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A series of 3d-4f heterometallic coordination polymers (CPs), namely, Ln2(CuL)2(nipt)3(H2O)]⋅nH2O (Ln = Sm 1, Nd 2, Gd 3, for 1–2 n = 2, for 3 n = 1.6), [Yb2(CuL)4(nipt)3]·3.5H2O (4), [Pr2(NiL)(nipt)3(H2O)]⋅1.5H2O (5), [Sm2(NiL)(nipt)3(H2O)2]CH3OH⋅H2O (6), [Er2(NiL)2(nipt)3(H2O)2]⋅3H2O (7) (ML, H2L = 2, 3-dioxo-5, 6, 14, 15-dibenzo-1, 4, 8, 12-tetraazacyclo-pentadeca-7, 13-dien; H2nipt = 5-nitroisophthalic acid) were obtained by a solvothermal method and structurally characterized. Complexes 1–3 have 3,3,4,5-connected (3.4.5)(32.42.5.63.72)(42.63.8)(42.6) topological structure consisting of two different chains. 4 exhibits a two-dimensional (2D) heterometallic structure with 3-connected (63) topology. 5 displays a 2D framework formed by four-strand meso-helical chains and characterized by 6,6,4,4,4-connected (411.64)(412.63)(43.62.8)(45.6)2 topology. Compound 6 has 3,4,4,3-connected (43)(44.62)(42.124)(42.6) topological structure formed by three-strand meso-helical chains. In 7, two kinds of μ3-bridged nipt2− ligands together with NiL connect the eight-coordinated Er3+ ions to form a 2D structure, and the 2D layers are extended by μ2-bridged nipt2− into a three-dimensional (3D) microporous framework with 4,4,3,3-connected (4.62.83)2(4.82)2 topology. Interestingly, for 1, 2 and 4, CuL-sensitized the near-infrared emissions form Sm(III), Nd(III) and Yb(III) were firstly found under visible light irradiation. Moreover, the magnetic properties of 1, 2, 4 and 5 are also discussed.

Catalysis of C1 chemistry, especially for carbon monoxide (CO), carbon dioxide (CO2) and methane (CH4), is critically important for the clean production of fuels and chemicals and future energy sustainability. However, due to the relatively inert nature and low reactivity of these C1 molecules, their activation and transformation into clean fuels and high value-added chemicals still remain formidable challenges. In this context, metal-organic frameworks (MOFs), as relatively new emerging crystalline porous materials, have been shown to be promising heterogeneous catalysts or supports/precursors in the design and synthesis of various functional nanomaterials for addressing these challenges. In this review, the recent advances in MOF-based heterogeneous catalysts for transforming CO, CO2 and CH4 into high value-added chemicals are systematically reviewed. Emphasis is mainly placed on the catalytic reactivity, reaction mechanism and catalyst design. Additionally, major challenges and opportunities for MOF catalysts in the conversion of C1 chemistry are discussed to outline aspects for further development in this ongoing research field. It is anticipated that this review will provide a useful guide to chemists and material scientists attempting to design better MOF-based catalysts for the chemical conversion of C1 compounds.

The work presents a combinative merit of non-metal ion doping and active facet effect of Bi2O2CO3 photocatalyst. Br-doped Bi2O2CO3 nanosheets with exposed {0 0 1} facets were facilely prepared via a one-step hydrothermal reaction with the assistance of cetyltrimethylammonium bromide (CTAB) at a mild temperature of 60 °C for 4 h. The presence of CTAB not only influences the growth of Bi2O2CO3 crystalline but also leads to a Br-doping. Based on the crystal structure and DFT calculation, bromine from CTAB as dopant interstitially incorporates into Bi2O2CO3 lattice, which alters the band gap positions of Bi2O2CO3 and generates delocalized impurity states at the Fermi level. The improved electronic structure endows Br-doped Bi2O2CO3 with a broadened light-harvesting and accelarated charge migration. In addition, the thin nanosheet means more exposure of {0 0 1} active facets and larger internal electric field, which would also benefit for the charge separation. The sample with a trace Br content of 1.17 wt% shows the best degradation efficiency for RhB with a rate constant k enhanced by 3.6 folds compared with that of pure Bi2O2CO3 under simulated solar irradiation. Combining the effective catalytic sites and the detected active species, a possible migration mechanism of photogenerated e−/h+ pairs on the surface of Br-doped Bi2O2CO3 nanosheet is proposed. The work provides some new insights into the rational design and synthesis of non-metal doped semiconductor photocatalyst with facet dependency.

