Designing a Rare DNA-Like Double Helical Microfiber Superstructure via Self-Assembly of In Situ Carbon Fiber-Encapsulated WO3-x Nanorods as an Advanced Supercapacitor Material

Amorphous Fe-Containing Phosphotungstates Featuring Efficient Peroxidase-like Activity at Neutral pH: Toward Portable Swabs for Pesticide Detection with Tandem Catalytic Amplification

Peroxidase-mimetic materials are intensively applied to establish multienzyme systems because of their attractive merits. However, almost all of the nanozymes explored exhibit catalytic capacity only under acidic conditions. The pH mismatch between peroxidase mimics in acidic environments and bioenzymes under neutral conditions significantly restricts the development of enzyme-nanozyme catalytic systems especially for biochemical sensing. To solve this problem, here amorphous Fe-containing phosphotungstates (Fe-PTs) featuring high peroxidase activity at neutral pH were explored to fabricate portable multienzyme biosensors for pesticide detection. The strong attraction of negatively charged Fe-PTs to positively charged substrates as well as the accelerated regeneration of Fe²⁺ by the Fe/W bimetallic redox couples was demonstrated to play important roles in endowing the material with peroxidase-like activity in physiological environments. Consequently, integrating the developed Fe-PTs with acetylcholinesterase and choline oxidase led to an enzyme-nanozyme tandem platform with good catalytic efficiency at neutral pH for organophosphorus pesticide response. Furthermore, they were immobilized onto common medical swabs to fabricate portable sensors for paraoxon detection conveniently based on smartphone sensing, showing excellent sensitivity, good anti-interference capacity, and low detection limit (0.28 ng/mL). Our contribution expands the horizon of acquiring peroxidase activity at neutral pH, and it will also open avenues to construct portable and effective biosensors for pesticides and other analytes.

Animal- and Human-Inspired Nanostructures as Supercapacitor Electrode Materials: A Review

Human civilization has been relentlessly inspired by the nurturing lessons; nature is teaching us. From birds to airplanes and bullet trains, nature gave us a lot of perspective in aiding the progress and development of countless industries, inventions, transportation, and many more. Not only that nature inspired us in such technological advances but also, nature stimulated the advancement of micro- and nanostructures. Nature-inspired nanoarchitectures have been considered a favorable structure in electrode materials for a wide range of applications. It offers various positive attributes, especially in energy storage applications, such as the formation of hierarchical two-dimensional and three-dimensional interconnected networked structures that benefit the electrodes in terms of high surface area, high porosity and rich surface textural features, and eventually, delivering high capacity and outstanding overall material stability. In this review, we comprehensively assessed and compiled the recent advances in various nature-inspired based on animal- and human-inspired nanostructures used for supercapacitors. This comprehensive review will help researchers to accommodate nature-inspired nanostructures in industrializing energy storage and many other applications.

Active W Sites Promoted by Defect Engineering Enhanced C2H6S3 Sensing Performance of WO3 Nanosheets

Defect engineering has received extensive attention as an effective method to tune the gas sensing properties of semiconductor materials. Here, defective WO₃ (D-WO₃) nanosheets were obtained by a simple hydrogenation process with a detection limit as low as 5 ppb for dimethyl trisulfide (DMTS) and a response of 2.3 times that of the initial WO₃ nanosheets to 100 ppb DMTS. Importantly, X-ray photoelectron spectroscopy and Raman spectroscopy confirmed the partial loss of oxygen atoms in D-WO₃ nanosheets, and density functional theory calculations found that the W sites near the oxygen defect showed higher adsorption energy for DMTS and transferred more electrons during the gas interaction, indicating that the active W site caused by oxygen atom loss can effectively enhance the reactivity of two-dimensional WO₃ nanosheets. Different from the traditional oxygen defect model, this work reveals the positive effect of active metal sites on gas sensing for the first time, which is expected to provide an effective reference for the sensing application of defect engineering in metal oxides.

