Yolk-Shell-Structured Aluminum Phenylphosphonate Microspheres with Anionic Core and Cationic Shell

Synthesis Strategy Guided by Decision Tree for Morphology Control of Metal Phosphonates

The morphology control of metal phosphonates is always a difficulty because there are many challenges derived from the complexity of crystallization and the multivariable synthesis system. Responding to challenges, we propose a synthesis strategy guided by a decision tree for morphology control of metal phosphonates, through which directional design of the morphology-controlled synthesis can be realized. Specifically, any one synthetic condition involving the synthesis of metal phosphonates can be regarded as a decision problem to construct a binary decision tree. By means of the classification principle of the binary decision tree, the samples synthesized under the boundary value of each synthesis condition are classified based on crystal phase and morphology. The key synthetic conditions determining crystal phase and morphology can be precisely screened out to serve as decision nodes for the binary decision tree and are also rapidly optimized by the recursion level by level, whereas others cannot. Here, the β-polymorph of copper phenylphosphonate (β-CuPP) is selected as an example to elaborate the decision-tree-guided synthesis strategy for morphology control of metal phosphonates. From the constructed binary decision tree, it is clear that the right amount of methanol in the solvent is vital to obtain β-phase of CuPP, whereas the reactant concentration, pH value, and reaction time are important for morphology and phase transformation. Under the optimal synthetic conditions screened out by the binary decision tree, β-CuPP can thus be controlled to be hierarchically flower-like microsphere morphology through either the direct synthesis route or the solid-to-solid phase transformation route. This research work confirms that the decision-tree-guided synthesis is highly efficacious for the morphology control of metal phosphonates. Furthermore, the morphology-controlled synthesis guided by a decision tree may provide some valuable inspiration for morphology control of metal-organic frameworks (MOFs) and even coordinate compounds.

Nanoreactor Engineering Can Unlock New Possibilities for CO2 Tandem Catalytic Conversion to C-C Coupled Products

Climate change is becoming increasingly more pronounced every day while the amount of greenhouse gases in the atmosphere continues to rise. CO₂ reduction to valuable chemicals is an approach that has gathered substantial attention as a means to recycle these gases. Herein, some of the tandem catalysis approaches that can be used to achieve the transformation of CO₂ to C-C coupled products are explored, focusing especially on tandem catalytic schemes where there is a big opportunity to improve performance by designing effective catalytic nanoreactors. Recent reviews have highlighted the technical challenges and opportunities for advancing tandem catalysis, especially highlighting the need for elucidating structure-activity relationships and mechanisms of reaction through theoretical and in situ/operando characterization techniques. In this review, the focus is on nanoreactor synthesis strategies as a critical research direction, and discusses these in the context of two main tandem pathways (CO-mediated pathway and Methanol-mediated pathway) to C-C coupled products.

Hollow Structured Transition Metal Phosphates and Their Applications

Hollow nanostructures of transition metal phosphate are of immense interest in the existing and evolving areas of technology, due to their high surface area, presence of hollow void, and easy tuning of compositions and dimensions. Emerging synthesis methods such as template-free methods, hard-templating, and soft-templating are discussed in this review. Applications of these hollow metal phosphates dominate in energy storage and conversions, with specific advantages as supercapacitor materials. Other applications, including drug delivery, water splitting, catalysis, and adsorption, are reviewed. Finally, additional perspectives on the progress of these nanostructures, and their existing challenges related to the current synthesis routes are covered. Therefore, with the strategic modifications of the unique properties of these hollow metal phosphates, broader application requirements are fulfilled.

Formation of aluminum diphosphonate mesostructures: The effect of aluminum source

Mesostructured aluminum phosphonates (AOP-x) bridging with 1,1'-hydroxyl ethylidene groups, including a lamellar mesostructure (AOP-N) with crystalline framework, a well-ordered 2D-hexagonal mesophase (AOP-Cl), and a particle-packed mesostructure (AOP-S), were simply synthesized in the presence of surfactant cetyltrimethylammonium bromide in the ethanol-water system, by choosing Al(NO₃)₃, AlCl₃ and Al₂(SO₄)₃ as the aluminum source, respectively. The crystallinity, morphology, mesophase, and skeletal structure of the as-prepared materials were characterized by XRD, TEM, SEM, ²⁷Al, ³¹P and ¹³C MAS NMR, and nitrogen sorption techniques. After calcination under N₂ at 350 °C, the calcined AOP-x samples consist of aluminum phosphonate and phosphate, possessing desirable specific surface areas of 116-585 m²/g. The effect of the inorganic counteranions (NO₃^-, Cl^- and SO₄^2-) from the aluminum source on the formation of different AOP-x mesostructures was discussed in terms of their bind strength to the headgroups of the surfactant micelles, suggesting the potential for designed synthesis of non-silica-based mesostructured organic-inorganic hybrid materials.