Prussian Blue Analogues Mn3[Fe(CN)6]2·12H2O porous nanoparticles have been achieved by coprecipitation method and using polyvinyl pyrrolidone (PVP) as a protective matrix. The obtained nanoparticles were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TG), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). The X-ray diffraction measurement results show that all the obtained nanoparticles are face centered cubic structure. The infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) measurement results indicate that Mn3[Fe(CN)6]2·12H2O nanoparticles are mixed-valence, and the ratios of MnIIFeIII to MnIIIFeII in obtained nanoparticles are different in water and water-methanol mixed solvent. The magnetic studies of nanocubes (about 480 nm, coming from water synthesis) and nanospheres (about 200 nm, from co-solvent synthesis) materials show that both samples have spin-glass behavior, but magnetic property measurement results indicated Tc, Tb and Tg temperatures of Mn3[Fe(CN)6]2·12H2O decreases as the size of nanoparticle reduces.

The effect of bend angle on the stability, electronic structure and optical properties of S absorbed graphene system is studied by using density functional theory based on the first - principles. Within the scope of the current study, it is found that the C atoms which are closest to the S atom are pulled up, the graphene plane is distorted, and the band gap of the graphene is opened, which changes graphene from quasi-metal to semiconductors. Bending deformation decreases the structural stability of S atom adsorbed on graphene system. The adsorption energy decreases with the increase of bending angle. After the intrinsic graphene is bent, the band gap is opened, and the bandgap increases with the bending angle. When the bending angle is between 0°–20°, it still corresponds to the quasi-metal property. When the bending angle increases to 25°, it gradually changes from small bandgap semiconductor to medium bandgap semiconductor. The band gap of graphene adsorbed S atom system decreases with the increase of the bending angle, and it always corresponds to medium bandgap semiconductors. When the angle is increased to 30°, the system loses its stability. The rate of increase of absorption coefficient increases with the increase of bending angle. The deformation causes the maximum absorption peak and the maximum reflection peak of the system to red shift, and the degree of red shift increases with the increase of the bending angle.

MicroRNAs (miRNAs) are endogenous non-protein-coding small RNAs that play crucial and versatile regulatory roles in plants. Using a computational identification method, we identified 55 conserved miRNAs in tea (Camellia sinensis) by aligning miRNA sequences of different plant species with the transcriptome library of tea strain 1005. We then used quantitative real-time PCR (qRT-PCR) to analyze the expression of 31 identified miRNAs in tea leaves of different ages, thereby verifying the existence of these miRNAs and confirming the reliability of the computational identification method. We predicted which miRNAs were involved in catechin synthesis using psRNAtarget Software based on conserved miRNAs and catechin synthesis pathway-related genes. Then, we used RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) to obtain seven miRNAs cleaving eight catechin synthesis pathway-related genes including chalcone synthase (CHS), chalcone isomerase (CHI), dihydroflavonol 4-reductase (DFR), anthocyanidin reductase (ANR), leucoanthocyanidin reductase (LAR), and flavanone 3-hydroxylase (F3H). An expression analysis of miRNAs and target genes revealed that miR529d and miR156g-3p were negatively correlated with their targets CHI and F3H, respectively. The expression of other miRNAs was not significantly related to their target genes in the catechin synthesis pathway. The RLM-RACE results suggest that catechin synthesis is regulated by miRNAs that can cleave genes involved in catechin synthesis.

The electronic structure and optical properties of O adsorbed ReS2 monolayer under different biaxial strains were studied through Density Functional Theory. Strain reduces the band gap of O adsorbed ReS2 monolayer, the band gap varies greatly reaching 1.509 eV under strain of −10%. Both the absorption intensity and reflectivity change significantly under strains. The adsorption coefficient reaches maximum value of 27.08 × 104 cm−1 under strain of −10% within the ultraviolet range. Our research shows that strain can effectively modulate the optoelectronic properties of O adsorbed ReS2 monolayer, which provides helpful guidance for the application of ReS2 in nanoscale optoelectronic devices.

Three chelating energetic materials (CEM), [Co(SCZ)2(H2O)2](TNR)(H2O)2 (1), [Ni(SCZ)2(H2O)2](TNR)(H2O)2 (2) and [Zn(SCZ)2(H2O)2](TNR)(H2O)2 (3, SCZ = semicarbazide, H2TNR = styphnic acid), were synthesized and characterized by elemental analysis, FTIR spectroscopy and single-crystal X-ray diffraction analysis. Single-crystal X-ray diffraction analysis revealed that 1 mainly exhibits swathe construction, whereas 2 and 3 manifest grating structure. Thermal decomposition behaviors of 1–3 were studied by differential scanning calorimetry (DSC). The critical temperature of thermal explosion, the entropy of activation (ΔS≠), the enthalpy of activation (ΔH≠), and the free energy of activation (ΔG≠) were also calculated. Sensitivity tests revealed that 1–3 are insensitive to mechanical stimuli, and that the grating structure (2 and 3) shows better shock resistance and flame retardant property than the swathe construction (1) at the molecular level.

