Effect of Aggregation Structure on Capacitive Energy Storage in Conducting Polymer Films.

Conducting polymers (CPs), a significant class of electrochemical capacitor electrode materials, exhibit exceptional capacitive energy storage performance in aqueous electrolytes. Current research primarily concentrates on enhancing the electrical conductivity and capacitive performance of CPs via molecular design and structural control. However, the absence of a comprehensive understanding of the impact of molecular chain spatial order on ion/electron transport and capacitive performance impedes the development and optimization of advanced electrode materials. Here, a solvent treatment strategy is employed to modulate the molecular chain spatial order of PEDOT : PSS films. The results of electrochemical performance tests and Grazing Incidence Wide Angle X-ray Scattering (GIWAXS) show that Poly(3,4-ethylenedioxythiophene) : poly(styrenesulfonic acid) (PEDOT : PSS) films with both face-on and edge-on orientations exhibit exceptional electronic conductivity and ion diffusion efficiency, with capacitive performance 1.33 times higher than that of PEDOT : PSS films with only edge-on orientation. Consequently, molecular chain orientations conducive to charge transport not only enhance inter-chain coupling, but also effectively reduce ion transport resistance, enabling efficient capacitive energy storage. This research provides novel insights for the design and development of higher performance CPs-based electrode materials.

Fructose-Bisphosphate Aldolase A Regulates Hypoxic Adaptation in Hepatocellular Carcinoma and Involved with Tumor Malignancy.

BACKGROUND: Hypoxia is an important factor in malignant tumors, and glycolysis is a major metabolic contributor in their development. Glycolytic enzymes have gained increasing attention as potential therapeutic targets because they are associated with cancer-specific metabolism. Fructose-bisphosphate aldolase A (ALDOA), a key glycolytic enzyme, reportedly is associated with hepatocellular carcinoma (HCC). However, its role in pathogenesis and its clinical significance in HCC remain largely unknown. AIM: To explore the increased expression of ALDOA in HCC in correlation with tumor malignancy, and to investigate the potential regulatory role ALDOA plays in HCC progression through its regulation in hypoxia adaptation. METHODS AND RESULTS: To better understand ALDOA and its correlation with clinicopathological features of HCC, we analyzed 100 HCC clinical specimens using immunohistochemistry analysis. The results show that the ALDOA expression level is significantly higher in advanced HCC and in HCC with venous invasion. Using in vitro knockdown assays, we showed that higher ALDOA expression was positively associated with cell proliferation, cell cycle, apoptosis, and invasion under both normoxic and hypoxic conditions. Evidence shows that the underlying mechanism is due to the regulatory function of ALDOA in glycolysis, the cell cycle, matrix metalloproteinase-mediated extracellular matrix degradation, and epithelial-mesenchymal transformation. CONCLUSIONS: Data indicated that ALDOA is significantly upregulated in HCC tissue and is closely related to HCC malignancy. ALDOA is likely to regulate HCC progression by regulating HCC tumor cell proliferation, apoptosis, and invasion in both normoxic and hypoxic condition.

A poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-based electrochemical sensor for tert.-butylhydroquinone.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a readily available copolymer that comes as an aqueous dispersion with good processability. A flexible voltammetric sensor for the widely used food stabilizer tert.-butylhydroquinone (TBHQ) was constructed by using a film of PEDOT:PSS. The electron transfer efficiency of the electrode was enhanced by doping with dimethyl sulfoxide (DMSO), and mass transport at the electrode-electrolyte interface was increased by adding the cationic surfactant cetyltrimethylammonium bromide (CTAB) which acts as a sorbent for TBHQ. SEM, AFM, XPS, UV - vis and electrochemical analysis were conducted to characterize the properties of the electrode. After optimization of the experimental conditions, the electrode operated at a working potential of 0.17 V (vs. SCE) has a linear response in the 0.5-200 µM TBHQ concentration range and a lower detection limit of 0.15 µM (at S/N = 3). It was applied for the determination of TBHQ in spiked real samples, and recoveries ranged between 96.85 and 103.41%. Graphical abstractSchematic representation of an electrochemical flexible electrode for the determination of tert.-butylhydroquinone based on the use of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate).

