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Designing a highly active- and stable non-noble metal bifunctional oxygen catalyst for rechargeable Zn-air battery remains a great challenge. Herein, we develop a facile and melamine-assisted-pyrolysis (MAP) strategy for the synthesis of core–shell Co-based electrocatalysts@N-doped carbon nanotubes (Co@CNTs) derived from metal–organic frameworks. The Co@CNTs exhibited excellent bifunctional electrocatalytic performance for both oxygen evolution and reduction. DFT calculations demonstrated that the Gibbs free energy of the rate-determining step was small enough to improve ORR activities. As a result, a Zn-air battery assembled with Co@CNTs proves a lager power density, low voltage gap between charge–discharge and excellent stability. Thus, this work offers a facile strategy to realize the synthesis of non-noble metal electrocatalyst for Zn-air battery materials with high electrochemical performance.

The electrocatalytic reduction of CO2 to liquid fuels is a promising strategy to store the intermittent renewable energies into high-value chemicals. Here, two-dimensional SnO2 nanosheet (∼3 nm in ...

In the past few decades, polymer solar cells (PSCs) have been intensively investigated in academic fields. The study of non-fullerene polymer acceptors has become a hot research focus due to their excellent opto-electronic properties such as wide light-absorbing ability, appropriate molecular energy levels, and easy chemical modifications. The much higher power conversion efficiencies (PCEs) of non-fullerene PSCs relative to fullerene PSCs revealed the significant potential of non-fullerene acceptors in PSCs. This review systematically summarizes the recent advancements of efficient polymer acceptors, including perylene diimide-based, naphthalene diimide-based, diketopyrrolopyrrole-based, double B←N bridged bipyridyl-based, and other polymer acceptors. Their structure–property relationships were thoroughly analyzed and summarized, which may provide new guidance for the rational structural design of high-performance photovoltaic materials.

Multicomponent nanocomposite colloidal spheres were synthesized with NaYF4:Yb,Er upconversion nanoparticle and CdSe quantum dots for tailoring visible emission. The CdSe/NaYF4:Yb,Er colloidal spheres were synthesized by improved emulsion-based self-assembly approach. They are well-dispersed in the colloidal sphere by electron diffraction X-ray mapping patterns. The colloidal spheres exhibited near-infrared photoresponse property. The intensity of short-wavelength emission at 408 nm was drastically weakened, and a red emission at 655 nm is substantially increased. Both the mechanism and multi-photon process of upconversion photoresponse was determined. It offers facile strategy to assemble multicomponent nanocomposite colloidal spheres for tuning visible emission.

In this paper, uniform NaGdF4:Yb3+, Er3+ nanorods doped with Fe3+ were synthesized by a facile hydrothermal method. The prepared NaGdF4:Yb3+, Er3+ doped with Fe3+ displayed hexagonal phase structure from XRD pattern and uniform nanorods with narrow size distribution from TEM. The signal of Fe3+ is accompanied with the Yb3+ and Er3+ from EDX line-scanning, which was confirmed that Fe3+ was doped successfully. The NaGdF4:Yb3+, Er3+ nanorods doped with Fe3+ show absorption of near-infrared region from UV–Vis absorption spectra. The upconversion luminescence intensity enhances with increasing content of Fe3+ under 980 nm excitation. When stoichiometric ratio of Fe3+ is 20 mol%, the strongest upconversion emission intensity could be obtained. But the upconversion luminescence would become weak when the stoichiometric ratio of Fe3+ is above 20 mol%. Based on above analysis, it is inferred that there is energy conversion between Fe3+ and rare earth ions by the luminescence mechanism. In this work, it provides a facile method for preparation of NaGdF4:Yb3+, Er3+ nanorods, which displays improving upconversion luminescence by Fe3+ doping.

The electrochemical reduction of CO2 could play an important role in addressing climate-change issues and global energy demands as part of a carbon-neutral energy cycle. Single-atom catalysts can display outstanding electrocatalytic performance; however, given their single-site nature they are usually only amenable to reactions that involve single molecules. For processes that involve multiple molecules, improved catalytic properties could be achieved through the development of atomically dispersed catalysts with higher complexities. Here we report a catalyst that features two adjacent copper atoms, which we call an ‘atom-pair catalyst’, that work together to carry out the critical bimolecular step in CO2 reduction. The atom-pair catalyst features stable Cu10–Cu1x+ pair structures, with Cu1x+ adsorbing H2O and the neighbouring Cu10 adsorbing CO2, which thereby promotes CO2 activation. This results in a Faradaic efficiency for CO generation above 92%, with the competing hydrogen evolution reaction almost completely suppressed. Experimental characterization and density functional theory revealed that the adsorption configuration reduces the activation energy, which generates high selectivity, activity and stability under relatively low potentials. Anchored single-atom catalysts have recently been shown to be very active for various processes, however, a catalyst that features two adjacent copper atoms—which we call an atom-pair catalyst—is now reported. The Cu10–Cu1x+ pair structures work together to carry out the critical bimolecular step in CO2 reduction.