Facile fabrication, morphology control, and modification of polymeric yolk-shell microspheres

The fabrication and functionalization of polymeric yolk-shell microspheres (YSMs), possessing a hollow shell and a movable core, is interesting but challenging in materials science. Here we report the facile fabrication, morphology control, and fluorescent modification of polymeric YSMs, which have a spherical core of poly(vinylidene fluoride) (PVDF) and a hollow shell of poly(styrene-co-glycidyl methacrylate). First, flower-like microspheres with core-shell structures are synthesized via seeded surface nucleation in an emulsion polymerization of styrene, glycidyl methacrylate, and divinylbenzene by using PVDF microparticles as seeds. Both the feed ratio and the polymerization time are considered to manipulate the core-shell structures of the composite microparticles, which obviously influences the morphology of the YSMs obtained from the subsequent treatment of solvent etching to remove the seed. The hollow volume of the polymeric YSMs is easily adjusted by changing the etching time at different temperatures. Meanwhile, we realized three-dimensionally confined crystallization of PVDF in different morphologies of YSMs. Furthermore, YSMs with the same or different functional groups, inside and outside of the hollow shell, respectively, are chemically modified by the reaction of glycidyl groups on the shell with 2,2'-(ethylenedioxy) bis-ethylamine. Thus, strong fluorescence of the YSMs is observed by subsequent labeling with functional fluorescent groups.

Synthesis of Calcium Bisphosphonate/Calcium Polyacrylate Spheres for Gene Delivery

Calcium bisphosphonate/calcium polyacrylate spheres were synthesized by a facile method and applied for the first time as gene vectors for transfection. The colloidal spheres of the PAA-Ca²⁺-H₂O complex, formed by sodium polyacrylate and calcium ions in the solution, were used as template to synthesize a spherical PAA-Ca²⁺-BPMP composite (CaBPMP/CaPAA) in the presence of 1,4-bis(phosphomethyl)piperazine (BPMP). The CaBPMP/CaPAA composite exhibits uniform and well-dispersed spheres with a particle size of about 200 nm as expected. The cytotoxicity assays confirm that CaBPMP/CaPAA spheres are quite safe for different cells even at a high concentration of 500 μg/mL. In vitro transfection results show that CaBPMP/CaPAA spheres serving as gene vectors are capable of transferring exogenous genes into different cells with about 25% of transfection efficiency and good reproducibility. The transfection capacity of CaBPMP/CaPAA spheres may be attributed to the controllable sphere morphology, low cytotoxicity, moderate DNA loading capacity, and bioresorbable property. The application of calcium phosphonates with adjustable surface properties derived from the different organic groups of phosphonic acid in gene delivery provides a new design idea for gene vectors.

Laccase-mediated in situ oxidation of dopa for bio-inspired coloration of silk fabric

The mechanism of the biological coloration of silk fabric by laccase-mediated in situ oxidation of dopa is revealed.

Single Crystal Sub-Nanometer Sized Cu6(SR)6 Clusters: Structure, Photophysical Properties, and Electrochemical Sensing

Organic ligand-protected metal nanoclusters have attracted extensively attention owing to their atomically precise composition, determined atom-packing structure and the fascinating properties and promising applications. To date, most research has been focused on thiol-stabilized gold and silver nanoclusters and their single crystal structures. Here the single crystal copper nanocluster species (Cu6(SC7H4NO)6) determined by X-ray crystallography and mass spectrometry is presented. The hexanuclear copper core is a distorted octahedron surrounded by six mercaptobenzoxazole ligands as protecting units through a simple bridging bonding motif. Density functional theory (DFT) calculations provide insight into the electronic structure and show the cluster can be viewed as an open-shell nanocluster. The UV-vis spectra are analyzed using time-dependent DFT and illustrates high-intensity transitions involving primarily ligand states. Furthermore, the as-synthesized copper clusters can serve as promising nonenzymatic sensing materials for high sensitive and selective detection of H2O2.

Evaluation of different commercial hydrophobic supports for the immobilization of lipases: tuning their stability, activity and specificity

Immobilization of different lipases on diffferent hydrophobic supportsviainterfacial activation has permitted to tunning enzyme performance.

Hierarchical ternary Ni–Co–Se nanowires for high-performance supercapacitor device design

Large-scale uniform Ni–Co–Se bimetallic ternary nanowires have been successfully synthesized through a successive cation exchange.