One-pot Self-assembly Method Research Articles

Ce-doped NiCo-layered double hydroxide based self-supporting tremella-shaped nanoflower heterostructure as efficient electrocatalyst for the oxygen evolution reaction

NiCo-layered double hydroxide (NiCo-LDH) catalysts, which indicate a profound prospect of oxygen evolution reaction (OER) under alkaline conditions, are facing great challenges in terms of low electrical conductivity, restricted by poor conductivity, limited electrochemical reaction sites, and low-density of edge sites. The authors developed a simple and convenient in-situ one-pot self-assembly method. The Ce-doped defective NiCo-LDH hexagonal nanosheets and nitrogen-doped graphene fabricated the NiCoCe-LDH/RNF electrocatalyst on the nickel foam (NF) substrate, which demonstrated excellent OER activity under alkaline conditions, only needed 299 mV overvoltage to achieve 50 mA cm−2 current intensity, could last for 6 hours at 20 mA cm−2. The highly active OER benefited from the structural advantages of the novelty three-dimensional array structure. The novel geometric structure of tremella-shaped nanoflower integrated with curved nanosheets and curled edges loaded on NF provides more electrochemical reaction sites for intermediate coordination. The nitrogen-doped reduced graphene oxide accommodated better interaction between active materials and charge carriers, enhancing the conductivity and electron transfer performance of nanostructures. The effective synergistic between the heterostructures promoted the excellent OER electrocatalytic activity of NiFeCe-LDH/RNF nanocomposites. DFT calculations at the atomic level of pristine and Ce-doped NiCo-LDH exhibited that Ce-doping can reduce the Gibbs free energy of the potential-determining step and improve the catalytic activity of OER. This work has broadened the horizons for developing simple and highly available OER electrocatalysts.

The effect of solvent type and composition on the synthesis of boron-doped ordered mesoporous carbons

Boron-doped ordered mesoporous carbons (B-OMCs) were synthesized using different solvent types and compositions to study the effect of the solvent medium on the physical properties and oxygen reduction activities of the resultant structures. Materials were synthesized by a one-pot self-assembly method, using resorcinol and formaldehyde as carbon source, boric acid as boron source and triblock copolymer Pluronic F127 as the structure directing agent. Different solvents, namely ethanol, n-propanol, isopropanol and acetone were used as solvent media along with water as the cosolvent. Among different solvents, ethanol and n-propanol gave better-ordered structures and also had higher surface areas. At this stage, the highest boron doping percentage was obtained as 1.38 % with n-propanol. In the second stage, B-OMCs were synthesized with n-propanol in different water/n-propanol (W/N) molar ratios varying between 2.5 and 4.75. The orderliness was observed to be better in samples with low W/N ratios of 2.5 and 3.25 and the morphologies shifted from 2D to 3D interconnected type with the increase of water content. The average pore sizes of samples varied between 7.9 and 9.7 nm. On the other hand, the highest surface area (729 m2/g) and the highest boron doping percentage (1.53 %) were obtained with the W/N ratio of 4. XPS analysis showed that 23 % (w/w) of doped boron in this sample was in substitutional state while the remaining boron was found in mixed B–C and B–O states. Cyclic voltammetry measurements for the samples with W/N ratios of 2.5, 3.25 and 4 showed significant oxygen reduction activities at −0.28 and −0.29 V. Results showed that the properties of solvent play an effective role in the orderliness, pore structure and surface composition of B-OMCs, which in turn affect their electrochemical properties. Among different types of solvents, n-propanol can be used as an alternative to ethanol with the W/N ratio of 4 giving the highest surface area and boron doping percentage.

