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1.
Brian Holland 《Journal of Porous Materials》2003,10(1):17-22
Three-dimensionally ordered silica structures containing both mesopores and macropores are created using polystyrene coacervate spheres with a diameter of ca. 146 nm. The close-packed polystyrene coacervate spheres are intercalated with tetraethyl orthosilicate. The spheres are removed by calcination leaving an inverse silica replica with a spherical macropore cavity diameter of 110 nm. Due to the nature of these porous structures, pores leading into the macropore cavity are in the mesopore regime, 40 nm in diameter. The nitrogen adsorption data described in the following paper gives a pore size for both the macropore cavity and the mesopore openings leading into the cavity. The pore sizes as determined by nitrogen sorption are in good agreement with the pore sizes observed by scanning electron microscopy. Mercury intrusion porosimetry results confirm the size of the mesopore openings leading into the macropore cavity, however due to destruction of the sample upon intrusion, extrusion results can not be obtained to determine main cavity diameters. As a result, nitrogen sorption may be a viable option for determining pore sizes with these three-dimensionally ordered materials containing both mesopores and macropores. 相似文献
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Shipra Jain Jyoti Shah Nainjeet Singh Negi Chhemendra Sharma Ravinder Kumar Kotnala 《国际能源研究杂志》2019,43(9):4743-4755
Recent increase in energy demand and associated environmental degradation concern has triggered more research towards alternative green energy sources. Eco‐friendly energy in facile way has been generated from abundantly available iron oxides using only few microliters of water without any external energy source. Hydroelectric cell (HEC) compatible to environment benign, low cost oxygen‐deficient mesoporous hematite nanoparticles has been used for splitting water molecules spontaneously to generate green electricity. Hematite nanoparticles have been synthesized by coprecipitation method. Chemidissociated hydroxyl group presence on hematite surface has been confirmed by infrared spectroscopy (IR) and X‐ray photoelectron spectroscopy (XPS). Surface oxygen vacancies in nanostructured hematite have been identified by transmission electron microscopy (TEM), XPS, and photoluminescence (PL) measurement. Hematite‐based HEC delivers 30 mA current with 0.92 V emf using approximately 500 μL water. Maximum off‐load output power 27.6 mW delivered by 4.84 cm2 area hematite‐based HEC is 3.52 times higher than reported 7.84 mW power generated by Li‐magnesium ferrite HEC. Electrochemistry of HEC in different irreversible polarization loss regions has been estimated by applying empirical modeling on V‐I polarization curve revealing the reaction and charge transport mechanism of cell. Tafel slope 22.7 mV has been calculated by modeling of activation polarization overvoltage region of 0.11 V. Low activation polarization indicated easy charge/ion diffusion and faster reaction kinetics of Ag/Zn electrode owing to lesser energy barrier at interface. Dissociated H3O+ ions diffuse through surface via proton hopping, while OH? ions migrate through interconnected defective crystallite boundaries resulting into high output cell current. 相似文献
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Gene Delivery: Large‐Pore Ultrasmall Mesoporous Organosilica Nanoparticles: Micelle/Precursor Co‐templating Assembly and Nuclear‐Targeted Gene Delivery (Adv. Mater. 2/2015)
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4.
Junlei Xiao Hua Zhang Yifan Wang Chunmei Zhang Shuijian He Shaohua Jiang 《Frontiers of Chemical Science and Engineering》2023,17(4):387
Porous carbons with high specific area surfaces are promising electrode materials for supercapacitors. However, their production usually involves complex, time-consuming, and corrosive processes. Hence, a straightforward and effective strategy is presented for producing highly porous carbons via a self-activation procedure utilizing zinc gluconate as the precursor. The volatile nature of zinc at high temperatures gives the carbons a large specific surface area and an abundance of mesopores, which avoids the use of additional activators and templates. Consequently, the obtained porous carbon electrode delivers a satisfactory specific capacitance and outstanding cycling durability of 90.9% after 50000 cycles at 10 A∙g–1. The symmetric supercapacitors assembled by the optimal electrodes exhibit an acceptable rate capability and a distinguished cycling stability in both aqueous and ionic liquid electrolytes. Accordingly, capacitance retention rates of 77.8% and 85.7% are achieved after 50000 cycles in aqueous alkaline electrolyte and 10000 cycles in ionic liquid electrolyte. Moreover, the symmetric supercapacitors deliver high energy/power densities of 49.8 W∙h∙kg–1/2477.8 W∙kg–1 in the Et4NBF4 electrolyte, outperforming the majority of previously reported porous carbon-based symmetric supercapacitors in ionic liquid electrolytes. 相似文献
5.
