Shuaishuai Liang

Boron nitride nanosheets as oxygen-atom corrosion protective coatings

The research of two-dimensional nanomaterials for anticorrosion applications is just recently burgeoning. Herein, we demonstrate the boron nitride nanosheets (BNNSs) coatings for protecting polymer from oxygen-atom corrosion. High-quality BNNSs, which are produced by an effective fluid dynamics method with multiple exfoliation mechanisms, can be assembled into coatings with controlled thickness by vacuum filtration. After exposed in atom oxygen, the naked polymer is severely corroded with remarkable mass loss, while the BNNSs-coated polymer remains intact. Barrier and bonding effects of the BNNSs are responsible for the coatings protective performance. These preliminary yet reproducible results pave a way for resisting oxygen-atom corrosion.

Hydrodynamics-assisted scalable production of boron nitride nanosheets and their application in improving oxygen-atom erosion resistance of polymeric composites

Searching for a method for low-cost, easily manageable, and scalable production of boron nitride nanosheets (BNNSs) and exploring their novel applications are highly important. For the first time we demonstrate that a novel and effective hydrodynamics method, which involves multiple exfoliation mechanisms and thus leads to much higher yield and efficiency, can realize large-scale production of BNNSs. The exfoliation mechanisms that multiple fluid dynamics events contribute towards normal and lateral exfoliation processes could be applied to other layered materials. Up to ~95% of the prepared BNNSs are less than 3.5 nm thick with a monolayer fraction of ~37%. Compared to the conventional sonication and ball milling-based methods, the hydrodynamics method has the advantages of possessing multiple efficient ways for exfoliating BN, being low-cost and environmentally-friendly, producing high quality BNNSs in high yield and efficiency, and achieving concentrated BNNSs dispersions even in mediocre solvents. It is also shown for the first time that BNNSs can be utilized as fillers to improve the oxygen-atom erosion resistance of epoxy composites which are widely used for spacecraft in low earth orbit (LEO) where atom oxygen abounds. An addition of only 0.5 wt% BNNSs can result in a 70% decrease in the mass loss of epoxy composites after atom oxygen exposure equivalent to 160 days in an orbit of ~300 km. Overall, the demonstrated hydrodynamics method shows great potential in large-scale production of BNNSs in industry in terms of yield, efficiency, and environmental friendliness; and the innovative application of BNNSs to enhancing oxygen-atom erosion resistance of polymeric composites in space may provide a novel route for designing light spacecraft in LEO.

Graphene for reducing bubble defects and enhancing mechanical properties of graphene/cellulose acetate composite films

In this study, we have demonstrated a strategy by which graphene was used to reduce the bubble defects and enhance the mechanical properties in graphene/cellulose acetate (Gr/CA) composite films. Mono- and multilayer graphene flakes were successfully prepared in the water–acetone mixtures by a jet cavitation method. Moreover, outstanding enhancement of mechanical properties of Gr/CA composite films were obtained at relatively low concentration of graphene flakes. Young’s modulus of these composite films increased linearly with the graphene flakes loading, due to the significantly high surface area of graphene and strong interactions between graphene flake and CA. Furthermore, three-dimensional channel formed by graphene flakes could increase the degassing speed and reduce the negative effects of bubbles. The Gr/CA composite has excellent mechanical properties and, more importantly, it is a natural and environmentally friendly polymer composite.

One-step green synthesis of graphene nanomesh by fluid-based method

A fluid-based method is demonstrated for preparing graphene nanomeshes (GNMs) directly from pristine graphite flakes by a one-step process. The high efficiency is attributed to the combination of fluid-assisted exfoliation and perforation of the graphene sheets. Atomic force microscopy shows that the as-produced GNMs are less than 1.5 nm thick. The total area of the pores within 1 μm2 of the GNM sheet is estimated as ∼0.15 μm2 and the pore density as ∼22 μm−2, The yield of GNMs from pristine graphite powder and the power consumption for per gram GNM synthesis are evaluated as 5 wt% and 120 kW h, respectively. X-ray photoelectron spectroscopy, infrared spectroscopy, elemental analysis and Raman spectroscopy results indicate the purity of the GNMs and thus it is a green efficient method. The present work is expected to facilitate the production of GNMs in large scale.

One-step in situ preparation of liquid-exfoliated pristine graphene/Si composites: towards practical anodes for commercial lithium-ion batteries

The cost-effective, scalable, and reproducible production of a graphene/Si (Gra/Si) composite still holds the key to their commercialization as anodes for lithium-ion batteries (LIBs). Herein, we report the one-step in situ preparation of liquid-exfoliated Gra/Si composites towards practical anodes for commercial LIBs. The Gra/Si composites are prepared by exposing the mixture of pristine graphite flakes and Si nanoparticles to ultrasonication in water/surfactant solutions. The composites major ingredients are found to be highly exfoliated graphene and crystal Si nanoparticles. As the anode in LIBs, the composite with ∼47.3 wt% Si shows improved electrochemical performance, with superiorly rate performance and a high reversible capacity of 700 mA h g−1 after 100 cycles. The improved performance is ascribed to the graphene-derived 3D porous structure, which makes the Si nanoparticles well dispersed and buffers the volume change during the charge–discharge cycles. With respect to the simple and scalable liquid-exfoliated Gra/Si composite, the achieved performance here is fascinating for commercial LIBs.

Direct exfoliation of graphite in water with addition of ammonia solution

To bring graphene closer to its real-world applications, finding a green, low-cost, environment-friendly and less toxic solvent for production of high-quality graphene is highly demanded. However, water, the most widely used green solvent, is generally considered to be a poor solvent for hydrophobic graphene. In this study, we exfoliate graphene nanosheets directly in basic water without surfactants, polymers or organic solvents. The addition of a small amount of ammonia solution achieves the exfoliation of few-layer graphene nanosheets from pristine graphite. Diverse characterization methods are employed to investigate the morphology and quality of as-prepared graphene sheets. The release of gaseous ammonia plays the key role in exfoliation of graphene. The concentration of stable graphene dispersions can reach 0.058mg/mL.

The Study and Preparation of Petroleum Coke Oil Slurry for Diesel Engine

An amount of 1.8 μm of ultra-fine petroleum coke was prepared by air jet mill and used to prepare the petroleum coke oil slurry for a diesel engine. The results indicated that the viscosity of the slurry decreased from 587 to 305 mPa·S, when the amount of additive NDZ-105 increased from 0 to 2 wt%. The coke oil slurry was used in the modified R180 diesel engine, and the results showed that the engine maximum power reduced by 19% compared with burning diesel fuel, and the smoke emission was 2–5 times higher than burning diesel fuel.

AFM study of the vinyl triethoxysilane (A-151) film prepared by spraying deposition and dipping deposition

The vinyl triethoxysilane (A-151) film was prepared by the spraying deposition and dipping deposition technique. The surface topography and growth behavior of A-151 films was investigated by using atomic force microscopy (AFM) and static water contact angle measurements. The results indicate that the topography was strongly affected by the treatment conditions. The surface topography of silane film was changed from the islands morphology to the network morphology with the increasing temperature of SiO2 substrate, and the larger self-polymerized silane aggregation will be formed by using the ultrasonic technology. The hydrophobicity of the SiO2 substrate was improved after A-151 deposition.