Continuous-Flow Synthesis of ZnMnS Nanoparticles at Ambient Conditions.

With its large direct band gap and good chemical stability, ZnS is suitable for many applications, including light-emitting diodes, panel displays, and photodetection. Here, nanoparticles of ZnS are synthesized phase pure under ambient conditions by precipitation in a simple and scalable continuous-flow reactor. Furthermore, different degrees of Zn substitution with Mn have been investigated, ZnMnS, with = 0.

Composition space of PtIrPdRhRu high entropy alloy nanoparticles synthesized by solvothermal reactions.

High entropy alloy (HEA) nanoparticles hold promise in heterogeneous catalysis, and recently, simple and benign solvothermal synthesis was achieved for the equimolar PtIrPdRhRu. Here we experimentally explore the available composition space in this system, and we find that single-phase products can be obtained at significant deviations from the equimolar case.

New opportunities for sustainable bioplastic development: Tailorable polymorphic and three-phase crystallization of stereocomplex polylactide by layered double hydroxide.

Stereocomplexation between enantiomeric poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) is a promising sustainable approach and gaining momentum to overcome the shortcomings of polylactide (PLA) for its use as a replacement for fossil-based plastics. Filler addition in tailoring the crystallization of stereocomplex PLA (SC-PLA) has attracted extensive attention; however, research has primarily focused on the heterogeneous nucleation effect of filler. The impact of filler on the chain behavior of SC-PLA during crystallization has not been exclusively discussed, and the rigid amorphous fraction (RAF) development remains unknown.

Scrutinizing particle size related bond strengthening in anatase TiO.

A series of small, middle, and large anatase TiO particles were synthesized through the hydrolysis of titanium tetraisopropoxide (TTIP) to investigate the size-related chemical bond length and strength variation. Unit cell volume contraction with decreasing particle size is identified from Rietveld refinement of high-resolution synchrotron powder X-ray diffraction (PXRD) patterns. More titanium vacancies are also found for smaller anatase particles.

Synchrotron X-ray Electron Density Analysis of Chemical Bonding in the Graphitic Carbon Nitride Precursor Melamine.

Melamine is a precursor and building block for graphitic carbon nitride (g-CN) materials, a group of layered materials showing great promise for catalytic applications. The synthetic pathway to g-CN includes a polycondensation reaction of melamine by evaporation of ammonia. Melamine molecules in the crystal organize into wave-like planes with an interlayer distance of 3.

Synthesis of Phase-Pure Thermochromic VO (M1).

A highly reproducible, simple, and inexpensive synthesis method for obtaining phase-pure thermochromic monoclinic VO (M1) is presented. Vanadium(III) oxide and ammonium metavanadate were used as starting materials and no additional reducing agents are required. Heating a mixture of these two components under an argon atmosphere at 750 °C for 2-4 h provides the direct formation of VO (M1) without detectable impurity phases.

X-ray Electron Density Study of the Chemical Bonding Origin of Glass Formation in Metal-Organic Frameworks.

Glass-forming metal-organic frameworks (MOFs) have novel applications, but the origin of their peculiar melting behavior is unclear. Here, we report synchrotron X-ray diffraction electron densities of two zeolitic imidazolate frameworks (ZIFs), the glass-forming Zn-ZIF-zni and the isostructural thermally decomposing Co-ZIF-zni. Electron density analysis shows that the Zn-N bonds are more ionic than the Co-N bonds, which have distinct covalent features.

Tuning of bandgaps and emission properties of light-emitting diode materials through homogeneous alloying in molecular crystals.

Alloy formation is ubiquitous in inorganic materials science, and it strongly depends on the similarity between the alloyed atoms. Since molecules have widely different shapes, sizes and bonding properties, it is highly challenging to make alloyed molecular crystals. Here we report the generation of homogenous molecular alloys of organic light emitting diode materials that leads to tuning in their bandgaps and fluorescence emission.

Ceria Nanozyme and Phosphate Prodrugs: Drug Synthesis through Enzyme Mimicry.

Nanozymes can mimic the activities of diverse enzymes, and this ability finds applications in analytical sciences and industrial chemistry, as well as in biomedical applications. Among the latter, prodrug conversion mediated by nanozymes is investigated as a step toward site-specific drug synthesis, to achieve localized therapeutic effects. In this work, we investigated a ceria nanozyme as a mimic to phosphatase, to mediate conversion of phosphate prodrugs into corresponding therapeutics.

Bandgap Tuning in Molecular Alloy Crystals Formed by Weak Chalcogen Interactions.

We demonstrate systematic tuning in the optical bandgaps of molecular crystals achieved by the generation of molecular alloys/solid solutions of a series of diphenyl dichalcogenides-characterized by weak chalcogen bonding interactions involving S, Se, and Te atoms. Despite the variety in chalcogen bonding interactions found in this series of dichalcogenide crystals, they show isostructural interaction topologies, enabling the formation of solid solutions. The alloy crystals exhibit Vegard's law-like trends of variation in their unit cell dimensions and a nonlinear trend for the variation in optical bandgaps with respect to their compositions.

Strategies for synthesis of Prussian blue analogues.

We report a comparison of different common synthetic strategies for preparation of Prussian blue analogues (PBA). PBA are promising as cathode material for a number of different battery types, including K-ion and Na-ion batteries with both aqueous and non-aqueous electrolytes. PBA exhibit a significant degree of structural variation.

Tailoring the stoichiometry of CN nanosheets under electron beam irradiation.

