Novel hybrid organic-geopolymer materials

Novel hybrid organic–inorganic materials were prepared through an innovative synthetic approach based on a co-reticulation in mild conditions of epoxy based organic resins and an MK-based geopolymer inorganic matrix. A high compatibility between the organic and inorganic phases, even at appreciable concentration of resin, was realized up to micrometric level. A good and homogeneous dispersion (without the formation of agglomerates) of the organic particles was obtained just by hand mixing. These new materials present significantly enhanced compressive strengths and toughness in respect to the neat geopolymer allowing a wider utilization of these materials for structural applications.     

Novel polyfluorene copolymers containing porphyrin and thiophene moieties with broad absorption and efficient charge transfer and separation

Summary A novel series of soluble conjugated polyfluorene copolymers comprised of porphyrin and thiophene moieties were synthesized by palladium-catalyzed Suzuki coupling reactions with various feed ratios. Chemical structures of the copolymers were characterized by ¹H NMR and IR. All of the polyfluorene copolymers demonstrated good thermal stability, relatively high glass transition temperatures, and strong absorption over 600 nm and nearly cover 400∼700 nm visible region. It was revealed by cyclic voltammetry that the bandgaps of copolymers were between 1.96 and 2.03 eV. And the polymer:TiO₂ bulk-heterojunction films were made from mixtures of polymer and titanium isopropoxide (Ti(OC₃H₇)₄) via hydrolysis in air. The photoluminescence (PL) at 380∼800 nm of the blend film of PT-TPP20:TiO₂ bulk-heterojunction in the 20% Ti(OC₃H₇)₄ blend film was decreased compared to that of a pristine copolymer film. PL was significantly quenched in the 50% Ti(OC₃H₇)₄ blend film, indicative of rapid and efficient separation of photoinduced electron-hole pairs with electrons on the TiO₂ and holes on the polymer.     

Phase separation in sol–gel derived ZrO2–SiO2 nanostructured materials

Textures formed by phase separation and crystallization of sol–gel derived ZrO₂–SiO₂ materials with 30 mol% ZrO₂, were examined by X-ray diffraction, small angle X-ray scattering and transmission electron microscopy. An amorphous phase separation consisting in silica-rich and zirconia-rich interconnected domains was shown to be present before crystallization. In the initial stage crystallization of metastable tetragonal zirconia, nucleation was considered to occur in the ZrO₂-rich regions. The size and spatial distribution of crystalline particles, dispersed in the amorphous SiO₂-rich matrix, are controlled by the phase separation texture.     

Synthesis of 2-D nanostructured BiVO4:Ag hybrid as an efficient electrode material for supercapacitors

2-D BiVO₄ nanosheets with monoclinic phase were synthesized at room temperature, and incorporated with Ag to form BiVO₄:Ag hybrid materials. The experiments demonstrated that doping Ag has largely increased the electrochemical performances of supercapacitor. Furthermore, the specific capacitance can reach up to 109 F g^–1 at 1 A g^–1 (the undoped one is of 27 F g^–1); energy density has enhanced to 15.2 Wh kg^–1 compared with the pristine one without Ag (3.8 Wh kg^–1). Therefore, doping Ag into bismuth-based compound provides us an alternative approach for the synthesis of 2-D nanostructured hybrid as an efficient electrode material for supercapacitors     

新型有机分离体系渗透汽化膜材料

综述了固载活性基团促进传递膜、新型共聚物和树枝型聚合物材料在提高膜的选择性与渗透通量中的作用.介绍了从分子结构角度设计的材料在提高分离效果与成膜稳定性中的应用,指出了新型高聚物膜材料在渗透汽化分离有机混合物领域具有较好的工业化应用前景.     

