Superalkali-Alkalide Interactions and Ion Pairing in Low-Polarity Solvents.

The nature of anionic alkali metals in solution is traditionally thought to be "gaslike" and unperturbed. In contrast to this noninteracting picture, we present experimental and computational data herein that support ion pairing in alkalide solutions. Concentration dependent ionic conductivity, dielectric spectroscopy, and neutron scattering results are consistent with the presence of superalkali-alkalide ion pairs in solution, whose stability and properties have been further investigated by DFT calculations.

Performance of Fe-N/C Oxygen Reduction Electrocatalysts toward NO, NO, and NHOH Electroreduction: From Fundamental Insights into the Active Center to a New Method for Environmental Nitrite Destruction.

Although major progress has recently been achieved through ex situ methods, there is still a lack of understanding of the behavior of the active center in non-precious metal Fe-N/C catalysts under operating conditions. Utilizing nitrite, nitric oxide, and hydroxylamine as molecular probes, we show that the active site for the oxygen reduction reaction (ORR) is different under acidic and alkaline conditions. An in-depth investigation of the ORR in acid reveals a behavior which is similar to that of iron macrocyclic complexes and suggests a contribution of the metal center in the catalytic cycle.

In situ electrochemical quantification of active sites in Fe-N/C non-precious metal catalysts.

The economic viability of low temperature fuel cells as clean energy devices is enhanced by the development of inexpensive oxygen reduction reaction catalysts. Heat treated iron and nitrogen containing carbon based materials (Fe-N/C) have shown potential to replace expensive precious metals. Although significant improvements have recently been made, their activity and durability is still unsatisfactory.

Competition for graphene: graphynes with direction-dependent Dirac cones.

The existence of Dirac cones in the band structure of two-dimensional materials accompanied by unprecedented electronic properties is considered to be a unique feature of graphene related to its hexagonal symmetry. Here, we present other two-dimensional carbon materials, graphynes, that also possess Dirac cones according to first-principles electronic structure calculations. One of these materials, 6,6,12-graphyne, does not have hexagonal symmetry and features two self-doped nonequivalent distorted Dirac cones suggesting electronic properties even more amazing than that of graphene.