacitors via MXene Enhanced Ice-Templating Synthesis.

Developing flexible energy storage devices with good deformation resistance under extreme operating conditions is highly desirable yet remains very challenging. Super-elastic MXene-enhanced polyvinyl alcohol/polyaniline (AMPH) hydrogel electrodes are designed and synthesized through vertical gradient ice templating-induced polymerization. This approach allows for the unidirectional growth of polyaniline (PANI) and 2D MXene layers along the elongated arrayed ice crystals in a controlled manner. The resulting 3D unidirectional AMPH hydrogel exhibits inherent stretchability and electronic conductivity, with the ability to completely recover its shape even under extreme conditions, such as 500% tensile strain, 50% compressive strain. The presence of MXene in the hydrogel electrode enhances its resilience to mechanical compression and stretching, resulting in less variation in resistance. AMPH has a specific capacitance of 130.68 and 88.02mFcm-2 at a current density of 0.2 and 2mAcm-2, respectively, and retains 90% and 70% of its original capacitance at elongation of 100% and 200%, respectively. AMPH-based supercapacitors demonstrate exceptional performance in high salinity environments and wide temperature ranges (-30-80°C). The high electrochemical activity, temperature tolerance, and mechanical robustness of AMPH-based supercapacitor endow it promising as the power supply for flexible and wearable electronic devices.

Empowering TiO2–coated PVDF membranes stability with polyaniline and polydopamine for synergistic separation and photocatalytic enhancement in dye wastewater purification

Photocatalytic membranes are effective in removing organic dyes, but their low UV resistance poses a challenge. To address this, self-protected photocatalytic PVDF membranes were developed using polyaniline (PANI) and polydopamine (PDA), whaich are anti-oxidation polymers, as interlayers between the membrane and TiO2. PVDF membranes were first modified by a self-polymerization layer of either PANI or PDA and then coated with titanium dioxide (TiO2). The TiO2 remained firmly attached to the PANI and PDA layer, regardless of sonication and prolonged usage. The PANI and PDA layers enhanced the durability of PVDF membrane under UV/TiO2 activation. After 72 h of irradiation, PVDF–PDA–TiO2 and PVDF–PANI–TiO2 membranes exhibited no significant change. This process improved both separation and photocatalytic activity in dye wastewater treatment. The PVDF–PDA–TiO2 and PVDF–PANI–TiO2 membranes showed enhanced membrane hydrophilicity, aiding in the rejection of organic pollutants and reducing fouling. The modified membranes exhibited a significant improvement in the flux recovery rate, attributed to the synergistic effects of high hydrophilicity and photocatalytic activity. Specially, the flux recovery rate increased from 17.7% (original PVDF) to 56.3% and 37.1% for the PVDF–PDA–TiO2 membrane and PVDF–PANI–TiO2 membrane. In dye rejection tests, the PVDF‒PDA‒TiO2 membrane achieved 88% efficiency, while the PVDF‒PANI‒TiO2 reached 95.7%. Additionally, the photodegradation of Reactive Red 239 (RR239) by these membranes further improved dye removal. Despite an 11% reduction in flux, the PVDF–PDA–TiO2 membrane demonstrated greater durability and longevity. The assistance of PANI and PDA in TiO2 coating also improved COD removal (from 33 to 58–68%) and provided self-protection for photocatalytic membranes, indicating that these photocatalytic membranes can contribute to more sustainable wastewater treatment processes.

Lamellar sulfonated acid polymer-initiated in situ construction of robust LiF-rich SEI enabling superior charge transport for ultrastable and fast charging silicon anodes

