•The SnO micro/nanostructure was synthesized by electrochemical anodization.•The SnO micro/nanostructure exhibited the distribution of concentric annulus.•The growth mechanism of SnO micro/nanostructure was discussed.The SnO micro/nanostructure with interesting distribution characteristic was synthesized by electrochemical anodization. The structural, morphological and photocatalytic properties of the SnO micro/nanostructure were investigated. The experimental results showed that the SnO displayed an interesting distribution characteristic of concentric annulus. The SnO near the fracture region was uniform and well-defined octahedron-like pattern. By contrast, the SnO away from the fracture region was self-assembled frond-like pattern. A feasible formation mechanism of this unique SnO micro/nanostructure was deduced as well. Moreover, the film exhibited 82.87% photodegradation rate of methylene blue, which was attributed to the strong light absorption and low recombination rate of photogenerated electros and holes.

•Tin oxide micro/nanostructures were synthesized by electrochemical anodization.•Feasible dynamic growth mechanism was proposed to elaborate the synthesis process.•Proposed synthesis mechanism will have reference function on relevant research.•SnO2/Sn3O4 with 87.24% photodegradation rate of methylene blue was obtained.SnO micro/nanostructures with novel distribution characteristic of concentric annulus were successfully synthesized by electrochemical anodization of tin foils in sodium hydroxide electrolyte. The SnO structures near the central fracture region were uniform and well-defined octahedron-like. The SnO structures away from the fracture region gathered together and presented petal-like and flower-like patterns. The effects of anodizing parameters and annealing temperatures on the structure features of tin oxide micro/nanostructures were systematically investigated. We found that as-anodized SnO micro/nanostructures can be transformed to tetragonal phase SnO2 micro/nanostructures by a thermal annealing process, which still maintained its original structure features as well as distribution characteristic. The optical property and photocatalytic performance of the annealed samples were also analyzed. The high photocatalytic property of the sample annealed at 400 °C was attributed to the strong light absorption and efficient interfacial charge separation. Additionally, a synthesis mechanism was discussed to illustrate the evolution process of anodized SnO micro/nanostructures with the distribution characteristic of concentric annulus.As-synthesized tin oxide micro/nanostructures exhibited unique distribution characteristic of concentric annulus. The growth mechanism of anodized SnO micro/nanostructures was elaborated step by step.Download high-res image (129KB)Download full-size image

ZnO/Mn hierarchical structures have been synthesized by a facile one-step solution route at room temperature and their structure, morphology, photoluminescence, and photocatalytic activity fully investigated. Reduced crystallite size and increased microstrain of ZnO were found on incorporation of Mn ions. Room-temperature photoluminescence spectra of the as-synthesized ZnO/Mn hierarchical structures presented violet and blue emission. Meanwhile, ZnO/Mn hierarchical structures exhibited enhanced photocatalytic activity compared with pristine ZnO. Optimal content (5%) of Mn ions in the ZnO matrix will lead to the highest photodegradation efficiency.

•Nanoporous tin oxide structures were synthesized by electrochemical anodization.•The influences of anodizing conditions on structure features were investigated.•i-t curves were used for the analysis of electrocrystallization process.•Growth mechanisms in both kinetics and thermodynamics were proposed.Nanoporous tin oxide structures were synthesized by electrochemical anodization of tin substrates at various anodizing conditions, including electrolyte species and concentration, anodizing potential, anodizing temperature and duration of the process. The influences of anodizing conditions on the structure features of anodized oxide films were investigated in detail. It is worth stressing that the correlation of the morphologies and current density virtue time curves (i-t curves) was analyzed in our work. The structure features of as-prepared tin oxide layers were found to be strongly related to anodizing conditions. Significant increases of average pore diameter occurred with the increase of anodizing potential, temperature and time. In addition, it is noteworthy that strong linear dependences between average steady-state current density and electrolyte concentration, anodizing potential as well as temperature were observed. It indicates the anodizing process is limited by mass transfer in electrolyte. Moreover, growth mechanisms in both kinetics and thermodynamics were established to elaborate the growth process of porous structures during anodization.