Herein, NaGdF4:Yb,Er nanoparticles were anchored on a Material of Institute Lavoisier (MIL-101). In the well-defined heterostructure, MIL-101/NaGdF4:Yb,Er, the absorption and fluorescence could be tuned, and the composite facilitated the separation of photogenerated electron–hole pairs. Moreover, the heterostructure displayed a higher photocurrent and better degradation ability for Rhodamine B that its individual components owing to its synergistic effect.

Interface engineering is promising but still challenging for developing highly efficient and stable non-noble-metal-based electrocatalysts for water splitting. Herein, partially phosphidated core@shell Co@Co-P nanoparticles encapsulated in bamboo-like N, P co-doped carbon nanotubes (denoted as Part-Ph Co@Co-P@NPCNTs) are prepared through a pyrolysis-oxidation-phosphidation strategy. In this structure, each Co nanoparticle is covered with a thin Co-P layer to form a special core@shell heterojunction interface, and the core@shell structure is further encapsulated by N, P co-doped CNTs that not only protect the Co from corrosion but also guarantee an effective and fast electron transfer on cobalt phosphide. As a bifunctional catalyst for both the hydrogen evolution reaction and oxygen evolution reaction, it exhibits an excellent activity for overall water splitting, and enables long-term operation without significant degradation. Density functional theory calculations demonstrate that the interface of the Co/Co2 P heterojunction could lower the values of ΔGH * (hydrogen adsorption) and ΔGB (water dissociation), which are negatively correlated to the j10 , because of the electronic structures of up-shifted d-band center. This study not only presents an efficient and stable electrocatalyst for overall water splitting but also provides a special route for the interface engineering of heterostructures.

For electrochemical carbon dioxide reduction (CO2RR), metal–N sites exhibit promising catalytic activity, yet the structure–activity relationship remains largely unclear. Here we synthesize well-defined homogeneous catalysts containing four coordinating pyridine N atoms, regulate the coordination metal centers in immobilized molecular complexes, and investigate their catalytic performances in CO2RR. The resulting Co(qpy)/CNTs composite exhibit the highest efficiency. Its Faradaic efficiency for CO reaches >98% over the broad range from −0.5 V to −0.9 V (vs. RHE), with long-term stability over 100 h. Density functional theory calculations reveal that the larger electronic overlap between the catalytic site and intermediate can decrease the free energy change for *COOH formation. The calculation results are experimentally verified by changing the metal centers (Fe(qpy), Ni(qpy) and Cu(qpy)). This work unveils the relationship between metal–ligand coordination and CO2RR performance, and offers a strategy for the design and synthesis of high-performance catalysts for practical applications.

Highly monodispersed core-shell structured NaGdF4:Yb,Er@SiO2@Eu(TTA)3Phen(2-Thenoyltrifluoroacetone (TTA), 1,10-Phenanthroline monohydrate (Phen)) nanospheres were synthesized via two-step process. These nanospheres with diameter of 13 nm were encapsulated in SiO2 shell via micro-emulsion preparation. The ligand-sensitized Eu complexes attached to the outer surface of SiO2. The green (542 nm) and red (610 nm) light were excited by NIR and UV illumination, respectively. Thus, tunable photoresponse was possible in the core-shell structured hybrid nanocomposites. Under upconversion process, 5-fold increase at 542 nm and a 14-fold increase at 660 nm could be achieved under 980 nm laser, respectively.

In this research contribution, the idea is created that Ln3+-doped nanosolid micelles have first been applied to enhance the photovoltaic properties of novel hybrid polymer solar cells (HPSCs). Among other publications in the literature, we have never found the same or similar work to be published previously. The new method of Ln3+-doped diblock copolymer (DBC) to develop nanosolid micelle luminescent materials is established. Very importantly the applicable technique to incorporate nanosolid micelles into PSCs by spin-coating on the surface of the indium tin oxide (ITO) layer is accomplished after comparing the different cooperation methods. This research contribution elucidates two novel HPSCs containing Ln3+ nanosolid micelles formed by Ln3+-doped diblock copolymer (Ln3+-DBC) and organic conjugated ligands. The Ln3+-DBC luminescent nanosolid micelles (LNSMs) are formed via coordination between Ln3+ ions and DBC, and are readily dispersed in a hydrophobic solvent. Nanosolid micelles can be incorporated ...