The extreme volume expansion of the silicon (Si) anodes during repeated cycles seriously induces undesirable interfacial side reactions, forming an unstable solid electrolyte interphase (SEI) that degrades the electrode integrity and cycle stability in lithium-ion batteries, limiting their practical applications. Despite considerable efforts to stabilize the SEI through surface modification, challenges persist in the development of high-performance Si anodes that effectively regulate intrinsic SEI properties and simultaneously facilitate electron/ion transport. Here, a highly conductive and organic electrolyte-compatible lamellar p-toluenesulfonic acid-doped polyaniline (pTAP) layer is proposed for constructing a robust artificial SEI on Si nanoparticles to achieve fast charging, long-term cycle lifespan and high areal capacity. The spatially uniform pTAP layer, formed through a facile direct-encapsulation approach assisted by enriched hydrogen bonding, contributes to the effective formation of in situ SEI with an even distribution of the LiF-rich phase in its interlamination spaces. Furthermore, the integrated artificial SEI facilitates isotropic ion/electron transport, increased robustness, and effectively dissipates stress from volume changes. Consequently, a notably high rate performance of 570 mA h g−1, even at a substantially high current density of 10 A g−1, is achieved with excellent cyclic stability by showing a superior capacity over 1430 mA h g−1 at 1 A g−1 after 250 cycles and a high areal capacity of ca. 2 mA h cm−2 at 0.5 C in a full cell system. This study demonstrates that the rational design of conductive polymers with SEI modulation for surface protection has great potential for use in high-energy-density Si anodes.

Electrochemical polymerization of polyaniline/single-walled carbon nanotube bilayer films with enhanced thermoelectric properties

In this work, polyaniline (PANI) is coated on single-walled carbon nanotubes (SWCNT) via electrochemical polymerization method to fabricate PANI/SWCNT bilayer films with enhanced thermoelectric properties. Effects of deposition time and voltage, and acid types and concentrations on the thermoelectric properties of the films are studied. The results showed that PANI layer was effectively coated on the surface of SWCNT layer by electrochemical polymerization method. In addition, carrier transport and the electrical conductivity (σ) of the PANI/SWCNT bilayer film was improved due to interfacial π-π interaction between PANI and SWCNT, and the Seebeck coefficient (S) was increased due to the energy filtering effect at the interface of PANI/SWCNT. The maximum PF of PANI/SWCNT at room temperature was 155.3 ± 7.2 μW m−1 K−2 with the σ of 654.9 ± 41.8 S cm−1 and the S of 48.7 ± 0.5 μV K−1 when the deposition voltage and time were 1.0 V and 240.0 s using 0.5 M HCl, respectively. Finally, a self-powered thermoelectric device composed of five pairs of p-n junctions was prepared with PANI/SWCNT (1 V, 240 s) as the p-type legs and copper adhesives as the n-type legs, and the maximum output power was 0.27 μW at a temperature difference of 50 K. Therefore, this demonstrates that electrochemical polymerization is a feasible and effective way of fabricating conductive polymers/carbon nanotubes bilayer films with enhanced thermoelectric properties, which have potential application in powering wearable electronics.

A superhydrophilic composite membrane with excellent photo-Fenton antifouling performance for efficient removal of diverse contaminants

The development of multifunctional composite membranes with integrating membrane separation and catalytic degradation processes is of great significance for effectively eliminating diverse contaminants from water. Herein, a superhydrophilic PANI/Fe1.02Zr-MOF/PVDF composite membrane was designed and prepared via nonsolvent induced phase separation (NIPS) method followed by in situ polymerization to coat a polyaniline (PANI) layer. The introduction of Fe-doped Zr-MOF (Fe1.02Zr-MOF) imparts an excellent self-cleaning ability to the membrane due to in situ photo-Fenton reaction. The surface modification with a PANI layer enhances the membrane’s hydrophilicity and provides abundant active sites for contaminant enrichment. The composite membrane demonstrated remarkable removal efficiency towards a wide range of contaminants, including antibiotics, hexavalent chromium, and oil, as well as excellent antifouling ability. Moreover, continuous and rapid sewage purification was achieved by combining multiple membranes in a cascade configuration under a small additional pressure. The potential toxicities of intermediate products generated from the degradation of antibiotics were analyzed. The mechanisms involved in photo-Fenton degradation of antibiotic and photocatalytic reduction of Cr(VI) were studied. This work highlights a novel strategy to develop composite membranes with excellent photo-Fenton self-cleaning ability for efficient removal of diverse water contaminants.