Seven new 3d–4f heterometallic coordination polymers, [Ln(CuL)2(Hbtca)(btca)(H2O)]·2H2O (Ln = TbIII 1, PrIII 2, SmIII 3, EuIII 4, YbIII 5), [Nd(NiL)(nip)(Rnip)]·0·25H2O·0.25CH3OH (R= 0.6CH3, 0.4H) 6 and [Nd2(NiL)(nip)3(H2O)]·2H2O 7(CuL or NiL, H2L = 2, 3-dioxo-5, 6, 14, 15-dibenzo-1, 4, 8, 12-tetraazacyclo-pentadeca-7, 13-dien; H2btca = benzotriazole-5-carboxylic acid; H2nip = 5-nitroisophthalic acid) have been synthesized by a solvothermal method and characterized by single-crystal X-ray diffraction. Complexes 1–5 exhibit a double-strand meso-helical chain structures formed by [LnIIICuII2] units via the oxamide and benzotriazole-5-carboxylate bridges, while complex 6 exhibits a four-strand meso-helical chain formed by NdNi unit via the oxamide and 5-nitroisophthalate bridges. Complex 7 consists of a 2D layer framework formed by four-strand meso-helical chain via the nip2− bridges. Moreover, the magnetic properties of them were investigated, and the best-fit analysis of χMT versus T show that the anisotropic contribution of Ln(III) ions (arising from the spin-orbit coupling or the crystal field perturbation) dominates (weak exchange limit) in these complexes(for 3, λ = 214.6 cm−1, zj’ = −0.33 cm−1, gav = 1.94; for 5, Δ = 6.98 cm−1, zj’ = 1.53 cm−1, gav = 1.85).

Based on the law of approach to saturation and the experimental results of magnetic moments of PrNi 5 , the exchange interaction-effective field in PrNi 5 is given under a strong magnetic field and at low temperature, which is shown as H i n = a H e + b H e 3 / 2 + c H e 2 . By using the exchange interaction-effective field, the Zeeman Hamiltonian can be calculated directly without using the self-consistent method. Furthermore, the magnetic moment, the magnetic entropy and the magnetic entropy changes of PrNi 5 are calculated in the ranges of 0 H e 20 T and 2 T 60 K . The obtained results are in good agreement with the experimental data. The investigation indicates that the exchange interaction-effective field in PrNi 5, under the strong magnetic field and at low temperature, is only a function of the applied field.

New low-loss NiZrNb2O8 microwave dielectric ceramics were synthesized via conventional mixed oxide route. The morphology, crystal structure and microwave dielectric properties were investigated. It exhibited a monoclinic wolframite crystal structure, with the space group of P2/c ( C 2 h 4 ) . The lattice energy was carried out to evaluate the structural stability and sintering characteristics. Two kinds of grain shapes in dense samples, with similar elements ratios, were observed. Variations in the dielectric constant (er) were analyzed by relative density and porosity-corrected polarizability. The quality factor (Q × ƒ) was correlated with packing fraction and grain growth. The temperature coefficient of resonant (τƒ) was depended on the dielectric constant. The typical microwave dielectric properties of NiZrNb2O8 were er = 23.77, Q × ƒ = 40280 GHz, τƒ = −27.5 ppm/°C, sintered at 1200 °C.

Uniform ZnO nanospheres have been successfully synthesized through a facile solvothermal process. The structure and morphology of the products were characterized by powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that the products were ZnO nanospheres of 300–350 nm in diameter, which were composed of nanoparticles of ca. 5–10 nm. The size of the nanospheres can be tuned from ca. 300 nm to 1 μm by changing the concentration of the reactants. The gas sensing performance of the ZnO nanospheres with different size were investigated, which indicated that the ZnO nanospheres exhibited good gas sensitivity and selectivity towards n-butanol. In addition, the gas sensitivity of the ZnO nanospheres exhibited obvious size-dependent effect.

In this study, an effective BiOBr/Bi2O2CO3 p-n heterojunction was established via a precipitation conversion method at ambient temperature. The light response of the hybrid was broadened for 16 nm compared with that of Bi2O2CO3. More importantly, the charge transfer in BiOBr/Bi2O2CO3 heterojunction was greatly promoted as evidenced by photocurrent, ESI and PL results. So the photocatalytic ability of BiOBr/Bi2O2CO3 was greatly improved towards degradation of organic pollutants. The sample of Br amount of 0.094 wt% showed the optimal photoactivity for RhB degradation, with a rate constant k of 14.8 times as much as that of Bi2O2CO3. The reason is ascribed to the established built-in electrical field and resulted band matching between BiOBr and Bi2O2CO3. Based on the results, the migration mechanism of photoinduced charges at the interface of the heterojunction was put forward. This work provides a useful perspective in design and fabrication of Bi(III)-based heterostructure with an enhanced photocatalytic activity.