A new strategy to realize efficient spacial charge separation on carbonaceous photocatalyst

Dumbbell-like carbonaceous sodium hexagonal tungsten bronze (Na-HTB) materials are constructed as model photocatalysts to show the importance of carbon distribution for the photocatalysis of hybrid nanostructures. It is demonstrated that partially carbon coated on the ends of Na-HTB nanowire bundles shows better photoactivity than bare Na-HTB and overall carbon coated Na-HTB. Photoelectrochemistry measurements such as photocurrent measurement, electrochemical impedance spectroscopy (EIS) and Voltage of open-circuit (Voc) decay experiments are carried out to clarify the influence of carbon distribution on the photoactivity of carbonaceous Na-HTB materials, and the results show that the enhancement of photoactivity is attributed to the efficient spacial charge separation.     

Novel hybrid polyurethane/POSS materials via bulk polymerization

Novel polyurethane (PU)/polyhedral oligomeric silsesquioxane (POSS) hybrid elastomers were synthesised via reaction carried out in bulk. The isocyanate octasubstituted POSS (NCOPOSS) was used as the crosslinking agent for the polyurethane systems, which were similar to those commercially available for the production of urethane elastic materials (in contrast to model systems previously reported in literature). The structure and amorphous morphology of the resulting elastomers were confirmed by FTIR ATR spectroscopy and WAXS measurements, respectively. The elastomers were characterized by their mechanical (tensile, hardness) and thermal (T_g, thermal stability) properties. It was found that the incorporation of small amount (1.2–2.5 wt.%) of the NCOPOSS into the formulation resulted in an improvement or deterioration in mechanical properties of the polymer, depending on the diisocyanate used. Further increase in the NCOPOSS concentration resulted only in a loss of mechanical properties. A possible explanation is an over-crosslinking or wastage of POSS-deriving NCO groups (which did not react earlier with bulky polyols) in the reaction with the chain extender leading to cycle formation. Incorporation of the NCOPOSS into the PU elastomer reduced somewhat thermal stability of the latter probably due to the poor thermal stability of the NCOPOSS itself.     

Novel actuators based on polypyrrole/carbide-derived carbon hybrid materials

Polypyrrole (PPy) hybrid films incorporated with porous carbide-derived carbon (CDC) particles are synthesized through a novel one-step electrochemical synthesis process that provides a simple and efficient alternative for current tape-casting and inkjet printing technologies to make conducting polymer–CDC-based electroactive composites. The resulting porous, robust and electrically conductive hybrid layer was used to fabricate electroactive polymer actuators both as perpendicularly expanding actuators and as bending trilayer actuators. Raman and FTIR spectroscopy confirm successful incorporation of CDC in the PPy matrix. Cyclic voltammograms confirm slightly higher charging/discharging currents of the PPyCDC hybrid. This indicates the successful coupling of CDC in order to increase electric double-layer capacitance in the hybrid films. The maximum steady state electromechanical diametrical strain is 13% for hybrid material which is in the same order of magnitude as for PPy and 10× more than previously reported CDC films made with non-conducting polymer binders. Furthermore, the expanding actuators made from hybrid material are more efficient than non-modified PPy actuators, having doubled the amount of swelling per injected charge. This improvement is very important since the low energy efficiency is a major shortcoming for ionic electroactive polymers. The high pseudocapacitance makes these new hybrid materials also interesting for energy storage applications.     

Engineering interfaces in carbon nanostructured mats for the creation of energy efficient thermal interface materials

One of the few remaining opportunities to increase heat dissipation in IC circuitry is to substantially decrease the thermal interface resistance between solid–solid contacts from source to sink. In this study, heterogeneous nanostructured mats (1–100 μm thick, randomly oriented networks of nanostructures) are synthesized for use as thermal interface materials (TIMs). Recent studies suggest that mats composed entirely of carbon nanotubes (CNTs) or graphite nanofibers (GNFs) can act as thermal insulators due to significant phonon scattering at interfaces. In this work, graphene nanoplatelets (xGnPs) with high surface areas are included in CNT and GNF mats in order to increase the contact area between nanostructures and mitigate phonon scattering. Results indicate that an increase in contact area between nanostructures increases the thermal conductance across nanostructure networks by nearly an order of magnitude. Additionally, a study of the surface topography of CNT and GNF mats using atomic force microscopy (AFM) indicates that they are able to conform well to the asperities between rough, mating surfaces. Thus, an increase in contact area between CNT junctions not only produces a thermally conductive network, but also increases the reliability of a CNT mat TIM by avoiding common issues associated with the use of wetting agents.     