Constructing multifunctional polyvinyl alcohol composite hydrogels with human-like skin properties using polyaniline-coated boron nitride nanofibers

Flexible conductive nanofibers play a crucial role in constructing hydrogels with human-like skin properties. However, it is still a challenge to construct flexible conductive nanofibers with good comprehensive properties. In this paper, we prepare composite fibers with excellent comprehensive properties by coating polyaniline (PANI) on the surface of flexible boron nitride nanofiber (BNNFs) template. BNNFs-PANI/PVA multifunctional composite hydrogels are created through the integration of BNNFs-PANI as nanofillers with soft poly (vinyl alcohol) (PVA) matrix using a one-pot self-assembly method. The composite hydrogels exhibit outstanding plasticity, self-adhesion, and self-healing properties, with a self-healing efficiency reaching up to 96% within 120 s. Furthermore, the tensile strength of the composite hydrogels has been enhanced by 36%, with the elongation at break exceeding 1500%. The compressive strength of the composite hydrogels at 60% strain is increased by 62%. Beyond these mechanical and self-healing features similar to human skin, the composite hydrogels also can serve as electronic pen for painting on a touchable electronic screen, simulating the function of human skin. Moreover, the dynamic changes in the abundant conductive network contribute to the composite hydrogels’ high strain sensitivity. Compared with pure PVA hydrogels, it is improved by 29%. Notably, the strain sensitivity of the composite hydrogels is higher than that of most reported hydrogel sensors. Therefore, the composite hydrogels also can be employed as a real-time human motion sensor, capable of detecting and distinguishing various human movements. We believe that employing BNNFs as templates for crafting highly flexible and conductive nanofibers will foster the advancement of flexible conductive nanomaterials with comprehensive properties. Furthermore, the outstanding properties of the prepared composite hydrogels contribute to the ongoing development of conductive hydrogels with skin-like functionalities.

Pickering emulsion stabilized by quercetin-β-cyclodextrin-diglyceride particles: Effect of diglyceride content on interfacial behavior and emulsifying property of complex particles

This research develops diacylglycerol (DAG) based Pickering emulsions with enhanced oxidative stability stabilized by self-assembled quercetin/DAG/β-cyclodextrin (β-CD) complexes (QDCCs) using a one-step agitation method. Influence of DAG content (5%, 15%, 40%, and 80%, w/w) on the self-assembly behavior, interfacial properties, and emulsifying ability of complex particles was investigated. SEM, XRD and ATR-FTIR studies confirmed the formation of ternary composite particles. QDCCs in 80% DAG oil had the highest quercetin encapsulation efficiency (6.09 ± 0.01%), highest DPPH radical scavenging rate and ferric reducing antioxidant property (FRAP). β-CD and quercetin adsorption rates in emulsion with 80% DAG oil were 88.4 ± 2.53% and 98.34 ± 0.15%, respectively. Pickering emulsions with 80% DAG had the smallest droplet size (8.90 ± 1.87 μm) and excellent oxidation stability. This research develops a novel approach to regulate the physicochemical stability of DAG-based emulsions by anchoring natural antioxidants at the oil-water interface through a one-pot self-assembly method.

One-pot preparation of structurally tunable mesoporous hollow carbon spheres and their application for lithium‑sulfur battery with high sulfur content

Hollow carbon nanomaterials as sulfur hosts have been investigated extensively for lithium‑sulfur (LiS) battery. Herein, we report the preparation of structurally tunable mesoporous hollow carbon spheres (MHCs) by a simple one-pot self-assembly method. The structural parameters (specific surface area, pore capacity, pore size, and cavity) of the MHCs were adjusted by varying the concentration of the reactants. Three representative MHCs were characterized in detail, and the reasons for their formation were explained. Among them, the optimized MHC features a high specific surface area (1547.9 m2 g−1), large pore capacity (2.04 cm3 g−1), moderate pore size (∼ 6 nm), and internal cavity (r2/r1 = 0.62), which can meet the requirements of high sulfur loading, good carbon/sulfur contact, sufficient buffer space, and fast electron/ion transport channels. Consequently, the optimized MHC@S cathode exhibited improved electrochemical properties (maintaining a capacity of 484.7 mAh g−1 after 500 cycles at 0.5C with a decay rate of 0.068 %) under the condition of high sulfur content of 90.02 wt% and the electrolyte/sulfur ratio of 10 μL mg−1. Moreover, the raw materials are cost-effective, and the process is simple to operate without requiring expensive equipment. This study provides a promising candidate for carbon-based materials as sulfur hosts in practical LiS battery.