Four new coordination polymers, [Mn(CuL)(aipt)] (1), [Ni(CuL)(aipt)(H2O)]·H2O (2), [Mn(NiL)(tpt)]·1/4H2O (3) and [Mn(NiL)(atpt)] (4) (ML, H2L = 2, 3-dioxo-5, 6, 14, 15-dibenzo-1, 4, 8, 12-tetraazacyclo-pentadeca-7, 13-dien; H2aipt = 5-aminoisophthalic acid; H2tpt = terephthalic acid; H2aipt = 2-aminoterephthalic acid), have been synthesized by a solvothermal method and their structures are characterized by single-crystal X-ray diffraction. Complex 1 exhibits a 1D chain structure formed by Cu2Mn2 units connected via oxamide and 5-aminoisophthalate bridges, while complexes 2, 3 and 4 exhibit different 2D layered structures formed by Cu2Ni2 (2) and Mn2Ni2 (3–4) units, connected via oxamide and diverse carboxylate bridges. Magnetic studies demonstrate that antiferromagnetic interactions exist between the neighboring metal ions through the oxamide and/or carboxyl bridges in complexes 1–4.

In general, the preparation and photocatalysis of a semiconductor photocatalyst are carried out in two discrete reaction systems. Here we reported the simultaneous achievement of fabrication and in-situ photocatalysis of Ag/Bi2WO6 heterostructures in one system. By irradiating AgNO3/Bi2WO6 suspended organic pollutant solutions under simulated sunlight, Ag/Bi2WO6 heterostructures were on-line obtained via the photoreduction of AgNO3 and instantly participated in photocatalysis. The facile one-system process is rather time- and energy consumption. The results showed that monodispersed Ag nanoparticles of 10–20 nm were firmly anchored on Bi2WO6 surface. The decoration of Ag effectively broadened the visible-light response of Bi2WO6 and inhibited the recombination of photogenerated electron–hole pairs. The synergistic effect between Ag and Bi2WO6 brought about obviously enhanced photocatalytic activity to degrade organic contaminants compared with bare Bi2WO6. The sample with Ag molar ration of 0.1 presented the optimum photodegraded efficiency with rate constant 3.1-folds of Bi2WO6. And the composite is easily recovered with excellent circulation stability. The work provides some insights into the rational design and development of in-situ photocatalysis with high performance, which is more preferred for practical application.

Basic bismuth nitrate Bi6O6(OH)3(NO3)3•1.5H2O (BBN) modified Bi2WO6 heterostructures was facilely synthesized by one-pot hydrothermal strategy. The modification of BBN effectively improves the photocatalytic activity of Bi2WO6 for degradation and mineralization of Rhodamine B. The enhanced photocatalytic performance is attributed to the increased surface area and effective separation of photogenerated carriers induced by the potential difference at BBN/Bi2WO6 interface. Furthermore, the micro-scaled heterostructure is easily recycled with excellent circulating stability. The work provides some new insights for the rational design and synthesis of basic salt modified Bi-system photocatalyst with high efficiency.

BiOCl nanostructures including microspheres, microflowers, microplates, and nanoplates, have been synthesized by a simple solvothermal method using bismuth nitrate and sodium chloride as raw materials without adding any additives. Structure and morphology of the products were characterized by powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicated that the as-prepared microspheres and microflowers were composed of nanosheets. Although with different shape and lateral size, the nanoplates and microplates were all single-crystalline plates with exposed {0 0 1} facets. It was found that the volume ratio of polyethylene glycol 400 and H2O in the solvent played a key role in the morphology of the products, and the possible growth mechanism was also discussed. The photocatalytic measurements indicated that the BiOCl samples exhibit good photocatalytic properties towards Rhodamine B.

Cu 2 O/amorphous TiO 2 core–shell nanocomposites with uniform cubic structure were prepared by a hydrolysis method and CuO/TiO 2 core–shell nanocomposites were obtained by a post-calcination process. The structure and morphology of the products were characterized by powder X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The results showed that the cubic Cu 2 O/TiO 2 core–shell nanocomposites were of 110–140 nm in side length and the as-hydrolyzed TiO 2 shell layer was amorphous. The products transformed to quasi-spheric CuO/TiO 2 (anatase) nanocomposites after calcination. The visible-light photocatalytic properties of different products towards methyl orange (MO) were investigated. The results showed that the photocatalytic activity of the cubic Cu 2 O/amorphous TiO 2 core–shell nanocomposites was higher than that of pure Cu 2 O nanocubes, pure TiO 2 nanoparticles, and the spheric CuO/TiO 2 core–shell nanocomposites.

