Simple Route Research Articles

Photocatalytic Drug Degradation and Supercapacitor Applications of FeVO4 and rGO‐FeVO4 Nanocomposite

AbstractConstructing novel multifunctional materials is a promising approach to boost the catalytic activity and electrochemical performance simultaneously. Herein, hydrothermal synthesized FeVO4 nanosized particles dispersed on reduced graphene oxide (rGO) through cost‐effective simple sonochemical assisted route are developed as an efficient material for photocatalysis activity and high‐value‐added supercapacitor applications. The synthesized materials were characterized for structural and morphological purity and found to be in single phase and nanostructured. rGO‐FeVO4 composite shows excellent photodegradation of Levofloxacin (LVO) drug (100 % over 80 min) compared with FeVO4 owing to the bandgap in visible region and larger surface area. Further, the optimized rGO‐FeVO4 composite was employed into supercapacitors and it showed 3 times higher capacitance (211.4 F/g at 0.5 A/g) compared with FeVO4 (70.4 F/g) using half‐cell measurements. Moreover, the developed symmetric supercapacitors (full cell; SSCs) using rGO‐FeVO4 composite device showed 109 F/g capacitance at 0.5 A/g current density having high energy density of 13.6 Wh/kg at the power density of 450 W/kg. The proposed rGO‐FeVO4 composite proved its multifunctional outcomes, which can open new opportunities to develop such materials for numerous future applications.

Simple and Scalable Synthetic Route for Tunable Compositions of Multimetallic Oxyfluorides as Oxygen Evolution Reaction Catalysts

Simple and Scalable Synthetic Route for Tunable Compositions of Multimetallic Oxyfluorides as Oxygen Evolution Reaction Catalysts

In-situ preparation of titanic-based superhydrophilic self-cleaning glaze via a simple one-time firing route

In-situ preparation of titanic-based superhydrophilic self-cleaning glaze via a simple one-time firing route

Self-powered poly(3-hexylthiophene)/ZnO heterojunction ultraviolet photodetectors decorated by silver nanoparticles

Self-powered poly (3-hexylthiophene)/zinc oxide (P3HT/ZnO) heterojunction ultraviolet photodetectors decorated by silver nanoparticles (Ag NPs) were fabricated by sol-gel and spin-coating techniques. The ultraviolet photoresponse performance of the P3HT/ZnO heterojunction photodetectors influenced by the position of plasmonic Ag NPs was investigated. The responsivity and detectivity of the P3HT/Ag/ZnO photodetector with placed Ag NPs at the interface of ZnO and P3HT layers enhanced to 1.92 and 1.15 times compared to the reference devices. When the Ag NPs embedded into ZnO layer, the responsivity, detectivity and external quantum efficiency were 16.42 mA/W, 5.97 × 1011 Jones, and 5.36 %, respectively, which were 5.77 times, 4.64 times and 5.77 times to that of the pristine P3HT/ZnO photodetector. The enhancement mechanism of plasmonic metallic nanoparticles to the performance of the photodetectors was discussed in details. This study presents a simple route to high performance self-powered photodetectors.

Greatly Enhanced Thermoelectric Performance of Flexible Cu2-xS Composite Film on Nylon by Se Doping.

In this work, flexible Cu2-xS films on nylon membranes are prepared by combining a simple hydrothermal synthesis and vacuum filtration followed by hot pressing. The films consist of Cu2S and Cu1.96S two phases with grain sizes from nano to submicron. Doping Se on the S site not only increases the Cu1.96S content in the Cu2-xS to increase carrier concentration but also modifies electronic structure, thereby greatly improves the electrical properties of the Cu2-xS. Specifically, an optimal composite film with a nominal composition of Cu2-xS0.98Se0.02 exhibits a high power factor of ~150.1 μW m-1 K-2 at 300 K, which increases by ~138% compared to that of the pristine Cu2-xS film. Meanwhile, the composite film shows outstanding flexibility (~97.2% of the original electrical conductivity is maintained after 1500 bending cycles with a bending radius of 4 mm). A four-leg flexible thermoelectric (TE) generator assembled with the optimal film generates a maximum power of 329.6 nW (corresponding power density of 1.70 W m-2) at a temperature difference of 31.1 K. This work provides a simple route to the preparation of high TE performance Cu2-xS-based films.

