Browsing by Author "Hu, Chi-Chang"

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A dual TiO2/Ti-stainless steel anode for the degradation of orange G in a coupling photoelectrochemical and photo-electro-Fenton system
(2019-04-01)
Liu, Ching-Fang
;
Huangb, C. P.
;
Hu, Chi-Chang
;
Huang, Chihpin
;
環境工程研究所
A dual-anode consists of stainless steel and TiO2/Ti electrodes is used to study the kinetics of the degradation of hazardous chemicals exemplified by azo dye orange G (OG) using a coupling photoelectrochemical catalytic and photoelectro-Fenton (PEC/PEF) system. Concurrent generation of hydroxyl radicals on the TiO2/Ti photocatalyst and in-situ generation of Fenton reagents on the stainless steel electrode greatly enhances the performance of the PEC/PEF electrodes over that of the PEC and the PEF alone process. The efficiency of the PEC/PEF process is a function of Fe2+ and H2O2 concentration OH center dot in the solution bulk, which promotes the oxidative degradation of OG and its byproducts. The mean carbon oxidation state (COS) is estimated to reflect the degree of mineralization. Based on the pseudo first-order kinetics with respect to OH center dot, OG, Fe2+, the corresponding reaction rates is established. UV-Vis spectrometry reveals the presence of four major intermediates, which helps establish the OG degradation pathways. (c) 2018 Elsevier B.V. All rights reserved.
Anodic fabrication of advanced titania nanotubes photocatalysts for photoelectrocatalysis decolorization of Orange G dye
(2016-02-01)
Juang, Yaju
;
Liu, Yijin
;
Nurhayati, Ervin
;
Nguyen Thi Thuy
;
Huang, Chihpin
Titania nanotubes (TNTs) were fabricated on Ti mesh substrates by the anodizing technique. The effects of preparation variables, such as anodizing voltage, time and calcination temperature on the textural characteristics and photocatalytic activity of TNTs were investigated. The surface morphology, crystalline phase, and chemical composition were analyzed using field emission-scanning electron microscopy and X-ray diffraction. The photo-electrochemical properties of TNTs were examined by voltammetry. The TNTs were tested as a photoanode for advanced oxidation processes, such as photocatalytic, electrocatalytic, and photoelectrocatalytic decolorization of Orange G dye. The well-arranged TNTs electrode prepared in this work showed a high photocurrent density of 101 mu A cm(-2) at an optimum length-to-diameter aspect ratio of 31.2. In dye decolorization tests, the electrochemical photocatalytic system using TNTs as the photoanode achieved total decolorization and 64% mineralization under extended reaction time. These results show that TNTs prepared by this method is greatly stable in prolonged use and suitable as a photoanode in the photocatalytic/photoelectrocatalytic treatments of dye wastewater. (C) 2015 Elsevier Ltd. All rights reserved.
Effects of dynamic polarization on boron-doped NCD properties and on its performance for electrochemical-analysis of Pb (II), Cu (II) and Hg (II) in aqueous solution via direct LSV
(2015-12-17)
Nurhayati, Ervin
;
Juang, Yaju
;
Rajkumar, Muniyandi
;
Huang, Chihpin
;
Hu, Chi-Chang
Boron-doped diamond films electrode has been effectively applied in electroanalysis to detect numerous kinds of electroactive chemicals including heavy metals. The success of this application not only depends on the original quality of the films, but more than that, surface treatment or activation and analytical method applied play important role. Fabricated boron-doped nanocrystalline diamond (BD-NCD) in this work were electrochemically pretreated prior to the measurement of heavy metal ions in the solution. The surface properties of the films were evaluated with FE-SEM, AFM, Raman spectroscopy and XPS. The technique chosen for heavy metal measurement was linear sweep voltammetry (LSV) after comparing with differential pulse and square wave voltammetry. In this study, dynamic polarization applied on the BD-NCD electrode was proven to enhance its surface properties. The result of XPS analysis shows that polarized electrode exhibits diminution of Csp(2) and possess minimum adventitious carbon content on its surface. This leads to an increase of electrode kinetic and promotes its capability for Pb, Cu and Hg ions measurements in the aqueous solution using LSV technique without pre-concentration step. The linearity of current response with increasing heavy metals concentration in an acetate buffer is ranging from 1 to 22.5 mu M for Pb and Cu ions and 1 to 10 mu M for Hg ion. The detection limit and sensitivity are 1.339, 0.102 and 0.666 mu M, and 0.014, 0.104 and 0.057 mu A mu M-1 mm(2) for Pb, Cu and Hg, respectively. The BD-NCD electrode also exhibits capability in simultaneous multi-metals determination although the presence of Cu ion was found to be a disturbance in the system as well. On the other hand, the high content of organics in the real water sample such as lake water also demonstrated to hinder heavy metals measurement. Thus, this study confirms that the BD-NCD after undergoing dynamic polarization are capable of direct determination of Pb, Cu and Hg ions both individually and simultaneously either in the acetate buffer solution or natural water system, within mu M level. (C) 2015 Elsevier B.V. All rights reserved.
