• Analytical Science and Technology
• /
• v.11 no.5
• /
• pp.347-352
• /
• 1998

A study was carried out on the elelctrochemical characteristics of chemically modified electrodes (CMEs) by cyclic voltammetry. Fabrication of CMEs was made by coating with mixed valence (mv) inorganic-metal polymeric films on the glassy carbon electrode surface by potential cycling. Anodic oxidation behavior of methanol and L-ascorbic acid was studied by using CMEs working electrode. Deposition of films such as mv ruthenium oxo/ruthenium cyanide film (mv Ru-O/CN-Ru), mv ruthenium oxo/ferrocyanide film (mv Ru-O/$Fe(CN)_6$), and mv ruthenium oxo/ruthenium cyanide/Rhodium film (mv Ru-O/CN-Ru/Rh) was obtained to coat by scan rate of 50 mV/sec within the specified potential range (-0.5V ~ +1.2V). Film thickness was controlled by the repeat of the potential cycling. Anodic oxidation behavior of methanol was as follow. Calibration graph by using mv Ru-O/CN-Ru film showed linearly from 10 mM to 80 mM MeOH with slope factor of $-7.552{\mu}A/cm^2$. Although slope factor by using mv Ru-O/$Fe(CN)_6$ film was $-5.13{\mu}A/cm^2$, yet linear range of calibration graph could be extended from 10 mM to 100 mM MeOH. Anodic oxidation behavior of L-ascorbic acid was studied by mv Ru-O/CN-Ru film on the glassy carbon electrode and the glassy carbon electrode with Rh film, Glassy carbon electrode modified with Ru polymeric film was showed better sensitivity than the Rh-glassy carbon modified electrode (mv Ru-O/CN-Ru/Rh). Calibration graph was linear from 0.1 mM to 5 mM L-ascorbic acid by using glassy carbon electrode modified with Ru polymeric film. Solpe factor and relative coefficient are $-84.78{\mu}A/mM$ and 0.998, respectively.

• Environmental Engineering Research
• /
• v.25 no.3
• /
• pp.324-334
• /
• 2020

Tannery wastewater is known to contain high concentrations of organic compounds, pathogens, and other toxic inorganic elements such as heavy metals, nitrogen, sulfur, etc. Biological methods such as aerobic and anaerobic processes are unsuitable for tannery wastewater treatment due to its high salinity, and electrochemical oxidation offers a promising method to solve this problem. In this study, raw tannery wastewater treatment using DSA® Ti/RuO₂, Ti/IrO₂ and Ti/BDD electrodes with continuous flow systems was examined. Effects of current densities and electrolysis times were investigated, to evaluate the process performance and energy consumption. The results showed that a Ti/BDD electrode is able to reach higher treatment efficiency than Ti/IrO₂, and Ti/RuO₂ electrodes across all parameters, excluding Total Nitrogen. The main mechanism of tannery wastewater oxidation at a Ti/BDD electrode is based on direct oxidation on the electrode surface combined with the generation of oxidants such as °OH and Cl₂, while at DSA® Ti/RuO₂ and Ti/IrO₂ electrodes, the oxidation mechanisms are based on the generation of chlorine. After treatment, the effluents can be discharged to the environment after 6-12 h of electrolysis. Electrooxidation thus offers a promising method for removing the nutrients and non-biodegradable organic compounds in tannery wastewater.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.11a
• /
• pp.364-368
• /
• 1997

We have investigated Pt and RuO$_2$as a bottom electrode for a device application of PZT thin film. The bottom electrodes were prepared by using an RF magnetron sputtering method. We studied some of the property influencing factors such as substrate temperature, gas flow rate, and RF power. An oxygen partial pressure from 0 to 50% was investigated. The results show that only Ru metal was grown without supp1ying any O$_2$gas. Both Ru and RuO$_2$phases were formed for O$_2$partial pressure between 10∼40%. A Pure RuO$_2$ phase was obtained with O$_2$partial pressure of 50%. A substrate temperature from room temperature to 400$^{\circ}C$ was investigated with XRD for the film crystallinity examination. The substrate temperature influenced the surface morphology and the resistivity of Pt and RuO$_2$as well as the film crystal structure. From the various considerations, we recommend the substrate temperature of 300$^{\circ}C$ for the bottom electrode growth. Because PZT film growth on top of bottom electrode requires a temperature process higher than 500$^{\circ}C$, bottom electrode properties were investigated as a function of post anneal temperature. As post anneal temperature was increased, the resistivity of Pt and RuO$_2$was decreased. However, almost no change was observed in resistivity for an anneal temperature higher than 700$^{\circ}C$. From the studies on resistivity and surface morphology, we recommend a post anneal temperature less than 600$^{\circ}C$.

