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Hydroxyapatite ( HAp) hollow microspheres with hierarchically porous structure and nanorice-like architecture units were synthesized by the composite-hydroxide approach. NH4 H2 PO4 was first reacted with hydroxides to form a hydroxide-insoluble M3 PO4 (the term M represents either Na or K). The diffusing M3 PO4 at the liquid-solid interface then reacted with the Ca( OH)2, forming insoluble HAp hollow spheres by Kirkendall process. Results show that when reaction time is increased from 3 to 12 h, the average diameter of the microspheres increased from 2.64 to 4.16 μm. In addition, the size homogeneity of the hollow microspheres was improved gradually due to Ostwald ripening. The prepared hollow microspheres were treated by ultrasound, and nanorice-like component units with a large mass of mesopores (<10 nm) were displayed. These prepared HAp hollow microspheres might be expected to apply to ion adsorption and drug delivery. [ABSTRACT FROM AUTHOR]

Abstract: Crosslinked carbon network with interconnected pores were obtained from [furfuryl alcohol (FA) + phenol–formaldehyde resin (PF)] – ethylene glycol (EG) mixtures. The effect of FA/PF weight ratio (W F/P) on the pore structure of the porous carbons has been systematically investigated. The results showed that porous carbons with controlled pore size could be obtained by varying W F/P in the polymer system. With W F/P increased, the average pore size and apparent porosity increased from 11.8 to 127.7 nm and from 40.9 to 51.6%, respectively, and the pore size distribution broadened. The property change of the porous carbons was a result of polymerization dynamics change on curing of resin–glycol mixtures induced by varying W F/P in the polymer system. Increasing the initial W F/P led curing reactions to occur at relatively lower temperatures, and the degree of polymerization to increase after heat treatment at 150 °C for 16 h, thus cured bodies with different chemical structures were obtained. [Copyright &y& Elsevier]

Abstract: We prepared hydroxyapatite/alumina (HA/Al2O3) porous composite materials by the in situ growth of HA on lamellar Al2O3 ceramics. The procedure comprises two steps. First, lamellar Al2O3 ceramics with aligned pore channels were obtained by freeze casting Al2O3 slurry. Second, as-prepared monoliths were used as scaffolds and subjected to hydrothermal treatment in the HA precursor solution. We characterized the microstructure, chemical composition, and mechanical properties of synthesized HA/Al2O3. Experiment results show that the addition of H2O2 into the reaction solution plays an important role in controlling the microstructure of the cultivated HA. The formation of HA has no obvious influence on the lamellar architecture of Al2O3 ceramics. The prepared composite materials exhibit superior compressive strength. Combination of the high strength of lamellar Al2O3 with the excellent biological properties of HA increases the potential of obtained HA/Al2O3 for load-bearing biological applications. [Copyright &y& Elsevier]

Abstract: Hierarchically porous silica ceramics with unidirectionally aligned channel morphology have been synthesized by in situ mineralization of soluble starch monolith. The procedure followed two steps. First, soluble starch monoliths with well-defined uniaxial macroporous structure were prepared by unidirectional solidification process of starch hydrosol or starch hydrogel. Second, such an as-prepared artificial monolith, used as template, was soaked into a surfactant-templated sol–gel solution to mineralize the existing channel structure. It was shown that the macropore size, wall thickness, and macropore morphology in obtained soluble starch materials may be tuned in a certain range, through adjusting the concentration of starch slurry. When initial concentration changed from 10 wt.% to 15 wt.%, the macropore size of soluble starch materials decreased, while the wall thickness increased. Through the second step, porous silica ceramics were obtained after drying and calcining of organic–inorganic hybrid silicate compounds from solution. These resulting products preserved template microstructure in great detail and exhibited narrow macropore size distributions. It was observed that when the soaking time increased from 36h to 84h, the average pore size of the silica ceramics was decreased from 4.1μm to 3.6μm. In addition, in nanopore regime, all the silica monoliths obtained presented a coexistence of uniform worm-like nanopore and lamellar phase feature, and large BET and microporous surface area. [Copyright &y& Elsevier]

Abstract: Experiments have been performed to show that the mechanical properties of alumina porous ceramics may be improved by introducing glycerol into the raw slurries and then casting them under a constant cooling rate. The effects of glycerol on the freeze casting process and thereby on the microstructure and mechanical properties of porous ceramics obtained are investigated. It is shown that the addition of glycerol will increase both the slurry viscosity and sample sintered density. SEM images for microstructure of the final ceramics reveal that a good connection between ceramic lamellae has been promoted. This connection makes as-prepared porous ceramics obtain high mechanical properties. For the 30vol.% alumina slurry with glycerol, the axial and radial compression strengths reach to, respectively, 255.1MPa and 105.8MPa. [Copyright &y& Elsevier]

Abstract: Homogeneous porous carbons with narrow pore size distributions have been obtained from phenolic resin/furfuryl alcohol/ethylene glycol resin mixtures based on polymer blend carbonization. The effect of curing catalyst content (w b ) on the polymerization process of the resin mixtures and the pore structure of the porous carbons has been systematically investigated. The results show that higher w b results in bigger pore size, thicker carbon skeleton and higher apparent porosity. The morphological and pore structural change of the porous carbons is induced by phase separation dynamics and reaction kinetics change on curing of initial resin compositions, by varying w b in the resin–glycol mixtures. More curing catalyst results in chemical reactions between phenolic resin and furfuryl alcohol occurring at a higher speed and the polymerization degree of the cured bodies increases. [Copyright &y& Elsevier]