Novel self-assembled hierarchical BiVO4/Bi2WO6 heterostructured composites with different morphologies were controllably synthesized via a facile and template-free solvothermal method. The effects of the molar ratio of V to W on the structure, morphology, photocatalytic activity and photoelectrochemical properties of the BiVO4/Bi2WO6 composite photocatalysts were investigated in detail. The results showed that all the BiVO4/Bi2WO6 composites exhibited much better photocatalytic activities for methylene blue (MB) degradation and photoelectrochemical performances than pure BiVO4 and Bi2WO6. Among the composites, the BiVO4/Bi2WO6 microsphere with the molar ratio of V to W of 2:1 exhibited the best photocatalytic performance. The mechanism of enhanced activity was systematically investigated by UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, and photo-electrochemical methods including transient photocurrent responses, electrochemical impedance spectroscopy (EIS) and Mott–Schottky plots. The enhanced photocatalytic activity could be ascribed to the tetragonal–monoclinic heterophase structure, high surface oxygen vacancy concentration, narrow band gap energy and mainly the formed heterojunction structure which could effectively promote the separation of photogenerated electron–hole pairs. In addition, a possible photocatalytic mechanism for the enhanced photocatalytic activity was proposed on the basis of the calculated energy band positions of BiVO4 and Bi2WO6.

•Novel self-assembled BiVO4 samples were synthesized via a facile solvothermal route.•Flower-like microsphere and red blood cell-like structure were firstly fabricated.•The citric acid and pH controlling agent had great influences on the morphology.•The novel self-assembled BiVO4 samples exhibited excellent photocatalytic activities.Novel self-assembled BiVO4 samples with red blood cell-like shape and flower-like microsphere were successfully synthesized via a facile solvothermal approach by using Na2CO3 or NH3·H2O as the pH controlling agent and citric acid as the chelating agent. The photocatalytic activity was evaluated by the photocatalytic degradation of methylene blue (MB) under visible light irradiation. The results showed that both the citric acid and pH controlling agent had great influences on the morphologies of the samples. Besides, the relationship between the morphology and photocatalytic activity was studied in detail. Benefiting from the unique morphology, the prepared BiVO4 samples exhibited excellent photocatalytic activities for the degradation of MB dye under visible light irradiation.

•The m-BiVO4 samples were synthesized via a template-free solvothermal route.•The morphologies could be easily controlled by the simple change of the pH values.•The pH values could affect on the preferential growth oriented along {040} facets.Hierarchically structured m-BiVO4 samples with different morphologies have been synthesized via a template-free solvothermal route by adjusting the pH value of the precursor solution. The effects of pH value on structure, morphology and photocatalytic activity were investigated. The results showed that the pH value played a great influence not only on the formation of the hierarchical structures with different morphologies, but also on the preferential crystal growth of the BiVO4 oriented along {040} facets. The pinwheel-like sample with the highest relative intensities of the diffraction peaks I040/I–121 exhibited the best photocatalytic activity for the photodegradation of MB under visible light irradiation. According to the Ostwald ripening process, a possible oriented aggregation mechanism was proposed.

In order to achieve high performance in visible-light photocatalysis, V4+ and Ce3+ self-doped BiVO4/CeO2 heterostructured nanocomposites with high surface areas were prepared using the templating approach employing mesoporous silica MCM-41 as the hard template. X-ray photoelectron spectroscopy (XPS) spectra have demonstrated the presence of plentiful V4+ and Ce3+ species in the nanocomposites accompanied by the formation of oxygen vacancies. The presence of V4+ species is further identified by the electron spin resonance (ESR) spectrum. Furthermore, the BiVO4 and CeO2 could be affecting each other by arousing the structural changes in the formed nanocomposites. The V4+ and Ce3+ self-doped 0.4BiVO4/0.6CeO2 nanocomposite with the surface area as large as 78.35 m2/g exhibits the highest photocatalytic activity for the rhodamine B (RhB) and methyl orange (MO) degradation and photoelectrochemical performances. The enhanced photocatalytic mechanism is systematically studied via UV–vis diffuse reflectance spectra (DRS), photoluminescence (PL) spectra, transient photocurrent responses, and electrochemical impedance spectroscopy (EIS) spectra. The remarkable enhanced photocatalytic activity could be mainly attributed to the formed heterojunction nanostructures, the presence of defect states induced by oxygen vacancies, and self-doped V4+ and Ce3+ centers, as well as high surface areas. A possible photocatalytic mechanism over the V4+ and Ce3+ self-doped BiVO4/CeO2 nanocomposites is proposed based on the active species trapping experiments and calculated energy band structures.