A graphene sheet as an efficient electron acceptor and conductor for photoinduced charge separation

Tetrasulfonated zinc phthalocyanine (Pc) was bound to graphene (G) sheets by the π–π stacking supermolecular method. The few-layer graphene sheets were obtained by chemically reducing graphite oxide and characterized by AFM, IR and UV–vis absorption methods. Photoinduced electron transfer (PET) within the nano assembly is revealed by laser flash photolysis, time resolved and steady state fluorescence, as well as UV–vis absorption techniques. A graphene sheet can be attached by up to 52,000 Pc molecules to form a super molecule G(Pc)_52,000, in which many Pc molecules can be simultaneously photoexcited to the S₁ state. One graphene sheet can simultaneously quench thousands of excited Pcs with a large rate constant of the order of 10¹⁶ M⁻¹ s⁻¹ by PET. A graphene sheet not only accepts electrons from the excited Pcs on it but also delivers the captured electrons to its unexcited Pcs to form (Pc⁺)_nG(Pc⁻)_n, so that a large electron charge (i.e. n >> 1) is separated between unlinked Pc molecules with a small energy loss. These novel features of PET are explained by the following unique properties of graphene: (i) its excellent electron-transport and multi-electron-accepting ability, (ii) its multi-chromophore binding and concurrent multi-photon absorbing ability.     

Novel glycine functionalised amino acid materials for separation of aromatic amines

The synthesis of aminoacid based polymer, poly(methyl glycinate-bis-glycidyl methacrylate) and its utility as a separation material for aromatic amines has been investigated. Aromatic amines have been proved to be hazardous to the environment and removal of these from various sources is a matter of ecological concern. Copolymers of methyl glycinate-bis-glycidyl methacrylate with styrene and methylmethacrylate have been synthesized and their retention capacities were studied.     

Novel and efficient hybrid supercapacitor of chemically synthesized quaternary 3D nanoflower-like NiCuCo2S4 electrode

In this work, we employed a simple and cost-effective chemical route to obtain a highly stable and efficient quaternary mesoporous 3D nanoflower-like NiCuCo₂S₄ nanocomposite for supercapacitor applications. The NiCuCo₂S₄ composite exhibited a mixture of NiCo₂S₄ and CuCo₂S₄ phases, confirming the formation a quaternary NiCuCo₂S₄ thin film. A surface morphological analysis revealed the unique nanoflower-like nanostructure of the annealed composite. The electrochemical analysis of the NiCuCo₂S₄ electrode demonstrated a high specific capacity (Cs) of 414 mAh g^?1 at a lower scan rate of 10 mV s^?1 and a superior cycling stability up to 3000 cycles. A solid-state hybrid supercapacitor (SHS) was also constructed by the NiCuCo₂S₄ and AC powder as positive and negative electrodes, respectively. The NiCuCo₂S₄//AC hybrid cell produced a high Cs, energy density, and power density of 159 F g^?1, 35.19 Wh kg^?1, and 0.66 kW kg^?1, respectively at a current density of 10 mA with good cycling stability. The results demonstrated that the fabrication process is effective for the development of a novel quaternary transition metal sulfide (TMS) electrode.     

