An iridescent film of porous anodic aluminum oxide with alternatingly electrodeposited Cu and SiO2 nanoparticles.

The structurally colored surface of anodic aluminum oxide (AAO) is highly useful for decoration and anti-counterfeiting applications, which are of significance for both scientific and industrial communities. This study presents the first demonstration of the fabrication of an iridescent film of porous AAO on an industrial aluminum alloy substrate, with alternatingly electrodeposited Cu and SiO2 nanoparticles (NPs). A rainbow effect was effectively obtained for the optimized sample with appropriate alternating electrodeposition times. The structure and optical properties of a series of the electrodeposited AAO-based thin film were investigated. The Cu and SiO2 NPs were found to be uniformly deposited into the porous structure of the AAO film, and the alternating electrodeposition repeating twice led to the formation of the optimal AAO-based thin film that exhibited a rainbow effect and superior anti-corrosion performance.

One-Dimensional Porous Hybrid Structure of Mo2C-CoP Encapsulated in N-Doped Carbon Derived from MOF: An Efficient Electrocatalyst for Hydrogen Evolution Reaction over the Entire pH Range.

The development of outstanding noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER) has attracted broad interest. Herein, a novel one-dimensional (1D) HER hybrid catalyst consisted of cobalt phosphide (CoP) and molybdenum carbide (Mo2C) nanoparticles wrapped by nitrogen-doped graphitic carbon (called CoP/Mo2C-NC) was successfully fabricated by a facile continuous-flow method and a simple two-step annealing process. During these processes, the successful synthesis of the MoO3 nanorods coated with cobalt zeolitic imidazolate frameworks (Co-ZIF-67) (Co-ZIF-67@MoO3) through the continuous-flow method plays a key role. The as-synthesized CoP/Mo2C-NC hybrid electrocatalyst exhibits a significantly enhanced HER electrocatalytic activity over the entire pH range relative to that of the control materials CoP, Mo2C-NC, and physically mixed CoP and Mo2C-NC. The outstanding HER catalytic performance is mainly due to the fact that the electron cloud transfers from Co to Mo in CoP/Mo2C-NC through the Co-P-Mo bond, resulting in the formation of a high valence state for Co (Co3+) species and lower valence states for Mo (i.e., Mo2+, Mo3+) species, providing the abundant HER active sites. Moreover, the Gibbs free energy (Δ GH*) of CoP/Mo2C-NC obtained by the density function theory calculations indicates a good balance between the Volmer and Heyrovsky/Tafel steps in HER kinetics. Such a cobalt zeolitic imidazolate framework-mediated strategy depicted in this work offers an interesting perspective for developing highly efficient noble-metal-free electrocatalysts for hydrogen production.

Comparison of sodium hydroxide and calcium hydroxide pretreatments on the enzymatic hydrolysis and lignin recovery of sugarcane bagasse.

Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80°C for 2h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH)2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH)2-glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl2) at room temperature, but that in Ca(OH)2-water pretreatment liquor couldn't. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH)2 pretreatment.

Improving Visible Light-Absorptivity and Photoelectric Conversion Efficiency of a TiO2 Nanotube Anode Film by Sensitization with Bi2O3 Nanoparticles.

This study presents a novel visible light-active TiO2 nanotube anode film by sensitization with Bi2O3 nanoparticles. The uniform incorporation of Bi2O3 contributes to largely enhancing the solar light absorption and photoelectric conversion efficiency of TiO2 nanotubes. Due to the energy level difference between Bi2O3 and TiO2, the built-in electric field is suggested to be formed in the Bi2O3 sensitized TiO2 hybrid, which effectively separates the photo-generated electron-hole pairs and hence improves the photocatalytic activity. It is also found that the photoelectric conversion efficiency of Bi2O3 sensitized TiO2 nanotubes is not in direct proportion with the content of the sensitizer, Bi2O3, which should be carefully controlled to realize excellent photoelectrical properties. With a narrower energy band gap relative to TiO2, the sensitizer Bi2O3 can efficiently harvest the solar energy to generate electrons and holes, while TiO2 collects and transports the charge carriers. The new-type visible light-sensitive photocatalyst presented in this paper will shed light on sensitizing many other wide-band-gap semiconductors for improving solar photocatalysis, and on understanding the visible light-driven photocatalysis through narrow-band-gap semiconductor coupling.

Fabrication of novel luminor Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+) with core/shell heteronanostructure.

A novel polychromic phosphor with core-shell heteronanostructure has been prepared to improve the chromatic index of phosphors. As for the first example, Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+), its synthetic route, structure and optical properties are presented in this paper. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), energy-dispersive x-ray spectra (EDS) and photoluminescence (PL) were all employed to characterize the composite core-shell phosphors. The XRD, FE-SEM and HR-TEM results indicate that the SiO(2) and YVO(4):Eu(3+) layers have been successfully coated on Y(2)O(3):Eu(3+) nanoparticles and SiO(2) layer, respectively: these layers were further verified by the EDS. The PL showed that the red-emitting phosphor Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+) possessed the independent luminescent properties of both the core Y(2)O(3):Eu(3+) and the shell YVO(4):Eu(3+). The emissions were dominated by [Formula: see text] or [Formula: see text] transitions of Eu(3+) when excited with different wavelengths. Since this broad-band response to excitation in the range of 225-340 nm gave more red/dark red emissions found at 612, 616 and 620 nm, the novel phosphor Y(2)O(3):Eu(3+)@SiO(2)@YVO(4):Eu(3+) could have potential biological labeling applications with wide flexibility.