Amino Acid-Assisted Synthesis of Zeolites with Improved Catalytic Properties.

Conventional zeolites are limited in their ability to catalyze macromolecular reactions due to micropore constraints, resulting in sluggish reactant and product diffusion and subsequently pore clogging and catalyst deactivation. Consequently, the pore and textural refinement of zeolites to meet industrial demands has become a research hotspot. Herein, we review the amino acid-assisted methods in zeolite synthesis and scrutinize the principle and influential factors governing amino acid involvement in zeolite synthesis.

Research on the identification and evolution of health industry policy instruments in China.

The application of health industry policies could be discovered more quickly and comprehensively through the automated identification of policy tools, which could provide references for the formulation, implementation, and optimization of subsequent policies in each province. This study applies the Bidirectional Encoder Representation from Transformer (BERT) model to identify policy tools automatically, utilizes Focal Loss to reduce the unbalance of a dataset, and analyzes the evolution of policy tools in each province, which contains time, space, and topic. The research demonstrates that the BERT model can improve the accuracy of classification, that supply and environment policy tools are more prevalent than demand tools, and that policy instruments are organized similarly in four major economic regions.

In Situ Copper Coating on Silicon Particles Enables Long Durable Anodes in Lithium-Ion Batteries.

Addressing the significant obstacles of volume expansion and inadequate electronic conductivity in silicon-based anode materials during lithiation is crucial for achieving a long durable life in lithium-ion batteries. Herein, a high-strength copper-based metal shell is coated in situ onto silicon materials through a chemical combination of copper citrate and Si-H bonds and subsequent heat treatment. The formed Cu and CuSi shell effectively mitigates the mechanical stress induced by volume expansion during lithiation, strengthens the connection with the copper substrate, and facilitates electron transfer and Li diffusion kinetics.

Hollow STW-Type Zeolite Single Crystals with Aluminum Gradient for Highly Selective Production of p-Xylene from Methanol-Toluene Alkylation.

Zeolites with uniform micropores are important shape-selective catalysts. However, the external acid sites of zeolites have a negative impact on shape-selective catalysis, and the microporosity may lead to serious diffusion limitation. Herein, we report on the direct synthesis of hierarchical hollow STW-type zeolite single crystals with a siliceous exterior.

Amino-Acid-Assisted Synthesis of Hollow Hierarchical FER Zeolite with Improved Catalytic Performance.

Hierarchical zeolites are highly-desired catalysts in the petrochemical industry due to their shorter diffusion length, faster diffusion rate, and better accessibility to active acid sites compared with conventional zeolites. Herein, we report a simple amino-acid-assisted method to synthesize urchin-like hollow hierarchical FER zeolites with abundant mesopores and macroporous inner cavities. An amino acid (i.

A fluoride-free siliceous STW-type zeolite synthesized using a designed organic structure-directing agent.

A pure silica STW zeolite is synthesized with no impurities under a wide range of synthesis conditions with and without fluoride by using easily available 1-methyl-1,5-diazabicyclo[4.3.0]non-5-ene (MDBN) as a template.

One-step synthesis of uniformly distributed SiO-C composites as stable anodes for lithium-ion batteries.

SiO is one of the most promising anode materials for lithium-ion batteries (LIBs), due to its high theoretical capacity and low cost. However, the huge volume expansion and low electron/ion diffusion rate hinder its further commercial applications. Herein, a simple molecular polymerization method is developed to synthesize N,P co-doped SiO-C composites (denoted as SiO-C@CNT), in which SiO and carbon are uniformly dispersed at the atomic level, and the embedded carbon nanotubes improve the lithium ion diffusion kinetics.

Synthesis and Characterization of A Stable Extra-Large-Pore Zeolite with 15×12×12 Member-Ring Channels.

Extra-large-pore zeolites have great application potential in various industrial fields, such as oil refinery, fine chemicals and biomass processing. Herein, we report the synthesis of an extra-large-pore germanosilicate zeolite (named NUD-13) by using an easily obtained aromatic organic cation 1,2-dimethyl-3-propyl-benzimidazolium as organic structure-directing agents. NUD-13 possesses a rare 15-member ring extra-large-pore channel intersecting with two elliptical 12-member ring channels, which is isostructural to germanosilicate zeolite GeZA synthesized by using triphenylsulfonium.