Hollow self-assembled hybrid framework based on phytic acid for U(VI) capture from highly acidic aqueous media

Efficient removing uranium (U(VI)) from highly acidic environment remain a great challenge for the adsorbent. Herein, a novel hollow phytic acid-based hybrid material (P(Cr)E-7) was synthesized by a mild facile one-pot self-assembly method without template choosing Cr3+, phytic acid (PA) and ethylenediamine (EDA) as the inorganic and two organic building blocks. P(Cr)E-7 was employed for U(VI) capture in highly acidic wastewater. Thanks to the flexible segment assembled from EDA and PA, and the strong affinity of PA to U(VI), the maximum adsorption capacity of P(Cr)E-7 for U(VI) reached 282.8 mg/g under the condition of pH = 1.0 in static adsorption experiment. Simultaneously, P(Cr)E-7 showed the selectivity efficiency of almost 100 % for An-Ln and pH-dependent selectivity efficiency of 60 % for U(VI) in multi-ions solution with pH = 1.0. Moreover, P(Cr)E-7 showed excellent stability in 0.1 M HNO3 and reusability after three cycles at pH = 1.0 benefiting from stable segment from coordination of Cr(III) and PA. Additionally, the SEM, XRD, FTIR, and XPS analysis revealed the adsorption mechanism that U(VI) exchanges with positively charged EDA+/EDA2+in P(Cr)E-7 to obtain preferred coordination geometry and ligand environment and further coordinates with P-OH/P = O in PA. This study addresses the practical application of effective adsorption of uranium in highly acidic nuclear industrial wastewater and illustrated a novel material design strategy of adsorbents for uranium extraction.

Highly effective self-assembled porphyrin MOCs nanomaterials for enhanced photodynamic therapy in tumor

Porphyrins and their derivatives are excellent photosensitizers in photodynamic therapy (PDT). The modification of porphyrin molecules into metal-organic cages (MOCs) is a viable strategy to improve their bioavailability. In this work, MOC C66 based on porphyrin was synthesised by a one-pot self-assembly method. The three-dimensional structure of the metal-organic cage ameliorated the aggregation and self-quenching of porphyrins and increased the molar absorption coefficient in the visible light region, which enhanced the reactive oxygen species (ROS) yield of porphyrins and effectively improved the efficiency of photodynamic therapy. ROS generation ability tests in solution confirmed the improved reactive oxygen capacity of the cage, which showed greater phototoxicity to HeLa and MCF-7 cells in vitro, suggesting a new strategy for future modifications of the simple synthesis of porphyrins as photosensitizers.

A self-assembled metal-polyphenolic nanomedicine for mild photothermal-potentiated chemodynamic therapy of tumors

Engineering nanotherapeutics with simple ingredients but multiple functions at large-scale via easy methods is still a formidable challenge for cancer treatment. Herein, a novel multifunctional nanotherapeutic agent (named as FeEP-NP) was fabricated by a one-pot self-assembly method based on the coordination between FeII and (-)-epigallocatechin gallate (EGCG) with poly(vinylpyrrolidone) serving as a stabilizer. The designed FeEP-NPs could produce the toxic hydroxyl radical (•OH) effectively via Fenton reaction for chemodynamic therapy (CDT). Intriguingly, the unique binding between EGCG and FeII ions endows nanoparticles with strong absorption and photothermal conversion capabilities in the near-infrared (NIR) region, which could achieve mild hyperthermia-enhanced CDT under NIR laser irradiation. More impressively, the partially released EGCG could accelerate the FeIII/FeII conversion to augment the generation of •OH to further promote CDT, and simultaneously down regulate the intracellular expression of heat shock protein 90 (HSP 90) to enhance mild photothermal therapy (PTT). Both in vitro and in vivo results demonstrate that the low-temperature PTT-potentiated CDT based on FeEP-NPs could suppress tumors more efficiently. Overall, this work presents a novel multifunctional nanoplatform with succinct design, highlighting significant prospects for future clinical application.