Two-dimensional polymeric graphitic carbon nitride (g-C3N4) is a low-cost material with versatile properties that can be enhanced by the introduction of dopant atoms and by changing the degree of polymerization/stoichiometry, which offers significant benefits for numerous applications. Herein, we investigate the stability of g-C3N4 under electron beam irradiation inside a transmission electron microscope operating at different electron acceleration voltages. Our findings indicate that the degradation of g-C3N4 occurs with N species preferentially removed over C species.

Facile synthesis of brookite TiO nanoparticles.

Brookite is the most difficult TiO2 polymorph to obtain in phase pure form. Here we report on a facile synthesis method for phase-pure brookite nanoparticles using a broad range of titanium precursors. General availability of phase pure brookite opens up multiple research activities to explore both fundamental properties as well as applications.

Three-dimensional morphology of anatase nanocrystals obtained from supercritical flow synthesis with industrial grade TiOSO precursor.

Anatase TiO (a-TiO) nanocrystals are vital in catalytic applications both as catalysts (e.g. photodegradation) and as a carrier material (e.

Why Does BiWO Visible-Light Photocatalyst Always Form as Nanoplatelets?

BiWO nanocrystals exhibit excellent photocatalytic properties in the visible range of the solar spectrum, and intense efforts are directed at designing effective synthesis processes with control of size, morphology, and hierarchical structure. All known hydrothermal syntheses produce either nanoplatelet morphology or hierarchical structures based on such primary entities. Here we investigate the nucleation and growth of BiWO nanocrystals under hydrothermal conditions using X-ray total scattering (TS) and powder X-ray diffraction (PXRD) measurements.

Continuous flow hydrothermal synthesis of phase pure rutile TiO nanoparticles with a rod-like morphology.

Titania nanocrystals are used in numerous applications but specific polymorphs (anatase, rutile, brookite) are typically required in specific applications making synthesis control over the crystal phase essential. Supercritical continuous flow reactors constitute fast, scalable alternatives to conventional autoclave hydrothermal synthesis. They provide outstanding control over nanoparticle characteristics such as size, crystallinity, and morphology but previous studies have always resulted in anatase products.

Boosting Photocatalytic Hydrogen Production by Modulating Recombination Modes and Proton Adsorption Energy.

Solar-driven production of renewable energy (e.g., H) has been investigated for decades.

Low-Barrier Hydrogen Bonds in Negative Thermal Expansion Material H [Co(CN) ].

The covalent nature of the low-barrier N-H-N hydrogen bonds in the negative thermal expansion material H [Co(CN) ] has been established by using a combination of X-ray and neutron diffraction electron density analysis and theoretical calculations. This finding explains why negative thermal expansion can occur in a material not commonly considered to be built from rigid linkers. The pertinent hydrogen atom is located symmetrically between two nitrogen atoms in a double-well potential with hydrogen above the barrier for proton transfer, thus forming a low-barrier hydrogen bond.

Enhancement of magnetic properties through morphology control of SrFeO nanocrystallites.

Nanocrystallites of the permanent magnetic material SrFeO were synthesised using a conventional sol-gel (CSG) and a modified sol-gel (MSG) synthesis route. In the MSG synthesis, crystallite growth takes place in a solid NaCl matrix, resulting in freestanding nanocrystallites, as opposed to the CSG synthesis, where the produced nanocrystals are strongly intergrown. The resulting nanocrystallites from both methods exhibit similar intrinsic magnetic properties, but significantly different morphology and degree of aggregation.

The chemistry of ZnWO nanoparticle formation.

The need for a change away from classical nucleation and growth models for the description of nanoparticle formation is highlighted. By the use of total X-ray scattering experiments the transformation of an aqueous polyoxometalate precursor mixture to crystalline ZnWO nanoparticles under hydrothermal conditions was followed. The precursor solution is shown to consist of specific Tourné-type sandwich complexes.

Hydrothermal Synthesis of TiO2@SnO2 Hybrid Nanoparticles in a Continuous-Flow Dual-Stage Reactor.

TiO2@SnO2 hybrid nanocomposites were successfully prepared in gram scale using a dual-stage hydrothermal continuous-flow reactor. Temperature and pH in the secondary reactor were found to selectively direct nucleation and growth of the secondary material into either heterogeneous nanocomposites or separate intermixed nanoparticles. At low pH, 2 nm rutile SnO2 nanoparticles were deposited on 9 nm anatase TiO2 particles; the presence of TiO2 was found to suppress formation of larger SnO2 particles.

Quantitative analysis of intermolecular interactions in orthorhombic rubrene.

Rubrene is one of the most studied organic semiconductors to date due to its high charge carrier mobility which makes it a potentially applicable compound in modern electronic devices. Previous electronic device characterizations and first principles theoretical calculations assigned the semiconducting properties of rubrene to the presence of a large overlap of the extended π-conjugated core between molecules. We present here the electron density distribution in rubrene at 20 K and at 100 K obtained using a combination of high-resolution X-ray and neutron diffraction data.

In situ total X-ray scattering study of WO₃ nanoparticle formation under hydrothermal conditions.

Pair distribution function analysis of in situ total scattering data recorded during formation of WO3 nanocrystals under hydrothermal conditions reveal that a complex precursor structure exists in solution. The WO6 polyhedra of the precursor cluster undergo reorientation before forming the nanocrystal. This reorientation is the critical element in the formation of different hexagonal polymporphs of WO3.

Copper doped TiO2 nanoparticles characterized by X-ray absorption spectroscopy, total scattering, and powder diffraction--a benchmark structure-property study.

Metal functionalized nanoparticles potentially have improved properties e.g. in catalytic applications, but their precise structures are often very challenging to determine.