•A new application of Bi2Te3 for laser beam shaping was reported.•The ultrathin Bi2Te3 nanosheets of 10–20 nm thickness were synthesized by solvothermal method.•The Bi2Te3 nanosheets used as an optical media to generate the ring-shaped beams.Topological insulators are a new class of quantum matter which have a bulk band gap like ordinary insulators but a protected conducting state on their edge or surface. These unique properties render topological insulators ultra-broadband optical response and potential applications in the photonic devices. Herein, we experimentally demonstrate that topological insulator Bi2Te3 can be used as an optical media for the generation of ring-shaped beams. Ultrathin Bi2Te3 nanosheets with uniformly hexagonal morphology have been successfully synthesized by solvothermal method. These Bi2Te3 nanosheets are 500–800 nm in edge width and 10–20 nm in thickness. Subsequently, we adopted Bi2Te3 as an optical media to generate the ring-shaped beams. In summary, our work provides an application of Bi2Te3 as a kind of interesting optical materials for laser beam shaping.

Micro-sized spherical BiVO4 photocatalysts composed of nanoparticles were synthesized by the sol–gel combustion method. The effects of citric acid and urea on the structural and morphological characteristics of samples were studied by X-ray diffraction, field emission scanning electron microscopy, N2 adsorption and desorption and UV–Vis spectroscopy. The photocatalytic activity was evaluated by the photocatalytic degradation of rhodamine B under visible light. The results showed the sphere-shaped BiVO4 sample to have excellent photocatalytic performance compared with the bulk sample prepared by solid-state reaction. This enhancement could be attributed to the special spherical morphology, which enhanced the absorption ability, increased the separation efficiency of photon-generated carriers and improved surface reaction sites for consumption of photon-generated carriers.

Single phase of BaIrO3 powders, dense bulks, and thin films were prepared by re-calcination method, spark plasma sintering (SPS) technique, and pulsed laser deposition (PLD) technique, respectively. The phase evolutions, crystallinity, microstructure and electrical properties of samples were investigated. BaIrO3 powders obeyed normal distribution with DAV = 1.68 μm; BaIrO3 bulks were densified by SPS technique at 950–1050 °C under a pressure of 30 MPa, showing a dense microstructure and the highest relative density of about 96.8 %. The room temperature bulks resistance and carrier mobility were about 3 × 10−4 Ω m and 4 × 10−2 m2 V−1 s−1, respectively. Besides, BaIrO3 thin films with a slightly Ir deficiency were successfully prepared on Si(111) substrates at a deposition temperature of 200–400 °C by PLD technique, which was accompanied by the formation of Ir-rich composition on the surface of the laser-ablated polycrystalline BaIrO3 target. The reason for the Ir deficiency of BaIrO3 films was explained in this study.

Recent experiments and computer simulation studies on nanoconfined ionic liquids (ILs) have shifted the focus from perpendicular to lateral distribution, the understanding of which is crucial for IL performance in the field of energy storage systems and tribology. In this article, the structure of 1-ethyl-3-methylimidazolium bromide, [Emim][Br], confined by a hydroxyl group functionalized surface of kaolinite plates has been studied by molecular dynamics simulation. Depending on the degree of confinement, the IL anion can pack into a two-dimensional (2D) ordered structure with square symmetry, coexisting liquid–solid phase, or liquidlike structure. The ordered structure arises from surface-induced ionic orientational preference and the driving force from confinement that supports the formation of the 2D planar structure. The flexible H-bond formed between Br and surface hydroxyl group at fixed d-spacing results in the liquidlike ordering that breaks down the electrostatic network in ILs. The influence of water addition varies when confining plates are treated differently, namely, forming large H-bonding network and small isolated oligomers for relaxed and fixed d-spacing, respectively. This work reveals additional information about the relative importance of factors like packing constraints, interaction within ILs, and selective attraction in determining the structure and dynamics of confined ILs.

•The nanoparticles were prepared via a two-step sol–gel method without grinding.•Room temperature ferromagnetism were observed in Co doped ZnO nanoparticles.•A novel magnetism combined with both ferromagnetism and diamagnetism were observed.We have prepared Zn1−xCoxO (x=0%, 1%, 2%, 3% and 4%) microspheres via a two-step sol–gel method without grinding and investigated their composition, morphology and magnetic properties by means of X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer, respectively. The X-ray diffraction result demonstrates that Co has been successfully doped into hexagonal ZnO. The scanning electron microscope images of Zn0.98Co0.02O reveal an average particle size around 200 nm, which is larger than that of as-prepared ZnO nanoparticles (60 nm). Magnetic properties measurement indicates that room temperature ferromagnetism and diamagnetism were obtained in Co-doped ZnO at the same time.