Inorganic-organic nanocomposites are synthesized and applied in polymer solar cells (PSCs) for improving power conversion efficiency (PEC). The hexagonal NaYbF4:Tb/Eu nanocrystals are synthesized, and then two organic molecules, phenanthroline (Phen) and thenoyltrifluroacetone (TTA), are introduced to modify the surface of the NaYbF4:Tb/Eu. As organic antennas, Phen and TTA can absorb UV and then transfer energy to inorganic nanocrystals. The prepared nanocomposites combine upconversion (UC) and downshift (DS) process under excitation, which can convert them into visible light. Thus, the inorganic-organic nanocomposites display photoresponse both in UV and NIR region. Two organic ligands and Tb3+ play an indispensable role during the energy transfer process. The enhanced UC and tunable DS emission match well with absorption of active layer of PSC, which can enhance the performance of PSC. The open-circuit voltage (Voc) and short-circuit current density (Jsc) of the devices are about 0.77 V and 16.48 mA cm−2, respectively. And the PEC of PSC can be increased 7.85%, which is about 10.2% higher than that of the reference device without UC and DS.

The well-defined lanthanide co-doped upconversion nanoparticles(UCNPs) had been synthesized using a simple solvothermal route at 150 °C, which was lower than previous reports. The shuttle-like and spherical UCNPs co-doped by Yb 3+ /Tm 3+ had been prepared, respectively. The morphology, crystal phase and size distribution of various UCNPs could be easily controlled. The growth mechanism and morphology transition of UCNPs had been deduced by schematic diagram. UC luminescence could be tuned by employing different host lattices (GdF 3 , YF 3 , NaGdF 4 and NaYF 4 ). NaGdF 4 :Yb 3+ /Tm 3+ displayed the strongest UC luminescence at 475 nm among four kinds of UCNPs, and its emission intensity was almost 10 times higher than that of NaYF 4 :Yb 3+ /Tm 3+ . UC mechanism had been determined by energy level diagrams. It’s revealed that the accumulation and energy transfer of Gd 3+ could be demonstrated in polycrystalline structure. The work provided a simple method for preparation of UCNPs with tunable UC luminescence.

The influence of a graphene/silver (G/A) nanocomposite coating layer on the microstructural evolution and surface oxidation of a Mg–Ni–La hydride is investigated systematically by XRD, SEM, EDS and HRTEM in detail. SEM and EDS reveal that the existence of the G/A composite prevents the electrode from pulverizing and oxidizing. The oxygen content in the surface of the electrode is reduced from 21% to 10% after 50 cycles for a Mg-Ni-La electrode with 0.2 mass fraction of G/A. The crystallization process of the amorphous electrodes coated by G/A is reduced compared to the uncoated electrode and the stable Mg 2 NiH 4 , α-Mg, MgH 2 and La oxihydroxide phases are present with the grain size about 40–60 nm after 50 charge/discharge cycles. The G/A coating reduces the corrosion and oxidation of the electrode alloy and provides both a pathway for hydrogen diffusion and active sites for the redox reaction of hydrogen. All of these factors result in a significant improvement of the discharge capacity by about 200 mAh g −1 in each cycle (after activation) for Mg-Ni-La electrodes with 0.2 mass fraction of G/A nanocomposites.

Herein, NaGdF

Developing catalysts with high activity and high atom utilization as well as exploring catalytic active sites are the biggest challenges for the electrocatalytic hydrodechlorination technology. Herein, a novel strategy of Pd crystal transformation induced by in-situ doping was proposed, and a series of amorphous Pd–P nanoparticles (NPs) with controllable coordination environment were synthesized successfully. The amorphous Pd–P NPs catalyst exhibits the highest activity for electrocatalytic hydrodechlorination and good cycling stability when the Pd–P coordination number is 3 and the Pd–Pd coordination number is 4. The 4-chlorophenol hydrodechlorination efficiency of Pd–P-60 NPs reaches 100 % within 2 h, and the mass activity is 8.58 min−1 g−1, which is 5.57 times as high as that for crystalline Pd NPs catalyst. Theoretical calculation shows that Pd–P catalyst facilitates the desorption of phenol and weakens the toxic effect on active sites. Density of states indicate that the doping of P results in a downshift of d-band center, facilitating the desorption of phenol. This work discovers the crystal effect and coordination effect of amorphous Pd–P NPs for electrocatalytic hydrodechlorination, which lays an important theoretical foundation for the design and development of high-performance Pd-based catalysts for electrocatalytic hydrodechlorination.