Two comparative novel facile synthesis of Prussian blue/polyaniline bilayer films for supercapacitor electrode

A nanocomposite films of Prussian Blue/Polyaniline were prepared on ITO without binder, by two procedures: The first by forming thin multi layers of films of Prussian blue and Polyaniline alternatively, up to seven utilizing “layer by layer” technique. To prepare another film, a thick layer of Prussian Yellow was made under a Polyaniline layer with almost the same load of materials.PB successive layers were fabricated by dipping the ITO in a mixture of (Fe (NO3)3 + K3Fe(CN)6) solution, for a few minutes. next Pani layers were overlayed by electropolymerizing of aniline solution on the ITO/PY electrode. PY instantly was reduced by aniline as soon as dipped in solution, resulting in a nano Prussian Blue film on ITO.Uv-vis and FT-IR spectroscopy were used to characterize the fabricated films. AFM and SEM were utilized to study its morphology. The capacitive behavior of the two types of films was studied utilizing CVs and GCD techniques. The resistance of the electrode/electrolyte interface was studied by EIS. The electrochemical analysis confirmed that the multi-layer by layer thin film has much-improved specific capacitance of 255.6 F/g at 1 A/g current density and superior stability of 96.4 % of its initial value after 500 cycles.

Unlocking Maximum Synergy: Screen-Printing Fabrication of Heterostructured Microsupercapacitor Stacks.

A cost-effective and scalable approach for the fabrication of heterostructured microsupercapacitors (MSCs) employing screen-printing followed by sequential electrochemical and microspray deposition techniques has been demonstrated. The microsupercapacitor electrode (MSC) that composed of stacked layers of mesoporous carbon, polyaniline (PANI), and MXene hold significant promise for wearable electronics. By adjusting the deposition and spray cycles, the MSC can be readily coated with PANI and MXene. The sequentially stacked two layers of MXene and PANI on the mesoporous carbon spheres (PMPM-MSC) yielded a specific capacitance of 1003 mF cm-2 at 0.5mA cm-2, surpassing the performance of PANI/mesoporous carbon electrode by 1.6 times (771 mF cm-2). After 10,000 cycles of charge and discharge, PMPM-MSCs retained more than 86% of their initial capacitance. In-situ Raman spectroscopy confirmedthe synergistic effects between MXene and PANI within the heterostructured stacked PMPM-MSC electrodes, including enhanced electronic conductivity and improved electrolyte ion dissociation, which aligned with the electrochemical measurement results, such as fast charge/discharge rates and reduced internal and mass transport resistance. This study demonstrates the potential of screen-printed heterostructured MSC stacks with maximum electrochemical synergy for portable and wearable energy storage devices.

Design and performance evaluation of hierarchical ZnCo2S4@PANI core-shell nanorod arrays for high-efficiency supercapacitor applications

Ternary transition metal sulfides (TMS) have gained significant attention due to their excellent energy and power density as Faradaic electrode materials to be utilized in supercapacitors (SCs). Among various conducting polymers, polyaniline (PANI) has rapidly evolved as a valuable pseudo-capacitor material. Though it deprived cycling stability due to instability in structural transformation, which is the major obstacle to its practical level utilization in energy related applications. Herein, the synthesis of an efficient and reliable ZnCo2S4@PANI nonorod arrays (NRAs) anode with structure-to-performance hierarchical morphology is designed to achieve excellent performance. Heterostructured, extremely porous ZnCo2S4 nanorods have acted as a conductive core, which has provided the strain-buffer-support, along with nanoscaled PANI layer to act as an electrochemical active counterpart, and has demonstrated outstanding specific capacitance while retaining the remarkable cyclic performance and rate capability. Implementing the perfectly uniform and compactly coated PANI, the synthesized anode has demonstrated a high specific capacitance of ∼815 F g−1 at a current density of 1 A g−1 and exceptional ∼91 % capacitance retention even after 4000 cycles at high 2 A g−1 current density. Such outcomes are much superior to the most reported electrochemical performances of PANI-related pseudo-capacitors in the literature. The enhanced electrochemical properties of the as synthesized ZnCo2S4@PANI NRAs anode demonstrate the ability of the stable componential structure as a hybrid electrode design to provide a new direction for researchers to utilize such porous framework as an operative support for proficient energy storage devices.

