A novel inorganic-organic hybrid polyoxotungstate H4[Ni(en)2]2[Ni(en)(dap)]2[Ni(dap)2]2[Ni4(en2)(PW9O34)2]-{[Ni(H2O)5]2[Ni4(en)2(PW9O34)2]}·12H2O (1, en = ethylenediamine, dap = 1,2-diaminopropane) has been successfully synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis, respectively. Single-crystal structure analysis reveals that 1 exhibits a 2-D network structure based on two kinds of tetra-Ni-substituted sandwich-type Keggin polyoxoanions linked by different types of Ni-organoamine complexes.Graphic abstract

•Different morphologies of Ni(OH)2 nanocrystals were synthesized via a gas–liquid diffusion method at room temperature.•The possible formation mechanism of the Ni(OH)2 nanocrystals was discussed.•The evolution of the different morphologies of Ni(OH)2 nanostructures is due to the increase of precursor concentrations.•The microsphere-like Ni(OH)2 prepared at a concentration of 0.1 M NiSO4 exhibits the highest specific capacitance of 1799 F g−1.•The microsphere-like Ni(OH)2 shows 92.8% capacitance retention after 2000 cycles.In this work, Ni(OH)2 nanocrystals have been synthesized via a gas–liquid diffusion method at room temperature in the absence of any template or organic surfactant. The structure and morphology of as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), BET specific surface area and pore size distribution analyzer. It can be observed that the crystal phase, morphology and specific surface area of as-prepared samples can be controlled by altering the concentration of NiSO4 solution and reaction time. The electrochemical supercapacitive properties of Ni(OH)2 nanostructures prepared at different concentration of NiSO4 solution have been investigated by cyclic voltammetry and chronopotentiometry. Chronopotentiometry test results showed that Ni(OH)2 samples prepared with 0.1 M NiSO4 solution exhibited a highest specific capacitance of 1799 F g−1 at a current density of 4 A g−1 within the potential range of 0–0.5 V and the Ni(OH)2 samples retain 92.8% of the initial capacitance even after 2000 continuous charge–discharge cycles. The higher capacitance and excellent recycle ability indicate that Ni(OH)2 crystals prepared by the gas–liquid diffusion method are suitable for supercapacitor materials.

Sodium salt of styrene/methacrylic acid copolymer was synthesized via radical polymerization, and its absolute molecular mass and polydispersity index were measured by aqueous-based GPC coupled with MALLS in a mixed solvent containing 75/25, v/v%, methanol/water, 38.6 mM NaCl and 10.0 mM NaH2PO4 buffer, pH 6.0. Dynamic light scattering verified the absence of aggregation of copolymer in preferred mobile phase compositions.

Two new borate clusters, [C4H11N2O][C4H9N2][B5O6(OH)4]2 (1), [Cd(dien)2][B5O6(OH)4]2 (2, dien = diethylenetriamine), have been obtained under solvothermal conditions and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray structural analysis, respectively. Crystal data for 1: monoclinic, P21/c, a = 18.6975(5) Å, b = 15.3413(8) Å, c = 9.6691(3) Å, β = 90.462(3)°, Z = 4. Crystal data for 2: triclinic, P-1, a = 8.6107(4) Å, b = 9.3504(4) Å, c = 18.9631(4) Å, α = 103.798(4), β = 91.940(4)°, γ = 94.134(4)°, Z = 2. They all consist of [B5O6(OH)4]− clusters and further extend to 3-D frameworks via extensive hydrogen-bonding interactions. Interestingly, a novel in situ organic reaction between ethylenediamine and CH3COO− group has been observed during the formation of compound 1.

A new layered organic–inorganic hybrid lead borate [Pb(en)0.5][B5O8(OH)] (1, en = ethylenediamine), has been hydro(solvo)thermally synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, FT-IR spectroscopy and thermogravimetric analysis, respectively. Compound 1 crystallizes in triclinic system space group P-1 (No. 2), a = 6.6537(6) Å, b = 6.7157(6) Å, c = 10.6911(9) Å, α = 99.015(7)°, β = 93.657(7)°, γ = 118.915(9)°, V = 407.59(6) Å3, Z = 2. The structure consists of two infinite borate layers constructed from [B5O8(OH)]2− cluster building units, then two such layers are further connected by the linear [Pb2(en)]4+ complex linkers to form the novel bilayer structure.

•A new acentric metal borate Mg[B6O9(OH)2]·4H2O.•3-D framework built by 2-D novel [B6O11(OH)2]n layers and PbO6 octahedra.•UV cutoff edge below 200 nm and SHG efficiency about 1.1 times that of KDP.An acentric metal borate, Mg[B6O9(OH)2]·4H2O, has been successfully made under mild hydrothermal conditions. Its structure contains a novel 2-D layer constructed from the B6O11(OH)2 cluster units, which are further linked by the MgO6 polyhedra to form a 3-D framework. It has a UV cutoff edge below 200 nm and exhibits SHG efficiency approximately 1.1 times that of KDP.A new acentric Mg[B6O9(OH)2]·4H2O has been made under mild hydrothermal conditions. Its structure contains a novel [B6O11(OH)2]n layer and is further linked by MgO6 octahedra to form a 3-D framework, showing that it is phase-matchable with SHG signal intensity approximately 1.1 times that of KDP.

A new kind of vaterite calcium carbonate mesocrystal with a self-organized supernet structure was successfully achieved in the presence of polyoxyethylene (20) sorbitan monolaurate (Tween 20) and sodium dodecyl sulfate (SDS) using the liquid-diffusion method. A well-organized two-dimensional network structure is built up successfully with a mass of sub-micrometer fanlike single crystal units. Comparative experiments showed that the mixed system of Tween 20 and SDS played important roles in the morphological control of CaCO3. SDS and Tween 20 can form complicated reticular micelles in aqueous solution, and the adsorption of SDS molecules onto a certain crystal face leads to the generation of the least stable vaterite. X-ray powder diffraction (XRD), FT-IR spectrometer, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and field-emission scanning electron microscope (FE-SEM) equipped with energy-dispersive X-ray (EDX) were used to characterize the crystals.

Three series of CeO2/CuO samples were prepared by impregnation method and characterized by XRD, N2 adsorption-desorption, temperature-programmed reduction (TPR), XPS and TEM techniques. In comparison with the samples prepared with CuO as initial support, the samples with Cu(OH)2 as initial support have higher reducibilities and smaller relative TPR peak areas, and also larger specific surface areas at calcination temperatures of 400 °C–600 °C. As a result, Cu(OH)2 is better than CuO as initial support for preferential oxidation of CO in excess H2 (CO-PROX). The best catalytic performance was achieved on the sample calcined at 600 °C and with an atomic ratio of Ce/Cu at 40%. XPS analyses indicate that more interface linkages Ce-O-Cu could be formed when it was calcined at 600 °C. And the atomic ratio of Ce/Cu at 40% led to a proper reducibility for the sample as illustrated by the TPR measurements.The samples with Cu(OH)2 as initial support exhibited higher catalytic activities for CO-PROX due to their higher reducibilities and more interface linkages.Download full-size image