Multifunctional Polyoxometalates-Based Ionohydrogels toward Flexible Electronics.

Multifunctional flexible electronics present tremendous opportunities in the rapidly evolving digital age. One potential avenue to realize this goal is the integration of polyoxometalates (POMs) and ionic liquid-based gels (ILGs), but the challenge of macrophase separation due to poor compatibility, especially caused by repulsion between like-charged units, poses a significant hurdle. Herein, the possibilities of producing diverse and homogenous POMs-containing ionohydrogels by nanoconfining POMs and ionic liquids (ILs) within an elastomer-like polyzwitterionic hydrogel using a simple one-step random copolymerization method, are expanded vastly. The incorporation of polyzwitterions provides a nanoconfined microenvironment and effectively modulates excessive electrostatic interactions in POMs/ILs/H2 O blending system, facilitating a phase transition from macrophase separation to a submillimeter scale worm-like microphase-separation system. Moreover, combining POMs-reinforced ionohydrogels with a developed integrated self-powered sensing system utilizing strain sensors and Zn-ion hybrid supercapacitors has enabled efficient energy storage and detection of external strain changes with high precision. This work not only provides guidelines for manipulating morphology within phase-separation gelation systems, but also paves the way for developing versatile POMs-based ionohydrogels for state-of-the-art smart flexible electronics.

Cathode materials for halide-based aqueous redox flow batteries: recent progress and future perspectives.

As the population increases sharply around the globe, huge shortages are occurring in energy resources. Renewable resources are urgently required to be developed to satisfy human demands. Unlike the lithium-ion batteries with safety and cost issues, the redox flow battery (RFB) is economical, stable, and convenient for the development of large-scale stationary electrical energy storage applications. Especially, the aqueous redox flow battery (ARFB) further exhibits a promising potential in larger power grids owing to its unique structural features of storing energy by filling the tank with electrolytes. The ARFB is capable of modulating battery parameters by controlling the volume and concentration of the electro-active species (EAS). Further, halogens show excellent properties, such as low cost and appropriate potential as an EAS for ARFB, further showing an efficient, safe, and affordable energy storage system (ESS). Moreover, to attain the demands of strong activity, high sensitivity, convenience as well as practicality, further attention needs to be paid to material (electrode) design and adjustment. In this mini-review, novel electrode materials, including their potential internal mechanisms and effective regulatory means, are summarized and applied in the zinc-halogen, hydrogen-halogen, and polysulfide-halogen ARFB systems, promoting the development of valuable material systems and the innovation of the energy storage/conversion technologies.

Bifunctional MOF Doped PEO Composite Electrolyte for Long-Life Cycle Solid Lithium Ion Battery.

A highly stable composite electrolyte was developed in this research to address the performance decline over time in a solid lithium ion battery (SLIB). It involved the synthesis of bifunctional MOF material (MOF-2) from two different functionalized UiO-66 materials containing carboxyl groups and amine groups, respectively, and the subsequent blending of PEO (polyethylene oxide) with the MOF-2 to form the novel composite solid electrolyte (PEO-MOF-2). The composite electrolytes showed higher ionic conductivity (5.20 × 10-4 S/cm) than that of pristine PEO. The LiFePO4||Li cells constructed with PEO-MOF-2 exhibited 98.45% capacity retention with 149.92 mA h/g after 100 cycles operation at 1.0 C, which was higher than those cells prepared with pristine PEO electrolyte or with PEO-based electrolytes that were only doped by aminated MOF or carboxylated MOF. Furthermore, our experiments showed that there was about a 40% increase in the potential window (from 3.5 to 5.0 V) and 80% increase in the lithium ion transfer number (from 0.20 to 0.36 at 60 °C) as a result of replacing pristine PEO electrolyte with PEO-MOF-2.

Synergistic Generation of Radicals by Formic Acid/H2O2/g-C3N4 Nanosheets for Ultra-efficient Oxidative Photodegradation of Rhodamine B.