The geometric size and distribution of magnetic nanoparticles are critical to the morphology of graphene (GN) nanocomposites, and thus they can affect the capacity and cycling performance when these composites are used as anode materials in lithium-ion batteries (LiBs). In this work, Fe3O4 nanorods were deposited onto fully extended nitrogen-doped GN sheets from a binary precursor in two steps, a hydrothermal process and an annealing process. This route effectively tuned the Fe3O4 nanorod size distribution and prevented their aggregation. The transformation of the binary precursor was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). XPS analysis indicated the presence of N-doped GN sheets, and that the magnetic nanocrystals were anchored and uniformly distributed on the surface of the flattened N-doped GN sheets. As a high performance anode material, the structure was beneficial for electron transport and exchange, resulting in a large reversible capacity of 929 mA·h·g–1, high-rate capability, improved cycling stability, and higher electrical conductivity. Not only does the result provide a strategy for extending GN composites for use as LiB anode materials, but it also offers a route for the preparation of other oxide nanorods from binary precursors.

In this article, we creatively incorporate naked Ag nanoparticles (nAgp), SiO2-covered Ag nanoparticles (SiAgp), and naked Ag nanoplates (nAgPl) into solution-processed tungsten oxide (WO3) hole transport layer in polymer solar cells (PSCs) to increase the light absorption through localized surface plasmon resonance (LSPR) effect. With optimized doping concentrations, nAgp decreases power conversion efficiency (PCE), however, SiAgp increases PCE by 13.2% and nAgPl increases PCE by 19.7%. In detail, the great PCEs discrepancies are mainly caused by the discrepancies of short circuit currents (J(sc)). The experiments results indicate that the naked surface of nAgp causes the exciton-quenching to decrease the J(sc) of PSCs. Whereas the capsulation of SiO2 at the surface of nAgp and the embedment of nAgPl in WO3 layer can prevent the exciton-quenching and help to use LSPR effect of Ag nano-dopants to enhance the J(sc) of PSCs. Crown Copyright (C) 2016 Published by Elsevier B.V. All rights reserved.

MnO2 with urchin-like nano/micro hierarchical architecture was synthesized through an easy hydrothermal method at low temperature and used to prepare MnO2/graphene hybrid composite as electrode materials through an easy and efficient solution-based method. The MnO2 particles in the composite with 66.7% mass ratio could achieve specific capacitance as high as 451.5 F g(-1) at a scan rate of 10 mV s(-1) and exhibit good cycle stability with 93.8% capacitance retention over 2000 cycles. These properties result from the unique urchin-like nano/micro hierarchical structure of MnO2 as well as the function of graphene in enhancing the conductivity and utilization of MnO2.

The electrochemical reduction of CO

In this article, diblock copolymer (DBC), poly (methyl methacrylate)-block-poly (acrylic acid) was synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT). The DBC-Eu3+ solid micelles were prepared through the complex interaction between DBC and Eu3+ ions. As cross-linker, Eu3+ ions accept the electron donation of the ligand groups (carboxyl) sited on the polar PAA segments of DBC and form the DBC-Eu3+ solid micelles. The observations by transmission electron microscopy showed the embedment of Eu3+ ions in DBC and the nonpolar segments [poly (methyl methacrylate)] of DBC play a role of compatible agent for DBC-Eu3+ solid micelles to disperse in hydrophobic solvent [for example, dimethyl formamide] or polymer matrix. Very importantly, we found the dependence of the morphological structure (i.e. the size of solid micelles) on the molecular weight of DBC. On the other hand, the dependence of photoluminescent property of DBC-Eu3+ solid micelles on the molecular weight of DBC and ...

A novel method to prepare fluorescent polymeric aggregates via Eu 3+ -induced self-assembly is described in this research contribution. The amphiphilic polymeric ligand, polystyrene-block-poly(N-vinylpyrrolidone) (PS-b-PNVP) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Eu 3+ ions that function as coordination crosslinking agents were added to the reactive solution to induce self-assembly within the PNVP block. Eu 3+ ions preferentially coordinate to PNVP segments, yielding coordinatively cross-linked networks with reduced solubility in the solvent. Polystyrene segments retain their solubility in solution due to the amphiphilic character of the block copolymer. Mechanisms for self-assembly and reversible network formation are discussed. Due to the unique optical properties of Eu 3+ ions, in-depth analysis of fluorescent data was performed. These aggregates were drip-coated onto the surface of silicon wafers, with subsequent investigation of polymer morphology near the interface with silicon. This represents the initial step in the development of opto-electronic and photovoltaic applications for these self-assembled fluorescent polymeric aggregates.

