Fermi Edge of Semimetallic Borophane Sheets and its Reduction by a Porous Structure.

Theoretically predicted materials are often synthesized in low yields, and unexpected relationships are often encountered between the target materials and byproducts. Recently, two-dimensional boron materials proposed on the basis of model simulations and first principles calculations and possessing abundant atomic structures have attracted considerable interest. Borophane or the hydrogen boride (HB) sheet has been predicted to be the Dirac nodal semimetal when it has a boron network of nonsymmorphic symmetry.

Untangling the Effect of Carbonaceous Materials on the Photoelectrochemical Performance of BaTaON.

The water oxidation reaction is a rate-determining step in solar water splitting. The number of surviving photoexcited holes is one of the most influencing factors affecting the photoelectrochemical water oxidation efficiency of photocatalysts. The solar-to-hydrogen energy conversion efficiency of BaTaON is still far below the benchmark efficiency set for practical applications, notwithstanding its potential as a 600 nm-class photocatalyst in solar water splitting.

Redetermination of the crystal structure of yttrium chromium tetra-boride, YCrB, from single-crystal X-ray diffraction data.

The structural parameters of yttrium chromium tetra-boride YCrB were refined based on single-crystal X-ray diffraction data. YCrB is ortho-rhom-bic, having a space group of type (No. 55) and with lattice parameters of = 5.

Accelerated Synthesis of Borophane (HB) Sheets through HCl-Assisted Ion-Exchange Reaction with YCrB.

We present an enhanced method for synthesizing sheets of borophane. Despite the challenges associated with low efficiency, we discovered that incorporating hydrochloric acid into the ion-exchange reaction significantly improved the production yield from 20% to over 50%. After a thorough examination of the reaction, we gained insight into the underlying mechanisms and found that the use of hydrochloric acid provides two key benefits: accelerated production of borophene and isolation of high-purity products.

Extraction of phase information approximating the demagnetization field within a thin-foiled magnet using electron holography observation.

This paper proposes a method that provides a phase image related to the demagnetization field (Hd) within a thin-foil permanent magnet using electron holography. The observation of Hd remains a significant challenge because electron holography in principle allows only imaging of the magnetic flux density (B), which is a mixture of the contributions from magnetization (M), stray magnetic field (Hs) outside of the specimen and Hd inside of the specimen. The phase map approximating Hd, which was determined by processing of the electron holography observation from a Nd2Fe14B single-crystalline specimen, showed a good agreement with the prediction by micromagnetic theory.

Direct identification of the charge state in a single platinum nanoparticle on titanium oxide.

A goal in the characterization of supported metal catalysts is to achieve particle-by-particle analysis of the charge state strongly correlated with the catalytic activity. Here, we demonstrate the direct identification of the charge state of individual platinum nanoparticles (NPs) supported on titanium dioxide using ultrahigh sensitivity and precision electron holography. Sophisticated phase-shift analysis for the part of the NPs protruding into the vacuum visualized slight potential changes around individual platinum NPs.

Redetermination of the crystal structures of rare-earth trirhodium diboride RhB ( = Pr, Nd and Sm) from single-crystal X-ray data.

The crystal structures of the rare-earth () trirhodium diborides praseo-dymium trirhodium diboride, PrRhB, neodymium trirhodium diboride, NdRhB, and samarium trirhodium diboride, SmRhB, were refined on the basis of single-crystal X-ray diffraction data. The crystal chemistry of RhB (: Pr, Nd, and Sm) compounds has previously been analyzed mainly on the basis of powder samples [Ku (1980 ▸). .

Detoxifying SARS-CoV-2 antiviral drugs from model and real wastewaters by industrial waste-derived multiphase photocatalysts.

The use of antiviral drugs has surged as a result of the COVID-19 pandemic, resulting in higher concentrations of these pharmaceuticals in wastewater. The degradation efficiency of antiviral drugs in wastewater treatment plants has been reported to be too low due to their hydrophilic nature, and an additional procedure is usually necessary to degrade them completely. Photocatalysis is regarded as one of the most effective processes to degrade antiviral drugs.