Dual-functional aniline-assisted wet-chemical synthesis of bismuth telluride nanoplatelets and their thermoelectric performance.

The wet-chemical approach is of great significance for the synthesis of two-dimensional (2D) bismuth telluride nanoplatelets as a potential thermoelectric (TE) material. Herein, we proposed a simple and effective solution method with the assistance of aniline for the fabrication of bismuth telluride nanoplatelets at a low temperature of 100 °C. The choice of aniline with its dual function avoided the simultaneous use of a capping regent and a toxic reductant. The as-synthesized nanoplatelets have a large size of more than 900 × 500 nm2 and a small thickness of 15.4 nm. The growth of bismuth telluride nanoplatelets are related to the Bi/Te ratio of precursors indicating that a larger content of the Bi precursor is more conducive to the formation of 2D nanoplatelets. The bismuth telluride nanoplatelets pressed into a pellet show a smaller electrical resistivity (∼6.5 × 10-3 Ω · m) and a larger Seebeck coefficient (-135 µV K-1), as well as a lower thermal conductivity (0.27 W m-1 K-1) than those of nanoparticles. The next goal is to further reduce the electrical resistivity and optimize the TE performance by disposing of the residual reactant of aniline adsorbed on the surface of the nanoplatelets.

Solution-processed two-dimensional layered heterostructure thin-film with optimized thermoelectric performance.

Graphene-based two-dimensional (2D) heterostructures have ignited intensive interest in recent years because of their excellent physical performance. However, the most common method to prepare them uses chemical vapor deposition, which has the drawback of a complex process unsuitable for large-scale production. In this respect, reduced graphene oxide and transitional metal dichalcogenides (rGO-TMDs) composite thin-films were fabricated by a simple solution-processing method and their thermoelectric performance was investigated systematically. Addition of rGO nanosheets (NSs) efficiently improved the electrical conductivity of MoS2 and WS2 (MS2) NSs, due to the excellent electron transport performance of rGO. Furthermore, it should be noted that an optimized content of rGO can effectively avoid direct contact between TMDs NSs by forming a rGO-TMDs heterojunction, leading to significantly increased electrical conductivity and a slight variation in its Seebeck coefficient. Our work obtained high thermoelectric performance heterostructures by inducing two kinds of layered materials using a simple method that may potentially be applied to other 2D layered materials to construct heterostructures for energy conversion.

Electrochemical Treatment for Effectively Tuning Thermoelectric Properties of Free-Standing Poly(3-methylthiophene) Films.

The degree of oxidation of conducting polymers has great influence on their thermoelectric properties. Free-standing poly(3-methylthiophene) (P3MeT) films were prepared by electrochemical polymerization in boron trifluoride diethyl etherate, and the fresh films were treated electrochemically with a solution of propylene carbonate/lithium perchlorate as mediator. The conductivity of the resultant P3MeT films depends on the doping level, which is controlled by a constant potential from -0.5 to 1.4 V. The optimum electrical conductivity (78.9 S cm(-1) at 0.5 V) and a significant increase in the Seebeck coefficient (64.3 µV K(-1) at -0.5 V) are important for achieving an optimum power factor at an optimal potential. The power factor of electrochemically treated P3MeT films reached its maximum value of 4.03 µW m(-1) K(-2) at 0.5 V. Moreover, after two months, it still exhibited a value of 3.75 µW m(-1) K(-2) , and thus was more stable than pristine P3MeT due to exchange of doping ions in films under ambient conditions. This electrochemical treatment is a significant alternative method for optimizing the thermoelectric power factor of conducting polymer films.

Thermoelectric performance of restacked MoS2 nanosheets thin-film.

MoS2 has been predicted to be an excellent thermoelectric material due to its large intrinsic band gap and high carrier mobility. In this work, we exfoliated bulk MoS2 by the assistance of lithium intercalation and fabricated the restacked MoS2 thin-film using a simple filtration technique. These MoS2 thin-films with different thickness showed different thermoelectric performance. It was found that with the increase of thickness, carrier concentration, electrical conductivity and Seebeck coefficient all showed an increasing trend. In particular, the maximum Seebeck coefficient was able to reach 93.5 µV K(-1). This high thermopower indicates that MoS2 will have ideal thermoelectric performance in the future through optimizing its structure. The highest figure of merit (ZT = 0.01) is calculated in this experiment.