Water pollution is a global challenge endangering people's health. In this work, an ultra-efficient photodegradation system of Rhodamine B (RhB) has been established using a graphitic carbon nitride nanosheet (CNNS) as the semiconductor photocatalyst, from which energy is harvested on both the conduction band and valence band by formic acid and hydrogen peroxide, respectively. The optimized FA/H2O2/CNNS system increases the apparent photodegradation rate of RhB by 25 folds, from 0.0198 to 0.4975 min-1. Through a comprehensive investigation with reactive oxygen species scavengers, electron paramagnetic resonance, high-performance liquid chromatography-mass spectrometry, etc., an oxidative mechanism for RhB photodegradation has been proposed, which combines enhanced charge carrier migration and synergistic generation of multiple radicals. Comparable performance improvements have also been observed for similar systems with different semiconductors, suggesting that such a catalytic system could afford a general approach to enhance semiconductor-catalyzed photodegradation.

Fe Single-Atom Catalyst for Efficient and Rapid Fenton-Like Degradation of Organics and Disinfection against Bacteria.

The Fenton-like reaction has great potential in water treatment. Herein, an efficient and reusable catalytic system is developed based on atomically dispersed Fe catalyst by anchoring Fe atoms on nitrogen-doped porous carbon (Fe SA/NPCs). The catalyst of Fe SA/NPCs exhibits enhanced performance in activating peroxymonosulfate (PMS) for organic pollutant degradation and bacterial inactivation. The Fe SA/NPCs + PMS system demonstrates a high turnover frequency of 39.31 min-1 in Rhodamine B (RhB) degradation as well as a strong bactericidal activity that can completely sterilize an Escherichia coli culture within 5 min. Meanwhile, the degradation activity of RhB by Fe SA/NPCs is improved up to 28 to 371-fold in comparison with the controls. Complete degradation of RhB can be achieved in 30 s by the Fe SA/NPCs + PMS system, demonstrating an efficiency much higher than most traditional Fenton-like processes. Experiments with different radical scavengers and density functional theory calculations have revealed that singlet oxygen (1 O2 ) generated on the N-coordinated single Fe atom (Fe-N4 ) sites is the key reactive species for the effective and rapid pollutant degradation and bacterial inactivation. This work innovatively affords a promising single-Fe-atom catalyst/PMS system for applying Fenton-like reactions in water treatment.

Advanced TexSy-C Nanocomposites for High-Performance Lithium Ion Batteries.

This study is dedicated to expand the family of lithium-tellurium sulfide batteries, which have been recognized as a promising choice for future energy storage systems. Herein, a novel electrochemical method has been applied to engineer micro-nano TexSy material, and it is found that TexSy phases combined with multi-walled carbon nanotubes endow the as-constructed lithium-ion batteries excellent cycling stability and high rate performance. In the process of material synthesis, the sulfur was successfully embedded into the tellurium matrix, which improved the overall capacity performance. TexSy was characterized and verified as a micro-nano-structured material with less Te and more S. Compared with the original pure Te particles, the capacity is greatly improved, and the volume expansion change is effectively inhibited. After the assembly of Li-TexSy battery, the stable electrical contact and rapid transport capacity of lithium ions, as well as significant electrochemical performance are verified.

Carbon-Based Electrocatalysts Derived From Biomass for Oxygen Reduction Reaction: A Minireview.

Oxygen reduction reaction (ORR) electrocatalysts derived from biomass have become one of the research focuses in hetero-catalysis due to their low cost, high performance, and reproducibility properties. Related researches are of great significance for the development of next-generation fuel cells and metal-air batteries. Herein, the preparation methods of various biomass-derived catalysts and their performance in alkaline, neutral, and acidic media are summarized. This review clarifies the research progress of biomass carbon-based electrocatalysts for ORR in acidic, alkaline and neutral media, and discusses the future development trends. This minireview can give us an important enlightenment to practical application in the future.

Nerve growth factor and Tropomyosin receptor kinase A are increased in the gastric mucosa of patients with functional dyspepsia.

BACKGROUND: Nerve growth factor (NGF) and enteric glial cells (EGCs) are associated with visceral hypersensitivity and gastrointestinal motility disorder, which may represent the pathogenesis of functional dyspepsia (FD). This study aimed to investigate the expression of NGF, its high affinity receptor tropomyosin receptor kinase A (TrkA) and the EGC activation marker glial fibrillary acidic protein (GFAP) in the gastric mucosa of patients with FD and the association of these proteins with dyspeptic symptoms. METHODS: Gastric mucosal biopsies taken from 27 FD patients (9 epigastric pain syndrome (EPS) patients, 7 postprandial distress syndrome (PDS) patients and 11 EPS overlap PDS patients) and 26 control subjects were used for analysis. The expression of NGF, TrkA and GFAP was examined, and the association of these proteins with dyspeptic symptoms, including epigastric pain, postprandial fullness, early satiation and epigastric burning, was analysed. RESULTS: The expression levels of NGF, TrkA, and GFAP in the gastric mucosa were significantly higher in the EPS group, the PDS group, and the EPS overlap PDS group than in the healthy control group. There was no significant difference between the FD subgroups. TrkA colocalized with GFAP, which indicated that TrkA was localized to EGCs, and the expression of TrkA in EGCs was significantly higher in the FD group than in the control group. Changes in the expression of NGF, TrkA, and GFAP were positively correlated with epigastric pain, postprandial fullness and early satiation but had no significant relationship with epigastric burning. CONCLUSIONS: The increased expression of gastric NGF, TrkA and GFAP might be involved in FD pathophysiology and symptom perception.