Self-Assembled Nanocomposites and Nanostructures for Environmental and Energy Applications

Self-assembled nanocomposites are attracting considerable attention owing to their controllable architectures and self-assembly processes, as well as the increase in worldwide environmental effects and energy needs. Further understanding of the self-assembly procedure for improving environmental and energy applications would advance the design and manufacture of nanomaterials for various applications. These materials can be grouped into major categories for various application fields, including powder photocatalysts, membrane photocatalysts, and thin-film thermoelectric nanomaterials. These self-assembled nanomaterials can be used for environmental and energy applications, such as wastewater purification, hydrogen production by water splitting, energy storage, and energy harvesting. In this review, a brief introduction to the definitions and classifications of self-assembled nanocomposites is provided. We aim to provide a summary of the recent research related to self-assembled nanocomposites and nanostructures used for environmental and energy applications. Moreover, typical examples and discussions are aimed at demonstrating the advantages of self-assembled nanostructures. At the end of each section, the structural properties and the application of the nanocomposite or nanostructure are summarized. Finally, we provide perspectives for future research on the design and fabrication of self-assembled nanocomposites and nanostructures.

Oxygen vacancy enriched Cu-WO3 hierarchical structures for the thermal decomposition of ammonium perchlorate

Cu-WO3 hierarchical structures are rapidly prepared and they exhibit excellent catalytic activity in AP decomposition due to their rich oxygen vacancies and Lewis acid sites.

High-Throughput and Controllable Fabrication of Helical Microfibers by Hydrodynamically Focusing Flow

Due to the unique spiral geometry, different functional helical fibers are fabricated to perform vital tasks, including cargo transportation, medical treatment, cell manipulation, and so on. Although microfluidic techniques are widely used to fabricate helical fibers, the problems of channel blockage and spinning instability have not been well solved, which limits the mass preparation and practical application of spiral microfibers. In addition, the spinning mechanism is simply limited to liquid rope coiling, which has little impact on the design of microfluidic devices. Here, new types of microfluidic devices, which were easy to make and exhibited excellent spiral spinning performance, were designed. It was found that adding a sleeve layer outside the inner core needle in a coaxial microfluidic device could effectively promote the stable formation of helical microfibers. This novel microchannel could fabricate helical microfibers of more than 100 m in length continuously at one time with almost no blockage or deformation, and the key parameters of the fibers could be precisely adjusted. Combined with micro-particle image velocimetry (micro-PIV) measurements, it was confirmed that the improvement in the spinning performances was mainly attributed to the emergence of a focusing flow in the presence of the sleeve layer. After loading magnetic nanoparticles, the helical microfibers exhibited excellent motion manipulation capabilities, which showed great potential for drug delivery, cargo transportation, clogging removal, etc. This new design not only realized the high-throughput fabrication of helical microfibers but also provided deeper insights into the underlying mechanisms of spiral generation and new ideas for the design of microfluidic devices.

Preparation of chitosan crosslinked with metal-organic framework (MOF-199)@aminated graphene oxide aerogel for the adsorption of formaldehyde gas and methyl orange

Chitosan crosslinked with metal-organic framework (MOF-199)@aminated graphene oxide aerogel (MOF-199@AFGO/CS) were prepared to adsorb formaldehyde and methyl orange. The prepared MOF-199@AFGO/CS aerogel was well characterized via SEM, EDX, FT-IR, XRD and XPS to reveal the microstructure and composition. Besides, the mechanical property and the stability of MOF-199@AFGO/CS aerogel were investigated. The results showed that MOF-199@AFGO/CS aerogel had good stability in water, compression resilience and thermostability. The study on the ability to adsorb formaldehyde gas and methyl orange showed that the adsorption capacity of MOF-199@AFGO/CS aerogel was related to the pore size and the surface functional groups of MOF-199@AFGO/CS aerogel. When the pore size is moderate, as the amino group and MOF-199 on the aerogel increased, the adsorption capacity of formaldehyde gas (197.89 mg/g) and methyl orange (412 mg/g) can reach the maximum. Furthermore, the adsorption process at equilibrium followed the Freundlich isotherm model. The kinetic behavior was well fitted by the pseudo-second-order model, indicating chemisorption as the rate-determining step. This work can provide a reliable basis for the adsorbent to remove pollutants in different forms at the same time, and has potential application in simultaneously adsorbing liquid pollutants and gas pollutants.

