Controlled Synthesis of Coral-Like CuO Dendrites with Enhanced Photocatalytic Performance.

In this work, coral-like CuO dendrites were successfully synthesized by a solvothermal method in the mixed solvent of distilled water and ethanol with assistance of dodecyl trimethyl ammonium bromide (DTAB). The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analysis techniques, to investigate their structure and morphology. The coral-like CuO dendrites were about 1 µm in length, with many dendrites pointing to a common center. The influence of experimental conditions on morphology, such as volume ratio of water to ethanol, surfactant DTAB and molar ratio of Na2CO3 and Cu(CH3COO)2, was also discussed. Time-dependent experiment was carried out to explore the formation mechanism while a "particle-sheet-dendrite (PSD)" mechanism was proposed to explain the growth process. The as-prepared CuO dendrites were used to degrade methylene blue (MB) under visible light irradiation in the presence of H2O2, where over 98% of methylene blue (MB) was degraded in 1 h. Results from the study demonstrated that the as-prepared coral-like CuO dendrites exhibited enhanced photocatalytic performance and excellent stability and reusability.

Tuning C-C sp2/sp3 ratio of DLC films in FCVA system for biomedical application.

Diamond like carbon (DLC) films with different C-C sp2/sp3 ratios were prepared by tuning the N2 flow rate in a filtered cathodic vacuum arc (FCVA) system. The increase of N2 flow rate facilitated the increase of C-C sp2/sp3 ratio (1.09-2.66), the growth of particle size (0.78-1.58 nm) and the improvement of surface roughness. The SBF immersion results, as well as WCAs (77.57°~71.71°), hemolysis rate (0.14-1.00%) and cytotoxicity level (0) demonstrated that the as-fabricated DLC film was promising for biomedical application. As a result of surface charge effect, the apatite layers formed in the SBF increased with the increase of C-C sp2/sp3 ratio until 1.74 and then showed a tiny decrease during 1.74-2.66. A raise of hemolysis and cytotoxicity was observed when sp2/sp3 ratio was increased. Moreover, a decrease of friction coefficient of Si surface induced by increasing sp2/sp3 ratio was respectively evidenced in ambient air and SBF lubrication environments.

A Facile Green Approach for Synthesis of Selenium Nanowires with Visible Light Photocatalytic Properties.

In this work, high purity trigonal selenium (t-Se) nanowires were synthesized through a simple one-step solvothermal process at 50 °C. Sodium formaldehyde sulfoxylate (SFS) was used as a reducing agent. To our knowledge, this is the first time that SFS was used as the reducing agent for synthesis of Se nanostructures. In this method, Se nanowires were obtained at lower temperature, shorter period of reaction time and without using complex equipment. The experimental parameters, such as reaction duration, temperature and amount of surfactant, were investigated. The as-prepared Se nanowires have a diameter of about 100-200 nm and length of up to 10 µm. A "Solid-Solution-Solid" growth mechanism was proposed. In the presence of H2O2, the Se nanowires showed good catalytic performance, where over 99% of methylene blue (MB) was degraded in 3.0 h. Results from this study demonstrated that the Se nanowires exhibit a promising application for photodegradation.

Convenient Route to Well-Dispersed Cu2O Nanospheres and Their Use as Photocatalysts.

A simple and facile method was developed to synthesize well-dispersed cuprous oxide nanospheres with uniform morphology and the size in the range of 400-600 nm. Cuprous oxide nanospheres were obtained through the chemical reduction of copper acetate by fructose in the presence of ethylene glycol and de-ionized water. X-ray powder diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), UV-Vis spectroscopy (UV-Vis) and transmission electron microscopy (TEM) as well as high-resolution transmission electron microscopy (HRTEM) were used to characterize the obtained nanoparticles. The influence of time, temperature and the solvent on the formation of cuprous oxide was investigated. The growth process of cuprous oxide was analyzed and the mechanism of crystal growth was proposed. The photocatalytic activity of degradation of methyl orange (MO) under visible light irradiation was also investigated. It was found that the product of cuprous oxide had efficient catalytic for degradation MO.