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Abstract Polylactide (PLA), a promising biodegradable and renewable polymer, finds many applications, particularly, used as biodegradable fiber in textile industry. The key is to improve its heat resistance. In this work, small amount of poly (D-lactide) (PDLA) was added firstly into poly (L-lactide) (PLLA) matrix to form stereocomplex polylactide (SC-PLA), which has much better heat resistance than that of PLLA matrix. Then two melting temperatures were adopted for fiber spinning, the one (210 °C) is far below the melting temperature of SC-PLA (i.e., 220–230 °C), and the other (225 °C) is close to the melting temperature of SC-PLA. The boiling water shrinkage and tensile strength of PLLA/PDLA fibers were investigated as function of PDLA content. It was found, the boiling water shrinkage could be largely reduced to as low as 5.6% and a satisfactory tensile strength (628 MPa) is achieved for fibers spun at 225 °C, compared with fibers spun at 210 °C (7.5% and 500 MPa, respectively), as the PDLA content is 3 wt%. SEM observation suggests a formation of nanofibrillar like SC-PLA structure as spun at 225 °C, while only spherical SC-PLA particles as spun at 210 °C. DSC result indicates that adding PDLA could largely enhance the crystallization rate of PLLA, but almost a constant crystallinity and SC-PLA content were observed for both spun fibers, disregarding the spinning temperatures. Herman's orientation parameters of spun fiber were obtained from 2D-WAXD, which suggests that fiber spun at 225 °C has higher orientation than that of fiber spun at 210 °C. Thus it can be concluded that the formation of nanofibrillar like SC-PLA and enhanced orientation degree contribute mainly to the improved heat resistance and tensile strength. This work presents a feasible and effective way to fabricate all-PLA-based fibers with the outstanding heat resistance by adding a small amount of PDLA and using a suitable spinning temperature. Graphical abstract Image 1 Highlights • The influence of spinning temperature on the orientation and properties of PLLA/PDLA fibers was depicted in detail. • A critical PDLA content of increasing PLLA/PDLA fibers' heat resistant and mechanical property was revealed.. • All-PLA-based fiber with outstanding heat resistance was manufactured by melt spinning process. [ABSTRACT FROM AUTHOR]

Abstract Recently, powder metallurgy inspired low-temperature (below the melting temperature) sintering has been proposed as an innovative technology for the processing of eco-friendly stereocomplex-type polylactide (SC-PLA) from its nascent powder, without triggering noticeable thermal degradation. The physicochemical performances of the obtained SC-PLA products are governed by the newly formed SC crystallites with a remarkable ability to weld the interfaces between adjacent powder particles, however, the insufficient interdiffusion of poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) chains across the interfaces makes it challenging to form sufficient amounts of new SC crystallites. In the present work, we describe a facile and robust strategy to address this challenge by coating a trace amount (e.g., 0.001 wt%) of disentangled carbon nanotubes (CNTs) on the SC-PLA particle surfaces. During the subsequent sintering, these interface-localized CNTs can function as efficient nucleating agent to substantially promote the SC crystallization of PLLA/PDLA chains on their surfaces and finally countless SC crystallites are formed to strongly weld the interfaces as welded joints. Accordingly, SC-PLA/CNTs products possessing superb heat/solvent resistances and mechanical strength have been fabricated. Impressively, with the introduction of 0.001 wt% CNTs, the tensile strength is significantly enhanced from 45.8 MPa to 67.2 MPa. Most importantly, there is a linear relationship between the tensile strength and the content of the CNTs induced SC crystallites. Overall, this wok could provide a practical guidance for the design and fabrication of high-performance SC-PLA products through low-temperature sintering assisted by nanofillers like CNTs. Graphical abstract Image 1 Highlights • SC-PLA products with superb performances has been fabricated by CNTs assisted low-temperature sintering. • The disentangled CNTs were coated on the surface of SC-PLA powder particles before sintering. • These CNTs can substantially promote SC crystallization across particle interfaces as nucleating agent. • Countless new SC crystallites are induced to strongly weld the interfaces and thus enhance the product performances. • The linear relationship between tensile strength and CNTs induced SC crystallites has been established. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) was compounded with β-nucleating agent and injection-molded at 180 °C or 220 °C. The samples were subsequently treated by supercritical carbon dioxide (scCO 2 ) at different temperatures. Results show that processing temperature and scCO 2 treatment could strongly influence the tensile and impact properties of β-nucleated PP. In particular, the sample processed at 220 °C and treated at 120 °C exhibit much enhanced impact strength (4.8 times that of its untreated counterpart). FTIR, WAXD, SEM and DMA were performed to explore the effects of processing temperature and scCO 2 treatment on structure of the samples. Deformation-induced plastic flow and micro-voids were also evaluated to construct structure-property relations. It was found that the influence of processing temperature on mechanical properties is mainly associated with the β-form content and β-crystalline morphology, while the structural changes in the crystalline lamellar scale may be responsible for the toughening effect of scCO 2 treatment. [ABSTRACT FROM AUTHOR]