Three novel electrochemical electrodes for the fabrication of conducting polymer/SWCNTs layered nanostructures and their thermoelectric performance.

Single-walled carbon nanotubes (SWCNTs), PEDOT: PSS/SWCNTs, and SWCNTs/ PEDOT: PSS nanofilms were used as working electrodes to electrodeposit polyaniline (PANI) in a mixed alcohol solution of isopropyl alcohol (IPA), boron trifluoride ethyl ether (BFEE), and polyethylene glycol (PEG). The thermoelectric (TE) performances of the resulting nanofilms were systematically investigated. SWCNTs/ PEDOT: PSS/PANI nanofilms showed a relatively high electrical conductivity value of 232.0 S cm(-1). The Seebeck coefficient was enhanced and exhibited the values of 33.8, 25.6, and 23.0 µV K(-1) for the SWCNTs/PANI, PEDOT:PSS/SWCNTs/PANI, and SWCNTs/ PEDOT: PSS/PANI films, respectively. The maximum power factor achieved was 12.3 µW m(-1) K(-2). This technique offers a facile and versatile approach to a class of layered nanostructures, and it may provide a general strategy for fabricating a new generation of conducting polymer/SWCNTs materials for further practical applications.

Facile synthesis of low-dimensional PdPt nanocrystals for high-performance electrooxidation of C 2 alcohols.

Low-dimensional noble-metal materials (LDNMs) with different structural advantages have been considered as the high-performance catalysts for C2 alcohol electrooxidation. However, it is still a great challenging to precisely construct nanomaterials with low-dimensional composite structure thus to take advantages of various dimension, especial without the surfactant participation. Most studies focus on the modulation of the single dimensional nanocatalysts, the correlation between electrocatalytic performances and low-dimension composite have been rarely reported. Herein, we engineered a simple one-step approach to design multi-low-dimensional PdPt nanomaterials by using different Pd precursors. The low-dimensional PdPt nanocrystals (NCs) composed of zero dimension (0D) dendrite-like nanoparticles and two dimension (2D) nanosheets were obtained by using Pd(OAc)2, and meanwhile the 2D PdPt nanosheet assemblies (NAs) were synthesized by the introduction of NaPdCl4. Specifically, benefitting from the unique low-dimension structures with fast electron/mass transfer, and optimized electronic and synergistic effect, the multi-low-dimensional 0D-2D PdPt NCs showed the highest ethanol oxidation reaction (EOR)/ethylene glycol oxidation reaction (EGOR) mass activities, which were much higher than 2D PdPt NAs. The 0D-2D PdPt NCs also exhibited the highest structural stability. Generally, this work could inspire more advanced designs for surfactant-free synthesis and promote the fundamental engineering on nanocatalysts with low-dimension composite structure for electrocatalytic fields.

p-n hybrid bulk heterojunction enables enhanced photothermoelectric performance with UV-Vis-NIR light.

Infrared light accounts for the vast majority of natural light energy, however, the challenge of converting infrared light directly into electricity is too difficult. The photothermoelectric (PTE) effect (connecting the photothermal (PT) and thermoelectric (TE) effects) provides a feasible solution for the indirect conversion of infrared light into electrical energy. Therefore, it is of great significance to actively seek and explore materials with good PT and TE performance to fully harvest infrared light energy. Here, we prepared an organic-inorganic hybrid bulk heterojunction film by combining poly(3,4-ethylene-dioxythiophene):polystyrenesulphonate (PEDOT:PSS) and ZnO nanowires (ZnO-NWs). This common composite strategy is able to utilize the ultra-wide spectrum ranging from ultraviolet-visible (UV-Vis) to near-infrared (NIR) light to realize light-to-electricity conversion based on the PTE effect. ZnO-NWs can not only increase the Seebeck coefficient of PEDOT:PSS, but also enhance the absorption of the hybrid film under the NIR light. Thereby, the enhancement of the photothermal-induced voltage was achieved due to the separation of generated electron-hole pairs in the built-in electric field induced by a photothermal gradient. This study provides a new suggestion for improving the PTE performance of the material and making better use of solar energy.

