Cluster–support interaction in Au–Fe3O4 system

Advances in Naked Metal Clusters for Catalysis

The properties of sub-nano metal clusters are governed by quantum confinement and their large surface-to-bulk ratios, atomically precise compositions and geometric/electronic structures. Advances in metal clusters lead to new opportunities in diverse aspects of sciences including chemo-sensing, bio-imaging, photochemistry, and catalysis. Naked metal clusters having synergic multiple active sites and coordinative unsaturation and tunable stability/activity enable researchers to design atomically precise metal catalysts with tailored catalysis for different reactions. Here we summarize the progress of ligand-free naked metal clusters for catalytic applications. It is anticipated that this review helps to better understand the chemistry of small metal clusters and facilitates the design and development of new catalysts for potential applications.

Template growth of Au, Ni and Ni–Au nanoclusters on hexagonal boron nitride/Rh(111): a combined STM, TPD and AES study

The unique electronic structure of hexagonal boron nitride/Rh(111) promotes the template growth of Au, Ni, and Ni–Au bimetallic nanoclusters, as well as the formation of an unusual core–shell nanostructure.

Adsorption of gold subnano-structures on a magnetite(111) surface and their interaction with CO

Gold deposited on iron oxide surfaces can catalyze the oxidation of carbon monoxide.

Synthesis and characterization of magnetite/silver/antibiotic nanocomposites for targeted antimicrobial therapy

The article is devoted to preparation and characterization of magnetite/silver/antibiotic nanocomposites for targeted antimicrobial therapy. Magnetite nanopowder was produced by thermochemical technique; silver was deposited on the magnetite nanoparticles in the form of silver clusters. Magnetite/silver nanocomposite was investigated by XRD, SEM, TEM, AFM, XPS, EDX techniques. Adsorptivity of magnetite/silver nanocomposite towards seven antibiotics from five different groups was investigated. It was shown that rifampicin, doxycycline, ceftriaxone, cefotaxime and doxycycline may be attached by physical adsorption to magnetite/silver nanocomposite. Electrostatic surfaces of antibiotics were modeled and possible mechanism of antibiotic attachment is considered in this article. Raman spectra of magnetite, magnetite/silver and magnetite/silver/antibiotic were collected. It was found that it is difficult to detect the bands related to antibiotics in the magnetite/silver/antibiotic nanocomposite spectra due to their overlap by the broad carbon bands of magnetite nanopowder. Magnetic measurements revealed that magnetic saturation of the magnetite/silver/antibiotic nanocomposites decreased on 6-19 % in comparison with initial magnetite nanopowder. Pilot study of antimicrobial properties of the magnetite/silver/antibiotic nanocomposites were performed towards Bacillus pumilus.

Adsorption of Aun (n = 1–4) clusters on Fe3O4(001) B-termination

The adsorption of Au_n (n = 1–4) clusters on stoichiometric, reduced and hydrated Fe₃O₄(001) B-terminations were studied using the GGA density functional theory including the Hubbard parameter (U) to describe the on-site Coulomb interaction.

Ordered array of single adatoms with remarkable thermal stability: Au/Fe3O4(001)

Gold deposited on the Fe3O4(001) surface at room temperature was studied using scanning tunneling microscopy (STM) and x-ray photoelectron spectroscopy (XPS). This surface forms a (√2 × √2)R45° reconstruction, where pairs of Fe and neighboring O ions are slightly displaced laterally producing undulating rows with "narrow" and "wide" hollow sites. At low coverages, single Au adatoms adsorb exclusively at the narrow sites, with no significant sintering up to annealing temperatures of 400 °C. We propose the strong site preference to be related to charge and orbital ordering within the first subsurface layer of Fe3O4(001)-(√2 × √2)R45°. Because of its high thermal stability, this could prove an ideal model system for probing the chemical reactivity of single atomic species.