The improvement of catalysts for the four-electron oxygen-reduction reaction (ORR; O(2) + 4H(+) + 4e(-) → 2H(2)O) remains a critical challenge for fuel cells and other electrochemical-energy technologies. Recent attention in this area has centred on the development of metal alloys with nanostructured compositional gradients (for example, core-shell structure) that exhibit higher activity than supported Pt nanoparticles (Pt-C; refs 1-7). For instance, with a Pt outer surface and Ni-rich second atomic layer, Pt(3)Ni(111) is one of the most active surfaces for the ORR (ref. 8), owing to a shift in the d-band centre of the surface Pt atoms that results in a weakened interaction between Pt and intermediate oxide species, freeing more active sites for O(2) adsorption. However, enhancements due solely to alloy structure and composition may not be sufficient to reduce the mass activity enough to satisfy the requirements for fuel-cell commercialization, especially as the high activity of particular crystal surface facets may not easily translate to polyfaceted particles. Here we show that a tailored geometric and chemical materials architecture can further improve ORR catalysis by demonstrating that a composite nanoporous Ni-Pt alloy impregnated with a hydrophobic, high-oxygen-solubility and protic ionic liquid has extremely high mass activity. The results are consistent with an engineered chemical bias within a catalytically active nanoporous framework that pushes the ORR towards completion.

Highly optimized embedded-atom-method (EAM) potentials have been developed for 14 face-centered cubic (fcc) elements across the periodic table. The potentials were developed by fitting the potential energy surface (PES) of each element derived from high-precision first-principle calculations. The as-derived potential energy surfaces were shifted and scaled to match experimental reference data. In constructing the PES, a variety of properties of the elements were considered, including lattice dynamics, mechanical properties, thermal behavior, energetics of competing crystal structures, defects, deformation paths, liquid structures, and so forth. For each element, the constructed EAM potentials were tested against the experiment data pertaining to thermal expansion, melting, and liquid dynamics via molecular dynamics (MD) computer simulation. The as-developed potentials demonstrate high fidelity and robustness. Owing to their improved accuracy and wide applicability, the potentials are suitable for highquality atomistic computer simulation of practical applications.2

The authors report the surface enhanced Raman scattering (SERS) of nanoporous gold with nanopore sizes ranging from 5to700nm. Their comprehensive investigations prove that the strongest SERS enhancement of nanoporous gold takes place from the samples with an ultrafine nanopore size of ∼5–10nm. Both the enhancement factor and detection limit of the ultrafine nanoporous substrate are one to two orders of magnitude better than those of coarsened nonporous gold with smooth surfaces. Moreover, careful microstructure characterization reveals that the anomalous SERS enhancement of the annealed nanoporous gold arises from roughsurfaces with characteristic surface irregularities.