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Co-based nanomaterials have been intensively explored as promising noble metal free oxygen evolution reaction (OER) electrocatalysts. Herein, we first report phase selective synthesis of novel hierarchical CoTe2 and CoTe nanofleeces for efficient OER catalyst. The CoTe2 nanofleeces exhibited excellent electrocatalytic activity and stablity for OER in alkaline media. It has been discovered that the CoTe2 catalyst exhibited superior OER activity to the CoTe catalyst and comparable to the state-of-the-art RuO2 catalyst. Density functional theory calculations showed that the binding strength and lateral interaction of the reaction intermediates on CoTe2 and CoTe are essential for the order of their overpotential and the trend variation at different condition. This study provides value insights for rational design of noble metal free OER catalysts with high performance and low cost by use of Co-based chalcogenides.

Pt-alloy nanoparticles (NPs) that contain 3d transition metals (such as Fe, Co, Ni, and Cu) that are typically supported on a high-surface-area carbon support represent a class of highly active electrocatalysts for the cathodic oxygen-reduction reaction (ORR) in fuel cells. To achieve high activities, thermal annealing at elevated temperatures either during or after the synthesis of the catalysts is generally required. Such annealing can increase the extent of alloying, form a new Pt-skin surface, or induce the transformation from a disordered phase into an ordered intermetallic compound; all of these structural features can result in higher intrinsic activities and/or stabilities. Despite these benefits, thermal annealing at high temperatures also resulted in the sintering of the nanoparticles, thus leading to a decrease in the active surface area and, hence, low overall mass activities, which hindered their practical applications. To further advance the synthesis and application of highly active and robust ORR catalysts, understanding the sintering of carbon-supported Pt alloy NPs during thermal annealing is crucial, although it is remains largely un-addressed. Nevertheless, there have been a number of studies on the catalyst-sintering mechanisms for monometallic catalysts (e.g. , Pd and Pt) that are dispersed over oxide supports. In principle, the driving force for particle sintering is the high surface energy of NPs compared to the bulk surface, although Ostwald ripening and particle migration/coalescence are the two main mechanisms. The former process involves the diffusion of atomic species from smaller particles towards larger ones, according to the Gibbs–Thomson effect, and the latter process involves the migration of nanoparticles over the support and the subsequent coalescence of neighboring particles. Both of these mechanisms can be regarded as mass-transport over the catalyst support and the support can also impact the sintering process, owing to metal–support interactions. Basically, the knowledge of the sintering mechanisms that has been reported for oxide-supported monometallic catalysts can be applied to carbon-supported Ptand Pt-alloy catalysts. However, the influence of different (carbon) supports, as well as the existence of a second metal in the Pt-alloy NPs, on their sintering mechanisms still needs to be studied. Herein, we investigate the sintering effect during the thermal annealing of a series of carbon-supported Pt1–xNix NPs, which are a class of highly active and stable ORR catalysts, in particular at higher Ni content, as recently reported. By using high-resolution transmission electron microscopy (HRTEM), we uncover an unexpected solid-state transformation of the carbon support into graphene-like multilayers, catalyzed by the Ni-richer alloy NPs. The resultant instability of the carbon support in turn promotes the particle migration and coalescence, thereby leading to more-significant particle coarsening in the Ni-richer alloy catalysts. Our results demonstrate unique metal–support interactions during the thermal annealing, thus providing important implications for the synthesis of carbonsupported Pt-alloy fuel-cell catalysts. [a] Dr. L. Gan, S. Rudi, Dr. C. H. Cui, Prof. Dr. P. Strasser The Electrochemical Energy, Catalysis and Materials Science Laboratory TC03, Institute of Chemistry Technical University Berlin Strasse des 17. Juni 124, Berlin (Germany) Fax: (+49) (030)31422261 E-mail : pstrasser@tu-berlin.de Thermal annealing is an important and widely adopted step during the synthesis of Pt bimetallic fuel-cell catalysts, although it faces the inevitable drawback of particle sintering. Understanding this sintering mechanism is important for the future development of highly active and robust fuel-cell catalysts. Herein, we studied the particle sintering during the thermal annealing of carbon-supported Pt1–xNix (PtNi, PtNi3, and PtNi5) nanoparticles, a reported recently class of highly active fuel-cell catalysts. By using high-resolution transmission electron microscopy, we found that annealing at an intermediate temperature (400 8C) effectively increased the extent of alloying without particle sintering; however, high-temperature annealing (800 8C) caused severe particle sintering, which, unexpectedly, was strongly dependent on the composition of the alloy, thus showing that a higher Ni content resulted in a higher extent of particle sintering. This result can be ascribed to the solid-state transformation of the carbon support into graphene layers, catalyzed by Ni-richer catalyst, which, in turn, promoted particle migration/coalescence and, hence, more-significant sintering. Therefore, our results provide important insight for the synthesis of carbon-supported Pt-alloy fuel-cell catalysts.