反胶束法制备感光聚酰亚胺/TiO2纳米杂化感光材料

采用反胶束法合成TiO2纳米粒子与感光聚酰亚胺溶液混合制备纳米杂化感光材料,用热台偏光显微镜表征了杂化材料的光刻能力及形貌,用UV光谱表征了杂化材料的TiO2纳米粒子的存在,用椭圆偏振仪测定了杂化材料薄膜的折光指数。     

耦合膜分离的新型CO2低温捕集系统性能优化

CO₂捕集作为温室气体排放控制的有效手段已成为重要研究课题。作为新兴捕集技术之一,低温CO₂捕集因产品纯度高、无附加污染等优势受到关注。然而,该技术能耗和捕集率对于气体中CO₂浓度十分敏感,对于高CO₂浓度气体可获得较高的CO₂捕集率和较低能耗水平。基于此,本文提出了耦合膜分离的新型CO₂低温捕集系统,通过膜材料选择渗透性实现待捕集气体CO₂浓度主动调控,并在最优浓度下进行CO₂低温捕集。首先基于不同传统低温捕集系统特点,对比分析了不同耦合系统模式,从而确定了最优耦合系统结构。针对最优耦合系统进行了运行参数优化,并分别基于实现系统捕集能耗最低与捕集率最高的目标,获得了膜渗透侧CO₂浓度与进气CO₂浓度间的关系式,为该耦合系统中膜组件选型提供指导。研究表明,本文提出的耦合系统捕集能耗为1.92MJ/kgCO₂,相比于传统单一低温系统捕集能耗可降低16.5%。     

Novel organic–inorganic chemical hybrid fillers for dental composite materials

A series of new polymethacrylate–silica chemical hybrid dental fillers has been prepared by the sol–gel reactions of poly[methyl methacrylate-co-3-(trimethoxysilyl) propyl methacrylate] or poly[3-(trimethoxysilyl)propyl methacrylate] with tetraethyl orthosilicate at various compositions. In these hybrid fillers, the polymethacrylate chains are uniformly distributed in and covalently bonded to the silica networks at molecular level without macroscopic organic–inorganic phase separation. The contact angle and surface tension parameters indicate that the hybrid fillers have better wetting properties with the 2,2-bis(p-2-hydroxy-3-methacryloxypropoxyphenyl)propane/triethyleneglycol dimethacrylate resin and stronger interfacial bonding with the polymer matrix than pure silica fillers. The compressive testing results demonstrate that the dental composites prepared with the hybrid fillers tend to have enhanced mechanical properties in comparison to those with the silane-treated fused silica and the pure sol-gel silica fillers at the same silica content. Scanning electron micrographic study reveals that upon compressive tests the dental composites with the hybrid fillers have fewer failures at the filler–matrix interface than those with pure silica fillers. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1689–1699, 1998     

Fabrication of novel Mn0.43Cd0.57S/ZnCo2O4 p-n heterojunction photocatalyst with efficient charge separation for highly enhanced visible-light-driven hydrogen evolution

The construction of efficient and low-cost photocatalytic systems is a major challenge in the field of photocatalysis. An efficient heterojunction photocatalyst designed for water splitting is also an interesting prospect in energy conversion. In this study, a novel Mn_0.43Cd_0.57S/ZnCo₂O₄ p-n heterojunction photocatalyst was prepared via a simple solvothermal method. Mn_0.43Cd_0.57S was loaded on the surface the of noble metal-free transition metal oxide ZnCo₂O₄ to prevent the agglomeration of particles, resulting in efficiently improving the photocatalytic performance of the material. Due to the Fermi level balance, the band bending of the two materials constructs a p-n heterojunction, which stimulates the transfer of photogenerated electrons from the CB of Mn_0.43Cd_0.57S to the CB of ZnCo₂O₄. The uniformly dispersed p-n heterojunction structure effectively suppresses the recombination of photoinduced charges and preserves stronger redox charges. As a result, the established Mn_0.43Cd_0.57S/ZnCo₂O₄ heterojunction showed the best photocatalytic hydrogen production concentration (92.1 mmol g^?1 h^?1), which was 4.7 times that of the original Mn_0.43Cd_0.57S (19.4 mmol g^?1 h^?1) and 54.2 times that of ZnCo₂O₄ (1.7 mmol g^?1 h^?1). This strategy will provide new insights into the development of new photocatalysts.     

