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A freestanding single layer of hexagonal boron nitride (h-BN) has been successfully fabricated by controlled energetic electron irradiation through a layer-by-layer sputtering process. We have successfully resolved atomic defects in h-BN with triangle shapes by means of an aberration corrected high-resolution transmission electron microscopy with exit-wave reconstruction. Boron monovacancies are found to be preferably formed and the dominating zigzag-type edges are proved to be nitrogen terminated.

Sirolimus was efficacious and well tolerated in these study patients with complicated vascular anomalies. Clinical activity was reported in the majority of the disorders.

The development of active and durable bifunctional electrocatalysts for overall water splitting is mandatory for renewable energy conversion. This study reports a general method for controllable synthesis of a class of IrM (M = Co, Ni, CoNi) multimetallic porous hollow nanocrystals (PHNCs), through etching Ir-based, multimetallic, solid nanocrystals using Fe ions, as catalysts for boosting overall water splitting. The Ir-based multimetallic PHNCs show transition-metal-dependent bifunctional electrocatalytic activities for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in acidic electrolyte, with IrCo and IrCoNi PHNCs being the best for HER and OER, respectively. First-principles calculations reveal a ligand effect, induced by alloying Ir with 3d transition metals, can weaken the adsorption energy of oxygen intermediates, which is the key to realizing much-enhanced OER activity. The IrCoNi PHNCs are highly efficient in overall-water-splitting catalysis by showing a low cell voltage of only 1.56 V at a current density of 2 mA cm , and only 8 mV of polarization-curve shift after a 1000-cycle durability test in 0.5 m H SO solution. This work highlights a potentially powerful strategy toward the general synthesis of novel, multimetallic, PHNCs as highly active and durable bifunctional electrocatalysts for high-performance electrochemical overall-water-splitting devices.

Semiconducting MoS₂(₁-x) Se₂x mono-layers where x = 0-0.40 are successfully grown over large areas. A random arrangement of the S and Se atoms and a tunable bandgap photoluminescence are observed. Atomically thin, 2D semiconductor alloys with tunable bandgaps have potential applications in nano- and opto-electronics. Field-effect transistors fabricated with the monolayers exhibit high on/off ratios of >10(5).