Aromatic poly (amino acids) as an effective low-temperature demulsifier for treating crude oil-in-water emulsions.

Amphiphilic aromatic poly (amino acids) polymers were designed as biodegradability demulsifiers with higher aromaticity, stronger polarity, and side chain-like combs. The effects of demulsifier dosage, structural characteristics and emulsion properties such as pH, salinity, and oil content on the demulsification efficiency were investigated. The results show that the poly (L-glutamic-benzyl ester)-block-poly (L-phenylalanine) (PBLG15-b-PPA15) as the demulsifier can remove more than 99.97% of the oil in a 5.0 wt% oil-in-water (O/W) emulsion at room temperature within 2 min. The poly (L-tyrosine)-block-poly (L-phenylalanine) (PTyr15-b-PPA15) with environmental durability demonstrates high effectiveness, universality, and demulsification speed. It achieves a remarkable demulsification efficiency of up to 99.99% for a 20.0 wt% O/W emulsion at room temperature. The demulsification mechanism indicates that demulsifiers have sufficient interfacial activity can quickly migrate to the oil-water interface after being added to the emulsions. Additionally, when demulsifiers are present in a continuous phase in the molecular form, their "teeth" side chains are beneficial for increasing coalescence and flocculation capacities. Furthermore, according to the Density Functional Theory (DFT) calculations, enhancing the intermolecular interactions between demulsifiers and the primary native surfactants that form an oil-water interfacial film is a more efficient approach to reducing demulsification temperature and improving demulsification efficiency and rate.

Superprotonic conductivity of ketoenamine covalent-organic frameworks grafted by imidazole-based units.

The achievement of covalent organic frameworks (COFs) with high stability and exceptional proton conductivity is of tremendous practical importance and challenge. Given this, we hope to prepare the highly stable COFs carrying CN connectors and enhance their proton conductivity via a post-modification approach. Herein, one COF, TpTta, was successfully synthesized by employing 1,3,5-triformylphloroglucinol (Tp) and 4,4',4″-(1,3,5-triazine-2,4,6-triyl)-trianiline (Tta) as starting materials, which has a ß-ketoenamine structure bearing a large amount of -NH groups and intramolecular H-bonds. TpTta was then post-modified by inserting imidazole (Im) and histamine (His) molecules, yielding the corresponding COFs, Im@TpTta and His@TpTta, respectively. As a result, their proton conductivities were surveyed under changeable temperatures (30-100 °C) and relative humidities (68-98 %), revealing a degree of temperature and humidity dependence. Impressively, under identical conditions, the optimum proton conductivities of the two post-modified COFs are 1.14 × 10-2 (Im@TpTta) and 3.45 × 10-3 S/cm (His@TpTta), which are significantly greater than that of the pristine COF, TpTta (2.57 × 10-5 S/cm). Finally, their proton conduction mechanisms were hypothesized based on the computed activation energy values, water vapor adsorption values, and structural properties of these COFs. Additionally, the excellent electrochemical stability of the produced COFs was expressed, as well as the prospective application value.

Effect of Template-Mediated Alumina Nanoparticle Morphology on Sapphire Wafer Production via Heat Exchange Method.

The sapphire crystal, the most commonly used LED substrate material, has excellent optical and chemical properties and has rapidly developed in recent years. However, the challenge of growing large-size sapphire crystals remains. This paper presents a novel approach using alumina nanoparticles synthesized with abietic acid as a template to enhance sapphire growth via the heat exchange method. This study explores the effects of temperature, time, and template amount on the structure and morphology of the synthesized alumina nanoparticles. The results show that the morphology of the raw material, particularly spherical alumina nanoparticles, positively affects the quality and yield stability of sapphire products. Furthermore, the light output power of GaN-based LED chips made with the experimentally fabricated sapphire substrate increased from 3.47 W/µm2 to 3.71 W/µm2, a 6.9% increase compared to commercially available sapphire substrates. This research highlights the potential of using abietic acid as a template for alumina nanoparticle synthesis and their application in sapphire growth for LED production.

The Morphologically Controlled Synthesis and Application of Mesoporous Alumina Spheres.

The control of alumina morphology is crucial yet challenging for its various applications. Unfortunately, traditional methods for preparing alumina particles suffer from several limitations such as irregular morphology, poor dispersibility, and restricted application areas. In this study, we develop a novel method for preparing spherical mesoporous alumina using chitin and Pluronic P123 as mixed templates. The effects of reaction temperature, time, and the addition of mixed templates on the phase structure, micromorphology, and optical absorption properties of the samples were investigated. The experimental results indicate that lower temperature and shorter reaction time facilitated the formation of spherical mesoporous alumina with excellent CO2 adsorption capacity. The periodic density functional theory (DFT) calculations demonstrate that both the (110) and (100) surfaces of γ-Al2O3 can strongly adsorb CO2. The difference in the amount of CO2 adsorbed by Al2O3 is mainly due to the different surface areas, which give different numbers of exposed active sites. This approach introduces a novel strategy for utilizing biological compounds to synthesize spherical alumina and greatly enhances mesoporous alumina's application efficiency in adsorption fields. Moreover, this study explored the electrochemical performance of the synthesized product using cyclic voltammetry, and improved loading of electrocatalysts and enhanced electrocatalytic activity were discovered.