The role of toll-like receptor 4 and mast cell in the ameliorating effect of electroacupuncture on visceral hypersensitivity in rats.

BACKGROUND: Visceral hypersensitivity is one of the main pathogenesis of irritable bowel syndrome (IBS) and mast cell activation is closely related to visceral hypersensitivity. As a critical molecule of the innate immune system, toll-like receptor 4 (TLR4) may modulate the activation of mast cell. Alleviating effect of electroacupuncture (EA) on visceral hypersensitivity has been proved, whereas, whether the TLR4 and mast cell is involved in this process remains unclear. METHODS: Forty Sprague-Dawley rats were randomly divided into five groups: control group, model group, EA group, sham EA group, and mast cell stabilizer (MCS) group. Visceral sensitivity during colorectal distension was assessed by the measurement of visceral motor reflex (VMR). TLR4 mRNA and protein expression were assessed by real-time PCR and immunohistochemistry, respectively. Mast cell number and mast cell tryptase (MCT) expression were detected. The level of inflammatory cytokine in serum was detected with ELISA. KEY RESULTS: Visceral sensitivity was significantly higher in the model group than in the control group. EA and MCS significantly reduced VMR score at 0.8 mL and 1.2 mL distention pressures. Compared with model group, TLR4 mRNA expression, the protein expression of TLR4 and MCT, and the number of mast cells with degranulation in the colonic tissue, serum concentration of IL-1ß and IL-8 were all significantly decreased in EA and MCS group. CONCLUSIONS & INFERENCES: Electroacupuncture ameliorated visceral hypersensitivity in colon-sensitized model probably via decreasing the level of pro-inflammatory cytokines released by mast cell which were decreased when the TLR4 expression in the colonic tissue was downregulated by EA.

Spiky nanohybrids of titanium dioxide/gold nanoparticles for enhanced photocatalytic degradation and anti-bacterial property.

We present a facile two-step procedure for synthesizing spiky nanohybrids of titanium dioxide/gold (TiO2/Au) nanoparticles. In this process, spiky TiO2 is obtained using a hydrothermal method, followed by the introduction of plasmonic Au nanoparticles (AuNPs) via a photoreduction approach in which titanium fluoride and chloroauric acid tetrahydrate are used as raw materials. The photodegradation property of the resulting sample was evaluated according to the removal of Rhodamine B (RhB) and ciprofloxacin (CIP) via excitation with visible light. Additionally, the antimicrobial property of the spiky TiO2/Au nanoparticles was examined with respect to the suppression of the growth of Escherichia coli (E. coli). Compared with commercial TiO2, the spiky TiO2/Au nanoparticles exhibited a significantly enhanced photocatalytic efficiency in persistent organic pollutant degradation and bacteria inactivation under simulated environmental conditions. The photocatalysis mechanism primarily entails the combination of AuNPs with spiky TiO2 nanoparticles, which increases the optical path owing to the unique spiky structures of the latter. This results in an improved light-harvesting efficiency based on the localized surface plasmon resonance (LSPR) of AuNPs and the promotion of the charge-separation efficiency through electron-trap processes. These nanoparticles realize the objective of effectively addressing the inherent weaknesses of bare TiO2 and potentially facilitate new fitting approaches for applications in sewage treatment and marine antifouling paint.

Sponge-like N-doped carbon materials with Co-based nanoparticles derived from biomass as highly efficient electrocatalysts for the oxygen reduction reaction in alkaline media.