Six new coordination polymers, [Co(NiL)(aipt)] (1), [Co2(ML)(hipt)2(CH3OH)(H2O)]·CH3OH (M = Cu (2), Ni (3)), [Co2(C2O4)2(CuL)2] (4), [Co4(NiL)4(ipt)4(H2O)2] (5) and [Co(CuL)(tpt)] (6) (H2L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-dien; H2aipt = 5-aminoisophthalic acid; H2hipt = 5-hydroxyisophthalic acid; H2ipt = isophthalic acid; H2tpt = terephthalic acid), have been synthesized by a solvothermal method and characterized by single-crystal X-ray diffraction. Complexes 1, 4 and 5 exhibit different infinite chain structures formed by CoNi (1), Co2Cu2 (4), Co4Ni4 (5) units, respectively, via oxamide and diverse carboxylate bridges, while complexes 2, 3 and 6 exhibit different two-dimensional network structures formed by Co2M or Co2M2 units via oxamide and 5-hydroxyisophthalate or terephthalate bridges. The results of magnetic determination show weak antiferromagnetic interactions in 1–3 and 5–6, and the spin–orbit coupling interaction of Co(II) is a primary factor in the magnetic behaviors.

Uniform Cu2O nanoparticles have been successfully synthesized through a facile additive-free aqueous solution route at room temperature. The structure and morphology of the products were characterized by powder X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The results showed that the products were Cu2O nanocubes of 110–130 nm in side length. The size of the nanocubes can be tuned from 20 nm to 500 nm by changing the concentration of the sodium hydroxide solution and the kind of copper salts. The visible-light photocatalytic properties of the as-obtained Cu2O products were investigated. The results showed that these Cu2O nanoparticles exhibited good photocatalytic activity towards methyl orange (MO).

Graphical abstract: - Highlights: • α-Fe{sub 2}O{sub 3}/Bi{sub 2}WO{sub 6} heterostructures were facilely fabricated by an impregnation method. • The Bi{sub 2}WO{sub 6} matrix was modified by α-Fe{sub 2}O{sub 3} nanoparticles of 10–20 nm on the surface. • The visible-light absorption region of the composite was effectively red-shifted. • The composite exhibited enhanced photocatalytic activity to RhB below Fe-0.4%. • The band gap coupling effect between α-Fe{sub 2}O{sub 3} and Bi{sub 2}WO{sub 6} was interpreted. - Abstract: α-Fe{sub 2}O{sub 3} modified Bi{sub 2}WO{sub 6} mesostructures were facilely prepared by an impregnation method. The characterizations of phase structure, morphology, microstructure, UV–vis absorption, photoluminescence, BET and solar simulated photocatalytic behavior were systematically conducted. The Fe{sub 2}O{sub 3}/Bi{sub 2}WO{sub 6} heterostructure with a Fe mass percentage in 0.05–0.2% presented obviously enhanced photocatalytic activity for the degradation of Rhodamine B than pristine Bi{sub 2}WO{sub 6}. In particular, the apparent reaction rate constant with Fe-0.1% was 2.24-folds of that of pure Bi{sub 2}WO{sub 6}. UV–vis diffuse reflectance spectra showed that the modification of α-Fe{sub 2}O{sub 3} broadened the visible light absorption of Bi{sub 2}WO{sub 6}. The decreased photoluminescence indicated an effective suppression of the recombination of electron–hole pairs at Fe{sub 2}O{sub 3}/Bi{sub 2}WO{sub 6} interface.more » The band-gap coupling effect between Fe{sub 2}O{sub 3} and Bi{sub 2}WO{sub 6} was interpreted via comparison of relative valence and conductance potentials, which confirmed an irreversible flow of electrons and holes in the interface of Fe{sub 2}O{sub 3}/Bi{sub 2}WO{sub 6}. Moreover, the composite showed excellent circulation stability, suggesting potential application in dealing with environmental pollutions.« less

Two novel two-dimensional copper–nitroxide coordination polymers of formula [Cu2(NIT3Py)2(glu)2]n (1) and {[Cu2(NIT3Py)2(adip)2] · CH3OH · 0.5H2O}n (2) (NIT3Py = 2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, H2glu = glutaric acid and H2adip = adipic acid), have been synthesized and characterized structurally as well as magnetically. The crystal structures of both polymers contain the paddle-wheel binuclear Cu(II) units axially coordinated by NIT3Py ligands which are bridged by the flexible glutarate or adipate anions into the corrugated 2D sheets. Interestingly, complex 1 displays a 2D helical layer structure rarely found in metal–nitroxide systems. The magnetic measurements show the strong antiferromagnetic interactions in the binuclear Cu(II) units and weak antiferromagnetic interactions between copper ions and nitroxides.