Alloying Iron into Palladium Nanoparticles for an Efficient Catalyst in Acetylene Dicarbonylation.

Motivated by the prominent catalytic performance and durability of nanoalloy catalysts, the Pd-based bimetallic nanoalloy catalysts were prepared using an aqueous reduction method. The Fe-Pd bimetallic nanoalloy catalyst (nano-Fe/Pd) demonstrated 98.4% yield and 99.7% selectivity for the unsaturated 1,4-dicarboxylic acid diesters. Moreover, the inductively coupled plasma (ICP) analysis shows that the Pd leaching of the catalyst can be effectively suppressed by alloying Fe atoms into the Pd crystal lattice for acetylene dicarbonylation. The detailed catalyst structure and morphology characterization demonstrate that introducing Fe into the Pd nanoparticles tunes the electronic-geometrical properties of the catalyst. Theoretical calculations indicate that the electrons of Fe transfer to Pd in the nano-Fe/Pd catalyst, enhancing activation of the C≡C bond in acetylene and weakening CO absorption capacity on catalyst surfaces. Alloying Fe into the Pd nanocatalyst effectively inhibits active metal leaching and improves catalyst activity and stability under high-pressure CO reactions.

Effect of the metal-support interaction in platinum anchoring on heteroatom-doped graphene for enhanced oxygen reduction reaction.

Three kinds of Pt anchoring on heteroatom-doped graphene were synthesised and their effects on catalytic performance were discussed. The introduction of N and P into graphene is helpful to decrease the Pt particle size with a homogeneous distribution and favor the electronic configuration for the ORR.

Ultra-Broadband Strong Electromagnetic Interference Shielding with Ferromagnetic Graphene Quartz Fabric.

Flexible electromagnetic interference (EMI) shielding materials with ultrahigh shielding effectiveness (SE) are highly desirable for high-speed electronic devices to attenuate radiated emissions. For hindering interference of their internal or external EMI fields, however, a metallic enclosure suffers from relatively low SE, band-limited anti-EMI responses, poor corrosion resistance, and non-adaptability to the complex geometry of a given circuit. Here, a broadband, strong EMI shielding response fabric is demonstrated based on a highly structured ferromagnetic graphene quartz fiber (FGQF) via a modulation-doped chemical vapor deposition (CVD) growth process. The precise control of the graphitic N-doping configuration endows graphene coatings on specifically designable quartz fabric weave with both high conductivity (3906 S cm-1 ) and high magnetic responsiveness (a saturation magnetization of ≈0.14 emu g-1 under 300 K), thus attaining synergistic effect of EMI shielding and electromagnetic wave (EMW) absorption for broadband anti-EMI technology. The large-scale durable FGQF exhibits extraordinary EMI SE of ≈107 dB over a broadband frequency (1-18 GHz), by configuring ≈20 nm-thick graphene coatings on a millimeter-thick quartz fabric. This work enables the potential for development of an industrial-scale, flexible, lightweight, durable, and ultra-broadband strong shielding material in advanced applications of flexible anti-electronic reconnaissance, antiradiation, and stealthy technologies.

Phosphorus-Doped Graphene Electrocatalysts for Oxygen Reduction Reaction.

Developing cheap and earth-abundant electrocatalysts with high activity and stability for oxygen reduction reactions (ORRs) is highly desired for the commercial implementation of fuel cells and metal-air batteries. Tremendous efforts have been made on doped-graphene catalysts. However, the progress of phosphorus-doped graphene (P-graphene) for ORRs has rarely been summarized until now. This review focuses on the recent development of P-graphene-based materials, including the various synthesis methods, ORR performance, and ORR mechanism. The applications of single phosphorus atom-doped graphene, phosphorus, nitrogen-codoped graphene (P, N-graphene), as well as phosphorus, multi-atoms codoped graphene (P, X-graphene) as catalysts, supporting materials, and coating materials for ORR are discussed thoroughly. Additionally, the current issues and perspectives for the development of P-graphene materials are proposed.

Experimental and Simulation Research on the Preparation of Carbon Nano-Materials by Chemical Vapor Deposition.