Flexible lithium-ion batteries (LIBs) have recently attracted increasing attention with the fast development of bendable electronic systems. Herein, a facile and template-free solvothermal method is presented for the fabrication of hybrid yolk-shell CoS2 and nitrogen-doped graphene (NG) sheets. The yolk-shell architecture of CoS2 encapsulated with NG coating is designed for the dual protection of CoS2 to address the structural and interfacial stability concerns facing the CoS2 anode. The as-prepared composite can be assembled into a film, which can be used as a binder-free and flexible electrode for LIBs that does not require any carbon black conducting additives or current collectors. When evaluating lithium-storage properties, such a flexible electrode exhibits a high specific capacity of 992 mAh g(-1) in the first reversible discharge capacity at a current rate of 100 mA g(-1) and high reversible capacity of 882 mAh g(-1) after 150 cycles with excellent capacity retention of 89.91%. Furthermore, a reversible capacity as high as 655 mAh g(-1) is still achieved after 50 cycles even at a high rate of 5 C due to the yolk-shell structure and NG coating, which not only provide short Li-ion and electron pathways, but also accommodate large volume variation.

The plasmonic Ag nanoparticles match with vertically aligned N-doped TiO2 nanotube arrays, which display improving photoelectrochemical performance. N-doped anatase nanotube arrays are fabricated firstly, and then cubic Ag nanoparticles of diameter 5 nm are deposited on TiO2 nanotubes without organic additives at room temperature. X-ray photoelectron spectroscopy shows that the oxygen vacancies and N impurity are revealed in N-doped TiO2. The electrical properties of samples are investigated by systematic photoelectrochemical measurement. The charge transfer ability of TiO2, N-doped TiO2 and Ag/N-doped TiO2 is presented directly by Electrochemical impedance spectroscopy and Mott–Schottky measurement, respectively. The carrier density of Ag/N-doped TiO2 is higher 2 orders of magnitude enhancement of TiO2. Furthermore, its photocurrent responds rapidly with illumination owing to fast photoelectron transport. And photocurrent density is 0.14 mA cm−2 at 1.23 VRHE, which is the highest among samples. Finally, the mechanism of improving photoelectrochemical activity is schematically displayed. The plasmonic Ag/N-doped TiO2 composties are favorable for the separation for photoelectron-hole pairs and increasing electron transfer, leading to a considerably photoelectrochemical performance under sunlight. The modified nanotube arrays provide potential application in photoelectrochemical cell.

In this work, ethyl benzenecarboxylate (EB) was creatively selected as the additive in a blend of poly(3-hexylthiophene)/phenyl-C71-butyric acid methyl ester (P3HT/PC71BM) in non-halogenated solvent toluene (TL). With the optimized incorporating concentration of EB (i.e. 2 vol%) in toluene, a great power conversion efficiency (PCE) enhancement of 4.11% was achieved without thermal annealing, whereas a maximum PCE of 4.82% with thermal annealing was achieved under the same conditions. According to our systematic characterization results, we could conclude that we successfully regulated the micro-structures, including phase separation, the domain sizes of P3HT or PC71BM and the crystallinity of P3HT by incorporating 2 vol% EB in TL solution. The effectiveness of EB as a TL additive in P3HT/PC71BM can be interpreted based on its Hansen solubility parameters (HSPs) and its high boiling point.

The paper describes a template-free solvothermal synthesis of α-Fe2O3 hollow nanotube arrays over a large area. The columnar nanotubes on the substrate have closed tips and smooth defined walls. The thickness of the nanowall is about 10 nm, which could offer short diffusion distances and decrease recombination of electron–hole pairs. And the preferential orientation is the [110] axis. The cubic Au nanocrystals were decorated by a photocatalytic reduction process, and the corresponding EDX mappings intuitively display the distributions of the composites. Au nanocrystals matched the absorption of α-Fe2O3 hollow nanotube arrays, which improved photoactivity under visible light (wavelength > 420 nm). The photoactivity of the sample was investigated based on systematic photoelectrochemical (PEC) measurements. These revealed that the photocurrent density of Au/α-Fe2O3 is almost 6 times higher than that of pure α-Fe2O3. And its photocurrent density increases to 0.16 mA cm−2 at 1.23 VRHE under irradiation. The mechanism of enhanced visible light PEC activity has been discussed using schematics. Hence, the study presents not only a route for formation of α-Fe2O3 hollow nanotube arrays but also PEC applications of plasmonic composites.

Molybdenum disulfide is a promising candidate for the anode material in lithium-ion batteries due to its high theoretical specific capacity. However, volume change during cycling causes poor cycling stability and rate performance, and improving cycle life is a major research challenge. Herein, we present a strategy by fabricating phosphorus-doped graphene-wrapped molybdenum disulfide hollow spheres to improve the electrochemical performance of molybdenum disulfide in lithium storage. It is demonstrated that the obtained composite shows excellent electrochemical performance as anode material for lithium-ion batteries. The composite exhibits the high specific capacity of ∼1097 mA h g−1 at a current of 100 mA g−1, as well as excellent cycling stability and high-rate capability. The unique hollow structure combined with phosphorus-doped graphene wrapping definitely contributes to this versatile electrochemical performance.