Selective localization of nanoparticles at the interface of immiscible polymer blends has been witnessed as an efficient method to improve blend properties and even provide some added functionalities. Nevertheless, it is still a great challenge to achieve thermodynamically stable interface-localization of the nanoparticles mainly due to their low interfacial stabilities as well as high transfer speeds between the blend phases, especially for those with high aspect ratios. In this work, taking poly( l -lactide)/poly( d -lactide) grafted ethylene-acrylic ester copolymer/multi-walled carbon nanotubes (PLLA/EGD/MWCNTs) ternary composite as an example, we describe a new and facile strategy to address this challenge via anchoring high-aspect-ratio MWCNTs at the interface of PLLA/EGD blends using interface-localized stereocomplex (SC) crystallites as anchoring agents. During melt mixing of EGD with PLLA/MWCNTs mixture, such SC crystallites can be rapidly formed at the blend interface to prevent MWCNTs transferring from the thermodynamically unfavorable PLLA matrix into favorable EGD phase as physical barriers, and meanwhile some of these transferring MWCNTs could serve as nucleating agents to induce SC crystallization on their surfaces. As a result, many MWCNTs are firmly anchored at the blend interface by these SC crystallites. The anchored MWCNTs can not only function as effective interfacial enhancers to remarkably enhance interfacial strength and resulting impact toughness of PLLA/EGD blends but also enable the formation of electrical conductive pathway in the network-like PLLA/EGD blends at a much lower percolation threshold. This wok could offer a promising opportunity for preparing high-performance and multifunctional PLLA-based composites through controlling particle localization at the interface of immiscible PLLA blends with the aid of SC crystallization. [ABSTRACT FROM AUTHOR]

Heterojunctioned architectures were facilely fabricated using hydrothermally treated electrospun TiO 2 nanofibers in an alkaline Sr(NO 3 ) 2 precursor solution in an electronic oven. TiO 2 on the fiber surface was partially dissolved into Ti 4+ to react with Sr 2+ in favor of the nucleation of SrTiO 3 on TiO 2 nanofibers, and thus a heterojunction was formed between SrTiO 3 and TiO 2 , which will benefit the improvement of photocatalytic activity. And then a multifunctional membrane was created by functionalizing the surface of commercial cellulose acetate (CA) membrane with heterojunctioned SrTiO 3 /TiO 2 nanofibers. This newly structured membrane exhibited excellent water purification performances in a concurrent photocatalytic membrane filtration system under the irradiation of UV light, because it is able to integrate the advantages of photocatalysis and membrane filtration while minimizes their disadvantages. The high water purification performances in terms of high photodegradation ability and high permeate flux are attributed to the high photocatalytic activity of heterojunctioned SrTiO 3 /TiO 2 nanofibers architectures and their structured porous functional layer favorable for fast water pass through. [ABSTRACT FROM AUTHOR]

The performance of semicrystalline polymers is significantly dependent on the crystal morphology and lamellae orientation. In this work, the crystal superstructure and mechanical properties of polylactide (PLA) with different amounts of nucleating agent (tetramethylene-dicarboxylic dibenzoyl-hydrazide, TMC-306) were investigated. It was found that TMC-306 can be dissolved in PLA melt and re-crystallize into fibrils upon cooling. These fibrils can serve as nucleation templates to induce the crystallization of PLA on their surface, resulting in a large enhancement in crystallization rate. More importantly, PLA lamellae can grow perpendicular to the long axis of TMC-306 fibrils, inducing the formation of shish-calabash, shish-kebab and needle-like structures, depending on the concentration of TMC-306 used. Taking advantage of shear flow experienced in injection molding, TMC-306 fibrils tend to align in PLA melt along the shear flow direction, inducing the formation of highly orientated PLA lamellae in injection-molded articles. In this way, a simultaneous improvement in impact toughness, tensile strength and elongation at break is achieved. This work provides a good example of using a fibrous nucleating agent as a template to tailor the crystal morphology and lamellae orientation, thus achieving greatly enhanced properties for PLA. [ABSTRACT FROM AUTHOR]