Electrochemical photocatalytic degradation of dye solution with a TiO2-coated stainless steel electrode prepared by electrophoretic deposition
(2013-08-01)
Lin, Wei-Chieh
;
Chen, Chien-Hung
;
Tang, Han-Yu
;
Hsiao, Yu-Cheng
;
Pan, Jill Ruhsing
This study demonstrates a new model for the treatment of azo dye wastewater by means of a heterogeneous photocatalytic degradation coupled with the homogeneous electrochemical Fenton reaction, and is called electrochemical photocatalytic (ECPC) degradation. Titanium dioxide-coated stainless steel (P25-TiO2/SS) mesh was employed as a photo-anode, covered with a uniform layer of P-25-TiO2 using electrophoretic deposition (EPD) in a 2-propanol suspension with 10(-4) M Zn(NO3)(2), at a deposition time of 1 min. After annealing in air at 350 degrees C for 1 h, a crack-free, porous P25-TiO2 layer of ca. 2.14 mu m was obtained. Potential bias was used to enhance the photocatalytic degradation of P25-TiO2/SS towards the target pollutant, azo dye orange G, in an undivided cell under ultraviolet light irradiation. Heterogeneous photocatalytic degradation and a homogeneous electro-Fenton reaction occurred in the system simultaneously when H2O2 and Fe2+ were electrochemically generated on the graphite cathode and photo-anode, respectively, under a suitable potential bias, enhancing the de-colorization and removal of total organic carbon. (C) 2013 Elsevier B.V. All rights reserved.
Electrochemical Photocatalytic Degradation of Orange G Using TiO2 Films Prepared by Cathodic Deposition
(2014-01-01)
Wu, Tsai-Fang
;
Lin, Wei-Chieh
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Hsiao, Yu-Cheng
;
Su, Chih-Hao
;
Hu, Chi-Chang
Herein, we report that organic dyes with poor adsorption on photocatalysts (e. g., OG (orange G) on TiO2) can only be significantly degraded via the indirect oxidation process by the electrochemical photocatalytic (EPC) or photo-electro-Fenton (PEF) mechanisms because of their enhanced electron-hole separation for generating H2O2. The TiO2/Ti photo-anodes were prepared by cathodic deposition from a bath containing TiCl3, HCl, H2O2, and NaNO3 under a two-electrode mode for EPC dye degradation. Effects of the deposition cell voltage, deposition time, and annealing temperature on the photocatalytic activity of TiO2 films, evaluated by the photocurrent density, are systematically investigated. The surface morphologies and crystalline structure of various TiO2 films were studied using scanning electron microscopic (SEM) and X-ray diffraction (XRD) analyses. The EPC characteristics of TiO2/Ti photo-anodes combined with a graphite cathode toward the OG degradation have also been evaluated. The maximal photocatalytic activity is obtained for the TiO2/Ti photo-anode deposited at a cell voltage of 2.6 V for 20 min and annealed at 700 degrees C in air for 1 hr, which exhibits a photocurrent density of 22.86 mu Amg(-1). The order of degradation modes with respect to decreasing the degradation efficiency of OG is: PEF > EPC > PC (photocatalytic) > EC (electrocatalytic) oxidation. (C) 2014 The Electrochemical Society. All rights reserved.
