The hydrogen oxidation reaction (HOR) in alkaline electrolyte was conducted on carbon-supported Ru nanoparticles (Ru/C) of which size was controlled in the range from approximately 2 to 7 nm. The HOR activity of Ru/C normalized by the metal surface area showed volcano shaped dependence on the particle size with a maximum activity at approximately 3 nm. The HOR activity of approximately 3 nm Ru/C was higher than commercially available Pt nanoparticles (ca. 2 nm) supported on carbon. The structural analysis of Ru/C using Cs-corrected scanning transmission electron microscopy with atomic resolution revealed the unique structural change of Ru/C different from Pt/C: Ru nanoparticle structure changed from amorphous-like structure below 3 nm to metal nanocrystallite with roughened surface at approximately 3 nm and then to that with well-defined facets above 3 nm, although Pt/C kept well-defined facets even at approximately 2 nm. It is proposed that the generation of unique structure observed on approximately 3 nm Ru nanoparticles, that is, long bridged coordinatively unsaturated Ru metal surface atoms on its nanocrystallite, is a key to achieve high HOR activity.

Gold forms rings: AuCl‐catalyzed cyclization of (α‐alkoxy alkyl) (ortho‐alkynyl phenyl) sulfides 1 proceeds under mild conditions to give 3‐(α‐alkoxy alkyl) benzothiophenes 2 in high yields for a wide range of substrates (see scheme). The starting materials are readily available through acetalization of ortho‐bromobenzenethiol and subsequent Sonogashira coupling. This methodology provides an atom‐economic route to sulfur‐containing heteroarenes.

Undoped 0.5-lm-thick BaSi 2 epitaxial films were grown on Si(111) substrates with various ratios of the Ba deposition rate to the Si deposition rate (R Ba /R Si) ranging from 1.0 to 5.1, and their electrical and optical properties were characterized. The photoresponse spectra drastically changed as a function of R Ba /R Si , and the quantum efficiency reached a maximum at R Ba /R Si ¼ 2.2. Hall measurements and capacitance versus voltage measurements revealed that the electron concentration drastically decreased as R Ba /R Si approached 2.2, and the BaSi 2 films with R Ba /R Si ¼ 2.0, 2.2, and 2.6 exhibited p-type conductivity. The lowest hole concentration of approximately 1 Â 10 15 cm À3 was obtained for the BaSi 2 grown with R Ba /R Si ¼ 2.2, which is the lowest value ever reported. First-principles calculations suggest that Si vacancies give rise to localized states within the bandgap of BaSi 2 and therefore degrade the minority-carrier properties.

Highly oriented and ordered lamellar polymer film was prepared by simply annealing the poly(N-dodecylacrylamide) film under humid conditions.