We facilely fabricate hierarchical 3D microspheres consisting of 2D V 2 O 5 (vanadium pentoxide) nanosheets by a low temperature hydrothermal method and use it to structure hierarchical 3D micro-/nano-LIBs (lithium ion batteries) cathode. This is a template-free and facile method easy for scale-up production of hierarchical 3D micro-/nano-structured V 2 O 5 spheres beneficial for high performance LIBs applications. Such a facile method resulted hierarchical 3D micro-/nano-V 2 O 5 possess many unique features good for LIBs: (1) 2D V 2 O 5 nanosheets facilitate the Li + diffusions and electron transports; (2) hierarchical 3D micro-/nano-cathode structure built up by V 2 O 5 nanosheet spheres will lead to the close and sufficient contact between electrolytes and activate materials and at the same time will create buffer volume to accommodate the volume change during discharging/charging process; and (3) micro-scale V 2 O 5 spheres are easy to result in high cell packing density beneficial for high power battery. As revealed by the experimental results, the micro-/nano-V 2 O 5 electrode demonstrates high initial discharge and charge capacities with no irreversible loss, high rate capacities at different currents and long-lasting lifespan. The high-energy and high-power performances of the micro-/nano-V 2 O 5 electrode is ascribed to the unique hierarchical micro-/nano-structure merits of V 2 O 5 spheres as abovementioned. In view of the advantages of facile fabrication method and unique features of 3D micro-/nano-V 2 O 5 spheres for high power and high energy LIB battery, it is of great significance to beneficially broaden the applications of high-energy and high-power LIBs with creating novel hierarchical micro-/nano-structured V 2 O 5 cathode materials. [ABSTRACT FROM AUTHOR]

In this work, influence of matrix crystallization on the electrical conductivity and mechanical properties of poly( l -lactide)/multiwalled carbon nanotubes (PLLA/MWCNTs) nanocomposites has been investigated. By introducing trace amount of nucleating agent (0.15 wt%) and controlling isothermal crystallization time (0.1–8 min) of PLLA matrix in a hot mould (130 °C), the injection molded bars of the nanocomposites with different matrix crystallinities (5–45%) were prepared. Interestingly, the electrical conductivity is found to be linearly increased with increasing matrix crystallinity for nanocomposites with low concentrations of MWCNTs (below the percolation threshold). This could be attributed to the volume exclusion effect and the straightening effect of MWCNTs provided by PLLA crystallization, as evidenced from SEM observations. However, matrix crystallization induced reconstruction of MWCNTs network cannot effectively enhance the electrical conductivity when the concentration of MWCNTs is high enough (above the percolation threshold). More interestingly, the reconstructed MWCNTs network shows a better reinforcement effect in the nanocomposites as compared with that initially formed in the amorphous matrix. [ABSTRACT FROM AUTHOR]

Highlights: [•] Multifunctional nanocomposites (GO-TiO2-Ag) was synthesized by a two-phase method. [•] Remarkably enhanced photocatalytic activities were demonstrated under solar irradiation. [•] Excellent intrinsic antibacterial activity and better photo-biocidal capability toward Escherichia coli. [•] The influence of Ag content was revealed with systematical studies. [•] Different mechanisms for enhanced photocatlytic activities were illustrated clearly. [ABSTRACT FROM AUTHOR]

Abstract: Enhancing matrix crystallization has been demonstrated to be an effective method to simultaneously improve the impact toughness and heat resistance of poly(l-lactide) (PLLA) modified with flexible polymers, such as poly(ε-caprolactone) (PCL). Unfortunately, increasing PLLA matrix crystallinity alone cannot guarantee the enhancement of impact toughness in most cases, so other structural parameters should be considered. In this work, taking PLLA/PCL (80/20) blend as an example, the combined roles of matrix crystallization and impact modifier particle size in the toughening have been investigated. PLLA matrix crystallinity was controlled by adding a highly effective nucleating agent and PCL particle size was tailored by varying processing conditions while maintaining constant interfacial adhesion. It is interesting to find that toughening is efficient only if matrix crystallinity and particle size are well matched. With the significant increase of matrix crystallinity, an evident decrease of optimum particle size for toughening PLLA has been identified for the first time. Therefore, suitable particle size is the precondition for highly crystalline matrix to work effectively in the toughening because only small particles (0.3–0.5 μm) are effective in trigger shear yielding mechanism of the matrix needed for good toughness, whereas relatively large particles (0.7–1.1 μm) are only capable of toughening amorphous matrix effectively by initiating multiple crazing of the matrix. Importantly, our findings can be used to well explain the reason for the different roles of matrix crystallization in the toughening of different PLLA blends reported in the literature. Furthermore, the heat resistance of the blend with a highly crystalline matrix is much better than that of the blend with an amorphous one as expected. This work could not only provide a new insight into the synergistic roles of matrix crystallization and modifier particle size in the toughening of PLLA but also set up a universal framework for designing high-performance PLLA products with both good impact toughness and high heat resistance. [Copyright &y& Elsevier]