Electroless deposition of RuO2-based nanoparticles for energy conversion applications
(2019-01-01)
Li, Jing-Mei
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Hu, Chi-Chang
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Wu, Tzu-Ho
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Hsu, Yung-Jung
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材料科學與工程學系
This study reports a delicate electroless approach for the deposition of RuO2 center dot nH(2)O nanoparticles on the VOx center dot mH(2)O nanowires and this method can be extended to deposit RuO2 center dot nH(2)O nanoparticles on various material surfaces. Electrochemical characterizations, including linear sweep voltammetry (LSV), electrochemical quartz crystal microbalance (QCM) analysis and rotating ring-disc electrode (RRDE) voltammetry, were carried out to investigate the growth mechanism. The deposition involves the catalytic reduction of dissolved oxygen by the V4+ species of VOx center dot mH(2)O, which drives the oxidation of RuCl3 to proceed with the growth of RuO2 center dot nH(2)O. This core/shell VOx center dot mH(2)O/RuO2 center dot nH(2)O shows a better catalytic activity of the oxygen reduction reaction (ORR) than RuO2 center dot nH(2)O, which is ascribed to the pronounced dispersion of RuO2 center dot nH(2)O. Such an electroless approach was applicable to the preparation of a RuO2-based nanoparticle suspension as well as the deposition of nanocrystalline RuO2 center dot nH(2)O on other functional supports like TiO2 nanowires. The thus-obtained RuO2-decorated TiO2 nanorods exhibit significantly an enhanced photoactivity toward photoelectrochemical water oxidation. The versatility of the current electroless approach may facilitate the widespread deployment of nanocrystalline RuO2 center dot nH(2)O in a variety of energy-related applications.
Evaluating the sensitizing effect on the photocatalytic decoloration of dyes using anatase-TiO2
(2014-04-27)
Hsiao, Yu-Cheng
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Wu, Tsai-Fang
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Wang, Yu-Sheng
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Hu, Chi-Chang
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Huang, Chihpin
This work tries to clarify the contribution of the dye-sensitizing effect on the photocatalytic decoloration of dyes dissolved in aqueous media using an anatase TiO2 (A-TiO2) photocatalyst. The photocurrentvoltage (J-V) curves of a typical dye-sensitized solar cell (DSSC) with the A-TiO2 photoanodes adsorbed with various dyes, including methylene blue (MB), orange G (OG), rhodamine B (RhB), metanil yellow (MY), acid black 24 (AB24), and N719, are employed to demonstrate the sensitizing characteristics of dyes on A-TiO2. Unlike RhB, the MB, OG, MY, and AB24 cannot work as the photo-sensitizer on A-TiO2 from the J-V curves of DSSCs, reasonably due to the unmatched band position between dyes and A-TiO2. In the photocatalytic decoloration test of these dyes on A-TiO2 in aqueous media, dye adsorption onto A-TiO2 becomes the key factors affecting the photocatalytic decoloration rate because the generation of oxidants species (e.g., Oi(2)(-center dot), OH center dot or photo-excited holes) occurs on the A-TiO2 surface. The contribution of dye-sensitizing on the photocatalytic decoloration of RhB is negligible since the dye-sensitizing/electron-injection/dye-regeneration cycle cannot be completed in the degradation media while adsorbed RhB molecules are unstable when few photo-generated electrons have been injected into the conduction band of A-TiO2, probably leading to the decomposition of RhB. (C) 2013 Elsevier B.V. All rights reserved.
Fabrication of boron-doped diamond-like carbon (BDDLC) electrode and its applications for the measurements of Hg2+, Cu2+, and Pb2+ ions in aqueous solutions
(2014-08-10)
Juang, Yaju
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Nurhayati, Ervin
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Huang, Chihpin
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Hu, Chi-Chang
;
Rajkumar, Muniyandi
Graphite Supported Stainless-Steel Electrode for the Degradation of Azo Dye Orange G by Fenton Reactions: Effect of Photo-Irradiation
(2019-01-01)
Liu, Ching-Fang
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Huang, C. P.
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Juang, Yaju
;
Hu, Chi-Chang
;
Huang, Chihpin
An electrode, stainless steel supported on graphite, was used for the degradation of hazardous organic compounds, azo dye Orange G (OG), using the photoelectro- Fenton (PEF) process. Results showed that the applied current controlled the electrogeneration rate of both ferrous ion and hydrogen peroxide, which in turn affected the dye degradation kinetics. At an applied current density of 45Acm-2, the SS-graphite electrode yielded a molar [H2O2]/[Fe2+] ratio of 3.6, which was optimal for dye degradation. Under otherwise identical conditions, UV irradiation significantly enhanced OG degradation, i.e.,PEF is more effective than electro-Fenton (EF) process. At the optimal applied current density of 45Acm-2, or optimal molar [H2O2]/[Fe2+] of 3.6, OG decolorization and total organic carbon removal were 83% (in 3h) and 55% (in 7h), versus 75% (in 3h) and 20% (in 7h) by PEF and EF, respectively. OG degradation by both PEF and EF processes followed the pseudo first-order kinetics, which suggested the major role of OH radical in OG decolorization.