A Systematic Study of Nonionic Di- and Multiborane Catalysts for the Oligomerization and Polymerization of Epoxides.

Borane catalysis has emerged as a powerful technology in epoxide polymerization. Still, the structure-activity correlations for these catalysts are not fully understood to date, especially regarding compounds with nonionic backbones. Thus, in this work, 13 different borane catalysts of this respective type are described and investigated for their epoxide oligomerization and polymerization performance, using propylene oxide (PO), 1-butylene oxide (BO) and allyl glycidyl ether (AGE) as monomers. Structurally, special emphasis is put on catalysts with different linker lengths and linker flexibilities as well as the introduction of more than two borane functionalities. Importantly, this screening is conducted both under typical polymerization conditions as well as under the chain transfer agent (CTA)-rich conditions relevant for large-scale production. It is found that suitable preorganization of the borane groups, such as present in biphenyl derivatives, offers a simple route to high-performing catalysts and quantitative monomer conversion of the investigated epoxides. Furthermore, it is demonstrated that a diborane-catalyzed oligomerization can be kept active over weeks, whereby repeated addition of monomer batches (14 steps) constantly results in full conversion and well-defined oligoethers, underlining the practical potential of this method. The absence of co-initiating counter ions is suggested as an inherent advantage of nonionic catalysts.

Covalent organic framework membranes reconstructed pore channels through metal-phenolic complexation for dye/salt separation

Covalent organic frameworks (COFs) characterized by high porosity, ordered channels, and remarkable chemical stability are potential candidates for the fabrication of nanofiltration separation membranes. In general, COFs membranes, generated through the process of interfacial polymerization, exhibit superior permeance without comparatively poor selectivity toward small molecules. Hereby, it was addressed with a simplified route to construct an extra selective layer on the COFs membranes. Concretely, COFs (TpPa/HPAN) membranes were first fabricated via interfacial polymerization on the hydrolyzed polyacrylonitrile (HPAN) membranes by utilizing monomers of 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa). Then, a selective layer of metal-phenolic complex was constructed on the TpPa/HPAN membranes by electrostatic adsorption and metal-phenolic complexation. The introduction of a metal-phenolic complex selective layer masked the intrinsic pore size of TpPa and enhanced the hydrophilicity and electronegativity of the membrane, which improved the rejection property of the membranes for dyes larger than 350 Da. The fabricated M-TpPa/HPAN membranes showed exceptional performance in dye desalination with a water permeance of 92.1 L‧m−2‧h−1‧bar−1, rejections of Congo red and Eriochrome black T (EBT) over 99 %, 78.6 % of acid fuchsin rejection, 85.3 % of acid orange 7 rejection, low rejection of salts (e.g., 6.2 % for NaCl rejection), and the NaCl/EBT separation factor up to 243. Additionally, the M-TpPa/HPAN membranes maintained excellent stability during long-term filtration. The strategy of building an extra selection layer with eco-friendly, cost-effective, and scaled-up methods is also extensible for the other COFs and framework-based membranes.

Femtosecond Laser Carburization of WS2 Flakes to W2C for Enhanced Photothermal Conversion Efficiency

Photothermal therapy is a new, promising approach for treating cancer in a noninvasive way. Herein, a photothermally efficient nanomaterial is synthesized by exposing bulk WS2 powder, dispersed in carbon‐rich acetonitrile, to high‐intensity femtosecond laser pulses. The photothermal measurements show a significantly higher rise in temperature and enhance photothermal efficiency for the laser‐treated material. The attribution is on the enhancement to the formation of tungsten semi‐carbide (W2C), which is verified by morphological and structural characterization. The tungsten semi‐carbide is formed by laser‐induced carburization; intense laser pulses knock S atoms out of the WS2 lattice and dissociate the acetonitrile molecules, resulting in the formation of W2C. Interestingly, the hexagonal W2C has a two‐dimensional (2D) layered morphology like that of the WS2, suggesting its morphology is not random and might be determined by the morphology of the parent material. The study provides a simple route to transform a 2D transition‐metal dichalcogenide into a 2D transition‐metal carbide, which is useful for applications including photothermal therapy.

