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关键词： Oxides   Nanowires   Electrical properties   Electrodes   Metal organic frameworks  

摘要： Metal-organic frameworks (MOFs) can serve as high-surface-area templates to generate hierarchically ordered nanoporous carbon electrodes for high-performance supercapacitor devices. Here we describe a simple chemical approach to synthesize dense three-dimensional (3D) arrays of core-shell ZnO@ZIF-8 and Co(CO3)(0.5)(OH)center dot 0.11H(2)O@ZIF-67 nanowires on a conductive carbon cloth. Annealing the core-shell structures at high temperatures converted the MOF shell into a composite of nanoporous carbon (NC) mixed with conductive metal oxides. The conformal nature of the MOF-coating process generates a NC film with continuous conductive paths from the outer surfaces of the nanowires down to the flexible carbon electrode. Carbonization of ZIF-67 transforms the material into conductive sp(2) type carbon mixed with Co3O4 nanostructures. Because Co3O4 is a faradic metal oxide with a high theoretical capacitance, these Co3O4/NC hybrid heterostructure arrays are a promising candidate material for use in an electrochemical supercapacitor device. The Co3O4/NC hybrid electrodes had good performance and exhibited a high areal capacitance of 1.22 ***(-2) at 0.5 ***(-2). Conformal deposition of MOFs via the chemical vapor method offers a promising new platform to design conductive, ultrahigh surface area electrodes that preserve the 3D morphology for applications in supercapacitors and electrocatalysis.

关键词： Coral sand aggregate   Supplementary cementitious materials   Durability   Microstructure   Internal curing  

摘要： This paper was investigated the durability performances of coral sand concrete (CSC) production by using porous coral sand aggregate and supplementary cementitious materials (SCMs) compared to river sand concrete (RSC). The durability properties of CSC were evaluated in terms of chloride penetration, water absorption, drying shrinkage, accelerated carbonation, and sulfate drying-wetting cycle. The results indicated that the CSC exhibited higher drying shrinkage, capillary water absorption, carbonation depths, and a slightly lower later compressive strength compared with RSC. However, porous coral aggregate provided a more rapid early age strength, better resistance to chloride ion penetration, and sulfate drying wetting cycle than the RSC due to its internal curing. Additionally, the combinations of internal curing and pozzolanic reaction contributed to the microstructure improvement of CSC, which conformed good durability properties of CSC containing SCMs. Moreover, the ecological evaluation demonstrated that the CSC incorporation of SCMs resulted in a significant reduction of CO2 emission. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Silicon oxide   Reduced graphene oxide   Meso-porous structure   Hybrid material   Anode material for LIBs  

摘要： rGO wrapped SiOx with ordered meso-porous structure material is fabricated via a facile route. This meso-porous SiOx/rGO composite, used as anode in LIBs, exhibits a reversible capacity of 580 mAh g(-1) under the applied current density of 100 mAg(-1) up to 200 cycles. And it still can deliver a reversible capacity of 120 mAh g(-1) even at 10,000 mA g(-1) rate. The high cyclic stability and superior rate performance is attributed to the graphene layer as well as the inert products formed in the reduction of SiOx, which can buffer the volume expansion elastically, thus preserve the integrity of the electrode. Moreover, the ordered meso-porous structure can provide high specific surface area, sufficient void space to shorten the pathway of Li ions, improve the electrolyte penetration and enhanced the electrochemical Li ion storage. (c) 2018 Elsevier Ltd. All rights reserved.