Microstructural and thermal characterizations of light-emitting diode employing a low-temperature die-bonding material
(2016-08)
Wang, Tzu-Hao
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Lee, Hsuan
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Chen, Chih-Ming
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Chen, Ming-Guan
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Hu, Chi-Chang
A Sn/Bi bilayer was deposited on a hot air solder leveling (HASL)-treated metal-core printed circuit board (MCPCB) using electroplating as a low-temperature die-bonding material for light-emitting diode (LED). The eutectic feature of the Sn/Bi contact enabled the die-bonding process to accomplish through a liquid/solid reaction at 185 degrees C with a proper compression force. A high-temperature die-bonding structure composed of a Bi layer sandwiched by two intermetallic compounds (IMCs) formed after thermocompression. Employment of the Sn/Bi bilayer for low-temperature die-bonding prevented the LEDs from thermal stress problems, and the resulting high-temperature IMC/Bi/IMC die-bonding structure was capable of withstanding multiple bonding reactions and high temperature/current operation environment. Durability tests including mechanical, thermal, and optical performance were systematically performed and compared with other commercially available die-bonding materials (Ag paste and solder alloys). (C) 2016 Elsevier Ltd. All rights reserved.
Photoelectrochemical degradation of dye wastewater on TiO2-coated titanium electrode prepared by electrophoretic deposition
(2016-06-13)
Liu, Ching-Fang
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Huang, C. P.
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Hu, Chi-Chang
;
Juang, Yaju
;
Huang, Chihpin
The degradation of azo dye Orange G (OG) on TiO2/Ti electrode was studied using a photoelectrocatalytic system. TiO2/Ti electrode was prepared by electrophoretic deposition (EPD) process. Results of surface analyses, namely, X-ray diffraction (XRD), SEM, X-ray photoelectron spectroscopy (XPS), and linear sweep voltammetry (LSV), revealed that the optimal EPD condition was a deposition potential of 180 V for 1 min and annealed at 350 degrees C. The TiO2/Ti electrode was used as photoanode and a graphite cathode for the degradation of OG. The coupling effect of photocatalytic and electrochemical oxidation processes was evaluated in terms of the decolorization of OG. The degradation of OG increased in the following increasing order: photocatalysis < electrochemical oxidation < photoelectrochemical degradation. A decolorization of 54.3% was achieved at an applied current density of 75 A cm(-2). The degradation of Orange G follows the first-order kinetics in those three treatment processes, which suggests the participation of OH radicals in the decolorization reaction. (C) 2016 Elsevier B.V. All rights reserved.
Preparation of TiO2 nanotube arrays/Ti electrode by anodic oxidation method for the degradation of dye in aqueous solutions
(2014-08-10)
Liu, Yi-Jin
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Liu, Ching-Fang
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Huang, Chihpin
;
Hu, Chi-Chang
;
環境工程研究所
Synthesis of Petal-Like Carbon Nanocapsule@MnO2 Core-Shell Particles and Their Application in Supercapacitors
(2014)
Lee, Ting-Ting
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Hong, Jing-Ru
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Lin, Wei-Chen
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Hu, Chi-Chang
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Wu, Pu-Wei
Carbon nanocapsule (CNC)@MnO2 core-shell particles are prepared with a reaction of KMnO4 with CNC at 90 degrees C. Birnessite-type MnO2 nanoflakes are grown on CNC seeds, resulting in CNC@MnO2 particles with a petal-like structure. The electrochemical characteristics of the prepared materials show that the highest specific capacitance (163 Fg(-1)) was obtained with a scan rate of 2 mVs(-1) in 1 M Na2SO4. In addition, the synthesized material has superior cycling stability. The capacitance retains 97.8% of its initial value after 5000 cycles with a scan rate of 100 mVs(-1). (C) 2014 The Electrochemical Society. All rights reserved.