Given the harsh operating conditions in hydrogen/oxygen fuel cells, the stability of catalysts is one of the critical questions affecting their commercialization. We describe a distinct class of oxygen reduction (ORR) core-shell electrocatalysts comprised of nitride metal cores enclosed by thin Pt shells that is easily synthesized. The synthesis is reproducible and amenable to scale up. Our theoretical analysis and the experimental data indicate that metal nitride nanoparticle cores could significantly enhance the ORR activity as well as the durability of the core-shell catalysts as a consequence of combined geometrical, electronic and segregation effects on the Pt shells. In addition to its fuel cells application, this class of catalysts holds promise to significantly contribute in resolving the problem of platinum scarcity and furthermore indicates the guidelines for future research and development.

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The kinetics of the oxygen reduction reaction (ORR) on a series of electrodeposited normalPt100−xnormalNix and normalPt100−xnormalCox alloy films were examined in comparison to electrodeposited Pt and mechanically polished polycrystalline Pt. The alloys were electrodeposited at potentials positive of that required to grow the pure iron group metal. The growth process is ascribed to strong bonding enthalpy between Pt and the iron group metals that can be envisioned as iron-group underpotential deposition (upd) on Pt surface sites coupled with ongoing Pt overpotential electrodeposition. Rotating disk electrode measurements of the ORR kinetics, normalized for the H upd electroactive area, indicate a ∼1.9 to 2.7-fold catalytic enhancement on normalPt100−xnormalCox and normalPt100−xnormalNix, when x is in the range of 25–35, as compared to electrodeposited Pt films grown under similar conditions. An even greater ORR enhancement factor, between 3 and 4.8, was noted for dealloyed transition metal-rich (x75) films. Different schemes for integrating the electrodeposition (and dealloying) process into the fabrication of fuel cell membrane electrode array are also briefly discussed.

BackgroundEnteroviruses (EVs) are the leading cause of aseptic meningitis, which is the most frequent central nervous system infection worldwide. We aimed to characterize the EVs involved in an aseptic meningitis outbreak in Korea in 2008. In Korea, Echovirus type 30 (E30) and E6 have been associated with outbreaks and frequent meningitis.MethodsDuring 2008, through nationwide surveillance, we collected specimens from 758 patients with aseptic meningitis-related clinical manifestations. The detection of EVs from specimens was subjected to a diagnostic real-time RT-PCR in the 5' NCR. A semi-nested polymerase chain reaction (PCR) to amplify sequences from the VP1 region and sequence comparison with reference strains registered in Genbank was performed for the genotype determination.ResultsMost patients (98%) in this outbreak were children < 15 years of age. The temporal distribution of the E6 and E30 epidemics showed an obvious seasonal pattern during the short period from June to July. A large majority of the EV-positive patients experienced fever, headache, vomiting, and neck stiffness. Some patients also showed cold symptoms, sore throat, altered mental status, and seizures. We did not observe a higher fatality rate in children with E6 or E30 infection. Most of the patients recovered uneventfully. In most cases, the cerebrospinal fluid (CSF) profile was studied, and generally showed a higher than normal white blood cell count (≥ 5/mm3). We detected EVs from 513 patients (67.68%) and identified the EV genotype in 287 patients. E30 (n = 155, 50.4%) and E6 (n = 95, 33.1%) were the predominant genotypes. E9, E1, E7, E16, coxsackievirus A3, 4, 6, coxsackievirus B1, 3, and 10 were also identified. According to phylogenetic analysis, E30 belonged to subgroup 4b, and E6, to the C4 subgroup.ConclusionsConclusively, aseptic meningitis was the most common manifestation in children with either echovirus 30 or 6 infection. Identification of E6 and E30 as the prominent EVs in the 2008 outbreak in South Korea shows the potential of EVs to cause a serious disease in an unpredictable (fashion. Our findings provide new) insights into the clinical and virological features of the aseptic meningitis outbreak caused by E30 and E6.