14 research outputs found
Synthesis of Well-Defined, Surfactant-Free Co<sub>3</sub>O<sub>4</sub> Nanoparticles:The Impact of Size and Manganese Promotion on Co<sub>3</sub>O<sub>4</sub> Reduction and Water Oxidation Activity
Abstract: A surfactant-free synthetic route has been developed to produce size-controlled, cube-like cobalt oxide nanoparticles of three different sizes in high yields. It was found that by using sodium nitrite as salt-mediating agent, near-quantitative yields could be obtained. The size of the nanoparticles could be altered from 11 to 22Â nm by changing the cobalt concentration and reaction time. These surfactant-free nanoparticles form ideal substrates for facile deposition of further elements such as manganese. The effect of size of the cobalt oxide nanoparticles and the presence of manganese on the reducibility of cobalt oxide to metallic cobalt was investigated. Similarly, the effect of these parameters was investigated with a visible light promoted water oxidation system with cobalt oxide as catalyst, together with [Ru(bpy) 3] 2+ light harvester dye and an electron acceptor. Graphical Abstract: A novel surfactant-free synthetic route has been developed to produce size-controlled, cube shaped cobalt oxide nanoparticles in high yields. [Figure not available: see fulltext.]. </p
Transmission Electron Microscopy as indispensable tool for imaging and chemical characterization of heterogeneous catalysts
Dehydrogenation of ethanol over carbon-supported Cu–Co catalysts modified by catalytic chemical vapor deposition
Surface phenomena involved in the formation of Co nanoparticles on amorphous Carbon and SiO<sub>2</sub> deposited by magnetron sputtering
High-pressure DC magnetron sputtering was used for the deposition of cobalt on amorphous carbon (a-C) and SiO. Deposition conditions, substrate surface morphology and annealing parameters are investigated in order to promote the synthesis of large arrays of nanoparticles, with regular size and shape. Uniformly distributed Co nanoparticles a few nanometers in size were formed under annealing at 700°C in H. Particle nucleation and growth are discussed based on X-ray photoelectron spectroscopy, transmission and scanning electron microscopy and kinetic Monte Carlo modeling (KMC). © Springer-Verlag 2010