Effect of miR-183-5p on Cholestatic Liver Fibrosis by Regulating Fork Head Box Protein O1 Expression.

Liver fibrosis is a common pathological feature of end-stage liver disease and has no effective treatment. MicroRNAs (miRNAs) have been found to modulate gene expression in liver disease. But the potential role of miRNA in hepatic fibrosis is still unclear. The objective of this research is to study the potential mechanism and biological function of miR-183-5p in liver fibrosis. In this study, we used high-throughput sequencing to find that miR-183-5p is upregulated in human fibrotic liver tissues. In addition, miR-183-5p was upregulated both in rat liver fibrosis tissue induced by bile-duct ligation (BDL) and activated LX-2 cells (human hepatic stellate cell line) according to the result of quantitative real-time PCR (RT-qPCR). Moreover, the inhibition of miR-183-5p alleviated liver fibrosis, decreased the fibrotic biomarker levels in vitro and in vivo, and led toLX-2 cell proliferation inhibition and, apoptosis induction. The result of dual-luciferase assay revealed that miR-183-5p suppressed fork head box protein O1 (FOXO1) expression by binding to its 3'UTR directly. Next, we used lentivirus to overexpress FOXO1 in LX-2 cells, and we found that overexpression of FOXO1 reversed the promotion of miR-183-5p on liver fibrosis, reducing the fibrotic biomarker levels inLX-2 cells, inhibitingLX-2 cell proliferation, and promoting apoptosis. Furthermore, overexpression of FOXO1 prevented the activation of the transforming growth factor (TGF)-ß signaling pathway in TGF-ß1-induced LX-2 cells according to the result of western blotting. In conclusion, the findings showed thatmiR-183-5p might act as a key regulator of liver fibrosis, and miR-183-5p could promote cholestatic liver fibrosis by inhibiting FOXO1 expression through the TGF-ß signaling pathway. Thus, inhibition of miR-183-5pmay be a new way to prevent and improve liver fibrosis.

Flexible fiber-shaped hydrogen gas sensor via coupling palladium with conductive polymer gel fiber.

Rational design of fiber-shaped gas sensors with both excellent mechanical properties and sensing performance is of great significance for boosting future portable and wearable sensing electronics, however, it is still a challenge. Herein, we develop a novel fiber-shaped hydrogen (H2) sensor by directly electrochemically growing palladium (Pd) sensing layer on conductive poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) fiber electrode. This approach produces free-standing functional fiber (PEDOT:PSS@Pd) with promising mechanical features of flexibility, light weight, knittability and high mechanical strength, and good H2 sensing performance at room temperature. The PEDOT:PSS@Pd fiber sensor exhibits short response time of 34 (± 6) s@1% and 19 (± 4) s@4% H2 and excellent cycling stability. In addition, the fiber sensor remains good sensing behavior under different mechanical bending states, showing potential for constructing wearable sensor devices for timely H2 leak detection. Therefore, this work has provided a smart design strategy of fiber-based gas sensor, offering an effective sensing platform and is believed to stimulate the development of wearable electronics.

Regulating monomer assembly to enhance PEDOT capacitance performance via different oxidants.

The development of poly(3,4-ethylenedioxythiophene) (PEDOT) with high specific capacitance is the key to pursuing high-performance supercapacitors, and the electrochemical properties of PEDOT are closely related to the oxidation degree and conjugated chain length of its molecular chain. In this work, the influences of various oxidants (FeCl3, Fe(Tos)3 and MoCl5) on the molecular chain structure and capacitive properties of PEDOT via vapor phase polymerization were systematically investigated. Fe(Tos)3 can significantly improve the degree of oxidation and the length of the conjugated chain of PEDOT compared to FeCl3 and MoCl5, enhancing the conductivity and providing more active sites for Faraday reaction. Therefore, the PEDOT/P(Fe(Tos)3) electrode displays a considerable conductivity of 73 S cm-1, high areal capacitance (419 mF cm-2) and excellent electrochemical stability under the different bent state. Moreover, the conjugated structure strengthens the interaction between PEDOT chains, achieving good cycle stability. Therefore, Fe(Tos)3 is an ideal oxidant for obtaining high-performance PEDOT electrode materials.