Direct Synthesis of An Aluminosilicate POS Zeolite with Intersecting 12×11×11-Member-Ring Pore Channels by Using a Designed Organic Structure-Directing Agent.

Large and extra-large pore zeolites have been widely applied in industrial areas as catalysts, adsorbents, etc. Among them, silica and/or aluminosilicate zeolites have been attracted great attention due to their excellent hydrothermal stability and strong acidity. However, a great deal of zeolite structures are still not available in the form of silica and/or aluminosilicate.

Structure-direction towards the new large pore zeolite NUD-3.

The new zeolite NUD-3 possesses a three-dimensional system of large pore channels that is topologically identical to those of ITQ-21 and PKU-14. However, the three zeolites have distinctly different frameworks: a particular single 4-membered ring inside the denser portion of the zeolite is missing in PKU-14, disordered in ITQ-21 and fully ordered in NUD-3. We document these differences and use molecular simulations to unravel the mechanism by which a particular structure directing agent dication, 1,1'-(1,2-phenylenebis(methylene))bis(3-methylimidazolium), is able to orient this inner ring.

Solvent-Induced Growth of Free-Standing 2D Si Nanosheets.

2D Si nanomaterials draw great interest owing to their fascinating properties and potential applications in electronic devices, catalysts, and energy storage and conversion devices. However, high-quality and large-scale synthesis of Si nanosheets remains a big challenge, despite the limited reports on their preparations via chemical exfoliation of layered Zintl silicide, magnesiothermic reduction of layered silicon oxide, and chemical vapor deposition. In this work, a facile, solution method to produce free-standing Si nanosheets in high yields and low cost, based on the reaction of commercial magnesium powder with trichlorosilane and tripropylamine in dichloromethane under mild conditions, is reported.

Synthesis, Structure and Properties of an Extra-Large-Pore Aluminosilicate Zeolite NUD-6.

Pure silica zeolites possessing uniform micropores, large surface area and high thermal and chemical stability have been widely studied and used in the fields of fine chemicals and oil industry. The incorporation of aluminium into the framework of silica zeolites changes their properties, making them more industrially useful as adsorbents and catalysts. Herein, we report the synthesis and characterization of an extra-large-pore aluminosilicate zeolite NUD-6 with a 16-membered-ring pore channel.

Synthesis and characterization of a layered aluminosilicate NUD-11 and its transformation to a 3D stable zeolite.

Aluminosilicate zeolites are a well-known class of crystalline materials that have wide applications in various industrial fields due to their selective adsorption, acidic sites, and stable hydrothermal stability. Great efforts have been devoted to discovering new zeolite structures. As one of the effective methods, layered silicates have been used as precursors to produce stable zeolites through topotactic transformation.

One-pot solution synthesis of carbon-coated silicon nanoparticles as an anode material for lithium-ion batteries.

Carbon-coated silicon nanoparticles were in situ synthesized via a facile one-pot solution synthesis method, which delivered an excellent cycling performance with a retained discharge capacity of 1120 mA h g-1 and almost no capacity decay after 500 cycles at 2 A g-1 when evaluated as an anode material in lithium ion batteries.

An Extra-Large-Pore Pure Silica Zeolite with 16×8×8-Membered Ring Pore Channels Synthesized using an Aromatic Organic Directing Agent.

Extra-large-pore zeolites for processing large molecules have long been sought after by both the academia and industry. However, the synthesis of these materials, particularly extra-large-pore pure silica zeolites, remains a big challenge. Herein we report the synthesis of a new extra-large-pore silica zeolite, designated NUD-6, by using an easily synthesized aromatic organic cation as structure-directing agent.

Ionothermal Synthesis of Crystalline Nanoporous Silicon and Its Use as Anode Materials in Lithium-Ion Batteries.

Silicon has great potential as an anode material for high-performance lithium-ion batteries (LIBs). This work reports a facile, high-yield, and scalable approach to prepare nanoporous silicon, in which commercial magnesium silicide (MgSi) reacted with the acidic ionic liquid at 100 °C and ambient pressure. The obtained silicon consists of a crystalline, porous structure with a BET surface area of 450 m/g and pore size of 1.

Charge, adsorption, water stability and bandgap tuning of an anionic Cd(ii) porphyrinic metal-organic framework.