• Korean Chemical Engineering Research
• /
• v.47 no.1
• /
• pp.11-16
• /
• 2009

Composite electrodes for redox supercapacitor were prepared potentiodynamically by the deposition of $RuO_2$ and the co-deposition of Ru-Co mixed oxide on the surface of single-walled carbon nanotube. Electrode of Ru-Co mixed oxide, in which Ru(13.13 wt%) and Co(2.89 wt%) were deposited on the carbon nanotube, exhibited a similar specific capacitance(${\sim}620\;F\;g^{-1}$) with $RuO_2$ electrode at a low potential scan rate($10\;mV\;s^{-1}$), but showed a superior one ($570\;F\;g^{-1}$) at a high scan rate($500\;mV\;s^{-1}$) than that of $RuO_2$($475\;F\;g^{-1}$). Such increase in the specific capacitance at high scan rate by the co-deposition of Ru and Co species was due to the structural support of Co species to provide the electronic conduction through Ru species.

• Environmental Engineering Research
• /
• v.24 no.4
• /
• pp.646-653
• /
• 2019

Recovery of valuable metals in the industrial wastewater and sludge has attracted an attention owing to limited metallic resources in the earth. In this study, we firstly fabricated Ti/Ir-Ru electrodes by spin coating technique for effective recovery of Cu in electrowinning process. Two different Ti/Ir-Ru electrodes were fabricated using 100 and 500 mM of precursors (i.e., Ir-Ru). SEM-EDX and AFM revealed that Ir and Ru were homogenously distributed on the surface of Ti plate by the spin coating, in particular the electrode prepared by 500 mM showed distinct boundary line between Ir-Ru layer and Ti substrate. XRD, XPS, and cyclic voltammetry also revealed that characteristics of IrO₂, RuO₂, and TiO₂ and its electrocatalytic property increased as the concentration of coating precursor increased. Finally, we carried out Cu recovery experiments using two Ti/Ir-Ru as anodes in electrowinning process, showing that both anodes showed a complete removal of Cu (1 and 10 g/L) within 6 h reaction, but much higher kinetic rate constant was obtained by the anode prepared by 500 mM. The findings in this study can provide a fundamental knowledge for surface characteristics of Ti/Ir-Ru electrode prepared by spin coating method and its potential feasibility for effective electrowinning process.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.34 no.2
• /
• pp.55-60
• /
• 2024

Two-dimensional (2D) RuO₂ nanosheets with nanometer thickness were synthesized using a chemical exfoliation method. The synthesized 2D-RuO₂ was hybridized with Ag-nanowire (NW), which is attracting attention as a next-generation transparent electrode material. After coating Ag-NW on the substrate, 2D-RuO₂ was subsequently coated on the Ag-NW. Although there was a decrease in optical transmittance, the hybridization of 2D-RuO₂ confirmed the effect of reducing sheet resistance. Furthermore, the flexibility of the fabricated transparent electrodes was also studied. It was confirmed by the change in sheet resistance after bending. The additional coating of 2D-RuO₂ improved the flexibility of the transparent electrodes.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.11
• /
• pp.715-719
• /
• 2012

We investigated the effects of electrochemical characteristics and generation of chlorine by the different amount of Ru coating which was prepared for $RuO_2$/Ti electrode coated with 1.5 mg, 2.5 mg, 5.5 mg, 8.5 mg Ru per unit area ($cm^2$). As a Result of the cycle voltammetry experiments, chlorine overvoltage of Ru-coated electrodes showed to be the nearly sustained value of approximately 1.15V (vs. Ag/AgCl). By contrary, According to the results of the AC impedance spectroscopy and potentiodynamic polarization tests, the amount of Ru per unit area ($cm^2$) included 2.5 mg, 3.5 mg as $RuO_2$/Ti offered the highest levels of durability which was electrode resistance and corrosion rate appeared to be $0.4582{\Omega}$, $0.5267{\Omega}$ and 0.082 mm/yr, 0.058 mm/yr, respectively. It was also observed that generation of chlorine coated with 3.5 mg per unit area ($cm^2$) was the highest value of 15.2 mg/L.