The structure of biomimetic approach to converting sunlight was applied for design of composite materials. Here, hierarchical tree-like heterostructure Ag/ZnO (Ag wt%: 8.9%) arrays were fabricated by two-step electrodeposition, and it exhibited improved activity during photoelectrochemical water oxidation. The wurtzite-structured ZnO arrays prepared are the “trunk”. Ag nanoclusters were selectively deposited on the top of arrays as the “leaf”, which can strongly interact with visible light due to surface plasmon resonance. The inducted electromagnetic fields around Ag would efficiently propagate energy to composites by hot electrons injection. Based on morphology and crystal structure analysis, the linear sweep voltammagrams display that photocurrent increase to 0.17 mA/cm 2 at 1.23 V RHE , and the photo-to-hydrogen generation is 0.23%. Additionally, the amperometric I-t curves collected without voltage displayed better photocurrent response under sunlight. The kinetics of PEC process at the electrode surface was investigated by electrochemical impedance spectroscopy (EIS). The mechanism was deduced based on the energy level of ZnO and Ag. The designed plasmonic crystal system exhibited that tree-like heterostructure is favorable for improving sunlight absorption and photoeletrochemical performance.

Amorphous Mg–Ni–La hydrogen-storage alloys were prepared by melt-spinning. The phase structures of the ribbons before and after charge/discharge cycling were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analysis, respectively. The effects of different contents of La are discussed on the basis of discharge-capacity, the morphology, limiting current density and electrochemical impedance spectra of the Mg–Ni–La electrodes. The Mg 65 Ni 27 La 8 alloy exhibits the best reaction kinetics performance, the lowest contact resistance and a maximum discharge capacity of 582 mAh g −1 at room temperature. The non-isothermal dehydrogenation process of Mg 65 Ni 27 La 8 alloy was analyzed in detail by differential scanning calorimetry (DSC) and thermogravimetry (TG). The experimental results showed a maximum 4.0 wt.% of released hydrogen at a heating rate of 5 °C min −1 . The non-isothermal dehydrogenation process of the alloy can be divided in two steps, corresponding to the dehydrogenation of amorphous phase (1.45 wt.% H) and Mg 2 NiH 4 (2.55 wt.% H), respectively. It indicated that the amorphous structure was a key factor to achieve high discharge capacity and good cycling stability.

In this article, we creatively incorporated Ag–SiO2 core–shell nanoparticles (Ag–SiO2-NPs) into photo-/electro-active layers consisting of poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) in polymer solar cells (PSCs). By this way, the photovoltaic performances of PSCs have largely been enhanced. The results demonstrate a 13.50% enhancement of short-circuit photocurrent density (Jsc) and a 15.11% enhancement of power conversion efficiency (PCE) as the weight percent of doped Ag–SiO2-NPs is 1.5 wt% in the active layer of corresponding PSCs. We attribute the enhancement to the localized surface plasmon resonance (LSPR) effect of Ag–SiO2-NPs, by which the incident light harvesting is enlarged. Whereas, the incorporated bare Ag nanoparticles (Ag-NPs) in the active layer of PSCs decreases the PCE, which is ascribed to the quenching of excitons at the surface of Ag-NPs and the poor dispersion of Ag-NPs in the active layer. Importantly, this work provides a new approach to enhance the performance of PSCs via the LSPR effect of Ag–SiO2-NPs other than via non-circular nanometals.

A combined and sequential use of quantum mechanical (QM) calculations and classical molecular dynamics (MD) simulations was made to investigate the σ and π types of hydrogen bond (HB) in benzene-water and pyrrole-water as clusters and as their liquid mixture, respectively. This paper aims at analyzing similarities and differences of these HBs resulted from QM and MD on an equal footing. Based on the optimized geometry at ωb97xD/aug-cc-pVTZ level of theory, the nature and property of σ and π types of HBs are unveiled by means of atoms in molecules (AIM), natural bond orbital (NBO) and energy decomposition analysis (EDA). In light of the above findings, MD simulation with OPLS-AA and SPC model was applied to study the liquid mixture at different temperatures. The MD results further characterize the behavior and structural properties of σ and π types HBs, which are somewhat different but reasonable for the clusters by QM. Finally, we provide a reasonable explanation for the different solubility between benzene/water and pyrrole/water.