Efficient acetylene/carbon dioxide separation with excellent dynamic capacity and low regeneration energy by anion-pillared hybrid materials

Adsorptive separation of acetylene/carbon dioxide mixtures by porous materials is an important and challenging task due to their similar sizes and physical properties. Here, remarkable acetylene/carbon dioxide separation featuring a high dynamic breakthrough capacity for acetylene (4.3 mmol·g^–1) as well as an ultralow acetylene regeneration energy (29.5 kJ·mol^–1) was achieved with the novel TiF₆^2–-pillared material ZU-100 (TIFSIX-bpy-Ni). Construction of a pore structure with abundant TiF₆^2– anion sites and pores with appropriate sizes enabled formation of acetylene clusters through hydrogen bonds and intermolecular interactions, which afforded a high acetylene capacity (8.3 mmol·g^–1) and high acetylene/carbon dioxide uptake ratio (1.9) at 298 K and 1 bar. Moreover, the NbO₅^2– anion-pillared material ZU-61 investigated for separation of acetylene/carbon dioxide. In addition, breakthrough experiments were also conducted to further confirm the excellent dynamic acetylene/carbon dioxide separation performance of ZU-100.     

分子筛基CH4-N2分离材料的研究进展

实现CH₄-N₂高效分离能够极大地推动常规天然气和非常规天然气这一类绿色低碳能源的利用,分子筛基吸附剂和膜材料具有优良的气体分离特性,而且对CH₄-N₂的分离颇具应用潜力。本文从对N₂具有优先选择性吸附的N₂/CH₄分离（高浓度CH₄纯化脱氮）和对CH₄具有优先选择性吸附的CH₄/N₂分离（低浓度CH₄富集脱氮）两方面综述了国内外分子筛吸附剂及分子筛膜的研究进展。详细地分析了分子筛骨架和平衡阳离子与其CH₄-N₂吸附分离性能之间的构效关系,并结合本文作者课题组的工作,提出了电中性（近中性）骨架分子筛对CH₄-N₂分离具有较好的分离效果。最后总结和展望了CH₄-N₂分离用分子筛吸附剂及分子筛膜的未来发展趋势。     

面向CO2分离的膜-深冷耦合过程优化

二氧化碳的分离与纯化是当前的研究热点,而随着环保要求的提高,传统单一的分离手段难以满足行业要求,多种分离方法的集成逐渐得到研究者的重视。以整体煤气化联合循环发电系统（IGCC）流程中二氧化碳的分离与回收环节为例,在流程模拟的基础上,拟合出该体系状态方程的多项式形式。进一步,构建耦合膜-闪蒸超结构数学模型,在设定最低产物纯度和回收率的情况下,以最小化年度费用为目标,筛选出最优的分离序列。     

Solution-processed, nanostructured hybrid solar cells with broad spectral sensitivity and stability

Hybrid organic-inorganic solar cells, as an alternative to all-organic solar cells, have received significant attention for their potential advantages in combining the solution-processability and versatility of organic materials with high charge mobility and environmental stability of inorganic semiconductors. Here we report efficient and air-stable hybrid organic-inorganic solar cells with broad spectral sensitivity based on a low-gap polymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) and spherical CdSe nanoparticles. The solvents used for depositing the hybrid PCPDTBT:CdSe active layer were shown to strongly influence the film morphology, and subsequently the photovoltaic performance of the resulted solar cells. Appropriate post-deposition annealing of the hybrid film was also shown to improve the solar cell efficiency. The inclusion of a thin ZnO nanoparticle layer between the active layer and the metal cathode leads to a significant increase in device efficiency especially at long wavelengths, due to a combination of optical and electronic effects including more optimal light absorption in the active layer and elimination of unwanted hole leakage into the cathode. Overall, maximum power conversion efficiencies up to 3.7 ± 0.2% and spectral sensitivity extending above 800 nm were achieved in such PCPDTBT:CdSe nanosphere hybrid solar cells. Furthermore, the devices with a ZnO nanoparticle layer retained ～70% of the original efficiency after storage under ambient laboratory conditions for over 60 days without any encapsulation.