Due to the designability of metal-organic frameworks (MOFs), semiconductor MOFs have become the focus of research as photocatalysts of useful chemical processes utilizing clean solar energy. In this work, we developed a method of tuning the framework charge of MOF materials and determined how the framework charge can affect the band edge positions and bandgaps of the novel anionic Cd(ii) porphyrinic metal-organic framework (PMOF) 1 ([Cd(HTCPP)][(CH)NH]). It was constructed from HTCPP (HTCPP = tetrakis(4-carboxyphenyl)-porphyrin) and Cd(ii), forming a tube-like structure, and shown to have a negatively charged framework with a 60% occupancy of one type of Cd(ii) ion.

Solution Synthesis of Porous Silicon Particles as an Anode Material for Lithium Ion Batteries.

Nanostructured silicon-based materials with porous structures have recently been found to be impressive anode materials with high capacity and cycling performance for lithium-ion batteries. However, the current methods of preparing porous silicon have generally been confronted with the requirement for multiple steps and complex synthesis. In the present study, porous silicon with high surface area was prepared by using a high yielding and simple reaction in which commercial magnesium powder readily reacts with HSiCl with the help of an amine catalyst under mild conditions.

Nickel Molybdenum Nitride Nanorods Grown on Ni Foam as Efficient and Stable Bifunctional Electrocatalysts for Overall Water Splitting.

Non-noble-metal electrocatalysts for water splitting hold great promises for developing sustainable and clean energy sources. Herein, a highly efficient bifunctional electrode consisting of Ni-doped molybdenum nitride nanorods on Ni foam is prepared through topotactic transformation of NiMoO nanorods that are in situ hydrothermally grown on Ni foam. The electrode not only contains rich, accessible, electrochemically active sites but also possesses extraordinary chemical stability.

Transition-Metal Phosphide-Carbon Nanosheet Composites Derived from Two-Dimensional Metal-Organic Frameworks for Highly Efficient Electrocatalytic Water-Splitting.

The preparation of highly active, sustainable, nonprecious metal materials as hydrogen evolution and oxygen evolution reaction (HER and OER) catalysts that can relieve the environmental pollution and energy shortage problems present a great challenge to chemists. We herein report the fabrication of a highly active metal phosphide-carbon composite catalyst for HER and OER in acid and basic solution, respectively. The catalyst is derived through carbonization and subsequent phosphorization of two-dimensional (2D) cobalt porphyrinic metal-organic framework nanosheets.

Room-Temperature Solution Synthesis of Mesoporous Silicon for Lithium Ion Battery Anodes.

As an important optoelectronic and energy-storage material, porous silicon (PSi) has attracted great interest in various fields. The preparation of PSi, however, usually suffers from low yields and/or complicated syntheses. Herein, we report a facile solution method to prepare PSi with controllable high specific surface area.

Step-by-step assembly preparation of core-shell Si-mesoporous TiO composite nanospheres with enhanced lithium-storage properties.

Core-shell structured Si-mesoporous TiO (Si@mTiO) composite nanospheres are designed and prepared via a step-by-step assembly method. Si@mTiO exhibit excellent lithium-storage properties when used as anode materials in lithium ion batteries. The reversible specific capacity is maintained at as high as 700 mA h g with no capacity decay even after 200 cycles at 1 A g.

Cobalt-Borate Nanoarray: An Efficient and Durable Electrocatalyst for Water Oxidation under Benign Conditions.

The development of efficient earth-abundant electrocatalysts for oxygen evolution reaction (OER) under benign conditions is still urgent and challenging. Herein, we report the electrochemical generation of novel Co-Bi nanoarray on carbon cloth (Co-Bi NA/CC) from CoS nanoarray precursor. As a three-dimensional anode, such Co-Bi NA/CC exhibits excellent electrocatalytic performance for OER with the overpotential requirement of 411 mV to drive 10 mA cm.

Cascade photoredox/gold catalysis: access to multisubstituted indoles via aminoarylation of alkynes.

A new method for the synthesis of 3-arylindoles has been developed by visible light mediated dual gold/photoredox catalysis. This transformation has many features such as cascade catalysis, high efficiency, redox-neutral reaction conditions and good functional group tolerance. The reaction proceeds through the photoredox-promoted formation of an electrophilic arylgold(iii) intermediate that undergoes coupling with the arylamine nucleophile.