Peony-like spinel Li4Ti5O12 was synthesized via calcination of precursor at the temperature of 400 ℃, and the precursor was prepared through a hydrothermal process in which the reaction of hydrous titanium oxide with lith- ium hydroxide was conducted at 180 ℃. The as-prepared product was investigated by SEM, TEM and XRD, re- spectively. As anode material for lithium ion battery, the Li4Ti5O12 obtained was also characterized by galvanostatic tests and cyclic voltammetry measurements. It is found that the peony-like Li4Ti5O12 exhibited high rate capability of 119.7 mAh·g ^-1 at 10 C and good capacity retention of 113.8 mAh·g ^-1 after 100 cycles at 5 C, and these results indicate the peony-like Li4Ti5O12 has promising applications for lithium ion batteries with high performance.

Sn4+-doped FeS2 cubes with high yield thin films have been successfully synthesized on FTO glass through a simple hydrothermal process. The Sn4+-doped FeS2 cubes are single crystalline in cubic structure with (2 0 0) facet as the main exposed surface. The formation process was investigated. Sn2+ was found to play an important role during the formation process of FeS2 growing on FTO glass. The direct optical band gap value can be estimated to be 1.71 eV which is much larger than that of bulk FeS2 due to the Sn4+ doping. The photoelectrochemical properties of the Sn4+-doped FeS2 films were studied as well. There is a significant increase in photocurrent of Sn4+-doped FeS2 electrode compared to that of undoped sample.

The well-defined NaGdF4:Yb,Er nanorods (NRs) with various aspect ratios were synthesized using a facile hydrothermal method. The morphology and crystal phase of NRs could be controlled by reaction conditions. NaGdF4:Yb,Er NRs with various aspect ratios could be synthesized and their upconversion (UC) luminescence was tuned. It is displayed that the NRs with aspect ratios about 5 exhibited the strongest UC luminescence among samples. The growth mechanism and morphology transition of NRs had been deduced by schematic diagram. And UC mechanism had been determined by energy level diagrams. Compared with previous reports, the work provided a facial method for UCNRs with various aspect ratios at lower temperature.

Inorganic/polymer nanocomposite silica-poly(N-isopropylacrylamide) (SiO(2)-PNIPA) was successfully synthesized through a one-pot approach in supercritical carbon dioxide (scCO(2)). All raw materials, N-isopropylacrylamide (NIPA), vinyltriethoxysilane (VTEO), tetraethoxysilane (TEOS), initiator 2,2'-azobisisobutyronitrile (AIBN), crosslinker N,N'-methylenebisacrylamide (MBAM) and hydrolysis agent acetic acid (AA) were introduced into one autoclave and the parallel reactions of free radical polymerization and hydrolysis/condensation occurred simultaneously in the reaction mixture with scCO(2) as solvent. The obtained novel composite particles were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The swelling ratios (SR) and lower critical solution temperatures (LCSTs) of the prepared thermoresponsive microspheres were investigated by swelling tests and ultraviolet-visible (UV) spectrophotometry, respectively. TEM images demonstrated that well-dispersed particles with diameter less than 100 nm were formed. The composite microgels exhibited higher LCSTs than poly(N-isopropylacrylamide) (PNIPA) microgels did. The in vitro release simulation of the particles in situ impregnated with ibuprofen indicated that SiO(2)-PNIPA composites could improve the drug releasing effect of the microgels as controlled drug delivery systems.

Compared to conventional methods, a simple route is offered for synthesis of BaCO 3 with CO 2 and least energy consumption. And the morphology of BaCO 3 was tuned by controlling reaction conditions. The X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) were employed to characterize the products, the results showed that the products with various morphologies had the same crystal phase and growth direction. However, the distinct difference of the prepared products were determined by Raman and UV–vis spectra, showing shape-dependent optical properties. The results provide a useful model system for investigating the shape-dependent optical properties of carbonate nanocrystals.

The cubic PbS nanoflowers were successfully synthesized by the biomolecule-assisted method in the presence of supercritical carbon dioxide. This is an effective, simple and green synthetic method for the preparation of nanomaterials. It is noteworthy that the dosage of cetyltrimethylammonium bromide (CTAB) and chitosan as well as appropriate reaction time and pressure of system are crucial to form the unusual nanoflower structured PbS. The unique nanoflowers have numerous petals, which grow along the 〈100〉 direction as a single crystal. Especially, the nanoflower PbS indicates better sensitivity to the laser power via Raman spectra. Although the product size of PbS obtained is larger than the Bohr radius, its UV–vis absorption spectrum shows a remarkable blue-shift from that of bulk PbS due to quantum-confinement effects.

