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Hydrogen peroxide (H2O2) photoproduction in seawater with metal-free photocatalysts derived from biomass materials is a green, sustainable, and ultra environmentally friendly way. However, most photocatalysts are always corroded or poisoned in seawater, resulting in a significantly reduced catalytic performance. Here, we report the metal-free photocatalysts (RUT-1 to RUT-5) with in-situ generated carbon dots (CDs) from biomass materials (Rutin) by a simple microwave-assisted pyrolysis method. Under visible light (λ ≥ 420 nm, 81.6 mW/cm2), the optimized catalyst of RUT-4 is stable and can achieve a high H2O2 yield of 330.36 µmol/L in seawater, 1.78 times higher than that in normal water. New transient potential scanning (TPS) tests are developed and operated to in-situ study the H2O2 photoproduction of RUT-4 under operation condition. RUT-4 has strong oxygen (O2) absorption capacity, and the O2 reduction rate in seawater is higher than that in water. Metal cations in seawater further promote the photo-charge separation and facilitate the photo-reduction reaction. For RUT-4, the conduction band level under operating conditions only satisfies the requirement of O2 reduction but not for hydrogen (H2) evolution. This work provides new insights for the in-situ study of photocatalyst under operation condition, and gives a green and sustainable path for the H2O2 photoproduction with metal-free catalysts in seawater. [ABSTRACT FROM AUTHOR]

Cerium‐based Metal‐Organic frameworks (Ce‐MOFs) are attracting increasing interest due to their similar structural features to zirconium MOFs. The redox behavior of Ce(III/IV) adds a range of properties to the compounds. Recently, perfluorinated linkers have been used in the synthesis of MOFs to introduce new characteristic into the structure. We report the synthesis and structural characterization of Ce(IV)‐based MOFs constructed using two perfluorinated alkyl linkers. Their structure, based on hexanuclear Ce6O4(OH)412+ clusters linked to each other by the dicarboxylate ions, has been solved ab‐initio from X‐ray powder diffraction data and refined by the Rietveld method. The crystallization kinetics and the MOF formation mechanism was also invesitigated by Synchrotron radiation with XAS spectroscopies (EXAFS and XANES). The MOFs present the same fcu cubic topology as observed in MOF‐801 and UiO‐66, and they showed good stability in water at different pH conditions. The electronic structure of these MOFs has been studied by DFT calculations in order to obtain insights into the density of states structure of the reported compounds, resulting in band gaps in the range of 2.8–3.1 eV. Their catalytic properties were tested both thermally and under visible light irradiation for the degradation of methyl orange (MO) dye. [ABSTRACT FROM AUTHOR]

Growth of Co film on SiO2/Si substrates with surface roughness of 0.5 nm and 1.6 nm have been studied in-situ using magneto-optical Kerr effect (MOKE) and transport measurements. In-situ measurements jointly suggest that the films grow via Volmer-Weber growth process and proceed via a nonmagnetic, superparamagnetic and a ferromagnetic phase formation on both the substrates. Islands are found to coalesce at film thicknesses ~ 0.6 nm and at ~ 1.5 nm with continuous film formation around film thickness ~1.5 nm and ~ 3.0 nm for smooth and rough substrates, respectively. Ferromagnetic long-range ordering i.e., appearance of magnetic hysteresis loop in both films is observed just after coalesce stage. Observed azimuthal angular dependence of coercivity confirmed the presence of a weak uniaxial magnetic anisotropy (UMA) in both the films, whereas difference in UMA with substrate roughness is interpreted in terms of combined effect of domain wall pinning and internal stresses in the films. Origin of much higher UMA in case of the Co film deposited on ripple patterned substrate of similar root mean square roughness is attributed to the modified long range dipolar stray fields on the surface.

Large-scale green tides in the Yellow Sea occurred for 13 consecutive years since 2007. The unusual co-occurrence of green tides and golden tides occurred in the Yellow Sea in 2017. The causative species are Ulva prolifera and/or Sargassum horneri. Previous studies on physiological response characteristics of U. prolifera and S. horneri are done in the laboratory mainly, and there is no in-situ comparative study in this regard. In this study, the in-situ physiological response characteristics of both species were measured. The results indicated that cyclic electron flow and antioxidant system play more important roles in protecting U. prolifera, while non-photochemical quenching is more important for adapting to the environment in S. horneri. U. prolifera has a stronger ability to utilize nutrients to rapidly increase its biomass under a suitable condition compared to S. horneri. [ABSTRACT FROM AUTHOR]

Dust explosion is short-lived, but dangerous. Time-resolved small angle X-ray scattering (SAXS) with synchrotron radiation is an effective method to study the microscopic dynamics of dust explosion, but it needs high beam flux, fast detector and appropriate explosion equipment. The pink beam SAXS beamline at the upcoming high energy photon source (HEPS in Beijing, China) will possess high beam flux as 1015 phs/s and equip new advanced fast integral detector, which will provide ideal conditions for time-resolved experiment. This study aims to preliminarily develop an explosion equipment to integrate into the SAXS instrument at HEPS in the early future. The main body of the equipment is a 20 L Siwek sphere (spherical shell) of stainless steel to serve as the chamber for dust explosion. The sphere has a pair of single crystal diamond windows that are used to horizontally pass synchrotron radiation X-rays with the beam path slightly below the centre of the sphere. The powder is sprayed from bottom into chamber of the sphere and ignited by the ignition rods extending from the top to the centre of the sphere. A corresponding control system is used to conveniently integrate and logically control the dust explosion and the corresponding SAXS signals collection. The feasibility and safety of the system have been verified at the 1W2B experimental station at the Beijing Synchrotron Radiation Facility (BSRF). [ABSTRACT FROM AUTHOR]

[Display omitted] • The present work describes a unique method to form the multilayer by combining oblique angle deposition (OAD) and normal angle deposition (NAD), to achieve strong magnetic anisotropy along with better high thermal stability in polycrystalline films. • Depositing several thin FeCo layers in between normally deposited FeCo layers, a strong uniaxial magnetic anisotropy (UMA) is produced in a thick FeCo multilayer structure; otherwise, FeCo is magnetically isotropic. • This method is applicable for any nanostructured magnetic material of polycrystalline or amorphous nature, where magnetocrystalline anisotropy is absent due to the absence of long-range structural order. • The present study provides a new method to produce a thin-film layered structure using single material with controlled morphology. This may have prominent implications for future technological devices, including optical devices or any kind of radiation absorbing devices where use of any single material is required, etc. Iron-Cobalt (FeCo) columnar, multilayered structure is prepared by depositing several thin FeCo layers by varying the angle between the surface normal and the evaporation direction as 0° (normal) and 60°(oblique), alternatively. In situ X-ray scattering and magneto-optical Kerr effect (MOKE) measurements established the evolution of magnetic properties with that of the morphology and structure of the multilayer. The strong shape anisotropy and compressive stress of nanocolumns in alternative FeCo layers resulted in a well-defined uniaxial magnetic anisotropy (UMA) with the easy axis of magnetization along the projection of the tilted nanocolumns in the film plane. The stress in the film provides minimization of magnetoelastic energy along the in-plane column direction, which couples with the columnar shape anisotropy energies and results in the preferential orientation of the magnetic easy axis along the oblique angle deposition direction in the film plane. Drastic reduction in the in-plane UMA after annealing at 450 °C is attributed to the merging of columns and removal of stresses after heat treatment. The present study opens a new pathway to produce magnetically anisotropic multilayer structures using single material and thus may have prominent implications for future technological devices. [ABSTRACT FROM AUTHOR]