Flower-shaped porous Bi2WO6 superstructures assembled from squared nanoplates have been successfully fabricated by a facile hydrothermal method without any surfactants or additives. Parameter-dependent experiments show that the initial strong acidic condition of the hydrothermal precursor is essential for the construction of tiny nanoplates into hierarchical Bi2WO6 flowers. The sample exhibits improved visible-light-driven photocatalytic activity in the degradation of Rhodamine-B, compared with Bi2WO6 multilayered disks, isolated platelets prepared at elevated pH values and bulk Bi2WO6 obtained by solid state method, respectively. It is believed that the higher BET surface area and nano/mesopore structure can afford more reactive sites and abundant transport paths for the degradation reaction. Moreover, the sample shows excellent circulation stability, suggesting its potential application in dealing with enviromental pollutions.

A first-principles study was reported based on density functional theory of hydrogen vacancy, metal dopants, metal dopant-vacancy complex in LiBH 4 , a promising material for hydrogen storage. The formation of H vacancy and metal doping in LiBH 4 is difficult, and their concentrations are low. The presence of one kind of defect is helpful to the formation of other kind of defect. Based on the analysis of electronic structure, the improvement of the dehydrogenating kinetics of LiBH 4 by metal catalysts is due to the weaker bonding of B—H and the new metal-like system, which makes H atom diffuse easily; H vacancy accounts for a trace amount of BH 3 release during the decomposing process of LiBH 4 ; metal dopant weakens the strength of B—H bonds, which reduces the dehydriding temperature of LiBH 4 . The roles of metal and vacancy in the metal dopant-vacancy complex can be added in LiBH 4 system.

Porous α-Fe 2 O 3 nanorods with typical pore size of 2–4 nm were controlled prepared by a facile hydrothermal process of Fe(NO 3 ) 3 ·9H 2 O aqueous solution in the presence of NaOH, followed by a calcination treatment. Contrast experiments indicate that the morphology and crystalline structure of the hydrothermal products depend greatly on the quantity of NaOH. Hematite nanoparticles and microplates were respectively obtained under conditions without or with excess NaOH. The porous α-Fe 2 O 3 nanorods exhibit a high BET surface area of 105.1 m 2 g −1 and a pore volume of 0.13 m 3 g −1 . UV–vis measurement shows wide absorption to visible light and an obvious blue-shift of the adsorption edge due to the quantum size effect. The visible-light photocatalytic performances of the as-prepared samples were evaluated by photocatalytic decolorization of methylene blue at ambient temperature. The results indicate that the photocatalytic activity of the porous α-Fe 2 O 3 nanorods is superior to hematite nanoparticles and platelets and exhibit good reusable feature. The photocatalytic process of porous structure is determined to be pseudo-first-order reaction with apparent reaction rate constant of 1.04 × 10 −2 min −1 . And the optimum photocatalyst dosage is 20 mg per 100 mL of dye solution. The porous α-Fe 2 O 3 nanorods are considered potential photocatalyst for practical application due to the excellent photocatalytic behavior and good reusability.

Three new one-dimensional (1-D) chain metal–nitroxide complexes of the formula [M(NIT4Py)2(e,e-trans-1,4-chdc)(H2O)2]n (M = Co(II) 1, Ni(II) 2 and Zn(II) 3; NIT4Py = 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and 1,4-chdc = 1,4-cyclohexanedicarboxylate dianion) have been synthesized and characterized structurally as well as magnetically. The X-ray crystal structure analyses of complexes 1, 2 and 3 reveal that they are isostructural. Three complexes all crystallize in neutral 1-D chains where metal–nitroxide units [M(NIT4Py)2(H2O)2] are linked by the linear 1,4-cyclohexanedicarboxylate dianion. The 1,4-chdc completes the segregation and only possesses the e,e-trans-conformation, although there are both cis- and trans-isomers in the raw material. The magnetic measurements show that complexes 1 and 2 both exhibit weak antiferromagnetic interactions between the metal ions and the nitroxides.

Uniform hematite nanoparticles have been successfully synthesized through a surfactant mediated hydrothermal method. The structure and morphology of the products were characterized by powder X-ray diffraction, transmission electron microscope, scanning electron microscope, and Fourier transform infrared spectrometer. The results showed that the products were α-Fe2O3 nanoellipsoids of 115–140 nm in long axis and 60–80 nm in short axis. The growth mechanism of the products was proposed based on the experiments. Uniform nanospindles, nanoellipsoids, nanospheres, and nanopolyhedra with different sizes can be obtained by adjusting the reaction temperature, the amount of additive, and concentration of the reactants. The result may facilitate the exploration of controlled synthesis of α-Fe2O3 nanoparticles.

Single-crystal cuprous iodide semiconductor nanospheres were fabricated via a mild low-temperature solution route by using polyvinyl pyrrolidone as capping agent and the mixture of water and polyethylene glycol 400 as solvent. The structure, morphology, and properties of the products were characterized by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermal gravimetry and photoluminescence spectrometry. The results showed that the products were CuI nanospheres of ca. 280–650 nm in diameter and were composed of quasi-trigonal particles of ca. 20–40 nm. The phase transformation temperature and the melting point of the products decreased by ca. 12 and 8 °C compared with the bulk CuI. The possible formation mechanism was discussed on the basis of experimental results.