Highlights: [•] Novel-structured TiO2/CuO composite nanofibers was optimized for H2 generation. [ • ] Vivid changes of physicochemical properties influenced by calcinations temperature. [ • ] Significance of physicochemical properties synergy on H2 generation was revealed. [ • ] The optimized photocatalyst exhibited the highest H2 generation activity. [ • ] Reusable and stable with negligible Cu leaching. [Copyright &y& Elsevier]

Abstract: Hierarchical 3D dendritic TiO2 nanospheres building with ultralong 1D TiO2 nanoribbon/wires were hydrothermally synthesized via controlling the hydrolysis rate of precursor by EG. It is found that the EG and Cl− in the precursor solution are the dominant factors in controlling the hydrolysis rate of Ti4+ from TTIP, and the growing direction of 1D TiO2, respectively. Through optimizing the molar ratio of TTIP:EG, hierarchical 3D dendritic TiO2 nanospheres building with long 1D nanoribbons (TiO2 nanoribbon spheres) were synthesized at a molar ratio of TTIP:EG = 1:2. And hierarchical 3D dendritic TiO2 nanospheres building with even longer and thinner 1D TiO2 nanowires (TiO2 nanowire spheres) were synthesized via further reducing the hydrolysis rate of Ti4+ by increasing the content of EG at a molar ratio of TTIP:EG = 1:3. The hierarchical 3D dendritic TiO2 nanoribbon/wire spheres were well characterized by a variety of techniques such as FESEM, TEM, XRD, N2 adsorption/desorption, UV–vis spectra, etc. A “win–win” strategy was developed to integrate the hierarchical TiO2 nanoribbon/wire spheres and membrane for high performance photocatalytic membrane water purification through maximizing the advantages of TiO2 photocatalysis and membrane, while minimizing their disadvantages. Hierarchical TiO2 nanoribbon/wire spheres exhibited high performance for water purification in terms of high flux, low fouling, high removal rate of pollutants, and long lifespan of membrane, both in concurrent dead end and cross flow membrane system. The rationale behind this phenomenon lies in that the hierarchical TiO2 nanoribbon/wire spheres in the concurrent system possess the advantages of mitigating the membrane fouling via photocatalytic degrading the organic pollutants relying on their high photocatalytic activities; and keeping high water flux owing to the porous functional layer favorable for water pass through. The experimental results demonstrated that the hierarchical TiO2 nanoribbon/wire spheres have better photodegradation ability of AO 7 and RhB pollutants so as to result in higher ability in mitigating fouling, and keep higher flux than TiO2 P25 under the same conditions. It is believable that this study is of great significances both in synthesizing hierarchical 3D dendritic TiO2 nanospheres building with ultralong 1D nanoribbon/wires, and in providing a “win–win” strategy for high performance concurrent photocatalytic membrane water purification featured as high flux, high removal rate of pollutants, low fouling and long membrane lifespan. [Copyright &y& Elsevier]

Abstract: It is still a challenge to photocatalytically cogenerate clean water and energy from dye wastewater owing to the relatively low photocatalytic efficiency of photocatalysts. In this study, novel-structured TiO2/CuO composite nanofibers were successfully fabricated via facile electrospinning. For the first time, the TiO2/CuO composite nanofibers demonstrated multifunctional ability for concurrent photocatalytic organic degradation and H2 generation from dye wastewater. The enhanced photocatalytic activity of TiO2/CuO composite nanofibers was ascribed to its excellent synergy of physicochemical properties: 1) mesoporosity and large specific surface area for efficient substrate adsorption, mass transfer and light harvesting; 2) red-shift of the absorbance spectra for enhanced light utilization; 3) long nanofibrous structure for efficient charge transfer and ease of recovery, 4) TiO2/CuO heterojunctions which enhance the separation of electrons and holes and 5) presence of CuO which serve as co-catalyst for the H2 production. The TiO2/CuO composite nanofibers also exhibited rapid settleability by gravity and uncompromised reusability. Thus, the as-synthesized TiO2/CuO composite nanofibers represent a promising candidate for highly efficient concurrent photocatalytic organic degradation and clean energy production from dye wastewater. [Copyright &y& Elsevier]