Thioacetamide-induced Ce2O2S nanostructures with tunable morphology for supercapacitors in wide pH range

Here, Rare-earth metal oxysulfide Ce₂O₂S nanostructures with tunable morphology are successfully grown on carbon cloth (CC) for supercapacitors (SCs) via a facile hydrothermal process followed by pyrolysis treatment for the first time. The feeding amount of sulfur source thioacetamide (TAA) plays an important role in the formation of Ce₂O₂S nanostructures with tunable morphology. Adjusting TAA feeding amount from 0.5 to 1.0, 1.5, and 2.0 g, the morphology of the resulted Ce₂O₂S nanostructure can change from pine bark-like agglomerated nanoparticles to fan-shaped nanosheets with edged branches, cuttlefish-like nanostructure with long terminal whiskers and polygon prism with spikes. Among them, Ce₂O₂S/CC-1.0 g TAA nanostructure with largest specific surface area and abundant mesopores exhibits a high specific capacitance of 670, 321.5 or 588.3 mF cm^-2 at 1 mA cm^-2 in an acid, neutral or alkaline electrolyte, respectively. Moreover, Ce₂O₂S/CC-1.0 g TAA electrode delivers excellent cycling stability with high capacitance retention of 93% after 5000 cycles in alkaline electrolyte. Our findings present a new strategy to fabricate rare-earth metal oxysulfide Ce₂O₂S nanostructures with controllable morphology and systematically reveal their electrochemical performance for SCs, moreover, provide new perspectives for boosting the preparation and application of metal oxysulfides in energy storage.

3D Printed Electrochromic Supercapacitors with Ultrahigh Mechanical Strength and Energy Density

With the accelerating update of advanced electronic gadgets, a great deal of attention is being paid today to the function integration and intelligent design of electronic devices. Herein, a novel kind of multitasking 3D oxygen-deficient WO_{3- x}  ∙ 2H₂ O/Ag/ceramic microscaffolds, possessing simultaneous giant energy density, ultrahigh mechanical strength, and reversible electrochromic performance is proposed, and fabricated by a 3D printing technique. The ceramic microscaffolds ensure outstanding mechanical strength and stability, the topology optimized porous lattice structure provides developed surface area for coloration as well as abundant easily accessible channels for rapid ion transportation, and the bifunctional oxygen-defective pseudomaterials enable the large areal capacity and impressive electrochromic performance. As a result, this 3D-printed multitasking microscaffolds simultaneously perform structure-designable, electrochromic, compression resistant, and energy storage functions, behaving with true 3D structure with tailorable curvatures, excellent compressive strength (61.9 MPa), large color variations (>145% in b* value), good aesthetic visual quality as well as exciting electrochemical performances for energy storage including ultrahigh areal capacitance (10.05 F cm^-2 at 5 mA cm^-2 ), record-high energy density (0.60 mWh cm^-2 ), and superior long-term cycling stability (88.6% capacity retention after 10 000 cycles). This work opens up the possibility for high-performance multi-functional coupling structural materials and integrated systems.

Advances in Electrochemical and Catalytic Performance of Nanostructured FeCo2 O4 and Its Composites

It is well established that the excessive and uncontrolled use of fossil fuels and organic chemicals have put a risk to the earth's environment and the life that sustains within it. Carbon-free, sustainable, alternative energy technologies have therefore become the prime focus of current research. Smart inorganic materials have emerged as the potential solution to suffice energy needs and remediate the organic pollutants discharged to the environment. One such promising, versatile material is FeCo₂ O₄ which has gained immense research interest in the present decade due to its high efficiency and performance in energy and environmental applications. Innovative material design strategies involving the interplay of nanostructured morphology, chemical composition, redox surface states, and defect engineering have significantly enhanced both electrochemical and catalytic properties of FeCo₂ O₄ . Therefore, this review article aims to provide the first-ever comprehensive account of the latest research and developments in design-synthesis strategies, characterization techniques, and applications of nanostructured FeCo₂ O₄ and its composites in various electrochemical as well as catalytic applications. A detailed account of the nanostructured FeCo₂ O₄ and its composites in various energy storage and conversion devices such as supercapacitors (SCs), batteries, and fuel cells has been presented. Furthermore, a special section has been devoted to highlight the role of FeCo₂ O₄ in enhancing the sluggish reaction kinetics of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in water splitting application. This review also highlights the role of nanostructured FeCo₂ O₄ in photocatalytic waste water treatment, gas sensing, and dual-phase membrane technologies wherein FeCo₂ O₄ has demonstrated promising performance.

High-performance supercapacitor electrode based on naphthoquinone-appended dopamine neurotransmitter as an efficient energy storage material

NQ-DP based organic material was successfuly synthesized and employed as an efficient pseudocapacitor material.

Designing neurotransmitter dopamine-functionalized naphthalene diimide molecular architectures for high-performance organic supercapacitor electrode materials

Naphthalenediimide-dopamine conjugates were successfully synthesized, and the influence of dopamine, a neurotransmitter, on the supercapacitor properties of a NDI scaffold was explored.