Nitrogen (N)-doped nanostructured carbons have been actively examined as promising alternatives for precious-metal catalysts in various electrochemical energy generation systems. Herein, an effective approach for synthesizing N-doped single-walled carbon nanohorns (SWNHs) with highly electrocatalytic active sites via controlled oxidation followed by N₂ plasma is presented. Nanosized holes were created on the conical tips and sidewalls of SWNHs under mild oxidation, and subsequently, the edges of the holes were easily decorated with N atoms. The N atoms were present preferentially in a pyridinic configuration along the edges of the nanosized holes without significant structural change of the SWNHs. The enriched edges decorated with the pyridinic-N atoms at the atomic scale increased the number of active sites for the oxygen reduction reaction, and the inherent spherical three-dimensional feature of the SWNHs provided good electrical conductivity and excellent mass transport. We demonstrated an effective method for promoting the electrocatalytic active sites within N-doped SWNHs by combining defect engineering with the preferential formation of N atoms having a specific configuration.

This paper describes the design of mesoporous polymer monoliths via a bottom-up approach which are compressible as a biological sponge and provide the rapid separation of oil–water mixtures. The monolithic networks can be prepared in a large scale by a facile condensation polymerization under non-agitated conditions, and contain cyanovinylene repeating units that give rise to a self-assembled fibrous structure and intrinsic mesopores without the need for a template. The sponge-like, polymer network readily absorbed considerable amounts of diverse organic solvents within 60 s due to the internal designed pores, while excluding water. Most of the absorbates were removed from the wet materials by simply squeezing by hand, and additional washing and drying completely regenerated the original state of materials for reuse. In particular, we observed that the intrinsic mesoporosity enhanced absorption properties of the monoliths when compared with microporous, spongy monolith or melamine foam, and thus demonstrated the rapid, selective separation of a model oil spill under water or on top of water.

Linear carbon chains (LCCs) are one-dimensional materials with unique properties, including high Debye temperatures and restricted selection rules for phonon interactions. Consequently, their Raman C-band frequency’s temperature dependence is a probe to their thermal properties, which are well described within the Debye formalism even at room temperatures. Therefore, with the basis on a semiempirical approach we show how to use the C band to evaluate the LCCs’ internal energy, heat capacity, coefficient of thermal expansion, thermal strain, and Grüneisen parameter, providing universal relations for these quantities in terms of the number of carbons atoms and the temperature.