111 oriented gold nanoplatelets on multilayer graphene as visible light photocatalyst for overall water splitting

[EN] Development of renewable fuels from solar light appears as one of the main current challenges in energy science. A plethora of photocatalysts have been investigated to obtain hydrogen and oxygen from water and solar light in the last decades. However, the photon-to-hydrogen molecule conversion is still far from allowing real implementation of solar fuels. Here we show that 111 facet-oriented gold nanoplatelets on multilayer graphene films deposited on quartz is a highly active photocatalyst for simulated sunlight overall water splitting into hydrogen and oxygen in the absence of sacrificial electron donors, achieving hydrogen production rate of 1.2 molH2 per gcomposite per h. This photocatalytic activity arises from the gold preferential orientation and the strong gold–graphene interaction occurring in the composite system.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ2012-32315) and Generalitat Valenciana (Prometeo 2013-019) is gratefully acknowledged. D.M. and I.E.-A. thank to Spanish Ministry of Science for PhD scholarships.Mateo Mateo, D.; Esteve Adell, I.; Albero Sancho, J.; Sánchez Royo, JF.; Primo Arnau, AM.; García Gómez, H. (2016). 111 oriented gold nanoplatelets on multilayer graphene as visible light photocatalyst for overall water splitting. Nature Communications. 2016(7):1-8. https://doi.org/10.1038/ncomms11819S1820167Lv, X. J., Zhou, S., Huang, X., Wang, C. & Fu, W. F. Photocatalytic overall water splitting promoted by SnOx-NiGa2O4 photocatalysts. Appl. Cat. B: Environ. 182, 220–228 (2016).Xu, J., Wang, L. & Cao, X. 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Ultrasensitive H₂S gas sensors based on p-type WS₂ hybrid materials

Abstract Owing to their higher intrinsic electrical conductivity and chemical stability with respect to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor applications. Herein, we explore the gas sensing behavior of WS₂ nanowire-nanoflake hybrid materials and demonstrate their excellent sensitivity (0.043 ppm⁻¹) as well as high selectivity towards H₂S relative to CO, NH₃, H₂, and NO (with corresponding sensitivities of 0.002, 0.0074, 0.0002, and 0.0046 ppm⁻¹, respectively). Gas response measurements, complemented with the results of X-ray photoelectron spectroscopy analysis and first-principles calculations based on density functional theory, suggest that the intrinsic electronic properties of pristine WS₂ alone are not sufficient to explain the observed high sensitivity towards H₂S. A major role in this behavior is also played by O doping in the S sites of the WS₂ lattice. The results of the present study open up new avenues for the use of transition metal disulfide nanomaterials as effective alternatives to metal oxides in future applications for industrial process control, security, and health and environmental safety

Advances in Lanthanide Single-Ion Magnets

We present an overview of the investigation methods of lanthanide-based single-ion magnet. The electronic structure of lanthanide ions is described in the picture of electron-electron interaction, spin-orbit coupling, and ligand-field effects. The ligand-field Hamiltonian is introduced in cooperation with equivalent operator method. In the part of experimental methods, we review the advanced methods of the angle-resolved magnetometry measurement and magnetic resonance spectroscopy on lanthanide ions. In the part of theoretical approaches, we describe the lanthanide-ion electron-density distribution anisotropy using the multipole-moment model, which is able to qualitatively describe the magnetic anisotropy behavior of various lanthanide ions. We introduce three approaches of determining ligand-field parameters. Additionally, we review four series of well-investigated lanthanide single-ion magnets.SCI(E)REVIEW111-14116

Il trattamento sanitario su minore o incapace: il miglior interesse del paziente vulnerabile fra (più) volontà e scienza.

New {TbCu₃} and {DyCu₃} single-molecule magnets (SMMs) containing a low-symmetry Ln^III center (shape measurements relative to a trigonal dodecahedron and biaugmented trigonal prism are 2.2–2.3) surrounded by three Cu^II metalloligands are reported. SMM behavior is confirmed by frequency-dependent out-of-phase ac susceptibility signals and single-crystal temperature and sweep rate dependent hysteresis loops. The ferromagnetic exchange interactions between the central Ln^III ion and the three Cu^II ions could be accurately measured by inelastic neutron scattering (INS) spectroscopy and modeled effectively. The excitations observed by INS correspond to flipping of Cu^II spins and appear at energies similar to the thermodynamic barrier for relaxation of the magnetization, ∼15–20 K, and are thus at the origin of the SMM behavior. The magnetic quantum number <i>M</i>_tot of the cluster ground state of {DyCu₃} is an integer, whereas it is a half-integer for {TbCu₃}, which explains their vastly different quantum tunneling of the magnetization behavior despite similar energy barriers