Organic/Inorganic Hybrid Boosting Energy Harvesting Based on the Photothermoelectric Effect.

Attracted by the capability of light to heat and electricity conversion, the photothermoelectric (PTE) effect has drawn great attention in the field of energy conversion and self-powered electronics. However, it still requires effective strategies to convert electricity from light based on the corresponding photothermoelectric generator. Herein, considering the broad photoresponse and large Seebeck effect of tellurium nanowires (Te NWs) as well as the high electrical conductivity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), PEDOT:PSS/Te NW hybrid thin films were fabricated to enhance the conversion efficiency by the photothermoelectric effect with respect to single thermoelectric performance. A detailed comparison has been achieved between the photothermoelectric and thermoelectric properties induced by light illumination and heating plates through current-voltage (I-V) transport, respectively. PEDOT:PSS/Te NW hybrid films also show an enhanced photothermal harvesting compared to pure PEDOT:PSS. A photothermoelectric device was assembled based on the as-fabricated PEDOT:PSS/Te NW hybrid films with 90 wt% Te NWs and achieved a competitive output power density with good stability, which may provide insights into improving solar energy harvesting-based photothermoelectric conversion by organic/inorganic hybrids.

Comparison of electrocatalytic activity of Pt1-x Pd x /C catalysts for ethanol electro-oxidation in acidic and alkaline media.

In this paper, a comparision of Pt1-x Pd x /C catalysts for ethanol-oxidation in acidic and alkaline media has been investigated. We prepared Pt1-x Pd x /C catalysts with different ratios of Pt/Pd (x at% = 0, 27, 53, 77 and 100) by the formic acid reduction method. The obtained Pt1-x Pd x /C catalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), induced coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Structural and morphological investigations of the as-prepared catalysts revealed that the metallic particle size increases with increasing Pd content in the catalyst. The electrocatalytic performances and stabilities of Pt1-x Pd x /C catalysts were tested by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry (CA) measurements for ethanol oxidation in acidic and alkaline media. The electrochemical measurements demonstrate that Pt1-x Pd x /C catalysts exhibit much higher electrocatalytic activity for alcohol oxidation in alkaline media than that in acidic media. The composition of Pt/Pd has a significant impact on the ethanol-oxidation in both acidic and alkaline media. The Pt23Pd77/C catalyst shows the highest electrocatalytic performance with a mass specific peak current of 2453.7 mA mgPtPd -1 in alkaline media, which is higher than the Pt77Pd23/C with the maximum of peak current of 339.7 mA mgPtPd -1 in acidic media. Meanwhile, the effect of electrolyte, CH3CH2OH concentrations and scan rates was also studied for ethanol-oxidation in acidic and alkaline media.

Photo-assisted peroxymonosulfate activation via 2D/2D heterostructure of Ti3C2/g-C3N4 for degradation of diclofenac.

In this paper, a two dimensional/two dimensional (2D/2D) heterostructure of Ti3C2/g-C3N4 (T/CN) was constructed and used to activate peroxymonosulfate (PMS) for the degradation of diclofenac (DCF) in water in the presence of light illumination. Compared with single photocatalytic process by T/CN (0.040/min) and with pure g-C3N4 nanosheets in PMS system (0.071/min), 5.0 and 3.0 times enhanced activities were achieved in the T/CN-PMS system at optimum Ti3C2 (1.0 wt%) loading under light illumination (0.21/min). Moreover, the decomposing processes of DCF in T/CN-PMS system were applicable in a wide initial pH range (3∼14), therefore, overcoming the limitation of pH dependence in traditional PMS system. Based on the synergistic effect of photocatalysis and PMS oxidation processes, the 1O2 was generated as primary reactive species for the removal of DCF in T/CN-PMS system. The DCF degradation mechanism was further proposed through the results of liquid chromatography-mass spectrometry (LC-MS) and density functional theory (DFT) calculations.