Abstract: Here, hierarchically meso/nanoporous TiO2 was successfully fabricated by a facile and efficient hydrolysis and calcination method using Ti(OC4H9)4 and K2S2O8 as precursors. The hydrosol was firstly prepared by drop-wise adding ethanol dissolved Ti(OC4H9)4 solution into acetone dissolved K2S2O8 solution under a vigorous stirring and heating condition. After being sufficiently hydrolyzed, the hydrosol was calcined to promote the crystallization of TiO2 and successfully dope S and C on TiO2. The calcination temperature significantly affects the doping of S and C on TiO2, crystallization of TiO2, formation of hierarchically meso/nanoporous structure of TiO2 and its light absorption capability. The S- and C-codoped TiO2 exhibits high photocatalytic H2 generation efficiency in a water/methanol sacrificial reagent system under the irradiation of UV light. The high photocatalytic efficiency is dependent on the comprehensively competing effects of the codoping of S and C, crystallization, specific surface area and light absorption capability. The S- and C-codoped TiO2 calcined at 600°C demonstrates the highest photocatalytic H2 generation efficiency, which is ascribed to the balanced synergy of the abovementioned factors. [Copyright &y& Elsevier]

Abstract: The effect of fabrication method on the properties of hierarchical 3D TiO2 nanostructures was investigated by employing and developing both hydrothermal method and calcination method to synthesize hierarchical 3D TiO2 nanorod spheres in this study. A comprehensive comparison in terms of morphologies, crystallization, specific surface areas, light absorption capabilities, and photoluminescence spectrum was conducted between 3D TiO2 nanorod spheres synthesized via hydrothermal method and that synthesized via calcination method. A better photocatalytic activity was demonstrated over the TiO2 nanorod spheres synthesized through calcination method. This was ascribed to the better crystallization and monodispersion of the hierarchical 3D TiO2 nanorod spheres resulted from the calcination method; thus rendering it with more superior characteristics such as larger specific surface area, enhanced light absorption capability and faster transfer of electrons which suppress the recombination of photogenerated electrons and holes. This study is thus significant not only in promoting the development of hierarchical 3D TiO2 nanorod spheres via different methods, but also in revealing the effect of fabrication method on the photocatalytic activity of hierarchical 3D TiO2 nanorod spheres. The calcination method is proposed to be a facile and promising method for scale-up production of the hierarchical 3D TiO2 nanorod spheres with high photocatalytic activity for efficient pollutants degradation. [Copyright &y& Elsevier]

Abstract: A novel photocatalyst was designed from the inspiration of natural forest''s high efficient on light harvesting and energy conversion. This novel “forest-like” photocatalyst was successfully synthesized by a facile continuously-conducted three steps methods: electrospinning TiO2 nanofiber acts as the trunks, hydrothermal growth ZnO nanorods on the surface of TiO2 nanofiber acts as the branches, while photodeposition of Cu nanoparticles on the surface of TiO2 nanofiber and ZnO nanorods act as the leaves. This novel photocatalyst demonstrated higher photocatalytic hydrogen generation rate than most of semiconductor catalysts and many newly developed catalysts such as Pt/TiO2 catalyst and artificial leaves Pt/N–TiO2 catalyst in a water/methanol sacrificial reagent system under the light irradiation as a result of its enhanced light absorption ability, enlarged specific surface area promoting mass transfer and providing more reaction sites and its potential on anti-recombination of electrons and holes. Meanwhile, it is interesting to note that the photocatalytic hydrogen generation activity has a liner relationship with the hierarchy of materials, which means higher hierarchy materials display higher photocatalytic hydrogen generation activity. It is reasonable to believe that this natural mimic photocatalyst without noble metals will benefit the energy generation and novel materials development. [Copyright &y& Elsevier]