Self-healing property of a gel-elastomer two-phase composite material

While self-healing silicones are required for many practical applications, conventional methods of incorporating self-healability in silicones involve generation of bond-forming moieties within the backbone of the oligomer itself. Such processes involve multiple synthesis steps that turn the silicone expensive and less amenable for scale-up. In contrast, hydrogels can be made self-healing by different simple yet robust chemical routes. Hydrogels however lack mechanical strength, necessary for most engineering applications. To meet the above need, we have introduced here a novel two-phase material, consisting of self-healing hydrogel droplets embedded as microscopic healers inside the continuous matrix of silicone. The hydrogel phase, consisting of starch and polyvinyl alcohol (PVA) as the oligomers and multivariate borate ion as the crosslinker is dispersed in silicone oligomer mixed with the curing agent and both phases are allowed to crosslink. Controlled fracture tests on the resultant crosslinked material show that two cut surfaces of it get joined instantaneously with the tensile failure stress reaching as high as 35 kPa; this material remains healable also over ten cycles of incision and reattachment. The hydrogel can act also as an external glue to heal two incised surfaces of the two-phase composite to achieve durable fracture strength and thereby help forming different polygonal structures with angled joints. We have demonstrated also bio-compatibility of the two-phase material thereby opening up its possible use in large variety of biomedical applications.

Facile synthesis of hierarchical W18O49 microspheres by solvothermal method and their optical absorption properties

In this study, a simple route for the synthesis of hierarchical W18O49 assembled by nanowires is reported. The morphologies and formation of W18O49 single-crystal could be controlled by changing the concentration of WCl6-ethanol solution. This synthesis strategy has the advantages that the hierarchical W18O49 microspheres could be economic synthesized at 180 °C without adding additives. Furthermore, efficient optical absorption properties in ultraviolet, visible and near-infrared region were obtained for the hierarchical W18O49 microspheres comparing with nanowires. These results will further promote the research of tungsten-based oxide nanomaterials.Graphical abstract

Xyloglucan-Cellulose Nanocrystals Mixtures: A Case Study of Nanocolloidal Hydrogels and Levers for Tuning Functional Properties.

The development of fully biobased hydrogels obtained by simple routes and in the absence of toxic or environmentally harmful reagents is a major challenge in meeting new societal demands. In this work, we discuss the development of hydrogels made from cellulose nanocrystals (CNCs) and xyloglucan (XG), two non-toxic, renewable, and biobased components. We present three strategies to fine-tune the functional properties. The first one consists in varying the XG/CNC ratio that leads to the modulation of the mechanical properties of hydrogels as well as a better comprehension of the gel mechanism formation. The second relies on tuning the XG chains' interaction by enzymatic modification to achieve thermoresponsive systems. Finally, the third one is based on the increase in the hydrogel solid content by osmotic concentration. The high-solid-content gels were found to have very high mechanical properties and self-healing properties that can be used for molding materials. Overall, these approaches are a case study of potential modifications and properties offered by biobased nanocolloidal hydrogels.

