Citation for published item:rrenD FgF nd o¤ %t hovskyD uF nd hot nD rF nd veroyD gFwF nd gornuzD wF nd tell iD pF nd r¡ e ertD gF nd oths hildD eF nd qr¤ tzelD wF @PHIQA 9sdentifying h mpion n nostru tures for sol r w terEsplittingF9D x ture m teri lsFD IP @WAF ppF VRPEVRWF Further information on publisher's website: httpXGGdxFdoiForgGIHFIHQVGnm tQTVR Publisher's copyright statement: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Charge transport in nanoparticle-based materials underlies many emerging energy conversion technologies, yet assessing the impact of nanometer-scale structure on charge transport across micron-scale distances remains a challenge. Here we develop an approach for correlating the spatial distribution of crystalline and current-carrying domains in entire nanoparticle aggregates. We apply this approach to nanoparticle-based α-Fe 2 O 3 electrodes that are of interest in solar-to-hydrogen energy conversion. In correlating structure and charge transport with nanometer resolution across micron-scale distances, we have identified the existence of champion nanoparticle aggregates that are most responsible for the high photoelectrochemical activity of the present electrodes. Indeed, when electrodes are fabricated with a high proportion of these champion nanostructures, the electrodes achieve the highest photocurrent of any metal oxide photoanode for photoelectrochemical water splitting under 100 mW cm -2 air mass 1.5 global sunlight.Batteries, fuel cells, and solar energy conversion devices have emerged as a class of important technologies that increasingly rely upon electrodes derived from nanoparticles 1 . These nanoparticle-based materials provide a unique challenge in assessing structure-property relationships because of the disordered arrangement of nanocrystals that results when nanoparticles collide and aggregate [2][3][4][5][6] . The morphological evolution that follows aggregation further obscures the influence of particle size, shape, and interfacial characteristics in defining the physical properties of these materials 7,8 . For the nanoparticle-based electrodes used in solar energy conversion, structural defects such as grain boundaries define pathways for charge transport by creating potential barriers and by promoting recombination 9 . Because of the complexity of these materials, within a single electrode there may exist a small proportion of "champion" nanostructures-by analogy with champion solar cells 10,11 , these are nanostructures that provide the highest solar conversion efficiencies-th...

A material is said to exhibit dichroism if its photon absorption spectrum depends on the polarization of the incident radiation. In the case of X-ray magnetic circular dichroism (XMCD), the absorption cross-section of a ferromagnet or a paramagnet in a magnetic field changes when the helicity of a circularly polarized photon is reversed relative to the magnetization direction. Although similarities between X-ray absorption and electron energy-loss spectroscopy in a transmission electron microscope (TEM) have long been recognized, it has been assumed that extending such equivalence to circular dichroism would require the electron beam in the TEM to be spin-polarized. Recently, it was argued on theoretical grounds that this assumption is probably wrong. Here we report the direct experimental detection of magnetic circular dichroism in a TEM. We compare our measurements of electron energy-loss magnetic chiral dichroism (EMCD) with XMCD spectra obtained from the same specimen that, together with theoretical calculations, show that chiral atomic transitions in a specimen are accessible with inelastic electron scattering under particular scattering conditions. This finding could have important consequences for the study of magnetism on the nanometre and subnanometre scales, as EMCD offers the potential for such spatial resolution down to the nanometre scale while providing depth information--in contrast to X-ray methods, which are mainly surface-sensitive.

Metal-free nanostructured elemental carbons and carbonbased composites (e.g. C 3 N 4 ) have proven to be attractive alternatives to conventional metal-based catalysts for several important reactions, such as dehydrogenation of aromatic hydrocarbons or alkanes, Friedel-Crafts Reaction.[1] Carbon as the catalytic substance has significant advantages over the conventional metal-supported systems owing to the unique controllability of both its surface acidity/basicity and pelectron density through surface functionalization. In a carbon material it is the short-and long-range ordering of atomic carbon that essentially determines the macroscopic properties (e.g. thermal and electronic conductivities, combustibility) and thus its long-term performance in any potential industrial process. However, the lack of basic knowledge on the nature of carbonmediated reactions remains the most critical restriction for the development of carbon-based catalysis. For oxidative dehydrogenation (ODH) reactions, surface quinone-type oxygen functional groups have been proposed as the active sites and the reaction has been assumed to proceed by a redox mechanism.[2, 3] However, no quantitative description of the elementary steps, or kinetic data can be derived from the literature. The few mechanistic studies reported were conducted either with remarkable secondary oxidation and deactivation [4] or over "impure" surfaces, for example, Pd-or Fe-coordinated polynaphthoquinone[2] or pre-coked metal phosphates or oxides.[5] More detailed and reliable information is expected to be obtained over a pure carbon surface in the kinetic reaction region. Most importantly, the Mars-van Krevelen model for redox reactions is widely accepted based on previous work on the ODH of ethylbenzene. [4, 5] However, this model is incorrect and without physical relevance.[6] Therefore there is an urgent need to describe the reaction pathway by a physically relevant model. Ordered nanocarbon is chemically homogeneous and thus could be seen as the most suitable platform for a mechanistic investigation. To date, all such investigations have been confined to pure or mostly sp 2 -hybridized carbons. [4, 7] In particular, conventional activated carbon which has long-range disorder and high porosity

Visible‐light emitting single‐walled carbon nanotubes (SWNTs)/organic hybrids have been successfully synthesized and promise to be a photon source to be used in future optoelectronic devices. The nanohybrids are “peapods” having sexithiophene molecules inside the hollow space of SWNTs. High‐resolution transmission electron microscopy and optical probes show evidence of the encapsulation while density functional theory calculations confirm the experimental findings and provide deeper insight into stability and electronic properties of these systems.

Bulk and dispersed cubic liquid crystalline phases (cubosomes), present in the body and in living cell membranes, are believed to play an essential role in biological phenomena. Moreover, their biocompatibility is attractive for nutrient or drug delivery system applications. Here the three-dimensional organization of dispersed cubic lipid self-assembled phases is fully revealed by cryo-electron tomography and compared with simulated structures. It is demonstrated that the interior is constituted of a perfect bicontinuous cubic phase, while the outside shows interlamellar attachments, which represent a transition state between the liquid crystalline interior phase and the outside vesicular structure. Therefore, compositional gradients within cubosomes are inferred, with a lipid bilayer separating at least one water channel set from the external aqueous phase. This is crucial to understand and enhance controlled release of target molecules and calls for a revision of postulated transport mechanisms from cubosomes to the aqueous phase.