Twisted Intramolecular Charge Transfer—Aggregation-Induced Emission Fluorogen with Polymer Encapsulation-Enhanced Near-Infrared Emission for Bioimaging

Fluorescence probes with strong near-infrared (NIR) emission and water solubility are considered useful visualization tools for localization marking as well as investigating cell migration and tran...

One-pot self-assembly preparation of thiol-functionalized poly(3,4-ethylenedioxythiophene) hollow nanosphere/Au composites, and their electrocatalytic properties.

In this work, we developed a thiol-functionalized poly(3,4-ethylenedioxythiophene) hollow sphere (poly(EDOT-MeSH)/Au) polymer through a simple one-pot self-assembly method using polyvinylpyrrolidone (PVP) as a soft template. The monomer was used as both a reductant and a stabilizer to decorate gold nanoparticles (Au NPs). FTIR, XRD, EDX, SEM and TEM analyses were used to characterize the composite hollow spheres. The chemical bond between S and Au was confirmed by XPS. The electrochemical performance of the composite hollow spheres was determined by cyclic voltammetry (CV) and an ampere response timing current test. The results revealed that the poly(EDOT-MeSH)/Au hollow-sphere-based electrochemical sensor possesses excellent conductivity and high redox reversibility with detection limits (S/N = 3) of 0.2, 0.02, 0.08 and 0.05 μM in the linear ranges of 0.1–650 μM, 0.05–100 μM and 0.1–600 μM for the determination of ascorbic acid (AA), dopamine (DA), uric acid (UA) and nitrate ions (NO2−), respectively. The preparation method for these composites will further the development of this type of conducting polymer/gold nano-composite material modified electrochemical sensor for biological species.

Degradable metal-organic framework/methylene blue composites-based homogeneous electrochemical strategy for pesticide assay

Precise screening of organophosphate (OP) and carbamate pesticides is of significant importance for safeguarding the environment and food resources. Herein, a facile immobilization-free homogeneous electrochemical sensing strategy was developed for sensitively detecting pesticides by using acetylcholinesterase (AChE) as a recognition component and zeolitic imidazolate framework-8 (ZIF-8) as a degradable carrier for encapsulating methylene blue (MB, an electroactive molecule). The pH-responsive ZIF-8/MB composites were synthesized by a simple one-pot self-assembly method and then directly used for pesticide detection. The sensing strategy is based on the dissolution of ZIF-8/MB composite in acidic condition induced by the AChE-catalyzed hydrolytic reaction, which then resulted in the release of numerous MB molecules for generating strong diffusion current. Therefore, OPs and carbamates, as AChE inhibitors, would be monitored by the decrease of the electrochemical signals. Benefitting from the large number of MB molecules entrapped in ZIF-8/MB nanoparticles, this sensing platform achieved high analytical performance for the detection of paraoxon with a detection limit of 1.7 ng/mL. Moreover, this strategy was versatile for other OP and carbamate pesticides and worked well in real samples, indicating that the proposed strategy offered an alternative approach for the sensitive assessment of pesticides in the food and environmental fields.

Oxygen Evolution Electrocatalysts: Self‐Assembled Ruddlesden–Popper/Perovskite Hybrid with Lattice‐Oxygen Activation as a Superior Oxygen Evolution Electrocatalyst (Small 20/2020)

In article number 2001204, Yinlong Zhu, Huanting Wang, and co-workers report a novel hybrid RP/P-LSCF consisting of a dominated Ruddlesden–Popper phase LaSr3Co1.5Fe1.5O10–δ (RP-LSCF) and second perovskite phase La0.25Sr0.75Co0.5Fe0.5O3–δ (P-LSCF), which is prepared by a facile one-pot self-assembly method, exhibiting exceptional oxygen evolution reaction activity due to surface lattice-oxygen activation triggered by strong metal oxygen-covalency and high oxygen-ion diffusion rate.

Self-Assembled Ruddlesden-Popper/Perovskite Hybrid with Lattice-Oxygen Activation as a Superior Oxygen Evolution Electrocatalyst.

