Formation of Si Nanorods and Discrete Nanophases by Axial Diffusion of Si from Substrate into Au and AuPt Nanoalloy Nanorods.

Interdiffusion between Si substrate and nanorod arrays of Au, Pt, and AuPt nanoalloys is investigated at temperatures lower than the AuSi eutectic temperature. When the nanorod is pure Au, Si diffusion from the substrate is very rapid. Au atoms are completely replaced by Si, converting the nanostructure into one of Si nanorod arrays.

The Self-Passivation Mechanism in Degradation of BiVO Photoanode.

BiVO is a promising photoanode material for solar-assisted water splitting in a photoelectrochemical cell but has a propensity to degrade. Investigations carried out here in 0.1 M NaSO electrolyte showed that degradation is by dissolution of V in the electrolyte while Bi is retained on the anode probably in the form of solid Bi oxide (BiO, BiO).

Superexchange Effects on Oxygen Reduction Activity of Edge-Sharing [Co Mn O ] Octahedra in Spinel Oxide.

Mn-Co containing spinel oxides are promising, low-cost electrocatalysts for the oxygen reduction reaction (ORR). Most studies are devoted to the design of porous Mn-Co spinels or to strongly coupled hybrids (e.g.

New insights into the photocatalytic activity of 3-D core-shell P25@silica nanocomposites: impact of mesoporous coating.

In this report, a three-dimensional (3-D) network of core-shell TiO (P25)-mesoporous SiO (P25@mSiO) nanocomposites was prepared via a controllable surfactant-assisted sol-gel method. The nanocomposites were investigated for photocatalytic reactions of organic dye degradation, water splitting, and CO reduction to understand the roles of the mSiO shell in these photocatalytic reactions. It was found that the mSiO shell accelerates the photodegradation of the organic dye, but dramatically reduces the photocatalytic activity of P25 in water splitting and CO reduction.

Improved Charge Separation in WO₃/CuWO₄ Composite Photoanodes for Photoelectrochemical Water Oxidation.

Porous tungsten oxide/copper tungstate (WO₃/CuWO₄) composite thin films were fabricated via a facile conversion method, with a polymer templating strategy. Copper nitrate (Cu(NO₃)₂) solution with the copolymer surfactant PluronicF-127 (Sigma-Aldrich, St. Louis, MO, USA, generic name, poloxamer 407) was loaded onto WO₃ substrates by programmed dip coating, followed by heat treatment in air at 550 °C.

Origin of Photocarrier Losses in Iron Pyrite (FeS2) Nanocubes.

Iron pyrite has received significant attention due to its high optical absorption. However, the loss of open circuit voltage (Voc) prevents its further application in photovoltaics. Herein, we have studied the photophysics of pyrite by ultrafast laser spectroscopy to understand fundamental limitation of low Voc by quantifying photocarrier losses in high quality, stoichiometric, and phase pure {100} faceted pyrite nanocubes.

Iron pyrite thin film counter electrodes for dye-sensitized solar cells: high efficiency for iodine and cobalt redox electrolyte cells.

Iron pyrite has been the material of interest in the solar community due to its optical properties and abundance. However, the progress is marred due to the lack of control on the surface and intrinsic chemistry of pyrite. In this report, we show iron pyrite as an efficient counter electrode (CE) material alternative to the conventional Pt and poly(3,4-ethylenedioxythiophene (PEDOT) CEs in dye-sensitized solar cells (DSSCs).

Ultrathin MnO(2) nanoflakes as efficient catalysts for oxygen reduction reaction.

Free-standing, ultrathin manganese dioxide nanoflakes were synthesized by cationic surfactant controlled reduction of KMnO4. MnO2 nanoflakes showed a much higher mass activity than other manganese based oxides as well as B and N doped nano carbons. The approach here demonstrates a facile chemical route towards efficient manganese dioxide catalysts.

Investigating the multiple roles of polyvinylpyrrolidone for a general methodology of oxide encapsulation.

Growing oxide shells on seed nanoparticles requires the control of several processes: (a) the nucleation and growth of the shell material; (b) the "wetting" of the shell material on the seeds; and (c) the aggregation of the nanoparticles. These processes are influenced by a number of factors, many of which are related. Without understanding the interdependence of these contributing factors, it is difficult to circumvent problems and achieve rational synthesis.

Nonlinear dielectric thin films for high-power electric storage with energy density comparable with electrochemical supercapacitors.

Although batteries possess high energy storage density, their output power is limited by the slow movement of charge carriers, and thus capacitors are often required to deliver high power output. Dielectric capacitors have high power density with fast discharge rate, but their energy density is typically much lower than electrochemical supercapacitors. Increasing the energy density of dielectric materials is highly desired to extend their applications in many emerging power system applications.

Magnetron sputtered nc-Al/alpha-Al2O3 nanocomposite thin films for nonvolatile memory application.

In this paper, we developed nc-Al/a-Al2O3 nanocomposite thin films using magnetron sputtering. The nc-Al/a-Al2O3 films were sputtered on p-type Si substrates from pure Al target in gas mixture of Ar and O2. X-ray photoelectron spectroscopy and high resolution transmission electron microscope studies confirm that the nanocrystalline Al are embedded in amorphous Al2O3 matrix thus nc-Al/ a-Al2O3 nanocomposite forms.

Effect of Ta nanobarrier in magnetron sputtering of Nd-doped SrBi2Ta2O9 thin films.

SrBi2Ta2O9 (SBT) is a bismuth layered perovskite with attractive ferroelectric properties for random access memory applications. Our previous studies showed that Nd-doped SBT (SNBT) thin films exhibited an improved remnant polarization and reduced coercivity. This paper concentrates on the effect of Ta nanobarrier in between the SNBT and the Pt layers.