Quasi-hexagonal α-Fe 2 O 3 nanoplates with lateral sizes of 40–60 nm and thickness of ca. 10 nm were fabricated by a facile poly(ethylene glycol 600) (PEG-600) assisted hydrothermal technique in combination with calcination method. The final α-Fe 2 O 3 nanoplates inherited perfectly the morphology of the preliminarily hydrothermal products with phases of dominant α-Fe 2 O 3 and minor α-FeOOH. The platelets could be tailored from nano- to meso- and to micro-scale via adjusting PEG-600 quantities. An adsorption-extension-attachment model was proposed to explain the formation and growth mechanism of the platelets. The as-obtained α-Fe 2 O 3 nanoplates exhibited a specific Langmuir surface area of 59 m 2 /g and a maximum N 2 adsorption of 137.3 cm 3 /g at 1 atm. UV–vis measurement showed a strong absorption in a wide range from UV to visible light with a blue-shifting band gap of 2.33 eV due to the nanosize effect.

High quality ceramics in Zn(Ta 1− x Sb x ) 2 O 6 (0.05≤ x ≤0.20) compounds were synthesized by the conventional solid-state reaction method. The effects of Sb 5+ ion substitution on microstructures, phase composition and microwave dielectric properties were investigated. A phase change or crossover from ZnTa 2 O 6 to ZnSb 2 O 6 occurred at x =0.1. Well-developed microstructures of ceramics can be achieved at 1250 °C and the distribution of grain size was optimized due to the existence of ZnSb 2 O 6 phase. With Sb 5+ ion substitution, the quality factors Qf values were enhanced effectively and ranged from 72,400 to 119,600 GHz owing to the meliorative grain size distribution. The dielectric constant and the temperature coefficient of resonant frequency ( τ f ) were strongly dependent upon the Sb 5+ ion concentration and the presence of the second phase of ZnSb 2 O 6 .

The fabrication and photocatalytic application of zinc ferrite nanocrystals were reported. Quasi-cube ZnFe2O4 nanocrystals with typical small sizes of 5–15 nm were successfully synthesized by a facile hydrothermal approach. ZnFe2O4/P25 nanocomposite was prepared by physically grinding the ZnFe2O4 nanocrystals with TiO2 (commercial Degussa P25) at ambient temperature, and it exhibited excellent photocatalytic activity for the mineralization of Rhodamine B. UV–vis measurement and photocatalytic test results showed that ZnFe2O4 nanocrystals exhibited effective band-gap coupling to P25 nanopowders by simply physical grinding without any surface modification or high-energy balling, which is usually adopted in conventional mixture process. This phenomenon can be attributed to the high surface activities of the as-obtained tiny ZnFe2O4 nanocrystals and commercial P25 nanoparticles. It may imply that the mixing process of composite materials would be simplified by further lowering the grain sizes of their component particles.

Nearly monodisperse Co 3 O 4 nanospheres were fabricated via a facile polyethylene glycol 400-mediated solventhermal route followed by a calcination process at 500 °C. The structure, morphology, and properties of the products were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, and UV–vis spectrometry. The results showed that the products were Co 3 O 4 nanospheres of 160–170 nm in diameter and were composed of nanoparticles of ca. 40 nm. The possible formation mechanism was discussed on the basis of experimental results. Furthermore, optical property of the products was characterized.

Supercritical fluid extraction (SFE) was used to extract cordycepin and adenosine from Cordyceps kyushuensis . An orthogonal array design (OAD) test, L 9 (3) 4 , including pressure, temperature, the mount of modifier and the flow rate of CO 2 was performed to get the optimal conditions. The process was then scaled up by 30 times with a preparative SFE system under 40 MPa, 40 °C, the mount of modifier (0.04 ml min −1 ) and a flow rate of CO 2 (2.0 l min −1 ). The preparative SFE extracts were separated and purified by high-speed counter-current chromatography (HSCCC) with a selected two-phase solvent system composed of ethyl acetate–n-butyl alcohol–water at an optimized volume ratio of 1:4:5, and the collected fractions were analyzed by high-performance liquid chromatography (HPLC). Two nucleosides were obtained and yielded 8.92 mg of cordycepin, 5.94 mg of adenosine with purities of 98.5 and 99.2% from 400 mg SFE crude extraction, in one-step separation, respectively.

