Facet-Dependent Cuprous Oxide Nanocrystals Decorated with Graphene as Durable Photocatalysts under Visible Light.

Three morphologies (octahedral, hierarchical and rhombic dodecahedral) of crystal Cu2O with different facets ({111}, {111}/{110}, and {110}) incorporating graphene sheets (denoted as o-Cu2O-G, h-Cu2O-G and r-Cu2O-G, respectively) have been fabricated by using simple solution-phase techniques. Among these photocatalysts, the r-Cu2O-G possesses the best photocatalytic performance of 98% removal efficiency of methyl orange (MO) with outstanding kinetics for 120 min of visible light irradiation. This enhancement is mainly due to the dangling “Cu” atoms in the highly active {110} facets, resulting in the increased adsorption of negatively charged MO. More importantly, the unique interfacial structures of Cu2O rhombic dodecahedra connected to graphene nanosheets can not only decrease the recombination of electron-hole pairs but also stabilize the crystal structure of Cu2O, as verified by a series of spectroscopic analyses (e.g., X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM)). The effective photocatalysts developed in this work could be applied to the efficient decolorization of negatively charged organic dyes by employing solar energy.

Highly visible-light-responsive Cu2O/rGO decorated with Fe3O4@SiO2 nanoparticles as a magnetically recyclable photocatalyst.

The rhombic dodecahedral cuprous oxide-reduced graphene oxide/core-shell Fe3O4@SiO2 composites (denoted as rCu2O-rGO/Fe3O4@SiO2) are successfully synthesized facilely via a wet-chemical route. The resulting rCu2O-rGO/Fe3O4@SiO2 combines the unique structure of Cu2O, electronic characteristics of reduced graphene oxide (rGO) and magnetic property of Fe3O4@SiO2 to be an effective and recoverable photocatalyst for the degradation of methyl orange (MO). The obtained results show that rCu2O-rGO/Fe3O4@SiO2 is capable of completely degrading MO in the presence of a very low catalyst concentration (0.125 g l-1) within a short time (60 min) under visible light compared to the reported catalysts. The observations may be due to the distinctive interfacial structures of rhombic dodecahedral Cu2O nanoparticles connected to rGO sheets that can enhance the separation of photogenerated electron-hole pairs, stabilize the Cu2O and increase MO adsorption, as evidenced by a variety of spectroscopic analyses (transmission electron microscopy, x-ray photoelectron spectroscopy and photoluminescence). More importantly, these efficient photocatalysts can easily be recovered under a magnetic field and remain highly photoactive towards the degradation of MO after cyclic tests, and may be promising photocatalysts for practical applications in the solar-energy purification of wastewater.

Visible-light-driven photodegradation of sulfamethoxazole and methylene blue by Cu2O/rGO photocatalysts.

The cuprous oxide-reduced graphene oxide (Cu2O/rGO-x) composites were prepared via a simple wet-chemical method by using CuSO4·5H2O and graphene oxide as precursors and ascorbic acid as a reducing agent, respectively. These Cu2O/rGO-x were employed as photocatalysts for degrading emerging contaminants and organic dye pollutants (i.e., sulfamethoxazole (SMX) and methylene blue (MB)) under visible light. A variety of different spectroscopic and analytical techniques, such as X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman scattering spectroscopy and UV-Visible spectroscopy were used to characterize the physical properties of photocatalysts. In the photodegrading experiments, it can be found that the Cu2O/rGO-80 photocatalyst has the superior visible-light response of ca. 50% removal efficiency of SMX within 120 min and 100% removal efficiency of MB within 40 min. These observations may be attributed the well-dispersed and visible-light-responsive Cu2O nanoparticles are supported on the surface of rGO sheets that can enhance absorption of visible light during photocatalysis.

[Effect of PP60c-Src on angiotensin II-induced signal transduction in rat vascular smooth muscle cells].

OBJECTIVE: To further clarify the mechanism of Ang II-induced intracellular signal transduction in vascular smooth muscle cells(VSMCs) proliferation by observing the effect of c-Src on Ang II-mediated MAPK activation and c-fos protein expressions in rat VSMCs. METHODS: Aortic VSMCs from SD rats were cultured primarily and subcultured, which were transfected with anti-sense c-Src oligodeoxynucleotides(ODNs) wrapped with lipofectin to inhibit c-Src activity and protein production. Untransfected VSMCs were used as control, to observe the role of Ang II stimulation in MAPK activation and c-fos protein expression in VSMC. Protein immunoprecipitation and kinase phosphorylation were employed to measure c-Src kinase activity; MAPK kinase activity was assessed by the phosphorylation rate of the substrate MBP(Myelin Basic Protein); Western blot was used to assess the protein expression of c-Src and c-fos. RESULTS: c-Src protein expressions in VSMC, which were transfected with different concentrations of anti-sense c-Src ODNs, were significantly decreased in a negative dose-effect manner (0.2 microm, 0.5 microm, 1.0 microm and 2.0 microm were 68.2%, 34.7%, 30.3% and 15.8% respectively compared with control). c-Src kinase activity was also obviously inhibited. Following stimulation of Ang II on VSMC transfected with anti-sense c-Src ODNs, the increase of c-Src activity was only 8.7% of control,the activity of MAPK only 1.6% compared with control, and the increase in c-fos protein expression 30.3% as control. CONCLUSION: Ang II can induce c-Src activation and intracellular signal transduction in VSMC which depend on c-Src activation, indicating that c-Src is a pivotal signal factor in VSMC proliferation.