《International Journal of Hydrogen Energy》2019,44(43):23975-23982
In order to simultaneously inhibit the Ni sintering and coke formation as well as investigate the effects of WO3 promoter on catalytic performance, the ordered mesoporous Ni–WO3/Al2O3 catalysts were synthesized by a facile one-pot evaporation-induced self-assembly method for CO methanation reaction to produce synthetic natural gas. Addition of WO3 species could significantly promote the catalytic activity due to the enhancement of the Ni reducibility and the increase of active centers, and the optimal N10W5/OMA catalyst with NiO of 10 wt% and WO3 of 5 wt% achieved the maximum CH4 yield 80% at 425 °C, 0.1 MPa and a weight hourly space velocity of 60000 mL g−1 h−1. Besides, the reference catalyst N10W5/OMA-Im prepared by the conventional co-impregnation method was also evaluated. Compared with N10W5/OMA, N10W5/OMA-Im showed lower catalytic activity due to the partial block of channels by Ni and WO3 nanoparticles, which reduced active centers and restrict the mass transfer during the reaction. In addition, the N10W5/OMA catalyst showed superior anti-sintering and anti-coking properties in a 425oC-100 h-lifetime test, mainly because of confinement effect of ordered mesoporous structure to anchor the Ni particle in the alumina matrix. 相似文献
6.
Jieqiong Qin Jianmei Gao Xiaoyu Shi Junyu Chang Yanfeng Dong Shuanghao Zheng Xiao Wang Liang Feng Zhong‐Shuai Wu 《Advanced functional materials》2020,30(16)
Planar integrated systems of micro‐supercapacitors (MSCs) and sensors are of profound importance for 3C electronics, but usually appear poor in compatibility due to the complex connections of device units with multiple mono‐functional materials. Herein, 2D hierarchical ordered dual‐mesoporous polypyrrole/graphene (DM‐PG) nanosheets are developed as bi‐functional active materials for a novel prototype planar integrated system of MSC and NH3 sensor. Owing to effective coupling of conductive graphene and high‐sensitive pseudocapacitive polypyrrole, well‐defined dual‐mesopores of ≈7 and ≈18 nm, hierarchical mesoporous network, and large surface area of 112 m2 g?1, the resultant DM‐PG nanosheets exhibit extraordinary sensing response to NH3 as low as 200 ppb, exceptional selectivity toward NH3 that is much higher than other volatile organic compounds, and outstanding capacitance of 376 F g?1 at 1 mV s?1 for supercapacitors, simultaneously surpassing single‐mesoporous and non‐mesoporous counterparts. Importantly, the bi‐functional DM‐PG‐based MSC‐sensor integrated system represents rapid and stable response exposed to 10–40 ppm of NH3 after only charging for 100 s, remarkable sensitivity of NH3 detection that is close to DM‐PG‐based MSC‐free sensor, impressive flexibility with ≈82% of initial response value even at 180°, and enhanced overall compatibility, thereby holding great promise for ultrathin, miniaturized, body‐attachable, and portable detection of NH3. 相似文献
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Zhenhao Wei Tengfei Xia Minghui Liu Qingsheng Cao Yarong Xu Kake Zhu Xuedong Zhu 《Frontiers of Chemical Science and Engineering》2015,9(4):450-460
The effects of alkaline treatment on the physical properties of ZSM-5 catalysts and on their activities for methanol to aromatics conversion have been investigated. A mild alkaline treatment (0.2 and 0.3 mol/L NaOH) created mesopores in the parent zeolite with no obvious effect on acidity. The presence of mesopores gives the catalyst a longer lifetime and higher selectivity for aromatics. Treatment with 0.4 mol/L NaOH decreased the number of Brønsted acid sites due to dealumination and desilication, which resulted in a lower deactivation rate. In addition, more mesopores were produced than with the mild alkaline treatment. As a result, the lifetime of the sample treated with 0.4 mol/L NaOH was almost five times that of the parent ZSM-5. Treatment with a higher alkaline concentration (0.5 mol/L) greatly reduced the number of Brønsted acid sites and the number of micropores resulting in incomplete methanol conversion. When the alkaline-treated catalysts were washed with acid, some of the porosity was restored and a slight increase in selectivity for aromatics was obtained. 相似文献
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A kind of core–shell hybrid composite (P@BMMs) as a drug carrier was prepared through seed polymerization method, in which, biomodal mesoporous materials (BMMs) as core and copolymer poly(N-isopropylacryl-acrylamide)-co-poly(acrylicacid) [P(NIPAM-co-AA)] with pH- and temperature-responsive characteristics as shell. Its structural features and textural parameters were characterized using various techniques. The kinetic and thermodynamic evaluation demonstrated the existence of hydrogen bond interaction between IBU and P(NIPAM-co-AA)-coated surfaces. Meanwhile, the smart thermo/pH-responsive properties of ibuprofen (IBU) release could be regulated through adjusting coated amount of copolymer. Specially, the responsive properties of P@BMMs were traced by small-angle X-ray scattering technique, suggesting the surface roughness and structural irregularities. 相似文献