Reconstructing and tracing the evolution of the road networks in the Haidai region of China during the Bronze and Early Iron Ages

Reconstructing ancient transportation networks is critical to studying past human mobility patterns. China’s Haidai region was a thriving political and economic hub during the Bronze and Early Iron Ages. We used GIS spatial analysis techniques to build a “Settlement Interaction Model” based on archaeological data from the Haidai region during the Bronze and Early Iron Age (Shang Dynasty, Western Zhou Dynasty, Spring & Autumn Period, and Warring States period). The eight-level road network maps with traffic attributes were distinguished based on topography and settlement size. The total lengths of the road networks were estimated to be 19,112 km in the Shang Dynasty, 35,269 km in the Western Zhou Dynasty, 51,555 km in the Spring & Autumn Period, and 77,456 km in the Warring States Period, with the average road flows of 6.6, 31.7, 42.8, and 75.5, respectively. The Z score and one-sample t-test (p < 0.01) confirmed the reliability of the reconstructed road networks. The Shang Dynasty saw the sporadic appearance of simple road routes. More complex routes emerged during the Western Zhou Dynasty and Spring & Autumn Period. The road networks were finally built during the Warring States Period. The development of road networks was closely related to population growth and urbanization. Exploring methods for reconstructing road networks may help us uncover ancient road networks and better understand ancient cultural exchanges.

Synthesis of NaYbF4:Er nanocrystals with controllable size, morphology, and multicolor upconversion luminescence for Anticounterfeiting applications

The dopant concentration of lanthanide ions plays one of the critical roles to manipulate size/morphology, photon population pathway, or luminescence color/intensity in upconversion nanoparticles (UCNCs), which have a significant effect on their application developments. Herein, a strategy is demonstrated for simultaneous size, morphology and multicolor luminescence tuning in the single doped lanthanide activator Er3+ ion system through simply tuning the concentration of Er3+ ions. The doping of different Er3+ ion amounts in NaYbF4:Er nanocrystals can control nanoparticle size (from several hundreds to tens of nanometers) and morphology. Moreover, multicolor upconversion luminescence involving green, yellow, orange and red can be obtained in the NaYbF4:Er UCNCs by changing the excitation power density of 980 nm laser. Mechanistic studies reveal the size and morphology evolution process as well as saturation/cross relaxation effects induced tunable multicolor emissions. These nanocrystals have demonstrated promising potential applications in anticounterfeiting. Our results not only provide a simple and feasible route for simultaneous size/morphology control and multicolor upconversion luminescence tuning, but also can further expand the utility of UCNCs in the frontier applications ranging from optical encoding to information security.

Insights into the electrochemical oxidation selectivity of hydroxymethylfurfural over humin-layered Au nanoparticles

Au nanoparticle catalysts are promising electrocatalysts for biomass upgrading. Starting from a pristine Au electrode, herein we demonstrate a simple route for the electrochemical preparation of Au NPs supported on thin layers of humin (Au/H). Utilizing an oxidized Au surface as a precursor, these electrocatalytic structures are formed upon reduction of 5-hydroxymethylfurfural (HMF) in alkaline media while performing a potential sweep. We subsequently utilize this Au/H structure for the electrochemical oxidation of ethanol and HMF in a rotating disk electrode (RDE) configuration and perform additional analysis via electrochemical surface-enhanced Raman Scattering (SERS). The RDE test reveals Au/H has different reaction kinetics towards alcohol and aldehyde functional groups, enabling a mechanistic understanding of the reaction pathway for HMF oxidation. The SERS experiment identifies the favorable reduction pathway from Au2O3 to gold, suggesting the possible active site on this catalyst for HMF oxidation.

Superior mechanical properties and multiple strengthening mechanisms of a V-alloyed FeMnCoCr high-entropy alloy

The FeMnCoCr-based high-entropy alloys (HEAs) have attracted much attention owing to their great potential to be used as engineering materials. Yet, due to the dominant face-centered cubic (FCC) structure, yield strength of those alloys is usually low, which limits their practical applications. In this study, we propose a method of obtaining the superior strength and ductility combination of the FeMnCoCr HEAs via V alloying combined with a simple processing route including cold rolling and partial recrystallization annealing. Yield strength of the partially recrystallized Fe50Mn25Co10Cr10V5 material reaches 900 MPa, which is 80 % higher than that of the Fe50Mn30Co10Cr10 alloy fabricated by the same processing route. Meanwhile, a uniform elongation of 17.7 % is maintained. These are attributed to the introduction of the second phase with the body-centered cubic (BCC) structure via V addition together with the improved strengthening by grain boundaries, dislocations and solid solution, while the transformation induced plasticity (TRIP) effect is still maintained during deformation. Additionally, the partial recrystallization annealing process also inhibits nucleation and growth of the hard and brittle σ phase in the Fe50Mn25Co10Cr10V5 alloy, making the uniform elongation reach more than three times that of the fully recrystallized material, while the yield strength is only 51 MPa lower than that of the latter. This study provides new insights for the design and development of advanced metallic materials with high performances.