Abstract: Porous carbons were prepared from resin mixtures containing furfuryl alcohol (FA) and phenolic-formaldehyde resin (PF) as the carbon precursors. The effect of FA/PF mass ratio on the pore structure of the porous carbons was systematically investigated. Crosslinked carbon network could be obtained with the mass ratio of FA and PF changing from 0:10 to 3:7. With increasing FA content in the mixtures, the pore size distribution of carbon monoliths broadened, and the average pore size and apparent porosity of the carbonized products increased from 11.8 to 127.7nm and from 40.9% to 51.6%, respectively. The morphological and pore structure change of the porous carbons was a result of polymerization kinetics change induced by varying the FA/PF mass ratio in the polymer system on curing of initial resin compositions. Increasing FA/PF mass ratio led increased atomic order to occur in the amorphous structure. [Copyright &y& Elsevier]

Abstract: TiO2/carbon paper composite materials with a hierarchically porous structure were synthesized by employing a filter paper as the support material and carbon source. The resorcinol–formaldehyde–block copolymer nanocomposite formed by the self-assembly of phenolic resin and F127 under acidic condition was selected as modifier of the microstructure of carbon paper. Results show that the as-adjusted carbon paper preserved the nanostructure of a pure carbonized filter paper. An ordered mesostructure was also formed. This micromorphology resulted in the increased specific surface area, as well as micropore and mesopore volumes, compared with the pure carbonized filter paper. When mesoporous TiO2 was deposited on the carbon paper with ordered mesopore by the evaporation-induced self-assembly route, the TiO2/carbon paper composite materials displayed excellent adsorption property and enhanced photocatalytic activity of methylene blue. [Copyright &y& Elsevier]

Abstract: The relative dielectric constant of three-phase porous composite materials was calculated by finite element methods, in which the geometric model was established by Monte Carlo technique and three kinds of materials were distributed in fixed proportion randomly. The variation of relative dielectric constant for three-phase materials coincided with the logarithm model very well, but for three-phase porous composite materials, changes of relative dielectric constant were different with that of three-phase materials. After careful consideration and trying, a calculation model was induced according to the computational solution. The values calculated by this model were in good agreement with the experimental findings. [Copyright &y& Elsevier]

Greenhouse effect has become one of the most rigorous topics of environmental protection. The emission of one of the most typical greenhouse gas SF 6 should be controlled and the waste gas treatment of SF 6 has become a major topic to reduce the greenhouse effect. Two-dimensional porous materials have been widely used in gas adsorption and separation which may be useful for adsorbing waste SF 6 gas. In this study, we report a promising adsorbent, transition metal dimer decorated C 2 N monolayer, for SF 6 treatment by theoretical evaluation. The adsorption of SF 6 molecule over the C 2 N surface are explored including the adsorption energy, electron transfer, magnetic moment and the electronic properties. Also, the decomposition process of SF 6 molecule over the TM 2 -C 2 N monolayer is also considered. The results show that the SF 6 can only be physical adsorption over the pristine C 2 N monolayer and experiences obvious decomposition over the Co 2 –C 2 N and Ni 2 –C 2 N monolayer. The adsorption with molecule decomposition can also significantly change the electronic properties of TM 2 -C 2 N. The low energy barrier of decomposition process over the TM 2 -C 2 N ensures good performance of adsorbent for SF 6 in practical applications. This study provides theoretical foundation for TM 2 dimer C 2 N monolayer as a promising adsorbent, scavenger and even catalytic material for degradation of greenhouse gas SF 6 and waste gas treatment. Image 1 • SF 6 can only be adsorbed over the pristine C 2 N monolayer without chemical bond formation. • SF 6 is easy to decompose to SF 4 fragment and two F atoms when adsorbing over the Co 2 –C 2 N and Ni 2 –C 2 N. • The desorption process experiences very low energy barrier over Ni 2 –C 2 N and no barrier over Co 2 –C 2 N. [ABSTRACT FROM AUTHOR]

Porous carbon materials and metal oxides are the most favorite electrode materials for supercapacitors. Herein, we put forward a novel biomass-derived carbon and metal oxide composite which denoted as AGC@MnO 2 (activated ganoderma lucidum spore-derived O and N co-doped nanoporous carbon and pompon-like MnO 2 composite). When tested as electrode material, AGC@MnO 2 exhibits an excellent capacity of 1324 F g−1 at 1 A g−1 in a three-electrode system. Besides, AGC@MnO 2 exhibits a high energy density of 43.75 Wh kg−1 at a low power density of 250 W kg−1 and an ultra-long cycling life of 92.3% retention after 5000 times charge and discharge at 20 A g−1. All of the electrochemical results indicate AGC@MnO 2 is a potential and valuable candidate of electrode materials for supercapacitors. Image, graphical abstract [ABSTRACT FROM AUTHOR]