The effect of magnetic field amplitude on permeability spectra was studied by using permeability spectroscopy. Results show that the permeability spectra can be greatly affected by magnetic field amplitude—they become complicated under a higher field, which means that the initial permeability increases with an increase of the applied field at first and then decreases with further increase. Meanwhile, another relaxation peak appears and the relaxation frequency increases during the same process. In addition, the permeability is improved significantly over the basic Finemet composition with appropriate substitution of Al for Nb. Moreover, the effect of annealing condition on the permeability spectra as well as the influence of eddy current was also discussed. All these phenomena were explained by using the dynamic magnetization theory and random anisotropy model.

Supercritical fluid extraction (SFE) was used to extract quinolizidine alkaloids from Sophora flavescens Ait. (Kushen). An orthogonal test L(9)(3)(4) including pressure, temperature, flow rate of CO(2) and the amount of modifier was performed to get the optimal conditions. The process was then scaled up by 30 times with a preparative SFE system under 25 MPa, 50 degrees C and a flow rate of CO(2) (2l/min) and the amount of modifier (0.04 ml/min). The crude extracts were separated and purified by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of chloroform-methanol-2.3 x 10(-2)M NaH(2)PO(4) (27.5:20:12.5, v/v), and the collected fractions were analyzed by high-performance liquid chromatography (HPLC). Three kinds of quinolizidine alkaloids were obtained, yielding 10.02 mg of matrine, 22.07 mg of oxysophocarpine and 79.93 mg of oxymatrine with purities of 95.6, 95.8, 99.6% in one-step separation, respectively.

A novel catalytic spectrophotometric method for the determination of superoxide anion radical (O 2 − ) and superoxide dismutase (SOD) activity is proposed. The method is based on the coupling reaction of 2,4-dichlorophenol (2,4-DCP) and 4-amino antipyrine in the presence of H 2 O 2 , catalyzed by a Schiff base metal complex included by β-cyclodextrin cross-linked polymer (β-CDP) as a mimetic enzyme. The contribution describes the design and synthesis of a novel Schiff base, salicylidene-2-amino-4-phenylthiazole (SAPTS) as well as a series of its metal complexes: M(II)–(SAPTS) 2 [M: Cu(II), Co(II), Zn(II), Ni(II)], among which Cu(II)–(SAPTS) 2 exhibits efficient horseradish peroxidase-like catalytic activity. Investigations of the optimum reaction conditions, the mechanism, and effects of coexisting substances are presented. The linear calibration range and the detect limit (3 σ ) of the developed method for superoxide is from 0.0 to 1.0×10 −3 and 7.54×10 −7 M, respectively. The determinations of SOD activity in human/rat blood, garlic, onion and scallion serve as models for the proposed method. A comparison of the results with established classical analysis is satisfactory.

A simple and sensitive kinetic-spectrofluorimetric method is described for the determination of iridium(IV) and the possible mechanism of catalytic reaction is proposed. The method is based on the fluorescent quenching reaction of salicylaldehyde p-nitro-benzoylhydrazone (SAP-NBH) with potassium periodate, inhibited by Ir(IV) in a water-ethanol (7.3+2.7, v/v) medium at pH 10.70 and 55 degrees C. Cetyltrimethyl ammonium bromide sensitized the determination obviously. SAP-NBH was newly synthesized and its ionization constants were established spectrophotometrically. The reaction was monitored by measuring the change rate of fluorescence (lambda ex/em=252/310 nm) after a fixed time of 5 min. The proposed method allowed the determination of iridium in the range of 0.11-18 ng ml(-1) with a RSD of 2.5% at a concentration of 10 ng ml(-1) and the detection limit was down to 0.09 ng ml(-1). The method was found to be relatively selective and was applied successfully to determine iridium in synthetic mixtures and mineral sample with the results consistent well with the ref. values.

The spin fluctuations of the magnetic ions play an important role on the magnetic properties of the crystals and lead to a new mechanism for the Curie–Weiss susceptibility. The exchange field Hexch acting on the rare-earth ions in Tb:YIG is improved based on the temperature dependence of the spin fluctuations, which is expressed as Hexch=n0(1+γT+βT−2)MYIG. By means of the improved exchange field, the magnetic and magneto-optical properties of Tb3+ ions in Tb:YIG are calculated. The calculated results are in good agreement with the measured data in the temperature range from 40 to 300 K.

Generally, the exchange-interaction on a magnetic ion is expressed as H → m = λ M → , here λ is a temperature independent constant and M → is the magnetization. However in some paramagnetic materials the exchange-interaction between the electrons in different magnetic ions depends on temperature. Actually, the spin-fluctuation of magnetic ions appears in some paramagnetic materials, and it depends on temperature. In this Letter, the effect of the spin-fluctuation on the effective field is considered by introducing a temperature dependent coefficient λ, and λ is expressed as λ = α + β T . Then, the Curie–Weiss law can be extended. The correctness of the extension is examined by comparing the calculated values of the magnetic susceptibility of CeF3 crystals with the measured ones.