Abstract: To counter the global water crisis such as water resources scarcity and water quality deterioration, membrane filtration has been widely used as a promising technology. Recently, nano-materials and its structured membranes demonstrated multifunctional water purification capability in terms of decontamination and disinfection. Here, hierarchical nitrogen (N)-doped “nut-like” ZnO nanostructured material was hydrothermally synthesized at large scale. This hierarchical N-doped “nut-like” ZnO nanostructured material was well characterized and successfully assembled on a piece of polymer membrane surface to create a multifunctional membrane. This newly developed membrane demonstrated high pollutants removal ability via rejection and photodegradation, and strong antibacterial growth ability under visible light irradiation. At the same time, this novel membrane holds the potential to produce clean water at a constant high flux. The experimental results indicated that the hierarchical N-doped ZnO “nut-like” nanostructured material enhanced the photocatalytic activity in a comparison to commercial ZnO powder. This is caused by enlarging the specific surface area and enhancing the light utilization rate. It is reasonable to believe this hierarchical N-doped “nut-like” ZnO nanostructured membrane would benefit the water purification field. [Copyright &y& Elsevier]

Abstract: Through hydrothermally growing SrTiO3 cubics on the surface of electrospun TiO2 nanofibers, SrTiO3/TiO2 nanofibers heterostructures were successfully fabricated in the present study. This process is able to ensure uniform distribution of SrTiO3 on the surface of TiO2 nanofibers and lead to close contact between SrTiO3 and TiO2, which is beneficial for the fast separation of photogenerated electrons and holes so as to suppress the recombination of photogenerated electrons and holes at the interphase of SrTiO3 and TiO2. Besides this, the long 1D fibrous structure easy for electron transfer, the hierarchical structure promoting mass transfer and allowing more light reflection and absorption, and the large specific surface area providing more reactions sites to facilitate the reactants to desired oxidation places all together create a synergistic effect on improving the photocatalytic activity of the hierarchical SrTiO3/TiO2 nanofibers heterostructures. Under the irradiation of UV light, in a water/methanol sacrificial reagent system, the SrTiO3/TiO2 nanofibers heterostructures generate five times more H2 than bare TiO2 nanofibers because of its high photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Innovative TiO2/SnO2 nanofibers were fabricated via electrospinning an innovated precursor solution and used for photocatalytic H2 generation. The nanofibers exhibited greatly enhanced H2 evolution rate compared to bare TiO2 nanofiber and P25. The enhanced efficiency of the TiO2/SnO2 nanofibers was attributed to its excellent synergistic properties: (1) its good mesoporosity; (2) the red-shift of absorbance spectra to enhance light absorbance capability; (3) its long nanofibrous structure and (4) anatase TiO2 – rutile TiO2 – rutile SnO2 ternary junctions favorable for the separation of electrons and holes. Based on our experimental results, the optimum ratio of TiO2/SnO2 nanofibers with 3% Sn demonstrated the highest efficiency in H2 generation. [Copyright &y& Elsevier]

Abstract: Novel high efficient photocatalyst is the key for photocatalytic hydrogen generation from water splitting. In this study, a novel hierarchical CuO/ZnO “corn-like” architecture was designed and synthesized via a combination of hydrothermal and photodeposition method. The as-prepared nanostructured materials was shown to effectively generate hydrogen in the mixture of methanol and water (v/v = 1:10). This is because the hierarchical CuO/ZnO “corn-like” architecture: 1) greatly enhances the light utilization rate due to its special architecture, 2) enlarges the specific surface area, providing more reaction sites and promoting mass transfer, 3) promotes the photogenerated electrons transfer from ZnO to CuO, achieving the anti-recombination effect of electrons and holes, and 4) avoids the photocorrosion of ZnO to improve the stability of ZnO as a catalyst during water splitting. Moreover, the novel hierarchical CuO/ZnO “corn-like” architecture is easily recovered for reuse. [Copyright &y& Elsevier]

Abstract: The dextran coated Fe3O4 magnetic nanoparticles (MNPs) have been successfully synthesized and used for brackish water desalination for the first time. The dextran coated Fe3O4 MNPs well meets the stringent criteria for draw solutes of forward osmosis (FO) process via technologically integrating the good solubility of dextran and strong magnetism of Fe3O4 nanoparticles. Our experimental results demonstrated that the dextran coated Fe3O4 MNPs are not only able to produce high osmotic pressure to draw clean water across FO membranes from brackish water, but also can be easily recovered from the diluted draw solution by an external magnet. Based on our currently conducted works, it is believed that the dextran coated Fe3O4 MNPs can be an ideal draw solute for brackish water desalination by using FO process in an environmental-friendly and energy-saving manner. [Copyright &y& Elsevier]

