Achieving ultrahigh electrochemical performance by surface design and nanoconfined water manipulation.

The effects of nanoconfined water and the charge storage mechanism are crucial to achieving the ultrahigh electrochemical performance of two-dimensional transition metal carbides (MXenes). We propose a facile method to manipulate nanoconfined water through surface chemistry modification. By introducing oxygen and nitrogen surface groups, more active sites were created for TiC MXene, and the interlayer spacing was significantly increased by accommodating three-layer nanoconfined water.

Experimental and Theoretical Solid-State Si NMR Studies on Defect Structures in La(SiO)O Apatite Oxide Ion Conductors.

Oxide ion conductors can be used as electrolytes in solid oxide fuel cells, a promising energy-conversion technology. Local structures around the defects in oxide ion conductors are key for understanding the defect stabilization and migration mechanisms. As the defect contents are generally low, it is rather difficult to characterize the defect structure and therefore elucidate how oxide ions migrate.

Seroconversion of hepatitis B surface antigen among those with previously successful immune response in Southern China.

Recommendations promoted worldwide have suggested a period of protection lasting more than 20 years against hepatitis B (HB) following primary immunization. Starting in 1987, universal HB vaccinations were carried out in Long An County, Guangxi Province, one of the earliest counties in which plasma-derived HB vaccine was delivered to newborns across China. Data collection targeted toward understanding the long term (26-33 years since primary immunization) immune effects of the plasma-derived HB vaccine was conducted in 2015; a second data collection was carried out in 2019 to assess seroconversion in the same cohort.

Crystallization of GdO nanoparticles: evolution of the microstructure via electron-beam manipulation.

NaGdF4 is one of the most commonly employed phosphor host matrices for lanthanide doping and is one of the most efficient infrared-to-visible up-conversion fluorescent host materials. Although the structure, morphology and luminescence properties of NaREF4 have been sufficiently investigated, there are very few reported instances of introducing localized order/crystallinity by electron-beam (e-beam) irradiation. In this work, we studied the phase transformation of Gd2O3 from an amorphous to crystalline form via manipulation by e-beam irradiation.

Elucidation of correlated disorder in zeolite IM-18.

Classical crystallography is based on the translational periodicity of crystals and the analysis of discrete Bragg reflections. However, it is inadequate for determining disordered structures, of which the diffuse scattering is vital to evaluate the disorder level. The correlated disorder of IM-18 presents as zigzag chains arranged in translational periodicity and the double four-ring units randomly distributed along two dimensions.

An Interrupted Zeolite PKU-26 and Its Transformation to a Fully Four-Connected Zeolite PKU-27 upon Calcination.

The thermal stability and structural transformation mechanism are critical for the industrial applications of zeolites and the design of new framework types. Herein, a new zeolite PKU-26 has been hydrothermally synthesized under fluoride conditions using a tetraethylammonium (TEA ) cation as the structure-directing agent (SDA) and its framework contains partial Q T atoms [Q for T(-O-T) OH]. Upon calcination, PKU-26 processed a single-crystal to single-crystal transformation to another novel zeolite PKU-27 with the elimination of terminal -OH groups and enhanced thermal stability up to 650 °C, exhibiting the first Q →Q transformation [Q for T(-O-T) ] in 3D zeolite frameworks.

Narrow-band blue emitting nitridomagnesosilicate phosphor SrMgSiN:Eu for phosphor-converted LEDs.

We report a novel narrow-band blue emitting phosphor Sr7.92Mg7Si9N22:0.08Eu2+.

Discovery of Layered Indium Hydroxide via a Hydroperoxyl Anion Coordinated Precursor at Room Temperature.

All reported layered metal hydroxides have brucite-like metal-hydroxyl host layers, and the discovery of other types of layered metal hydroxides could significantly extend the layered metal hydroxide families, which is meaningful in both theory and applications. Here, through hydroperoxyl anion coordinated In cations as a precursor, a new layered indium hydroxide was synthesized, where only a three-dimensional cubic phase had existed before. The layer of the product exhibits an unusual structure where In(OH) octahedra share edges and vertexes with each other to form layers, which is completely different from the common edge-sharing brucite-like metal-hydroxyl layers.