• Journal of Environmental Science International
• /
• v.17 no.9
• /
• pp.1023-1032
• /
• 2008

The feasibility study of the application of the photoelectrocatalytic and electrolytic/UV decolorization of Rhodamine B (RhB) was investigated in the photoelectrocatalytic and electrolytic/UV process with $TiO_2$ photoelectrode and DSA (dimensionally stable anode) electrode. Three types of $TiO_2$ photoelectrode were used. Thermal oxidation electrode (Th-$TiO_2$) was made by oxidation of titanium metal sheet; sol-gel electrode (5G-$TiO_2$) and powder electrode (P-$TiO_2$) were made by coating and then heating a layer of titania sol-gel and slurry $TiO_2$ on titanium sheet. DSA electrodes were Ti and Ru/Ti electrode. The relative performance for RhB decolorization of each of the photoelecoodes and DSA electrodes is: Ru/Ti > Ti > SG-$TiO_2$ > Th-$TiO_2$. It was observed that photoelectrocatalytic decolorization of RhB is similar to the sum of the photocatalytic and electrolytic decolorization. Therefore the synergetic effect was not showed in pthotoelectrocatalytic reaction. $Na_{2}SO_{4}$ and NaCl showed different decolorization effect between pthotoelectrocatalytic and electrolytic/UV reaction. In the presence of the NaCl, RhB decolorization of Ru/Ti DSA electrode was higher than that of the other photoelectrode and Ti electrode. Optimum current, NaCl dosage and UV lamp power of the electrolytic/UV process (using Ru/Ti electrode) were 0.75 A, 0.5 g/L and 16 W, respectively.

• Proceedings of the KIEE Conference
• /
• 1998.11c
• /
• pp.801-803
• /
• 1998

We investigated Pt and $RuO_2$ as a bottom electrode and PZT thin film for ferroelectric applications. XRD examination shows that a mixed phase of (111) and (200) Pt peak for the temperature ranged from RT to $200^{\circ}C$, and a preferred (111) orientation for the substrate temperature of $300^{\circ}C$. From the XRD and AFM results, we recommend the substrate temperature of $300^{\circ}C$, 80 W for the Pt bottom electrode growth. From the study of an oxygen partial pressure from 0 to 50%, we learned that only Ru metal was grown with $0{\sim}5%$, a mixed phase of Ru and $RuO_2$ for $10{\sim}40%$, pure $RuO_2$ at 50%. Having optimized the bottom electrode growth conditions, we employed two step process in PZT film capacitor: PZT film growth at the low substrate temperature of $300^{\circ}C$ and then post RTA anneal treatments. PZT films were randomly oriented on $RuO_2$ and (110) preferentially oriented on Pt electrode. Leakage current density of PZT film demonstrated two to three orders higher for $RuO_2$ bottom electrode. From C-V results we observed a dielectric constant of PZT film higher than 1200. This paper presents the optimized process conditions of the bottom electrodes and properties of PZT thin films on these electrodes.

• Corrosion Science and Technology
• /
• v.2 no.5
• /
• pp.238-242
• /
• 2003

The characteristics of Ru etching using $O_2/Cl_2$ plasmas were investigated by employing inductively coupled plasma (ICP) etcher. The changes of Ru etch rate, Ru to $SiO_2$ etch selectivity and Ru electrode etching slope with the gas flow ratio, bias power, total gas flow rate, and source power were scrutinized. A high etching slope (${\sim}86^{\circ}$) and a smooth surface after etching was attained using $O_2/Cl_2$ inductively coupled plasma.