Abstract: Hierarchical porous TiO2 hollow microspheres were synthesized by a facile approach from a one-step template method. This novel approach avoids tedious multiple steps from conventional template method for fabricating hierarchical porous and hollow microspheres. The as-prepared microspheres were characterized by XRD, SEM, TEM, nitrogen adsorption, and UV–vis DRS. Its photocatalytic activity was demonstrated in the photocatalytic degradation of Rhodamine B. Structural characterization indicates that the as-prepared microspheres had a hollow interior and a hierarchical porous structure with both large and small mesopores on its surface. The average diameters and BET surface areas of the hierarchical porous TiO2 hollow microspheres were 1.5μm and 117m2/g, respectively. Optical adsorption investigation shows that the hierarchical porous TiO2 hollow microspheres possessed the optical band gap of 3.42eV. A possible formation mechanism for the hierarchical porous TiO2 hollow microspheres was discussed. The hierarchical porous TiO2 hollow microspheres exhibited much higher photocatalytic activity than the commercial P25 TiO2. In addition, the as-prepared microspheres can be easily recycling for reuse. All these advantages show a bright future for this microspheric photocatalyst in environmental purification. [Copyright &y& Elsevier]

Abstract: Large amount of work has been reported on the annealing of polypropylene (PP) and the related changes in mechanical properties. However, the structure–property correlations and the physical origin of annealing induced microstructural evolution are still not very clear. In this work, taking β-form PP (β-PP) as example, the microstructural changes induced by annealing were investigated from macromolecular to crystalline lamellae level with Fourier transform infrared (FTIR) spectroscopy, conventional differential scanning calorimetry (DSC), temperature-modulated DSC (TMDSC), wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS) and dynamic mechanical analysis (DMA). Besides mobile amorphous fraction (MAF), the role of rigid amorphous fraction (RAF) in toughening PP is particularly taken into consideration. It is shown that annealing increases the chain mobility in MAF and decreases it in RAF. Such an effect is believed to be mainly associated with the formation of looser MAF and more RAF by the microstructural re-arrangement involving conformational ordering of partial amorphous chain segments and a significant interlamellae thickening. A thorough analysis of structure–property relationship through observing plastic deformation behaviors by scanning electron microscope (SEM) and estimating stress transmission between crystalline and amorphous phases, suggests that both MAF and RAF play important role on toughening β-PP. They can promote the initiation of microvoids effectively upon deformation by reducing the stress transmission. As a result, large-scale plastic deformation is triggered. This work is important and provides a new insight into the mechanisms of microstructural evolution and subsequent improvement in impact toughness during annealing. [Copyright &y& Elsevier]

In this study, bismuth/titanium oxide (Bi3+/TiO 2) composite nanofibers (herein after referred to as Bi/TiO 2) with enhanced physicochemical properties thus photocatalytic efficiency are successfully synthesized via electrospinning which maximizes the uniformity of Bi and Ti at molecular level. Bi/TiO 2 shows positive characterization through anatase crystallinity, large light utilization rate, high specific surface area and low electron holes pair recombination rate as a result of the novel materials synthesis approach. Glycerol as a typical pollutant of industrial wastewater, is used here to demonstrate the concurrent production of chean water and H 2 over the well synthesized Bi/TiO 2. Bi is incorporated to extend the light absorbance capability of TiO 2 to visible light region. Experimental data shows that 3% Bi/TiO 2 exhibits the highest H 2 generation and Total Organic Carbon (TOC) removal. The reduction of TOC of 8% means the conversion of glycerol into H 2 has been achieved, which is in favor of the production of clean water from highly polluted glycerol wastewater. An optimization study is undertaken by varying the calcination temperature to investigate properties-activity relationship of the new photocatalyst, which exhibited higher photocatlytic efficiency under both UV–visible and visible light compared with that of bare TiO 2. The mechanism illustration is derived from the novel materials synthesis and property optimization to explain the rationale behind this interesting phenomenon. It is worth to note that Bi/TiO 2 nanofibers represent a promising photocatalyst for environmental remediation and sustainability where it can be potentially used in glycerol by-product or waste from the industry under the renewable solar irradiation to generate H 2 and clean water simultaneously. [Display omitted] • Bi-incorporated TiO 2 nanofibers exhibited to be able to concurrently generate H 2 and clean water under solar irradiation. • Enhanced physico-chemical properties of Bi/TiO 2 nanofibers. • Enlarged specific surface area & unique mesoporosity. • Enhanced light absorption capability for better photocatalytic reaction, and. • Well-dispersed heterojunctions for an efficient electrons-holes separation. [ABSTRACT FROM AUTHOR]

