Functionalization of Hydrogenated Graphene: Transition‐Metal‐Catalyzed Cross‐Coupling Reactions of Allylic C−H Bonds

The chemical functionalization of hydrogenated graphene can modify its physical properties and lead to better processability. Herein, we describe the chemical functionalization of hydrogenated graphene through a dehydrogenative cross‐coupling reaction between an allylic C?H bond and the α‐C?H bond of tetrahydrothiophen‐3‐one using Cu(OTf)₂ as the catalyst and DDQ as the oxidant. The chemical functionalization was confirmed by X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy and visualized by scanning electron microscopy. The functionalized hydrogenated graphene material demonstrated improved dispersion stability in water, bringing new quality to the elusive hydrogenated graphene (graphane) materials. Hydrogenated graphene provides broad possibilities for chemical modifications owing to its reactivity.     

高支化梳型聚芳醚砜/咪唑鎓盐功能化氧化石墨烯阴离子交换复合膜的制备与性能

通过Williamson反应,在羟基化氧化石墨烯(GO-OH)表面修饰1-(6-溴己基)-3-甲基咪唑溴化物(6BrIm),合成了1-(6-溴己基)-3-甲基咪唑溴化物功能化氧化石墨烯(6BrIm-GO)。将6BrIm-GO引入高支化梳型聚芳醚砜(ImHBPES-8)基体中,经物理共混、浇铸成膜及离子交换,制备了一系列阴离子交换纳米复合膜(ImHBPES-8/x-6BrIm-GO). 6BrIm-GO的引入,既作为一种功能纳米填料,又提供了更多OH-离子传输位点,在提高ImHBPES-8膜机械强度的同时保证了离子电导率。研究了引入6BrIm-GO的含量对ImHBPES-8膜结构与性能的影响。研究结果表明,引入6BrIm-GO后,ImHBPES-8膜整体性能均得到改善。当6BrIm-GO含量为0. 75%时,ImHBPES-8/0. 75%-6BrIm-GO复合膜的综合性能最佳,其拉伸强度为18. 32 MPa,与ImHBPES-8膜相比,提高了22. 9%; 80℃下OH^-离子电导率最高达79. 8 mS/cm。将ImHBPES-8/0. 75%-6BrIm-GO...     

Density Functional Theory Study on NiNx (x = 1, 2, 3, 4) Catalytic Hydrogenation of Acetylene

In this study, using the application of density functional theory, the mechanism of graphene-NiN_x (x = 1, 2, 3, 4) series non-noble metal catalysts in acetylene hydrogenation was examined under the B3LYP/6-31G** approach. With the DFT-D3 density functional dispersion correction, the effective core pseudopotential basis set of LANL2DZ was applied to metallic Ni atoms. The reaction energy barriers of NiN_x catalysts are different from the co-adsorption structure during the catalytic hydrogenation of graphene-NiN_x (x = 1, 2, 3, 4). The calculated results showed that the energy barrier and selectivity of graphene-NiN₄ for ethylene production were 25.24 kcal/mol and 26.35 kcal/mol, respectively. The low energy barrier and high activity characteristics showed excellent catalytic performance of the catalyst. Therefore, graphene-NiN₄ provides an idea for the direction of catalytic hydrogenation.     

Theoretical Study on the Aggregation and Adsorption Behaviors of Anticancer Drug Molecules on Graphene/Graphene Oxide Surface

Graphene and its derivatives are frequently used in cancer therapy, and there has been widespread interest in improving the therapeutic efficiency of targeted drugs. In this paper, the geometrical structure and electronic effects of anastrozole(Anas), camptothecin(CPT), gefitinib (Gefi), and resveratrol (Res) on graphene and graphene oxide(GO) were investigated by density functional theory (DFT) calculations and molecular dynamics (MD) simulation. Meanwhile, we explored and compared the adsorption process between graphene/GO and four drug molecules, as well as the adsorption sites between carriers and payloads. In addition, we calculated the interaction forces between four drug molecules and graphene. We believe that this work will contribute to deepening the understanding of the loading behaviors of anticancer drugs onto nanomaterials and their interaction.     

石墨烯的结构、性能及潜在应用

石墨烯是一种二维零带隙半金属材料,近年来受到学术界和工业界的广泛关注。文章将石墨烯合成方法分为固、液、气三类并分别加以讨论,介绍了石墨烯的结构和缺陷特征及其电、光、热、力学等性能。石墨烯的应用研究主要集中在电学、力学、选择性分离膜、基底和生长衬底等方面。     

The Influence of N‐doped Carbon Materials on Supported Pd: Enhanced Hydrogen Storage and Oxygen Reduction Performance

N‐doped graphene has become an important support for Pd in both hydrogen storage and catalytic reactions. The molecular orbitals of carbon materials (including graphene, fullerene, and small carbon clusters) and those of the supported Pd species will hybrid much stronger as N dopants are introduced, owing to the increased electrostatic attraction at the interface. This enhances the carbon substrates′ catching force for the supported Pd, preventing its leaching and aggregation in many practical applications. The better dispersion and stabilization of Pd nanoparticles, which are induced by various carbon supports with N‐doping, are pleasing to us and could increase their efficiency and facilitate their recycling during various reaction processes in several fields.     

Graphene applications in electronic and optoelectronic devices and circuits

Recent progress of research for graphene applications in electronic and optoelectronic devices is reviewed, and recent developments in circuits based on graphene devices are summarized. The bandgap-mobility tradeoff inevitably constrains the application of graphene for the conventional field-effect transistor （FET） devices in digital applications. However, this shortcoming has not dampened the enthusiasm of the research community toward graphene electronics. Aside from high mobility, graphene offers numerous other amazing electrical, optical, thermal, and mechanical properties that continually motivate innovations.     

Resonant tunneling through double-barrier structures on graphene

Quantum resonant tunneling behaviors of double-barrier structures on graphene are investigated under the tightbinding approximation. The Klein tunneling and resonant tunneling are demonstrated for the quasiparticles with energy close to the Dirac points. The Klein tunneling vanishes by increasing the height of the potential barriers to more than 300 meV. The Dirac transport properties continuously change to the Schro¨dinger ones. It is found that the peaks of resonant tunneling approximate to the eigen-levels of graphene nanoribbons under appropriate boundary conditions. A comparison between the zigzag- and armchair-edge barriers is given.     

Thermal transport properties of defective graphene:A molecular dynamics investigation

In this work the thermal transport properties of graphene nanoribbons with randomly distributed vacancy defects are investigated by the reverse non-equilibrium molecular dynamics method. We find that the thermal conductivity of the graphene nanoribbons decreases as the defect coverage increases and is saturated in a high defect ratio range. Further analysis reveals a strong mismatch in the phonon spectrum between the unsaturated carbon atoms in 2-fold coordination around the defects and the saturated carbon atoms in 3-fold coordination, which induces high interfacial thermal resistance in defective graphene and suppresses the thermal conductivity. The defects induce a complicated bonding transform from sp2 to hybrid sp–sp2network and trigger vibration mode density redistribution, by which the phonon spectrum conversion and strong phonon scattering at defect sites are explained. These results shed new light on the understanding of the thermal transport behavior of graphene-based nanomaterials with new structural configurations and pave the way for future designs of thermal management phononic devices.