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Reacting MoAlB with ZnCl2 at 550 °C produces metastable Mo2AlB2 through a one-step topochemical transformation. This reaction showcases differences in reactivity between boride-based MAB phases and carbide-based MAX phases, which are solid-state precursors to an important family of 2-D materials. [ABSTRACT FROM AUTHOR]

We report predictive guidelines for the substoichiometric cation exchange of model two-component metal sulfide nanorods containing divalent cations of similar hardness. Unit cell volume changes, cation radii, solubility constants, and solid state interfaces influence selectivity during substoichiometric exchange of Cu+ when multiple products are possible. [ABSTRACT FROM AUTHOR]

Transition metal ditellurides are gaining widespread attention due to their rich polymorphism and distinct electronic properties when compared to transition metal disulfides and diselenides. Here, we report the direct synthesis of Td-WTe2 nanostructures via a low-temperature solution-based method. A comprehensive structural characterization reveals the anisotropic pathway by which the few-layer WTe2 nanostructures grow, as well as the co-existence of multiple stacking motifs. The versatility of this synthetic approach is further expanded to access nanostructured MoxW1−xTe2 alloys across the entire solid solution that spans the 1T′-MoTe2 and Td-WTe2 end members, where the elemental composition and crystal structure can be systematically tuned by modulating the metal reagent ratios. The ability to access transition metal ditellurides using solution synthesis methods complements traditional gas-phase fabrication techniques and provides an alternative strategy for manufacturing an expanded library of composition-tunable TMD nanostructures. [ABSTRACT FROM AUTHOR]

Bulk iron pyrite (FeS2) functions as an inexpensive, Earth-abundant, off-the-shelf catalyst capable of selectively hydrogenating a broad scope of substituted nitroarenes to their corresponding aniline derivatives using molecular hydrogen. [ABSTRACT FROM AUTHOR]

The efficient catalysis of water electrolysis using Earth-abundant materials is considered to underpin the large-scale implementation of several clean energy technologies. Here, we report the synthesis of molybdenum rich Co–Mo nanoparticles, which function as highly active and stable electrocatalysts for the hydrogen evolution reaction (HER) in alkaline aqueous solutions. The Co–Mo nanoparticles have an average diameter of approx. 3 nm, a Co : Mo ratio of approx. 1 : 9, and are poorly crystalline. The Co–Mo nanoparticles deposited onto Ti foil substrates at a loading of approx. 1 mg cm−2 required an overpotential of only −75 mV to produce an operationally relevant current density of −10 mA cm−2, placing them among the most highly active Earth-abundant HER catalysts in alkaline media. [ABSTRACT FROM AUTHOR]

CoP nanostructures that exposed predominantly (111) crystal facets were synthesized and evaluated for performance as electrocatalysts for the hydrogen-evolution reaction (HER). The branched CoP nanostructures were synthesized by reacting cobalt(ii) acetylacetonate with trioctylphosphine in the presence of trioctylphosphine oxide. Electrodes comprised of the branched CoP nanostructures deposited at a loading density of ∼1 mg cm−2 on Ti electrodes required an overpotential of −117 mV to produce a current density of −20 mA cm−2 in 0.50 M H2SO4. Hence the branched CoP nanostructures belong to the growing family of highly active non-noble-metal HER electrocatalysts. Comparisons with related CoP systems have provided insights into the impact that shape-controlled nanoparticles and nanoparticle–electrode interactions have on the activity and stability of nanostructured HER electrocatalysts. [ABSTRACT FROM AUTHOR]

Amorphous tungsten phosphide (WP), which has been synthesized as colloidal nanoparticles with an average diameter of 3 nm, has been identified as a new electrocatalyst for the hydrogen-evolution reaction (HER) in acidic aqueous solutions. WP/Ti electrodes produced current densities of -10 mA cm-2 and -20 mA cm-2 at overpotentials of only -120 mV and -140 mV, respectively, in 0.50 M H2SO4(aq). [ABSTRACT FROM AUTHOR]

A material specific peptide bound to Fe2O3 facilitates the selective sequestration of Au from a colloidal mixture of Au and CdS nanoparticles; the Au–Fe2O3 precipitate can then be magnetically separated from the colloidal CdS, and the Au nanoparticles can be recovered upon release from the Fe2O3. [ABSTRACT FROM AUTHOR]

Palladium is converted into palladium hydride, β-PdHx, in polyol solution using NaBH4 as a hydrogen source; nanocrystalline Pd reacts to form PdHx faster and at lower temperatures than bulk Pd, and can be made to release hydrogen to regenerate Pd. [ABSTRACT FROM AUTHOR]

Palladium is converted into palladium hydride, β-PdHx, in polyol solution using NaBH4as a hydrogen source; nanocrystalline Pd reacts to form PdHxfaster and at lower temperatures than bulk Pd, and can be made to release hydrogen to regenerate Pd. [ABSTRACT FROM AUTHOR]

Reacting MoAlB with ZnCl 2 at 550 °C produces metastable Mo 2 AlB 2 through a one-step topochemical transformation. This reaction showcases differences in reactivity between boride-based MAB phases and carbide-based MAX phases, which are solid-state precursors to an important family of 2-D materials.

Transition metal dichalcogenides (TMDs) are well known catalysts as both bulk and nanoscale materials. Two-dimensional (2-D) TMDs, which contain single- and few-layer nanosheets, are increasingly studied as catalytic materials because of their unique thickness-dependent properties and high surface areas. Here, colloidal 2H-WS 2 nanostructures are used as a model 2-D TMD system to understand how high catalytic activity and selectivity can be achieved for useful organic transformations. Free-standing, colloidal 2H-WS 2 nanostructures containing few-layer nanosheets are shown to catalyze the selective hydrogenation of a broad scope of substituted nitroarenes to their corresponding aniline derivatives in the presence of other reducible functional groups. Microscopic and computational studies reveal the important roles of sulfur vacancy-rich basal planes and tungsten-terminated edges, which are more abundant in nanostructured 2-D materials than in their bulk counterparts, in enabling the functional group selectivity. At tungsten-terminated edges and on regions of the basal planes having high concentrations of sulfur vacancies, vertical adsorption of the nitroarene is favored, thus facilitating hydrogen transfer exclusively to the nitro group due to geometric effects. At lower sulfur vacancy concentrations on the basal planes, parallel adsorption of the nitroarene is favored, and the nitro group is selectively hydrogenated due to a lower kinetic barrier. These mechanistic insights reveal how the various defect structures and configurations on 2-D TMD nanostructures facilitate functional group selectivity through distinct mechanisms that depend upon the adsorption geometry, which may have important implications for the design of new and enhanced 2-D catalytic materials across a potentially broad scope of reactions., (This journal is © The Royal Society of Chemistry 2019.)

SnS nanoflowers containing hierarchically organized nanosheet subunits were synthesized using a simple solution route, and they function as lithium ion battery anodes that maintain high capacities and coulombic efficiencies over 30 cycles.

By chemically modifying the nucleation burst that generates monodisperse FePt nanocrystals, a mixture of Pt and Fe(x)Pt(1-x) nanoparticles forms during a one-pot reaction that includes a small amount of Cu as a catalyst; size-selective precipitation yields a bi-disperse population of Fe(x)Pt(1-x) nanoparticles, which can assemble into high-quality AB2, AB5, and AB13 superlattice structures.

The layered trirutile phases HMWO6 (M = Nb, Ta) and the layered perovskite H2W2O7 (synthesized by acid leaching of Bi2W2O9) were exfoliated into nanoscale colloids by reaction with quaternary ammonium hydroxides.