Adding titanium dioxide (TiO 2 ) into Polylactide (PLA) matrix is an efficient way to improve the UV-resistance of PLA for outdoor applications. In this work, soft poly(ester)urethane elastomer was used to tailor the dispersion and distribution of TiO 2 nanoparticles and improve the toughness of PLA as well. It was observed that TiO 2 nanoparticels are selectively located at the interface between PU dispersed phase and PLA matrix to form a so called soft core-rigid shell structure. Interestingly, the addition of PU gives a significant rise to not only toughness, but also UV-resistance of PLA/TiO 2 composites. According to Fourier transform infrared spectroscopy (FTIR), the anhydride as the main photoproducts was confirmed for all the prepared samples, including PLA, PLA/PU blends, PLA/TiO 2 and (PLA/TiO 2 )PU nanocomposites, which indicates that the addition of PU or/and TiO 2 does not alter the photooxidation chemical mechanism of PLA. The enhancement of anti -UV performance is mainly ascribed to good UV-absorption ability of PU and TiO 2 nanoparticels. [ABSTRACT FROM AUTHOR]

Abstract: Obtaining network-like morphology (rubber particles are unevenly distributed in the matrix, forming a discontinuous rubber network structure) has been considered to be an effective strategy to optimize the toughness of rubber-toughened polymers. However, it is very difficult to achieve using conventional processing method. In this work, taking elastomer-toughened polylactide (PLA) as an example, we attempt to use hydrophilic silica (SiO2) nanoparticles with self-networking capability to control the phase morphology and the mechanical properties of PLA/poly(ether)urethane (PU) (85/15) blend. It is interesting to find that the selective localization of SiO2 nanoparticles in the PU phase and at the phase interface induces the morphological change from a common sea-island structure to a unique network-like structure constructed by discrete PU particles with irregular shapes, thus giving rise to a remarkable improvement in the impact toughness of the blend with strength and modulus unaffected. The formation of the network-like structure is attributed to the synergistic effect between the self-networking of the interface-localized SiO2 and the enhanced elasticity of the SiO2-localized PU phase. This inspiring result proves the introduction of nanoparticles with self-networking capability into polymers blends to be a universal platform to design their performance via tuning the phase structure. [Copyright &y& Elsevier]

• A novel airfoil flow field is proposed for fuel cells. • Airfoil flow field can enhance mass transfer while maintain low pressure drop. • Fuel cell with airfoil flow field is evaluated via experimental test and simulation. • Airfoil flow field increases the fuel cell's maximum power density effectively. • Airfoil flow field promotes the uniform distributions in fuel cells. Optimal configuration of bipolar plate (BP) embedding flow field is of great significance in improving the power density and durability of proton exchange membrane fuel cells (PEMFCs). Inspired by the airfoil in aircraft dividing the airflow into two streams causing pressure difference, a novel airfoil flow field (AFF) is designed to enhance the mass transfer capacity in channel and across the rib between two adjacent channels, which hardly increases the pressure drop in channel, unlike many baffle designs. The performance improvement achieved by implementing AFF in PEMFC is compared with common parallel flow field (PFF) and the wave flow field (WFF) by experimental test with respect to polarization curve and electrochemical loss and numerical simulation via a three-dimensional (3D) PEMFC model. The experimental results indicate that the novel AFF exhibits best fuel cell performance at various operation conditions (e.g. relative humidity, air stoichiometric ratio) mainly benefitted from the enhanced oxygen transfer, which contributes to the improvement of maximum power density by 8.85 % and 14.37 % compared to PFF and WFF, respectively. The modeling results indicate that the pressure drop increase in AFF is negligible compared with PFF, and is even slightly lower than WFF, indicating high practicability. Moreover, the utilization of AFF also helps the uniformity of oxygen concentration, current density and temperature in PEMFC. [ABSTRACT FROM AUTHOR]

Abstract: A facile polyol synthesis was used for the deposition of Ag nanoparticles on electrospun TiO2 nanofibers for the subsequent fabrication of Ag/TiO2 nanofiber membrane. The permeate flux of the Ag/TiO2 nanofiber membrane was remarkably high compared to commercial P25 deposited membrane. The Ag/TiO2 nanofiber membrane achieved 99.9% bacteria inactivation and 80.0% dye degradation under solar irradiation within 30 min. The Ag/TiO2 nanofiber membrane also showed excellent antibacterial capability without solar irradiation. Considering the excellent intrinsic antibacterial activity and high-performance photocatalytic disinfection/degradation under solar irradiation, this novel membrane proved to have promising applications in water purification industry. [Copyright &y& Elsevier]