Showing papers by "Tse-Chuan Chou published in 2003"
TL;DR: In this article, a nano-crystalline porous tungsten oxide film was prepared from WCl 6 by a sol-gel technique, and the surface morphology and sensitivity to NO2 of the TNO films calcined at various temperatures were investigated.
Abstract: Sensitive porous tungsten oxide nano-crystalline based NO2 sensor was fabricated by thin film microfabrication technique. The sensitivity of this NO2 sensor was at parts per billion (ppb) level. The nano-crystalline porous tungsten oxide film was prepared from WCl 6 by a sol–gel technique. The surface morphology and sensitivity to NO2 of the tungsten oxide films calcined at various temperatures were investigated. The NO2 adsorption behavior on the tungsten oxide surface was carried out by XPS measurement. Experimental results indicated that the tungsten oxide film calcined at 550 ◦ C for 1 h showed the best performance as a sensing material to NO2, and the optimal operational temperature of the sensor was 300 ◦ C. The sensor showed high sensitivity to low NO2 concentration in the range from 50 to 550 ppb with relatively fast response time (∼3 min) and recovery time (∼1 min), respectively. © 2003 Elsevier B.V. All rights reserved.
165 citations
TL;DR: The results revealed that the galvanostatic glucose biosensor fabricated at neutral pH condition exhibited much higher sensitivity than those fabricated at lower or higher pH conditions, and had a good linearity form zero to 10 mM glucose with the sensitivity of 7 nA/mM.
103 citations
TL;DR: In this paper, a solid-state calcium ion-selective electrode was developed using thick film metallization process, where silicone rubber or photoresist was combined with ionophore (ETH 129) forming calcium ionselective membrane which was coated onto different surfaces of electrode.
Abstract: A solid-state calcium ion-selective electrode was developed using thick film metallization process. Silicone rubber or photoresist was combined with ionophore (ETH 129) forming calcium ion-selective membrane which was coated onto different surfaces of electrode. Super-Nernstian equilibrium relationship between the phase boundary potentials and calcium ion concentrations was observed in the silicone rubber-based membrane that was doped with 10 −7 M CaCl 2 treated montmorillonite. This equilibrium relationship was eliminated when the membrane was doped with 0.1 M CaCl 2 treated montmorillonite. The use of photoresist simplified the manufacturing process for the membrane. The memory effect of the silicone rubber-based membrane could be eliminated when the membrane was conditioned with 0.1 M CaCl 2 . The response time of the electrode with silicone rubber and montmorillonite modified silicone rubber were less than 20 s and the one with photoresist was less than 3 min. The sensitivity of these calcium ion-selective electrodes were around 30 mV per decade, and the selectivity were in the rang from −2.9 to −3.8 for Na + , K + and Mg 2+ ions based on fixed primary ion method (FPIM).
20 citations
25 Oct 2003-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, microfabrication of Al2O3, TiO2, and ZrO2 hollow particles was carried out by spray precipitation that the fast polymerization is induced from dehydration or acid base neutralization on the interface of the sprayed droplet to form rigid shell structure, and then removing the remained solvent within the shell.
Abstract: Microfabrication of Al2O3, TiO2 and ZrO2 hollow particles were carried out by spray precipitation that the fast polymerization is induced from dehydration or acid–base neutralization on the interface of the sprayed droplet to form rigid shell structure, and then removing the remained solvent within the shell. High yield of the smooth hollow particles can be achieved by selecting a highly polymeric precursor, which has higher surface tension, viscosity and density than those of the precipitation agent. In this work, micro to nano scaled Al2O3, TiO2, and ZrO2 hollow particles are obtained, respectively, by spraying their precursor solutions including: aluminum chlorohydrate, titanium chloride, and zirconly chloride into the precipitation agents including acetone, triethylamine and tributylamine. Subsequently, the remained water in the inner shell particles are allowed to vaporize carefully and calcinated. A bottle structure was demonstrated by increasing the momentum of sprayed droplets to impact with the precipitation agent.
20 citations
TL;DR: Modeling results indicated that a systems using a Nafion separator and a small catholyte/anolyte volume ratio was better than a system using a ceramic separator for removing impurities from concentrated plating solutions if the impurities transported into the catholytes are deposited or precipitated.
Abstract: This study focuses on the electrolytic regeneration of spent chromium plating solutions. These solutions contain a significant amount of chromium and a lesser amount of other heavy metals, which makes them a significant environmental concern and an obvious target for recycling and reuse. The type of separator used is extremely critical to the performance of the process because they are the major resistance in the transport-related impurity (Cu(II), Ni(II), and Fe(III)) removals from contaminated chromic acid solutions. A Nafion 117 membrane and a ceramic diaphragm separator traditionally used in the industry were tested for comparison. It was found that the mobilities of Cu(II) and Ni(II) were similar and higher than that of Fe(III) using both separators. The mobility of each cation was smaller in the Nafion membrane than in the ceramic diaphragm. The measured conductivity of the ceramic diaphragm was slightly higher than that of Nafion membrane. However, the Nafion membrane was much thinner than the ceramic diaphragm resulting in the system using the Nafion membrane having higher impurity removal rates than the system using the ceramic diaphragm. The removal rates were approximately equal for Cu(II) and Ni(II) and lowest for Fe(III). Both current and initial concentration affected the removal rates of the impurities. Modeling results indicated that a system using a Nafion separator and a small catholyte/anolyte volume ratio was better than a system using a ceramic separator for removing impurities from concentrated plating solutions if the impurities transported into the catholyte are deposited or precipitated.