Polyaniline impact on graphitic C3N4’s structural and physicochemical properties for high stability energy storage systems: Practical and theoretical studies

Polyaniline (PANI), and graphitic C3N4 (GCU) have a significant research consideration owing to their properties. Accordingly, in the current study, PANI, GCU, and their composite (PANI@GCU) are synthesized through aniline chemical polymerization in the presence of C3N4. Materials characterizations are done using X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR). SEM images demonstrate that the PANI layers cover the surface of the GCU. Samples are studied through dielectric and electrochemical analysis. The electrical conductivity value shows a conductivity increment in the order: PANI@GCU > PANI > GCU. The PANI@GCU composite sample exhibits a bulk conductivity of 23 S/m at 10 MHz frequency. It also has a 584 F/g specific capacitance with 96.7 % stability after 1000 cycles at 1 A/g. The results of PANI@GCU supercapcitance performance are supported with molecular modelling that shows the interaction between GCU and PANI through the elongation of C-N bond of PANI beside of GCU layer bending to create arc and arrow structure. The structure of PANI@GCU has a lower band gap (ΔEgap) than PANI, and GCU separately which agrees with the enhancement of the conductivity of the composite than its constituent.

Facile synthesis of PA photocatalytic membrane based on C-PANI@BiOBr heterostructures with enhanced photocatalytic removal of 17β-estradiol

The prevalence of 17β-estradiol (E2) in wastewater has attracted widespread attention due to the negative impacts on ecological environments and human health. Nowadays, photocatalysis has been emerged as an efficient technology for E2 containing wastewater treatment. However, traditional powder photocatalysts face challenges such as easy agglomeration, secondary pollution and difficult recovery, limiting their large-scale application. In this study, a photocatalytic PA/C-PANI@BiOBr membrane was fabricated by immobilizing polyaniline (PANI) layer and BiOBr nanosheets on polyamide (PA) membrane through in-situ chemical bath deposition. This process leveraged the strong hydrogen bond interaction between PANI and PA, with the fine PANI fibers providing nucleation sites for the in-situ growth of BiOBr nanosheets. By repeating the immersion process, we controlled variations in the coverage density and morphology of BiOBr on the membrane surface. The PA/C-PANI@BiOBr membrane exhibited outstanding light absorption and photocatalytic performance. Notably, the optimal PA/C-PANI@BiOBr-10 membrane achieved 100 % removal efficiency of 3 mg L−1 E2 within 40 min. In dynamic cyclic experiments, PA/C-PANI@BiOBr-10 membrane maintained stable permeability and high removal efficiency of pollutants. The photocatalytic mechanism underlying these results was elucidated through photoelectric testing and further photocatalytic experiments. Furthermore, the PA/C-PANI/BiOBr-10 membrane demonstrated remarkable durability over multiple consecutive cycles, with E2 removal efficiency remaining above 96.5 % after 5 cycles.

Coupling hole-transporting polyaniline layer with a cobalt phthalocyanine cocatalyst to boost photoelectrochemical water oxidation of bismuth vanadate photoanodes

Though bismuth vanadate (BiVO4) exhibits a promising potential as a semiconductor photoanode toward photoelectrochemical (PEC) water oxidation, its PEC performance is still limited by the poor charge carrier transport and sluggish oxygen evolution kinetics. Herein, the polyaniline (PANI) and cobalt coordinated-phthalocyanines (CoTcPc) were introduced onto the BiVO4 semiconductor substrate, constructing the integrated CoTcPc/nPANI/BiVO4 (n = 30, 60 and 90, n represents the deposition time for PANI with the unit of s) composite photoanodes. It is demonstrated that the PEC water oxidation activity of BiVO4 is significantly boosted by the incorporation of PANI and CoTcPc, stemming from the improved electron/hole transfer, enhanced charge separation efficiency, and accelerated carrier mobility and water oxidation kinetics. CoTcPc/60PANI/BiVO4 composite photoanode with the optimized compositions exhibits an enhanced photocurrent density of 4.03 mA/cm2 at 1.23 V vs. RHE under illumination, ranking among the best records reported recently. Furthermore, the roles of electrodeposition time to generate PANI are also distinguished through experimental studies. These results reveal the crucial role of engineering the hole transfer layer to optimize the semiconductor photoanodes toward efficient PEC water oxidation.