The oxygen evolution reaction (OER) is pivotal in multiple gas-involved energy conversion technologies, such as water splitting, rechargeable metal-air batteries, and CO2 /N2 electrolysis. Emerging anion-redox chemistry provides exciting opportunities for boosting catalytic activity, and thus mastering lattice-oxygen activation of metal oxides and identifying the origins are crucial for the development of advanced catalysts. Here, a strategy to activate surface lattice-oxygen sites for OER catalysis via constructing a Ruddlesden-Popper/perovskite hybrid, which is prepared by a facile one-pot self-assembly method, is developed. As a proof-of-concept, the unique hybrid catalyst (RP/P-LSCF) consists of a dominated Ruddlesden-Popper phase LaSr3 Co1.5 Fe1.5 O10-δ (RP-LSCF) and second perovskite phase La0.25 Sr0.75 Co0.5 Fe0.5 O3-δ (P-LSCF), displaying exceptional OER activity. The RP/P-LSCF achieves 10 mA cm-2 at a low overpotential of only 324 mV in 0.1 m KOH, surpassing the benchmark RuO2 and various state-of-the-art metal oxides ever reported for OER, while showing significantly higher activity and stability than single RP-LSCF oxide. The high catalytic performance for RP/P-LSCF is attributed to the strong metal-oxygen covalency and high oxygen-ion diffusion rate resulting from the phase mixture, which likely triggers the surface lattice-oxygen activation to participate in OER. The success of Ruddlesden-Popper/perovskite hybrid construction creates a new direction to design advanced catalysts for various energy applications.

Aptamer-Anchored Rubrene-Loaded Organic Nanoprobes for Cancer Cell Targeting and Imaging

Aptamer-Anchored Rubrene-Loaded Organic Nanoprobes for Cancer Cell Targeting and Imaging

1D Coordination Polymer Based on the [Mo36O114(H2O)14]12− Building Block with [Cu(H2O)2]2+ Linker Exhibiting Electrocatalytic Activities for H2O2 Reduction

A new 1D coordination polymer [NH4]4[Hmorph]6[Cu(H2O)2][Mo36O114(H2O)14]·28H2O (1) has been isolated by utilizing a one-pot self-assembly method and structurally characterized. Compound 1 exhibits the first example of 1D chain framework constructed from the [Mo36O114(H2O)14]12− fragments linked alternately with [Cu(H2O)2]2+ units. Electrochemical experiments reveal that 1-CPE exhibits the multi-electron redox processes ascribed to MoVI centers, and shows good electrocatalytic activity for H2O2 reduction. The photophysical investigations indicate that compound 1 bears the band gap value at ca. 2.92 eV, which is similar to inorganic semiconductor materials.

Artificial Nanometalloenzymes for Cooperative Tandem Catalysis.

Artificial metalloenzymes that combine the advantages of natural enzymes and metal catalysts have been getting more attention in research. As a proof of concept, an artificial nanometalloenzyme (CALB-Shvo@MiMBN) was prepared by co-encapsulation of metallo-organic catalyst and enzyme in a soft nanocomposite consisting of 2-methylimidazole, metal ions, and biosurfactant in mild reaction conditions using a one-pot self-assembly method. The artificial nanometalloenzyme with lipase acted as the core, and the metallo-organic catalyst embedded in micropore exhibited a spherical structure of 30-50 nm in diameter. The artificial nanometalloenzyme showed high catalytic efficiency in the dynamic kinetic resolution of racemic primary amines or secondary alcohols compared to the one-pot catalytic reaction of immobilized lipase and free metallo-organic catalyst. This artificial nanometalloenzyme holds great promise for integrated enzymatic and heterogeneous catalysis.

Nonhierarchical Heterostructured Fe2 O3 /Mn2 O3 Porous Hollow Spheres for Enhanced Lithium Storage.