Superconductivity in Perovskite BaLn(BiPb)O (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu).

Solid solutions BaLn(BiPb)O (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; 0.00 ≤ x ≲ 0.15) have been prepared under 850 °C.

A crystalline AlPO-5 intermediate: designed synthesis, structure, and phase transformation.

AlPO-5 is the most extensively studied material in exploring the crystallization mechanism of aluminophosphate molecular sieves, and it can be synthesized using 4-dimethylaminopyridine (DMAP) as an organic structure-directing agent (OSDA). Achieving the AlPO-5 intermediate in the crystalline form would be of great importance and significance for this purpose. In this study, we proposed a concept that by carefully regulating the synthesis conditions, crystalline alumimophosphate intermediates could be rationally prepared.

Enhancement of Ferroelectricity for Orthorhombic (TbMn)MnO by Copper Doping.

Copper-doped (TbMn)MnO has been synthesized by the conventional solid state reaction method. X-ray, neutron, and electron diffraction data indicate that they crystallize in Pnma space group at room temperature. Two magnetic orderings are found for this series by neutron diffraction.

A multi-dimensional quasi-zeolite with 12 × 10 × 7-ring channels demonstrates high thermal stability and good gas adsorption selectivity.

A novel quasi-zeolite PKU-15, with a rare 3-dimensional structure containing interconnected large (12-ring), medium (10-ring) and small (7-ring) multi-pore channels, was hydrothermally synthesised and characterised. A unique tri-bridging O anion is found to be encapsulated in the cage-like (Ge,Si)O building unit and energetically stabilises the PKU-15 framework. The removal of this oxygen atom would convert PKU-15 into a hypothetical zeolite PKU-15H.

Multiferroicity Broken by Commensurate Magnetic Ordering in Terbium Orthomanganite.

TbMnO3 is an important multiferroic material with strong coupling between magnetic and ferroelectric orderings. Incommensurate magnetic ordering is suggested to be vital for this coupling in TbMnO3 , which can be modified by doping at the site of Tb and/or Mn. Our study shows that a self-doped solid solution Tb1-x Mny MnO3 (y≤x) can be formed with Mn doped into the site of Tb of TbMnO3 .

Syntheses, structure solutions, and catalytic performance of two novel layered silicates.

Two novel layered silicates, PKU-13 and PKU-13a, were hydrothermally synthesized by using trimethylpropylammonium hydroxide as the structure directing agent (SDA). Their structures were solved by using powder X-ray diffraction data in combination with electron diffraction technique and NMR spectroscopy. These two silicates are built from the same r52 layer in different stacking modes: the adjacent r52 layers in PKU-13a have a 0.

A 3D 12-ring zeolite with ordered 4-ring vacancies occupied by (H2O)2 dimers.

A germanate zeolite, PKU-14, with a three- dimensional large-pore channel system was structurally characterized by a combination of high-resolution powder X-ray diffraction, rotation electron diffraction, NMR, and IR spectroscopy. Ordered Ge4 O4 vacancies inside the [4(6) .6(12) ] cages has been found in PKU-14, in which a unique (H2 O)2 dimer was located at the vacancies and played a structure-directing role.

Solid-State (29)Si NMR and neutron-diffraction studies of Sr(0.7)K(0.3)SiO(2.85) oxide ion conductors.

K/Na-doped SrSiO3-based oxide ion conductors were recently reported as promising candidates for low-temperature solid-oxide fuel cells. Sr0.7K0.

Synthesis, structure, and magnetic properties of (Tb(1-x)Mn(y))MnO(3-δ).

Two compounds (Tb(1-x)Mn(y))MnO(3-δ) (W1, x = 0.089, y = 0.063; W2, x = 0.