Ultrathin and ultralong: Highly uniform, ultrathin (diameter 5-7 nm), and ultralong (aspect ratio >10(4)) PtPdTe nanowires (NWs) were synthesized by using a facile method employing Te NWs as both sacrificial templates and reducing agents. Fine-tuning of the molar ratios of Pt and Pd precursors afforded PtPdTe NWs with different compositions and enhanced electroactivity in the methanol oxidation reaction in comparison with a commercial Pt/C catalyst.

Thermosensitive poly(N-isopropylacrylamide) (PNIPAM)/Au nanoparticle (NP) nanocomposite hydrogels are synthesized by in situ γ-radiation-assisted polymerization of N-isopropylacrylamide monomer aqueous solution in the presence of HAuCl₄·4H₂O. In this reaction, the PNIPAM hydrogels and the Au NPs are formed simultaneously, thus demonstrating an easy and straightforward synthetic strategy for the preparation of a uniform nanocomposite. The results suggest that increasing the monomer content during the preparation of nanocomposite materials can increase the sizes of Au NPs. The effects of irradiation dose and concentration of HAuCl₄·4H₂O on the optical and thermal properties of the hydrogel are also investigated. The PNIPAM/Au nanocomposite hydrogels act as an excellent catalyst for the conversion of o-nitroaniline to 1,2-benzenediamine, and the catalytic activity of the composite hydrogel can be tuned by the volume transition of PNIPAM. The in situ polymerization of monomer and reduction of metal ions initiated by a "clean" and "green" γ-radiation technique can be extended to the efficient synthesis of other nanocomposite materials.

BACKGROUND: Acquired hemophagocytic syndrome (AHPS) is a severe inflammatory disorder often caused by Epstein-Barr virus (EBV). Proliferation of activated macrophages produces uncontrolled cytokine production. Thrombocytopenia is common in AHPS, previously attributed to inadequate or ineffective marrow platelet (PLT) production. PLT transfusion response is not well reported. Two patients with fatal AHPS developed unexplained PLT transfusion refractoriness before definitive diagnosis. CASE REPORTS: PLT refractoriness was noted during the care of two patients. The refractoriness was determined to be nonimmune and both demonstrated various clinical signs and laboratory findings consistent with AHPS. The first patient's AHPS was attributable to EBV infection. In the other patient, no underlying cause could be found. Both patients had an aggressive clinical course and succumbed to this relatively rare syndrome. The PLT refractoriness was evident before the AHPS diagnosis was made. DISCUSSION: AHPS is not generally a consideration in the evaluation of nonimmune PLT refractoriness. However, these illustrative cases make an argument for its consideration in the differential diagnosis of PLT refractoriness in severely ill patients. Once present, it is unclear if the refractoriness can be reversed by AHPS-targeted therapy.

A Pd-Au/CuO@Cu heterostructured nanoparticle tube catalyst is synthesized by a one-step electrodeposition route onto an anodic aluminium oxide template in anhydrous DMSO, and characterized by powder XRD, SEM, TEM, XPS, and cyclic voltammetry.

A Pd-Au/CuO@Cu heterostructured nanoparticle tube catalyst is synthesized by a one-step electrodeposition route onto an anodic aluminium oxide template in anhydrous DMSO, and characterized by powder XRD, SEM, TEM, XPS, and cyclic voltammetry.