We have demonstrated that the d-spacing and thermal stability of the alkylimidazolium intercalated kaolinite compounds can be controlled by adjusting chain length of the alkyl groups. The composites were synthesized by displacement method using selected imidazolium ionic liquids bearing different short alkyl chains as guest molecules. The effects of the length of alkyl side chain on d-spacing and thermal stability of the ionic liquids–kaolinite intercalations were investigated by XRD and TG-DSC. Results revealed that in these composites, increasing the length of alkyl substituent led to larger d-spacing and decreased thermal stability. Temperature was found to have influence on the intercalation ratio but not on the d-spacing of final product. The present study shows an easy way of tailoring the performance of these intercalations via small variation of guest ionic liquids, providing the possibility of finding “species-specific” modifier for fully exfoliated nanocomposites.

Mg2−xAlxNi (x = 0, 0.25) electrode alloys with and without multiwalled carbon nanotubes (MWCNTs) have been prepared by mechanical alloying (MA) under argon atmosphere at room temperature using a planetary high-energy ball mill. The microstructures of synthesized alloys are characterized by XRD, SEM and TEM. XRD analysis results indicate that Al substitution results in the formation of AlNi-type solid solution that can interstitially dissolve hydrogen atoms. In contrast, the addition of MWCNTs hardly affects the XRD patterns. SEM observations show that after co-milling with 5 wt. % MWCNTs, the particle sizes of both Mg2Ni and Mg1.75Al0.25Ni milled alloys are decreased explicitly. The TEM images reveal that ball milling is a good method to cut long MWCNTs into short ones. These MWCNTs aggregate along the boundaries and surfaces of milled alloy particles and play a role of lubricant to weaken the adhesion of alloy particles. The majority of MWCNTs retain their tubular structure after ball milling except a few MWCNTs whose tubular structure is destroyed. Electrochemical measurements indicate that all milled alloys have excellent activation properties. The Mg1.75Al0.25Ni-MWCNTs composite shows the highest discharge capacity due to the synergistic effects of MWCNTs and Al on the electrochemical hydrogen storage properties of Mg2Ni-type alloy. However, the improvement on the electrode cycle stability by adding MWCNTs is unsatisfactory.Highlights► Al substitution for Mg in Mg2Ni leads to the formation of AlNi-type solid solution. ► MWCNTs addition hardly affects the phase compositions of milled alloys. ► MWCNTs addition decreases the particle sizes of Mg2Ni and Mg1.75Al0.25Ni. ► MWCNTs aggregate along the boundaries and surfaces of milled alloy particles. ► MWCNTs and Al show synergistic effects on electrochemical properties of Mg2Ni.

ZnO, Zn0.90Fe0.10O and Zn0.90Fe0.08Co0.02O nanoparticles have been successfully prepared by the homogeneous precipitation method in an open system at room temperature. The structures and magnetic properties of the samples have been characterized by X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. The X-ray diffraction result demonstrates a hexagonal wurtzite structure and a secondary phase of spinel in doped ZnO. The scanning electron microscope image of Zn0.90Fe0.10O reveals an average particle size of 40 nm with uniform shape, while the Zn0.90Fe0.08Co0.02O nanoparticles present an uneven size range from 20 nm to 60 nm. Magnetic measurement indicates that Fe doping can induce weak room temperature ferromagnetism, and the coercivity was enhanced up to 762 Oe with strikingly magnetic saturation when co-doped with Co.Highlights► A simple homogeneous precipitation process was conducted at a relatively low temperature.► Zn0.90Fe0.10O and Zn0.90Fe0.08Co0.02O products were of nanosize. ► Room temperature ferromagnetism was found in Zn0.90Fe0.10O and Zn0.90Fe0.08Co0.02O nanoparticles.► Relatively high coercivity of 762 Oe (300 K) that has never been reported before was obtained in Zn0.90Fe0.08Co0.02O nanostructures.