The development of highly efficient and low-cost catalysts towards Oxygen Reduction Reaction (ORR) is of significance for renewable energy technologies such as proton-exchange membrane fuel cells and metal-air batteries. This study is to utilize the biomass of soybean straw as the supporting carbon materials to prepare nitrogen and cobalt dual-doped porous biocarbon electrocatalysts (CoNASS) possessing high content of N (1.92%), embedding cobalt nanoparticles and sponge-like structure with high specific surface area (1185.00 m2 g-1) as well as appropriate pore diameter (∼2.17 nm). Meantime, CoNASS exhibits a good electrocatalytic activity with a half-wave potential of 0.786 V (vs. RHE), comparable to a half-wave potential of 0.827 V (vs. RHE) for the commercial Pt/C. The detections of electrochemical kinetics show the electron transfer number of CoNASS is in the range of 3.84-3.92, which indicates 4-electron pathway dominantly occurs in ORR. And the limiting diffusion current density of CoNASS at 1600 rpm is around 5.8 mA cm-2 slightly higher than that of the benchmark Pt/C (5.6 mA cm-2). This work opens a new avenue to utilize soybean straw, one of agriculture waste of large quantity, to prepare high efficient and low-cost catalysts for ORR.

3D interconnected nitrogen-self-doped carbon aerogels as efficient oxygen reduction electrocatalysts derived from biomass gelatin.

Development of efficient metal-free electrocatalysts derived from biomass with high activity towards oxygen reduction reaction (ORR) has gained significance attention due to their low manufacturing cost, environmental friendliness and easy large-scale production. Hence, we present a facile method to prepare nitrogen-self-doped carbon aerogels (NSCAs) with a three-dimensional (3D) interconnected porous structure and large surface area. The sample is prepared via high-temperature pyrolysis using gelatin as precursor and sodium chloride (NaCl) as sacrificial template. The obtained NSCA-800 catalyst shows excellent ORR performance in O2-saturated alkaline electrolyte, which is comparable to a commercial Pt/C catalyst, in terms of its onset potential (0.92 V vs. RHE), half-wave potential (0.77 V vs. RHE), and limited current density (5.31 mA cm-2). Particularly, the NSCA-800 catalyst exhibits outstanding long-term stability, its ORR kinetic current still retains 95.7% after a continuous 4 h test while that for commercial Pt/C retains just 74.3%. The sustainable biomass gelatin is a promising precursor for the development of carbon materials as effective ORR catalysts.

Metallated porphyrin based porous organic polymers as efficient electrocatalysts.

Developing efficient, stable and low-cost catalysts for Oxygen Reduction Reaction (ORR) is of great significance to many emerging technologies including fuel cells and metal-air batteries. Herein, we report the development of a cobalt(II) porphyrin based porous organic polymer (CoPOP) and its pyrolyzed derivatives as highly active ORR catalysts. The as-synthesized CoPOP exhibits high porosity and excellent catalytic performance stability, retaining ∼100% constant ORR current over 50,000 s in both alkaline and acidic media. Pyrolysis of CoPOP at various temperatures (600 °C, 800 °C, and 1000 °C) yields the materials consisting of graphitic carbon layers and cobalt nanoparticles, which show greatly enhanced catalytic activity compared to the as-synthesized CoPOP. Among them, CoPOP-800/C pyrolyzed at 800 °C shows the highest specific surface area and ORR activity, displaying the most positive half-wave potential (0.825 V vs. RHE) and the largest limited diffusion current density (5.35 mA cm(-2)) in an alkaline medium, which are comparable to those of commercial Pt/C (20 wt%) (half-wave potential 0.829 V vs. RHE, limited diffusion current density 5.10 mA cm(-2)). RDE and RRDE experiments indicate that CoPOP-800/C directly reduces molecular oxygen to water through a 4-e(-) pathway in both alkaline and acidic media. More importantly, CoPOP-800/C exhibits excellent durability and methanol-tolerance under acidic and alkaline conditions, which surpass the Pt/C (20 wt%) system.

Recyclable, Biocompatible, Magnetic Titanium Dioxide Nanoparticles with Immobilized Enzymes for Biocatalysis.

Clean break: Magnetic nanoparticles are fabricated with mesoporous anatase shells, which are biocompatible for enzyme immobilization (see picture; HRP=horseradish peroxidase). The nanobiocatalyst can be easily collected with an external magnet and recycled. Immobilized enzymes with low activity after several cycles can be decomposed with UV radiation and thus the nanoparticles are recyclable for new enzyme immobilization.