Incommensurately modulated crystal structure of α' (O'3)-type sodium cobalt oxide NaCoO (x ∼ 0.78).

A single-phase sample of α' (O'3)-type layered sodium cobalt oxide NaCoO (x ∼ 0.78) was prepared and its incommensurately modulated crystal structure was analyzed using the (3+1)-dimensional superspace approach to the powder neutron diffraction data. The crystal structure of the cobaltate is accurately described based on the superspace group C2/m(α0γ)00, wherein the positions of Na atoms are most significantly modulated in the monoclinic a direction to form an ordered arrangement.

Flux Growth of Single-Crystalline Hollandite-Type Potassium Ferrotitanate Microrods From KCl Flux.

Hollandite-type crystals have unique and interesting physical and chemical properties. Here, we report the flux growth of hollandite-type single-crystalline potassium ferrotitanate (KFTO) with faceted surface features from a KCl flux. We varied the flux growth conditions, including the kind of flux, holding temperature, and solute concentration for growing faceted crystallites.

Effective photocatalytic removal of selected pharmaceuticals and personal care products by elsmoreite/tungsten oxide@ZnS photocatalyst.

In this study, elsmoreite/tungsten oxide is used to form a heterojunction with ZnS-containing industrial waste. The effect of the elsmoreite/tungsten oxide content on photocatalytic activity of ZnS using the different ratios of ZnS:NaWO in the synthesis solution is estimated. The initial ZnS:NaWO ratio leads to the formation of hexagonal WO∙0.

New Synthesis Route for Complex Borides; Rapid Synthesis of Thermoelectric Yttrium Aluminoboride via Liquid-Phase Assisted Reactive Spark Plasma Sintering.

YAlB ceramics are of high interest as high temperature thermoelectric materials with excellent p, n control. In this study, direct synthesis of dense polycrystalline YAlB (x ~0.64, 0.

Nanostructured core-shell metal borides-oxides as highly efficient electrocatalysts for photoelectrochemical water oxidation.

Oxygen evolution reaction (OER) catalysts are critical components of photoanodes for photoelectrochemical (PEC) water oxidation. Herein, nanostructured metal boride MB (M = Co, Fe) electrocatalysts, which have been synthesized by a Sn/SnCl redox assisted solid-state method, were integrated with WO thin films to build heterojunction photoanodes. As-obtained MB modified WO photoanodes exhibit enhanced charge carrier transport, amended separation of photogenerated electrons and holes, prolonged hole lifetime and increased charge carrier density.

Construction of Spatial Charge Separation Facets on BaTaON Crystals by Flux Growth Approach for Visible-Light-Driven H Production.

Low charge separation efficiencies are regarded as obstacles that limit the improvement in the photocatalytic performance of BaTaON. In this study, we demonstrated that the anisotropic facets ({100} and {110} facets) of BaTaON for efficient spatial charge separation were successfully constructed using the one-pot flux-assisted nitridation approach. As a result, the photocatalytic activity for H production on BaTaON with coexposed {100} and {110} facets was nearly 10-fold over that of BaTaON with only {100} facets and that of the conventional irregularly shaped sample.

A Simple, General Synthetic Route toward Nanoscale Transition Metal Borides.

Most nanomaterials, such as transition metal carbides, phosphides, nitrides, chalcogenides, etc., have been extensively studied for their various properties in recent years. The similarly attractive transition metal borides, on the contrary, have seen little interest from the materials science community, mainly because nanomaterials are notoriously difficult to synthesize.

Thin and Dense Solid-solid Heterojunction Formation Promoted by Crystal Growth in Flux on a Substrate.

In this work, we demonstrate the direct growth of cubic LiLaNbO crystal layer on the LiCoO substrate through the conversion of ultra-thin Nb substrate in molten LiOH flux. The initial thickness of the Nb layer determines that of the crystal layer. SEM and TEM observations reveal that the surface is densely covered with well-defined polyhedral crystals.

Multiple-wavelength neutron holography with pulsed neutrons.