New types of S2O82−/Al-x wt%Ce–Zn–O solid acid catalysts were prepared by the sol–gel method. Their catalytic performances for the synthesis of n-butyl acetate from acetic acid and n-butanol were investigated. The characterization of prepared catalysts was performed using XRD, IR, TG-DSC and SEM. The experimental results showed that the S2O82−/Al-2.5 wt%Ce–Zn–O solid acid catalyst exhibited an optimal esterification performance with 98.71% esterification efficiency under the optimum synthesis conditions. Moreover, the S2O82−/Al-2.5 wt%Ce–Zn–O solid acid catalyst retained its high activity with above 95% esterification efficiency after being used repeatedly for seven times, which indicated that the S2O82−/Al-2.5 wt%Ce–Zn–O solid acid catalyst had excellent stability.

The novel 3D coordination polymer {Cd2(C4H2O4)2(C4H6N2)2(H2O)2 · 2H2O}n (I) has been synthesized and characterized by standard solid state methods including single-crystal X-ray crystallography. The compound crystallizes in triclinic space group P\(\bar 1\) with a = 8.589(4), b = 10.585(3), c = 13.094(1) Å, α = 84.91(4)°, β = 79.21(0)°, γ = 83.76(4)°, V = 1159.5(1) Å3, Z = 2. The fumaric acid acts as a multimodal bridging ligand in the polymer unit. One of the fumaric acid ligands tridentately chelates to two Cd2+ cations in the same dinuclear unit, while the other bidentately chelates to two Cd2+ cations in another dinuclear unit. The two metal centers possess slightly distorted pentagonal bipyramid geometry with four Cd {(μ4-fumarato)-(μ2-fumarato)-bis(2-methylimidazolyl)-diaqua} units joining together to form a 28-membered ring. The whole molecule exhibits a through channel along y-axis and 2D layers in xz plane. With hydrogen bond and π-π interaction, the 2D layers construct a 3D microporous network.

CO2 reforming of CH4 over hexaaluminates LaNixMg1−xAl11O19+δ and LaNixMg0.8Al11.2−xO19+δ were studied. XRD analysis confirmed that modifier Ni as well as Mg was inlaid into the hexaaluminate lattice. Hexaaluminate LaNixMg1−xAl11O19+δ (1.0 ≥ x ≥ 0.4) showed better catalytic activities and higher resistance to carbon deposition, which was attributed to their pure magnetoplumbite-type structure. For this reaction, x-value between 0.6 and 0.4 was the most suitable.

According to the HRTEM study, the UHP jadeite–quartzite mineral (Rutile, TiO2) in Anhui Province, Dabie Mountains, China, has ultrastructures such as 〈011〉 two-dimensional commensurable modulated structures or superstructures, {011} twin domain structures, dislocations and crystal deformations. The SAED patterns and HRTEM images indicate the existence of the deformations and stacking faults on the interface of {011} twin crystal of rutile and its two-dimensional commensurate modulated structures with repetition period 0.753 nm (3d011) has tetragonal symmetry, cell parameters (), The modulated structures of rutile were probably caused by the isomorphic replacement of Ti4+ and position modulation or occupation modulation of oxygen atoms in different degree; the deformation structures reveal that during the process of crystallization and mineralization, this mineral may be affected by the geological environment (such as temperature, pressure and stress), metamorphism and deformation.

Defect microstructures of minerals are a potential indicator of extremely rapid and episodic exhumation of ultrahigh-pressure (UHP) metamorphic rock. The microstructure defects in the minerals from UHP jadeite quartzite at Shuanghe, Dabie Mountains, China, have been investigated using transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR). TEM observations indicate that three polymorphs, namely, submicron-scale nature monalbite (MA, C2/m) (about 0.8 μm), high albite (HA, CĪ), and low albite (LA, CĪ) occur in jadeite inclusions from jadeite quartzite. The existence of monalbite (MA) implies that high-temperature metamorphism (>930 °C) takes place during exhumation and rapid cooling, during retrogression. The occurrence of nanoscale coesite (about 80 nm) and halite daughter minerals in quartz inclusions provide evidence for the transformation of the original coesite to quartz and the existence of high-salty fluids at peak metamorphic conditions. Structural water (OH/H2O) in nominally anhydrous minerals (NAMs) exists in the structures of these minerals as defects. The FTIR results show that the average contents of structural water in jadeite, garnet, rutile, and quartz are 1000 × 10−6, (900–1600) × 10−6, > 2000 × 10−6, and < 4 × 10−6, respectively, and the estimated whole-rock water content is (490–600) × 10−6. The results reveal that the water in crust or protolith can transport into the earth's depth through NAMs during HP-UHP metamorphism. These unique defect microstructures can be rationalized by a high strain rate at local weakening and deep faulting of continental collision orogens.