Fluoride capping prevents the oxidation product from inhibiting the CeO2 nanozyme, and increases the oxygen vacancy concentration for more efficient catalysis.

The bonding mechanism of ethene to a nickel or palladium center is studied by the density matrix renormalization group algorithm, the complete active space self consistent field method, coupled cluster theory, and density functional theory. Specifically, we focus on the interaction between the metal atom and bis-ethene ligands in perpendicular and parallel orientations. The bonding situation in these structural isomers is further scrutinized using energy decomposition analysis and quantum information theory. Our study highlights the fact that when two ethene ligands are oriented perpendicular to each other, the complex is stabilized by the metal-to-ligand double-back-bonding mechanism. Moreover, we demonstrate that nickel-ethene complexes feature a stronger and more covalent interaction between the ligands and the metal center than palladium-ethene compounds with similar coordination spheres. Fig. 1 Schematic representation of the back-donation process. M refers to either palladium or nickel.

Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the core and nanofiber TiO2/Fe3O4/Ag nanoheterojunctions as the shell; and Ag nanoparticles with diameter of approximately 4 nm are loaded both on TiO2 nanofibers and inside the cavities of sea urchin-like Fe3O4@TiO2 nanocomposites uniformly. Ag nanoparticles lead to the production of more photogenerated charges in the TiO2/Fe3O4/Ag heterojunction via LSPR absorption, and enhance the band-gap absorption of TiO2, while the Fe3O4 cocatalyst provides the active sites for oxygen reduction by the effective transfer of photogenerated electrons to oxygen. So the photocatalytic performance is improved due to the synergistic effect of TiO2/Fe3O4/Ag nanoheterojunctions. As photocatalysts under UV and visible irradiation, the as-synthesized nanocomposites display enhanced photocatalytic and recycling properties for the degradation of ampicillin. Moreover, they present better broad-spectrum antibiosis under visible irradiation. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, makes this multifunctional nanostructure a promising candidate for antibiosis and remediation in aquatic environmental contamination in the future.

No abstract