Local structures around impurities in solids provide important information for understanding the mechanisms of material functions, because most of them are controlled by dopants. For this purpose, the x-ray absorption fine structure method, which provides radial distribution functions around specific elements, is most widely used. However, a similar method using neutron techniques has not yet been developed.

Elucidating the impact of A-site cation change on photocatalytic H and O evolution activities of perovskite-type LnTaON (Ln = La and Pr).

Transition metal (oxy)nitrides with perovskite-type structures have been regarded as one of the promising classes of inorganic semiconductor materials that can be used in solar water splitting systems for the production of hydrogen as a renewable and storable energy carrier. The performance of transition metal (oxy)nitrides in solar water splitting is strongly influenced by the crystal structure-related dynamics of photogenerated charge carriers. Here, we have systematically assessed the influence of A-site cation exchange on the visible-light-induced photocatalytic H and O evolution activities, photoanodic response, and dynamics of photogenerated charge carriers of perovskite-type LnTaON (Ln = La and Pr).

The contrasting effect of the Ta/Nb ratio in (111)-layered B-site deficient hexagonal perovskite Ba5Nb4-xTaxO15 crystals on visible-light-induced photocatalytic water oxidation activity of their oxynitride derivatives.

The effect of the Ta/Nb ratio in the (111)-layered B-site deficient hexagonal perovskite Ba5Nb4-xTaxO15 (0 ≤ x ≤ 4) crystals grown by a KCl flux method on visible-light-induced photocatalytic water oxidation activity of their oxynitride derivatives BaNb1-xTaxO2N (0 ≤ x ≤ 1) was investigated. The Rietveld refinement of X-ray data revealed that all Ba5Nb4-xTaxO15 samples were well crystallized in the space group P3[combining macron]m1 (no. 164).

Fabrication of La2Ti2O7 crystals using an alkali-metal molybdate flux growth method and their nitridability to form LaTiO2N crystals under a high-temperature NH3 atmosphere.

Flux growth is a promising method that allows one to control over the crystalline phase, crystal shape, crystal size, and crystal surface through the selection of a suitable flux. In this work, lanthanum titanate (La2Ti2O7) crystals with different morphologies were grown using the Na2MoO4, K2MoO4, NaCl, and mixed NaCl + K2MoO4 (molar ratio = 3:7) fluxes, and their nitridability to form LaTiO2N crystals under a high-temperature NH3 atmosphere was also investigated. The effects of the solute concentration and cooling rate on the growth of the La2Ti2O7 crystals were also studied.

Bulk-nanoporous-silicon negative electrode with extremely high cyclability for lithium-ion batteries prepared using a top-down process.

We synthesized freestanding bulk three-dimensional nanoporous Si using dealloying in a metallic melt, a top-down process. Using this nanoporous Si, we fabricated negative electrodes with high lithium capacity, nearing their theoretical limits, and greatly extended cycle lifetimes, considerably improving the battery performance compared with those using electrodes made from silicon nanoparticles. By operating the electrodes below the accommodation volume limit of their pores, we prolonged their cycle lifetime.

Fabrication of Ni compound nanocrystal/nanocarbon composites by cooling of chloride-based fluxes.

Unique Ni compound nanocrystals were successfully grown on carbon nanotubes (CNTs) by cooling a mixed chloride flux. Cup-stacked CNTs (CSCNTs) were used as the nanocarbon materials because of their structural features. The grown nanocrystals had a nanosheet structure, which was densely assembled and had a ribbon-like morphology.

Fabrication of highly crystalline NbOx nanotube/cup-stacked CNT nanocomposites.

Carbon nanotubes (CNTs) are promising catalyst supports for fuel cell applications. Metal oxide/CNT nanocomposites are also being studied for dye-sensitized solar-cell, photocatalyst, and sensor applications. The fabrication of nanocomposites consisting of highly crystalline NbOx nanotubes and cup-stacked carbon nanotubes (CSCNTs) is reported herein.

An environmentally friendly dispersion method for cup-stacked carbon nanotubes in a water system.

A dry process using VUV light was confirmed as a novel technique to attach functional groups onto cup-stacked carbon nanotubes and to develop their isolation in a water system without the use of dispersing agents.