The nanostructured ZnS of cubic nanocorals and open-benzene ring has been synthesized by the biomolecule-assisted method in mixture of supercritical carbon dioxide and water as reaction medium at 150 °C and 28 MPa. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, photoluminescence spectrum of sample were characterized. The sodium tripoly phosphate and CO 2 as well as high-pressure condition might be the key factors for formation of the particular morphologies and nanostructures of ZnS. This synthesis method could be employed for preparation of other semiconductor nanomaterials.

The grafting of the methyl methacrylate (MMA) monomer onto natural rubber (NR) was carried out by supercritical carbon dioxide (scCO2) swelling polymerization with benzoyl peroxide (BPO) as an initiator. Fourier transform–infrared spectroscopy (FT–IR) was used to confirm the formation of graft copolymers with the characteristic bands of symmetric CO and COC stretching vibrations at 1728 cm−1 and 1147 cm−1, respectively. The effects of the rubber-to-monomer ratio, amount of initiator, reaction time, and pressure on the monomer grafting level (GL) and grafting efficiency (GE) were investigated, and the optimum conditions for the preparation of NR-g-MMA were found to be 70:30 of the rubber-to-monomer ratio, 1.2% of the initiator content, and the reaction pressure of 23 MPa for 6 h. The thermal behavior of the NR and the different NR/MMA molar ratio grafted copolymer samples was studied by differential scanning calorimetry (DSC). The observed glass transition temperature (Tg) was consistent with the GL. The tensile strength, modulus of elasticity, elongation at break, hardness, and oil resistance of graft copolymers were determined and compared with the values of NR and that of polymerization products prepared in traditional toluene solution. The results showed that the tensile strength, modulus of elasticity, hardness and oil resistance were greatly improved after modification in scCO2. Copyright © 2007 John Wiley & Sons, Ltd.

Herein, we report a new method that has been developed to prepare thermoresponsive polymers. The white, dry, fine powders were obtained directly from cross-linking polymerization of N-isopropylacrylamide in supercritical carbon dioxide (scCO2) with N,N-methylenebisacrylamide as a cross-linker. The effects of the reaction pressure and time as well as the initial concentrations of the initiator, cross-linker, and monomer on the yield and morphology of the resulting polymer were investigated systematically. The polymer yield was increased with the concentrations of the cross-linker, monomer, and reaction time. Under the condition of using higher cross-linker concentrations, the cross-linked poly (N-isopropylacrylamide) microparticles with diameters of 50 nm were generated in scCO2 in high-yield and short reaction times. These results suggest that the synthetic method using scCO2 can be used to prepare biomedical materials such as the controlled drug-release system.

Biodegradable blends of poly(propylene carbonate) (PPC) and poly(ethylene-co-vinyl alcohol) (EVOH) were melt compounded in a batch mixer followed by compression molding. The processability, mechanical properties, thermal behavior, and morphologies of the blends were investigated with torque rheometer, Fourier transform infrared spectroscopy, tensile tests, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. Torque rheometry indicated good interfacial miscibility between PPC and EVOH phases, and then fourier transform infrared spectroscopy spectra demonstrated that a certain extent of hydrogen-bonding interactions between PPC and EVOH matrix in the blends. A study of the mechanical properties and thermal behavior showed that the EVOH incorporation can significantly enhance the tensile strength, thermal stability, and crystallinity of the blends. Moreover, dynamic mechanical analysis and differential scanning calorimetry both revealed that PPC and EVOH were compatible to some extent. Further, scanning electron microscopic examination also revealed the good interfacial adhesion between EVOH and PPC phases. POLYM. ENG. SCI., 47:174–180, 2007. © 2007 Society of Plastics Engineers

Biodegradable blends of poly(propylene carbonate)/ethylene-vinyl alcohol copolymers (PPC/EVOH) were melt prepared. The mechanical strength, crystallization and melting behavior, morphologies, and thermal properties of these blends were fully investigated using tensile tester, modulated differential scanning calorimetry, scanning electron microscopy, and thermogravimetric analysis, respectively. The results indicated that the thermal stability of blends could be enhanced by increasing EVOH content. No change was observed for the tensile strength when EVOH content was lower than 30 wt %. The tensile strength, however, increased obviously with increasing EVOH content when EVOH content was higher than 30 wt %. The crystallization behavior of the PPC/EVOH blends was studied accordingly. The degradability test showed that the weight loss of PPC/EVOH blends increased with increasing EVOH content because of the strong moisture sorption of EVOH. Morphology observation indicated that the PPC/EVOH blends exhibited a two-phase microstructure. The blends with EVOH contents ranging from 40 to 60 wt % showed the best comprehensive properties as biodegradable thermoplastic for many applications.