Direct Z-scheme charge transfer Bi2O3/UiO-66-NH2 heterojunctions for boosted photocatalytic degradation of tetracycline hydrochloride in different water systems

The development of hybrid heterostructure photocatalysts with enhanced visible light absorption capacity holds significant importance in environmental remediation. However, the challenge persists in exploiting strong visible-light responsive photocatalysts with both high efficiency and stability. Herein, we successfully synthesized a hybrid Z-scheme heterojunction of Bi2O3 and UiO-66-NH2 (Bi2O3/UiO-66-NH2) through a simple hydrothermal route. The visible light photocatalytic performance of Z-scheme Bi2O3/UiO-66-NH2 heterojunction is systematically evaluated for persistent antibiotic tetracycline hydrochloride (TC-HCl) both in the clean and real water matrix. All heterojunction catalysts exhibit superior photodegradation capabilities compared to pristine Bi2O3 and UiO-66-NH2. The optimal ratio of the two components heterojunction (BUN-150), in particular, demonstrates the highest removal efficiencies for TC-HCl (95 %) within a 90-min timeframe. This remarkable photocatalytic performance is credited to the Z-scheme charge transfer occurring at the interface of Bi2O3 and UiO-66-NH2 in Bi2O3/UiO-66-NH2 heterojunction. The active species experiments and electron paramagnetic resonance analyses are conducted to identify the active reactive species during the TC-HCl degradation (·OH, h+, and ·O2−), and a precise photocatalytic degradation mechanism is explained. Additionally, the photodegradation intermediates of TC-HCl are detected using the HPLC-MS analysis to explain the degradation pathways of TC-HCl. This research paves the way for the development of novel Z-scheme Bi2O3-based heterojunction catalysts for outstanding photocatalytic applications.

MIL-101(Fe)-derivatized cathode as an efficient oxygen electrocatalyst for rechargeable Zn-air battery

The exploration of multifunctional electrocatalysts with cost-effective and high kinetic activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is crucial for the development of advanced energy conversion and storage equipment. Herein, a novel hierarchical mesoporous/macropores MIL-101(Fe) derivative carbon catalyst material was prepared by a simple molten ZnCl2-assisted synthesis route. Specifically, 1H-benzotriazole (BTA) organic ligands were intentionally introduced as nitrogen sources in order to induce the formation of charge-rich regions through an electronegative nitrogen doping control strategy, and most importantly, the lone pair electron-rich nature of element N could facilitate the separation and anchoring of iron species enchanted the utilization rate of active sites. Because of these properties, the as-prepared catalyst (denoted as FeSACs/NxC) possesses unrivalled bifunction electrocatalytic activity and durability for the ORR and OER. The FeSACs/N1.25C as working electrode exhibits a quite satisfactory electrochemical performance for the ORR (half-wave potential of 0.82 V) and OER (a small overpotential of 302 mV at 10 mA cm−2) in the classic three-electrode configuration. Moreover, the FeSACs/N1.25C-based air cathode imparts encouraging performance in a rechargeable Zn–air battery prototype with an open-circuit voltage of 1.45 V, a specific capacity of 792.16 mAh g−1, an energy density of 871.38 Wh kg−1, and excellent stability for 120 h. This work has opened the way for the development of low-cost, fast kinetic and stable non-noble metal multifunctional catalysts.

Tailor-Made α-Glucans by Engineering the Processivity of α-Glucanotransferases via Tunnel-Cleft Active Center Interconversions.