Carbon nano-materials have been widely used in many fields due to their electron transport, mechanics, and gas adsorption properties. This paper introduces the structure and properties of carbon nano-materials the preparation of carbon nano-materials by chemical vapor deposition method (CVD)-which is one of the most common preparation methods-and reaction simulation. A major factor affecting the material structure is its preparation link. Different preparation methods or different conditions will have a great impact on the structure and properties of the material (mechanical properties, electrical properties, magnetism, etc.). The main influencing factors (precursor, substrate, and catalyst) of carbon nano-materials prepared by CVD are summarized. Through simulation, the reaction can be optimized and the growth mode of substances can be controlled. Currently, numerical simulations of the CVD process can be utilized in two ways: changing the CVD reactor structure and observing CVD chemical reactions. Therefore, the development and research status of computational fluid dynamics (CFD) for CVD are summarized, as is the potential of combining experimental studies and numerical simulations to achieve and optimize controllable carbon nano-materials growth.

Ultrafast Catalyst-Free Graphene Growth on Glass Assisted by Local Fluorine Supply.

High-quality graphene film grown on dielectric substrates by a direct chemical vapor deposition (CVD) method promotes the application of high-performance graphene-based devices in large scale. However, due to the noncatalytic feature of insulating substrates, the production of graphene film on them always has a low growth rate and is time-consuming (typically hours to days), which restricts real potential applications. Here, by employing a local-fluorine-supply method, we have pushed the massive fabrication of a graphene film on a wafer-scale insulating substrate to a short time of just 5 min without involving any metal catalyst. The highly enhanced domain growth rate (∼37 nm min-1) and the quick nucleation rate (∼1200 nuclei min-1 cm-2) both account for this high productivity of graphene film. Further first-principles calculation demonstrates that the released fluorine from the fluoride substrate at high temperature can rapidly react with CH4 to form a more active carbon feedstock, CH3F, and the presence of CH3F molecules in the gas phase much lowers the barrier of carbon attachment, providing sufficient carbon feedstock for graphene CVD growth. Our approach presents a potential route to accomplish exceptionally large-scale and high-quality graphene films on insulating substrates, i.e., SiO2, SiO2/Si, fiber, etc., at low cost for industry-level applications.

Green Hydrothermal Synthesis of N-doped Carbon Dots from Biomass Highland Barley for the Detection of Hg2.

Totally water-soluble N-doped Carbon dots (N-CDs) were synthesized by a green hydrothermal method from biomass using Highland barley as a carbon source and ethanediamine as nitrogen source. TEM and XRD showed the graphitic amorphous structure and narrow diameter distribution of these N-CDs. N-doping to the crystal lattice and carrying many hydrophilic groups on the surface of N-CDs were verified by XPS and FT-IR. The as-synthesized N-CDs emitted strong blue fluorescence at 480 nm and owned a relatively high quantum yield of 14.4%. The product also could sensitively and selectively detect Hg2+ ions in the range of 10-160 µM and the limit of detection was equal to 0.48 µM.

An aqueous fluorescent sensor for Pb2+ based on phenothiazine-polyamide.

A sensitive and selective fluorescent sensor for Pb2+ ion based on phenothiazine-polyamide was built (named sensor PP). Due to introducing of four diethanolamine groups to polyamide, this sensor was totally water soluble. PP could detect Pb2+ ion within 1 min in the presence of other metal ions in aqueous solution, the detect limit was 9.11 × 10-8 M.

A Ratiometric Fluorescent Sensor for Cd2+ Based on Internal Charge Transfer.

This work reports on a novel fluorescent sensor 1 for Cd2+ ion based on the fluorophore of tetramethyl substituted bis(difluoroboron)-1,2-bis[(1H-pyrrol-2-yl)methylene]hydrazine (Me4BOPHY), which is modified with an electron donor moiety of N,N-bis(pyridin-2-ylmethyl)benzenamine. Sensor 1 has absorption and emission in visible region, at 550 nm and 675 nm, respectively. The long wavelength spectral response makes it easier to fabricate the fluorescence detector. The sensor mechanism is based on the tunable internal charge transfer (ICT) transition of molecule 1. Binding of Cd2+ ion quenches the ICT transition, but turns on the π - π transition of the fluorophore, thus enabling ratiometric fluorescence sensing. The limit of detection (LOD) was projected down to 0.77 ppb, which is far below the safety value (3 ppb) set for drinking water by World Health Organization. The sensor also demonstrates a high selectivity towards Cd2+ in comparison to other interferent metal ions.

The Effect of Novel Synthetic Methods and Parameters Control on Morphology of Nano-alumina Particles.

Alumina is an inorganic material, which is widely used in ceramics, catalysts, catalyst supports, ion exchange and other fields. The micromorphology of alumina determines its application in high tech and value-added industry and its development prospects. This paper gives an overview of the liquid phase synthetic method of alumina preparation, combined with the mechanism of its action. The present work focuses on the effects of various factors such as concentration, temperature, pH, additives, reaction system and methods of calcination on the morphology of alumina during its preparation.