Mi Zhou

Low-Temperature Aluminum Reduction of Graphene Oxide, Electrical Properties, Surface Wettability, and Energy Storage Applications

Low-temperature aluminum (Al) reduction is first introduced to reduce graphene oxide (GO) at 100-200 °C in a two-zone furnace. The melted Al metal exhibits an excellent deoxygen ability to produce well-crystallized reduced graphene oxide (RGO) papers with a low O/C ratio of 0.058 (Al-RGO), compared with 0.201 in the thermally reduced one (T-RGO). The Al-RGO papers possess outstanding mechanical flexibility and extremely high electrical conductivities (sheet resistance R(s) ~ 1.75 Ω/sq), compared with 20.12 Ω/sq of T-RGO. More interestingly, very nice hydrophobic nature (90.5°) was observed, significantly superior to the reported chemically or thermally reduced papers. These enhanced properties are attributed to the low oxygen content in the RGO papers. During the aluminum reduction, highly active H atoms from H(2)O reacted with melted Al promise an efficient oxygen removal. This method was also applicable to reduce graphene oxide foams, which were used in the GO/SA (stearic acid) composite as a highly thermally conductive reservoir to hold the phase change material for thermal energy storage. The Al-reduced RGO/SnS(2) composites were further used in an anode material of lithium ion batteries possessing a higher specific capacity. Overall, low-temperature Al reduction is an effective method to prepare highly conductive RGO papers and related composites for flexible energy conversion and storage device applications.

Carbon dioxide capture in amorphous porous organic polymers

The sharply rising level of atmospheric carbon dioxide resulting from anthropogenic emissions is one of the greatest environmental concerns nowadays. Capture and storage of carbon dioxide (CCS) from coal- or gas-burning power plants is an attractive route to reducing carbon dioxide emissions into the atmosphere. Porous organic polymers (POPs) have been recognized as a very promising candidate for carbon dioxide capture due to their low density, high thermal and chemical stability, large surface area, tunable pore size and structure, and facilely tailored functionality. In this review, we aim to highlight the POPs for CO2 capture and summarize the factors influencing CO2 capture capacity, such as surface area and pore structure, swellable polymers, heteroatomic skeleton and surface functionalized porous organic polymers.

Directional architecture of graphene/ceramic composites with improved thermal conduction for thermal applications

Directional heat transfer can provide an efficient way for thermal management in thermal transfer, thermal energy storage, etc. A novel growth method is proposed to synthesize continuous graphene films on insulating substrates by Ni-assisted chemical vapor deposition (CVD) at relatively low temperature down to 800 °C. Uniformly dispersed Ni nanoparticles on ceramic substrates play an important role of capturing carbon atoms and accelerating the nucleation to grow high quality graphene rooted on insulating ceramic substrates (anodic aluminum oxide, cordierite). The graphene species consist of 1D isolated graphene tubes coated on AAO, which can act as the media for directional thermal transport. The graphene/Ni/cordierite composite contains an interconnected macroporous graphene framework with a low sheet electrical resistance down to 8.6 Ω sq−1 and thermal conductivity of 4.17 W m−1 K−1. The porous graphene/Ni/cordierite composite can hold phase change materials (woods alloy) to construct efficient thermal energy storage devices due to its high thermal conductivity, which can be used as heat sinks in thermoelectric devices. This work displays the great potential of CVD direct growth of graphene on insulating porous substrates for directional heat conduction, thermal management and thermoelectric applications.

Syntheses of 5′-O-glycosylnucleosides

Abstract A general synthetic approach to 2,3-unsaturated glycosides connecting with nucleosides involving Ferrier rearrangements of glycals is discussed. The new compounds were identified by NMR and MS (HRFAB + ). The hydroxylation of the resulting 2,3-unsaturated glycosides was completed using OsO 4 to give 5′- O -glycosylnucleosides in good yield.

A three-dimensional elastic macroscopic graphene network for thermal management application

A three-dimensional elastic macroscopic graphene network (3D-GN) was prepared with the assistance of porous SiO2 ceramic substrates by using ambient pressure chemical vapor deposition, which is suitable for thermal management application. The free standing elastic macroscopic 3D-GN possesses excellent electrical, mechanical and thermal transfer properties.

Rapid microwave synthesis of graphene directly on h-BN with excellent heat dissipation performance.

We report a new rapid household microwave method to successfully grow graphene on h-BN flakes without using any catalysts. We obtained a novel uniform multilevel matrix of vertical graphene sheets on h-BN flakes. The unique structure possessed outstanding electron conductivity and thermal properties (29.1 W m(-1) K(-1)).

3D metal-organic frameworks based on lanthanide-seamed dimeric pyrogallol[4]arene nanocapsules

Two novel 3D metal-organic frameworks (MOFs) with cds network, {[MeNH3]7[Ln8(PgC2)2(H2O)y(HCOO)7]}n·x(Solvent) (FJIY4, FJI=Fujian Institute, Ln=Gd, y=12; FJI-Y5, Ln=Dy, y=11; PgC2=C-ethylpyrogallol[4]arene), based on unprecedented dimeric pyrogallol[4]arene-based Ln8 metal-organic nanocapsule (MONC) supramolecular building blocks and formate linkers, have been prepared under solvothermal conditions. To our best of knowledge, they present not only the first two examples of 3D hierarchical structures constructed from MONCs in metal-pyrogallol[4]arene system, but also the first two examples of MOFs based on lanthanide MONCs. Remarkably, the inner cavity volume of the Ln8 capsule in FJI-Y4 and FJI-Y5 is approximately 151 Å3, which is larger than those found in previous transition metal-seamed dimeric PgCn-based MONCs. Magnetic investigation on FJI-Y4 suggests a significant magnetocaloric effect (23.97 J kg−1 K−1, ΔH=7 T, 2.5 K), while FJI-Y5 exhibits slow relaxation of the magnetization.