Quaternary sulfide Ba6Zn6ZrS14: synthesis, crystal structure, band structure, and multiband physical properties.

Ba6Zn6ZrS14 was synthesized by a traditional salt-melt method with KI as flux. The pale yellow crystals of Ba6Zn6ZrS14 crystallize in the tetragonal space group I4/mcm with a=16.3481 (4) Å and c=9.

On the structure of α-BiFeO3.

Polycrystalline and monocrystalline α-BiFeO3 crystals have been synthesized by solid state reaction and flux growth method, respectively. X-ray, neutron, and electron diffraction techniques are used to study the crystallographic and magnetic structure of α-BiFeO3. The present data show that α-BiFeO3 crystallizes in space group P1 with a = 0.

New high T(c) multiferroics KBiFe₂O₅ with narrow band gap and promising photovoltaic effect.

Intrinsic polarization of ferroelectrics (FE) helps separate photon-generated charge carriers thus enhances photovoltaic effects. However, traditional FE with transition-metal cations (M) of d⁰ electron in MO₆ network typically has a band gap (E(g)) exceeding 3.0 eV.

Microporous aluminoborates with large channels: structural and catalytic properties.

Channel zapping: PKU-1 and newly synthesized PKU-2 (Al(2)B(5)O(9)(OH)(3)⋅n H(2)O; see picture) possess microporous structures with 18-ring and 24-ring channels, respectively. They show high reactivity and size selectivity in the cyanosilylation of aldehydes as heterogeneous Lewis acid catalysts. The different channel sizes determine the substrate selectivity.

Syntheses and crystal structures of two new bismuth hydroxyl borates containing [Bi2O2]2+ layers: Bi2O2[B3O5(OH)] and Bi2O2[BO2(OH)].

Two new bismuth hydroxyl borates, Bi(2)O(2)[B(3)O(5)(OH)] (I) and Bi(2)O(2)[BO(2)(OH)] (II), have been synthesized under hydrothermal conditions. Their structures were determined by single-crystal and powder X-ray diffraction data, respectively. Compound I crystallizes in the orthorhombic space group Pbca with the lattice constants of a = 6.

Syntheses, structure, and luminescent properties of novel hydrated rare earth borates Ln2B6O10OH4•H2O (Ln = Pr, Nd, Sm, Eu, Gd, Dy, Ho, and Y).

Ln(2)B(6)O(10)(OH)(4)•H(2)O (Ln = Pr, Nd, Sm-Gd, Dy, Ho, and Y), a new series of hydrated rare earth borates, have been synthesized under hydrothermal conditions. A single crystal of Nd analogue was used for the structure determination by X-ray diffraction. It crystallizes in the monoclinic space group C2/c with lattice constants a = 21.

Hybrid Ag(2)S-Ag(3)SBr superionic conductor nanoparticles and their large-scale ordered arrays.

We report a simple aqueous-solution route to synthesize hybrid Ag(2)S-Ag(3)SBr superionic conductor nanoparticles with faceted-spherical and polyhedral morphologies at low temperature. The morphological control was achieved by adjusting the H(+) concentration in the presence of cetyltrimethylammonium bromide, which was used as both a Br(-) source and a capping reagent. The hybrid nanoparticles could self-organize into large-scale ordered arrays, and have potential applications in fabricating photonic crystals, mixed superionic conductors, high energy density batteries and near-infrared photoluminescent devices.

PKU-10: a new 3D open-framework germanate with 13-ring channels.

PKU-10, a germanate with the formula [(CH(3))(4)N](3)Ge(11)O(19)(OH)(9), is synthesized under hydrothermal conditions, and its structure is determined by single-crystal X-ray diffraction data. PKU-10 possesses 3D intersected 13-ring channels and presents a new 6-connectedness linkage mode of the Ge(7) cluster, T(3)P(2)O, forming a pcu topological network. Each Ge(7) cluster is, in fact, surrounded by eight Ge(7) clusters in a nearly perfect cube because the hydrogen bonds between Ge(7) clusters are also taken into account.