19 citations
TL;DR: In this paper, the authors measured the composition of the electrode to consist of Ni, O, Al, Mg and Pb, and found that only the nickel could sense the ethanol.
Abstract: Thick films ethanol sensors were prepared. The composition of the electrode was measured qualitatively to consist of Ni, O, Al, Mg and Pb. Among these composing elements, it was found that only the nickel could sense the ethanol. Both the infrared (IR) spectrum and cyclic voltammetry (CV) tests were employed to investigate its derivatives in the sensing reaction. It was found that the derivatives presented as adsorbed enol group and β-ketoaldehyde as enols. Besides, both the redox between Ni(II) and Ni(III), and solid-state electrochemical reactions in the electrode were found to occur in this system simultaneously. A linear dependence of response current vs. ethanol concentration with a detection limit of 37 ppm was obtained and the response time was estimated to be 140 seconds in this sensing system.
18 citations
TL;DR: In this paper, a paired electrooxidative method has been developed to synthesize D-arabinose in a divided cell, which has an important role in the production of vitamin B2 and DNA.
Abstract: A paired electrooxidative method has been developed to synthesize D-arabinose in a divided cell. D-arabinose is a material which has an important role in the production of vitamin B2 and DNA. Sodium gluconate was directly oxidized at the anode and indirectly oxidized in the catholyte by bubbling oxygen which was reduced to H2O2 and OH• free radicals. In the catholyte, indirect oxidation of sodium gluconate was mediated by Fe3+ and OH• free radicals. The optimal current efficiencies for D-arabinose production in the anolyte and catholyte were found to be 88.37% and 39.12%, respectively, and the total current efficiency of the paired electrooxidation was 127.49%. The paired electrosynthesis of D-arabinose is more economical in terms of power consumption than electrosynthesis that employ a single anode or cathode as the working electrode. The influence of cathodic/anodic CV and I/E curves, redox mediators and the amount of charge passed were also examined.
16 citations
TL;DR: In this paper, the authors investigated the factors involved in the ethanol oxidation of α-Ni(OH) 2 /Pt/Ti electrodes and found that the porosity and thickness of the a-Ni-OH 2 film was a major determinant of ethanol oxidation.
Abstract: The aim of this paper is to understand the factors involved in the ethanol oxidation of α-Ni(OH) 2 /Pt/Ti electrodes. α-Ni(OH) 2 films are formed on Pt in nickel nitrate solution by cathodic deposition. Both electrode deposition time and nickel nitrate concentration for preparing the working electrode affect the response current of ethanol oxidation. The results showed that oxidation of ethanol significantly depended on the thickness and porosity of α-Ni(OH) 2 . A 0.96 μm thick α-Ni(OH) 2 film could oxidize ethanol effectively. If the a-Ni(OH) 2 film was thicker than 5.09 μm. there was no response current of ethanol oxidation. The optimal operating conditions for preparing a desired thickness of α-Ni(OH) 2 /Pt/Ti electrode were 15 min at I mA cm -2 current density and I M Ni 2+ .
14 citations
TL;DR: In this paper, the phases of the deposited electrodes were identified to be Ni and β-Ni(OH) 2, respectively, and the response current for the ethanol was mainly contributed from that of β/β rather than α/γ.
Abstract: Electroless Co-doped sensors with good coverage were prepared to investigate their microstructure variation. The phases of the deposited electrodes were identified to be Ni and β-Ni(OH) 2 , respectively. Scanning electron microscopy was employed to observe the morphology evolution for various values of deposition time. According to the peak intensity of the energy dispersive spectrum and the composition change of the deposited film, the growth phenomena of the deposited film were obtained. A hardball model was constructed to describe the microstructure variation of this electrode. Nevertheless, this model was utilized to deduce the ethanol sensing mechanism. It was found that the response current for the ethanol was mainly contributed from that of β/β rather than α/γ and its sensitivity depended on the competition between the γ phase and β phase. Besides, the deterioration of the stability for sensitivity resulted from the decay in the phase ratio of the β-NiOOH to γ-NiOOH during charging.
5 citations
TL;DR: In this paper, the amperometric sensing of trichloroethylene (TCE) in the organic phase by using modified Pb electrode was described, and the influence of pretreatment, electrodeposition current density, electro-deposition time, and temperature for preparation of the working electrode were discussed.
Abstract: The amperometric sensing of trichloroethylene ~TCE! in the organic phase by using modified Pb electrode was described. The influence of pretreatment, electrodeposition current density, electrodeposition time, and electrodeposition temperature for preparation of the working electrode were discussed. The optimal conditions for preparation of modified Pb electrode were obtained as 0.1 M HNO3 pretreatment, 20 mA/cm 2 electrodeposition current density, and 30°C electrodeposition temperature. Additionally, the
4 citations