Gang-Juan Lee

Sonochemical synthesis of CuO nanostructures with different morphology.

This paper describes a highly efficient and rapid approach of synthesizing different CuO nanostructures in aqueous solutions using ultrasound irradiation of copper(II) acetate with urea/sodium hydroxide in the presence of polyvinylpyrrolidone (PVP), as stabilizing polymer. Field emission scanning electron microscope images clearly indicate the formation of CuO quasi-spherical microarchitectures and long-straw like structure in the presence of urea and sodium hydroxide. Other characterization techniques such as TEM, XRD and XPS are also provided to support the formation of such structures. One of the reasons for the formation of such CuO nanostructures may be due to the formation of a polymer-metal complex with the stabilizing polymer (PVP).

Recent Developments in Homogeneous Advanced Oxidation Processes for Water and Wastewater Treatment

This paper reports on recent developments in homogeneous Advanced Oxidation Processes (AOPs) for the treatment of water and wastewater. It has already been established that AOPs are very efficient compared to conventional treatment methods for degradation and mineralization of recalcitrant pollutants present in water and wastewater. AOPs generate a powerful oxidizing agent, hydroxyl radical, which can react with most of the pollutants present in wastewater. Therefore, it is important to discuss recent developments in AOPs. The homogeneous AOPs such as O3, UV/O3, UV/O3/H2O2, and UV/H2O2, Fe2

Investigation on photocatalytic potential of Au–Ta2O5 semiconductor nanoparticle by degrading Methyl Orange in aqueous solution by illuminating with visible light

A semiconductor photocatalytic process has shown great potential as a low cost, environmentally friendly and sustainable treatment technology for the treatment of wastewater. Hence, a wide band gap Ta2O5 semiconductor nanoparticle was prepared by the hydrothermal method and considerable efforts have been taken to narrow the band gap, i.e., the surface modification has been done with a noble metal (Au0) by a deposition precipitation method. As synthesized, Au–Ta2O5 semiconductor was well characterized by X-ray diffraction (XRD), X-ray photo electron spectroscopy (XPS), transmission electron microscopy (TEM) and diffused reflectance UV-vis spectroscopy (DRS). The photocatalytic potential of Au–Ta2O5 semiconductor was investigated by degrading Methyl Orange in the presence and absence of electron acceptors by illuminating with visible light of intensity 80 600 ± 10 Lux.

Preparation of bismuth oxide photocatalyst and its application in white-light LEDs

Bismuth oxide photocatalysts were synthesized and coated on the front surface of phosphor-converted white light-emitting diodes to produce a safe and environmentally benign lighting source. Bismuth oxide photocatalyst powders were synthesized with a spray pyrolysis method at 500°C, 600°C, 700°C, and 800°C. Using the absorption spectrum in the blue and UV regions of the bismuth oxide photocatalysts, the blue light and UV leakage problems of phosphor-converted white LEDs can be significantly reduced. The experimental results showed that bismuth oxide photocatalyst synthesized at 700°C exhibited the most superior spectrum inhibiting ability. The suppressed ratio reached 52.33% in the blue and UV regions from 360 to 420 nm. Related colorimetric parameters and the photocatalyst decomposition ability of fabricated white-light LEDs were tested. The CIE chromaticity coordinates (x, y) were (0.349, 0.393), and the correlated color temperature was 4991K. In addition, the coating layer of photocatalyst can act as an air purifier and diffuser to reduce glare. A value of 66.2 ± 0.60 ppmv of molecular formaldehyde gas can be decomposed in 120mins.

Facile synthesis of self-assembled biporous NiO and its electrochemical properties

In this article, we report the synthesis of self-assembled bi-porous nickel oxide on a large scale without using any templates or matrix. Porous NiO microspheres composed of particles were obtained by thermal decomposition of nickel oxalate, which was prepared using nickel salt and oxalic acid as precursors. The as-obtained nickel oxalate and nickel oxide were characterized using X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), thermogravimetric analysis (TGA), and nitrogen adsorption-desorption analysis. The influence of various experimental conditions on the formation nickel oxalate and NiO were studied. The nitrogen adsorption-desorption analysis showed that the synthesized NiO possesses a biporous (both mesoporous and macroporous) surface structur. The NiO microspheres showed a discharge capacity of 2929 mAh g−1. A plausible mechanism for the NiO self-assembly was proposed.

Synthesis of mesoporous Bi{sub 2}O{sub 3}/CeO{sub 2} microsphere for photocatalytic degradation of Orange II dye

We report on the visible-light responsive porous assembly of Bi2O3/CeO2 microspheres, which were synthesized via a simple hydrothermal reaction between Bi(NO3)3·5H2O and Ce(NO3)3·6H2O in the presence of ethylene glycol and ethanol. Systematic structural (X-ray diffraction (XRD)), morphological (field emission scanning electron microscopy (FE-SEM) and transmission electron microscopic (TEM)), BET surface area and diffuse reflectance spectral (DRS) analyses were carried out to characterize the formed product. The effects of experimental parameters on the microstructural and morphological behavior of Bi2O3/CeO2 composites were discussed. The semiconductor material as obtained was evaluated as a heterogeneous photocatalyst for the photolytic degradation of an azo dye in water and the degradation was found to follow pseudo-first-order rate kinetics. The study compares the rate constants of the new hybrid catalyst to a pristine Bi2O3 and CeO2, which has excellent catalytic properties under visible light irradiation for the degradation of Orange II dye.