Search

We reported a facile synthesis route for size controlled preparation of gold nanoparticles (Au NPs) by controlling concentration of the reducing agent and temperature. Nearly monodisperse Au NPs with mean diameters of 2-6 nm are acquired via the reduction of HAuCl4by NaBH4in the presence of tri-n-octyl amine and dodecanethiol in solvent of toluene. Results indicate that concentration of the reducing agent and temperature are key factors to tune the particle size and uniformity in the synthesis of Au NPs. The as-synthesized Au NPs show size dependent surface plasmonic properties between 510 and 525 nm, while Au NPs with size smaller than 3 nm do not clearly show the property.

For the first time, novel β-C3N4/CuO composites with superior photocatalytic activity are successfully fabricated via a facile reflux method followed by a thermal process. The morphologies, particle size and microstructure of the synthesized β-C3N4/CuO composites largely depended upon copper chloride and the volume ratio of V water:V ethanol in the mixed precursors. The fabricated β-C3N4/CuO nanoflakes exhibited obviously enhanced visible light photocatalytic activity for the degradation of methylene blue (MB) with an ~3.4 and 1.9 fold increase in efficiency over that of pure g-C3N4 and commercial P25, respectively. The β-C3N4/CuO composite photocatalyst also showed photocatalytic activity for the degradation of methyl orange (MO). Moreover, the β-C3N4/CuO nanoflakes showed almost no loss of photocatalytic activity after three recycles of the degradation of the MB. A multiple synergetic mechanism in β-C3N4/CuO nanoflakes, which is featured by the highly reactive {0 0 2} facets, exposed many active sites of nanoflakes and the efficient charge separation are proposed to account for the distinguished photocatalytic activity. This work provides a facile and cost-effective strategy for designing novel β-C3N4/CuO photocatalysts for application in environmental purification.

Metal nanoparticles or nanoclusters have been widely used to functionalize semiconductor metal oxide nanostructures-based gas sensors or photodetectors to significantly enhance the device performance. It is crucial to reach a thorough understanding of the interfacial coupling between the metal nanoclusters and the metal oxide nanostructures. Here, in situ X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) have been used to investigate the interfacial interactions between metals (Au and Co) and molybdenum trioxide (MoO3) films. In spite of the high work function ([Formula: see text]6.8[Formula: see text]eV) of the thermally evaporated MoO3 films, only weak interaction is observed at the Au/MoO3 interface. Au clusters or films can remain their neutral and nonchemically reacted state on MoO3 film. In contrast, the interfacial chemical reaction between Co and MoO3 is significantly strong. A band-bending in MoO3 and two interface states have been observed at the Co/MoO3 interface.