The function of polysaccharides is intimately associated with their size, which is largely determined by the processivity of transferases responsible for their synthesis. A tunnel active center architecture has been recognized as a key factor that governs processivity of several glycoside hydrolases (GHs), e.g., cellulases and chitinases. Similar tunnel architecture is also observed in the Limosilactobacillus reuteri 121 GtfB (Lr121 GtfB) α-glucanotransferase from the GH70 family. The molecular element underpinning processivity of these transglucosylases remains underexplored. Here, we report the synthesis of the smallest (α1 → 4)-α-glucan interspersed with linear and branched (α1 → 6) linkages by a novel 4,6-α-glucanotransferase from L. reuteri N1 (LrN1 GtfB) with an open-clefted active center instead of the tunnel structure. Notably, the loop swapping engineering of LrN1 GtfB and Lr121 GtfB based on their crystal structures clarified the impact of the loop-mediated tunnel/cleft structure at the donor subsites -2 to -3 on processivity of these α-glucanotransferases, enabling the tailoring of both product sizes and substrate preferences. This study provides unprecedented insights into the processivity determinants and evolutionary diversification of GH70 α-glucanotransferases and offers a simple route for engineering starch-converting α-glucanotransferases to generate diverse α-glucans for different biotechnological applications.

Morphology engineering and electronic structure remodeling of manganese-incorporated VN for boosting urea-assisted energy-saving hydrogen production

Urea-assisted water electrolysis offers a promising route to reduce energy consumption for hydrogen production and meanwhile treat urea-rich wastewater. Herein, we devised a shear force-involved polyoxometalate-organic supramolecular self-assembly strategy to fabricate 3D hierarchical porous nanoribbon assembly Mn-VN cardoons. A bimetallic polyoxovanadate (POV) with the inherent structural feature of Mn surrounded by [VO6] octahedrons was introduced to trigger precise Mn incorporation in VN lattice, thereby achieving simultaneous morphology engineering and electronic structure modulation. The lattice contraction of VN caused by Mn incorporation drives electron redistribution. The unique hierarchical architecture with modulated electronic structure that provides more exposed active sites, facilitates mass and charge transfer, and optimizes the associated adsorption behavior. Mn-VN exhibits excellent activity with low overpotentials of 86 mV and 1.346 V at 10 mA/cm2 for hydrogen evolution reaction (HER) and urea oxidation reaction (UOR), respectively. Accordingly, in the two-electrode urea-assisted water electrolyzer utilizing Mn-VN as a bifunctional catalyst, hydrogen production can occur at low voltage (1.456 V@10 mA/cm2), which has the advantages of energy saving and competitive durability over traditional water electrolysis. This work provides a simple and mild route to construct nanostructures and modulate electronic structure for designing high-efficiency electrocatalysts.

Ultrathin antioxidant intercalated layered double hydroxides for polypropylene composites: Fabrication and anti-aging performance related to thickness

A series of different layers ultrathin antioxidant intercalated layered double hydroxides (nL-LDHs, n = 1 to 10) were fabricated in a simple separate nucleation and aging steps route, and the anti-aging performance of nL-LDH/polypropylene (PP) composites was carefully investigated. With the increase of Mg2+concentration from 0.01 mol/L to 0.3 mol/L, the corresponding thickness of nL-LDHs was varied from 2.58 nm to 26.7 nm related to the layer number from n = 1 to n = 10, and the radical-scavenging activity of nL-LDHs was reduced from 51.5 % to 30.2 %. The ultrathin nL-LDHs antioxidants were well dispersed in PP to produce nL-LDH/PP composites with a mass loading of 0.4 wt% via a solvent mixing method. The nL-LDHs antioxidants as a multifunctional agent influence crystallization behavior of PP, and enhance anti-aging performance of nL-LDHs/PP composites. 3L-LDH exhibited the best anti-aging performance and appreciate anti-migration resistance for nL-LDHs/PP composites, which is better than commercial Irganox 1010.