A freestanding electrochromic copolymer for multicolor smart window.

Electrochromic devices with low-cost, energy-saving advantages, and controllable color switching have gained widely attention. Yet, electrochromic materials are limited for smart window due to challenges such as difficulty freestanding, monotonous color change, slow switching capability, and low optical contrast. In this work, a freestanding copolymers based on Poly(N-vinylcarbazole) (PVK) and 3, 4-ethoxylenedioxythiophene (EDOT) are designed. The copolymer as-synthesized by the good secondary film-forming of PVK not only contains the freestanding property of PVK, but also possesses the excellent electrical and electrochemical properties of poly(3, 4-ethoxylenedioxythiophene) (PEDOT). The freestanding copolymer was used to create the multicolor: brown, dark brown, purple, and blue. A high optical contrast of up to 39.1% and a color efficiency of up to 107.00 cm 2C-1 prove a significant coloration and bleaching effect, which is satisfactory for the application of electrochromic devices. Further, an electrochromic device based on P(PVK-co-EDOT) as coloring materials is constructed. This work contributes new ideas into the design of electrochromic smart materials.

Electrochromic polymers with multiple redox couples applied to monitor energy storage states of supercapacitors.

Two electrochromic polymers based on thiophene-benzene derivatives were prepared using an electrochemical method and exhibited multiple separate redox couples due to the introduction of side chains. The energy storage states of electrochromic supercapacitors based on the resulting polymers could be monitored by their appearance colour.

Flexible and lightweight Ti3C2Tx MXene@Pd colloidal nanoclusters paper film as novel H2 sensor.

Rational and smart design of hydrogen (H2) sensors especially those featured with flexibility and light weight is highly desirable, to meet the requirements for future development of portable H2 sensors. In this work, we demonstrate a novel paper film H2 sensor employing Ti3C2Tx MXene nanosheets with Pd colloidal nanoclusters (Pd CNC) as the activator. The MXene@ Pd CNC paper film was facilely prepared via an all-colloidal solution-based vacuum-filtration process, which is flexible, light-weight and endowed with a compact, glossy surface. The as-obtained MXene@ Pd CNC film sensor displayed moderate H2 response at room temperature at either flat or bent states. Specially, the MXene@Pd CNC film sensor delivered a response time of (32 ± 7) s and a sensitivity of S = (23.0 ± 4.0)%@4% H2. In addition, the MXene@Pd CNC sensor enabled "in-situ-mode" H2 detection directly along a piece of paper film with desired size. The strong H2 adsorption into lattice of ultrafine Pd CNC altered the work function thus induced the electron doping of MXene, which explained the gas sensing mechanism. Therefore, the facilely designed MXene@Pd CNC sensor is believed to contribute to development of future portable and wearable sensing electronics.

Fishnet-Like, Nitrogen-Doped Carbon Films Directly Anchored on Carbon Cloths as Binder-Free Electrodes for High-Performance Supercapacitor.

The low specific capacitance and energy density of carbon electrode has extremely limited the wide application of supercapacitors. For developing a high-performance carbon electrode using a simple and effective method, a fishnet-like, N-doped porous carbon (FNPC) film is prepared by calcining the KOH-activated polyindole precoated on carbon cloths. The FNPC film is tightly anchored on carbon cloths without any binder. The FNPC film with 3.8 at% N content exhibits a fairly high specific capacitance of 416 F g-1 at 1.0 A g-1. Moreover, the assembled button-type cell with two FNPC film electrodes shows a high energy density of 16.4 Wh kg-1, a high power density of 67.4 kW kg-1, and long-term cyclic stability of 92% of the initial capacitance after 10 000 cycles at 10 A g-1. The high performances mainly came from the integration of pseudocapacitance and electrical double-layer capacitance behavior, wettability, fishnet-like nanostructure, as well as the low interfacial resistivity. This strategy provides a practical, uncomplicated, and low-cost design of binder-free flexible carbon materials electrode for high-performance supercapacitors.