High capacity transition-metal oxides play significant roles as battery anodes benefiting from their tunable redox chemistry, low cost, and environmental friendliness. However, the application of these conversion-type electrodes is hampered by inherent large volume variation and poor kinetics. Here, a binary metal oxide prototype, denoted as nonhierarchical heterostructured Fe2 O3 /Mn2 O3 porous hollow spheres, is proposed through a one-pot self-assembly method. Beyond conventional heteromaterial, Fe2 O3 /Mn2 O3 based on the interface of (104)Fe2O3 and (222)Mn2O3 exhibits the nonhierarchical configuration, where nanosized building blocks are integrated into microsized spheres, leading to the enhanced structural stability and boosted reaction kinetics. With this design, the Fe2 O3 /Mn2 O3 anode shows a high reversible capacity of 1075 mA h g-1 at 0.5 A g-1 , an outstanding rate capability of 638 mA h g-1 at 8 A g-1 , and an excellent cyclability with a capacity retention of 89.3% after 600 cycles.

Ordered and disordered evolution of the pore mesostructure in hybrid silica anti-reflective films obtained by one-pot self-assembly method

Hybrid mesoporous silica films were prepared in acid-catalysed medium using a one-pot self-assembly method. A gradual content of methyl groups was introduced into the inorganic framework by co-condensation of tetraethyl orthosilicate and methyltriethoxysilane. To better understand how the ordered and disordered transition occurs in mesoporous hybrid organosilica sytem as function of the MTES molar ratio in the starting solution, textural, chemical and optical properties of the films were studied by transmission electronic microscopy (TEM), grazing-incident small angle X-ray scattering (GISAXS), transmission Fourier transformed infrared (FTIR) and UV–visible spectroscopy. Increasing the loading of the incorporated organic groups (up to 40% in the starting solution) led simultaneously to a disorganization of the pore mesostructure and a reduction in the pore diameter. Concomitantly, a disordered domain of the silica rings in the walls was observed, which created bond strains in the silica wall contributing also to the disorganization of the pore mesostructure. Furthermore, an optimal MTES content was identified in order to obtain antireflection coatings, exhibiting low reflection in the visible range.

Rh2O3/mesoporous MOx-Al2O3 (M = Mn, Fe, Co, Ni, Cu, Ba) catalysts: Synthesis, characterization, and catalytic applications

Recently, a one-pot self-assembly method was proposed for the synthesis of mesoporous Al2O3 and MOx-Al2O3 composite materials. However, few attempts have been made to use mesoporous MOx-Al2O3 composites to support metal oxides for catalysis. In the present work, mesoporous MOx-Al2O3 (M = Mn, Fe, Co, Ni, Cu, Ba) materials were prepared by a one-pot self-assembly method using Pluronic P123 as a structure-directing agent. The obtained mesoporous materials were loaded with Rh2O3 nanoparticles via impregnation with Rh(NO3)3 followed by calcination in air at 500 °C. The resulting catalysts were characterized by X-ray diffraction, N2 adsorption-desorption measurements, transmission electron microscopy, inductively coupled plasma optical emission spectrometry, X-ray photoelectron spectroscopy, and their catalytic activity and stability for CO oxidation and N2O decomposition were tested. The Rh2O3 nanoparticles were found to be on the order of 1 nm in size and were highly dispersed on the high surface area mesoporous MOx-Al2O3 supports. A number of the Rh2O3/mesoporous MOx-Al2O3 catalysts exhibited higher catalytic activity than the Rh2O3/mesoporous Al2O3 prepared for comparison.

Chemical fabrication and electrochemical performance of Bi2S3-nanorods charged reduced graphene oxide

Bi2S3-nanorods charged reduced graphene oxide (RGO) was prepared by an one-pot self-assembly method. The morphologies and structures of the samples were characterized by X-ray powder diffraction and transmission electron microscopy. The as-synthesized composite showed good crystallinity and one-dimensional nanostructures uniformly dispersed on the surface of nanorods with the diameter of 80–140nm. Combining advantages of RGO and Bi2S3, the Bi2S3/RGO composite exhibited superior electrochemical performance to bare Bi2S3. The higher discharge/charge specific capacity, better rate capability and cycling stability were achieved for graphene-backboned hybrid architectures.