Tailoring the electronic arrangement of graphene by doping is a practical strategy for producing significantly improved materials for the oxygen-reduction reaction (ORR) in fuel cells (FCs). Recent studies have proven that the carbon materials doped with the elements, which have the larger (N) or smaller (P, B) electronegative atoms than carbon such as N-doped carbon nanotubes (CNTs), P-doped graphite layers and B-doped CNTs, have also shown pronounced catalytic activity. Herein, we find that the graphenes doped with the elements, which have the similar electronegativity with carbon such as sulfur and selenium, can also exhibit better catalytic activity than the commercial Pt/C in alkaline media, indicating that these doped graphenes hold great potential for a substitute for Pt-based catalysts in FCs. The experimental results are believed to be significant because they not only give further insight into the ORR mechanism of these metal-free doped carbon materials, but also open a way to fabricate other new low-cost NPMCs with high electrocatalytic activity by a simple, economical, and scalable approach for real FC applications.

Iodine-doped graphene has been successfully fabricated through a simple, economical, and scalable approach. The new metal-free catalyst can exhibit a high catalytic activity, long-term stability, and an excellent methanol tolerance for the oxygen reduction reaction.

Searching the high‐efficient, stable, and earth‐abundant electrocatalysts to replace the precious noble metals holds the promise for practical utilizations of hydrogen and oxygen evolution reactions (HER and OER). Here, a series of highly active and robust Co‐doped nickel phosphides (Ni2−xCoxP) catalysts and their hybrids with reduced graphene oxide (rGO) are developed as bifunctional catalysts for both HER and OER. The Co‐doping in Ni2P and their hybridization with rGO effectively regulate the catalytic activity of the surface active sites, accelerate the charge transfer, and boost their superior catalytic activity. Density functional theory calculations show that the Co‐doped catalysts deliver the moderate trapping of atomic hydrogen and facile desorption of the generated H2 due to the H‐poisoned surface active sites of Ni2−xCoxP under the real catalytic process. Electrochemical measurements reveal the high HER efficiency and durability of the NiCoP/rGO hybrids in electrolytes with pH 0–14. Coupled with the remarkable and robust OER activity of the NiCoP/rGO hybrids, the practical utilization of the NiCoP/rGO‖NiCoP/rGO for overall water splitting yields a catalytic current density of 10 mA cm−2 at 1.59 V over 75 h without an obvious degradation and Faradic efficiency of ≈100% in a two‐electrode configuration and 1.0 m KOH.

To search for the efficient non-noble metal based and/or earth-abundant electrocatalysts for overall water-splitting is critical to promote the clean-energy technologies for hydrogen economy. Herein, we report nickel phosphide (NixPy) catalysts with the controllable phases as the efficient bifunctional catalysts for water electrolysis. The phases of NixPy were determined by the temperatures of the solid-phase reaction between the ultrathin Ni(OH)2 plates and NaH2PO2·H2O. The NixPy with the richest Ni5P4 phase synthesized at 325 °C (NixPy-325) delivered efficient and robust catalytic performance for hydrogen evolution reaction (HER) in the electrolytes with a wide pH range. The NixPy-325 catalysts also exhibited a remarkable performance for oxygen evolution reaction (OER) in a strong alkaline electrolyte (1.0 M KOH) due to the formation of surface NiOOH species. Furthermore, the bifunctional NixPy-325 catalysts enabled a highly performed overall water-splitting with ∼100% Faradaic efficiency in 1.0 M KOH electrolyte, in which a low applied external potential of 1.57 V led to a stabilized catalytic current density of 10 mA/cm(2) over 60 h.

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period of irradiation, and that the Ag particles display irregular shapes. Increasing the concentration of PVA in the system is found to be favorable for the formation of the shaped Ag particles. This result of the influence of the concentration of PVA on the shape of the Ag nanoparticles is very similar to that obtained by El-Sayed and co-workers, [19] who reported that the ratio of the concentration of the capping polymer material to the concentration of the platinum cations can influence the shapes and sizes of platinum nanoparticles. In the present study, the protecting agent PVA may also be a kind of capping polymer material, which usually acts as a molecularly dissolved surface modifier or steric stabilizer. Its presence in the system plays an important role in the formation of the Ag nanostructures. However, the mechanism of the shape-or morphology-dependent synthesis of colloidal nanoparticles is not yet known and needs to be investigated further.In summary, single-crystal Ag nanorods and elegant, highly ordered dendritic supramolecular nanostructures of Ag nanoparticles have been prepared via a novel ultraviolet irradiation photoreduction technique at room temperature using PVA as a protecting agent. It was found that the concentrations of both AgNO 3 and PVA play a significant role in the formation and growth of the Ag nanorods and dendrites. These Ag nanoparticles with unusual nanostructures may have important applications in catalysis. This method may be extended to prepare novel nanostructures of other noble metals.Many luminescent organic and polymer materials have been used for the fabrication of light-emitting diodes (LEDs). [1±3] Generally, electroluminescence (EL) was considered to originate from the singlet excited state [4] because for the majority of organic molecules, the triplet excited state exhibits a low emission quantum yield, thus does not contribute to EL emission. In EL, the existence of a bound triplet excited state can severely limit the quantum efficiency. If the triplet binding energy and corresponding cross section for forming a triplet from a pair of injected Fig. 3. The TEM image of the product obtained by irradiating the solution containing 3 wt.-% PVA and 10 ±2 M AgNO 3 .

A new form of nanoceria, porous nanorods of ceria (PN-CeO2), was prepared by a two-step hydrothermal synthesis. PN-CeO2has been found to display enhanced reducibility and capacity for oxygen storage.