• Bulletin of the Korean Chemical Society
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• v.28 no.3
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• pp.439-442
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• 2007

A solid state Hg(Au)/HgO reference electrode was prepared utilizing gold amalgam solid particles. Solid fine powder of the gold amalgam was prepared by chemical reduction of Au(III) with NaBH4 followed by reduction of Hg(II) in the presence of gold fine particles. The solid content in the suspension of the gold amalgam particles and fine mercury oxide particles in DMF containing PVC was precipitated by the addition of a large amount of water to give solid Hg(Au)/HgO/PVC mixture. After drying, the mixture was pressure-molded to a physically stable Hg(Au)/HgO composite reference electrode material. The electrochemical characteristics of the electrode as a reference electrode were very similar to an ordinary Hg/HgO reference electrode. The electrode material can be molded and fabricated in any desired shape and size. The surface can be renewed by a simple polishing process whenever contaminated or deactivated. The applicability of the electrode in the electrochemical detection of carbohydrates after anion exchange separation was evaluated.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3128-3132
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• 2010

A disposable solid-state pH sensor was realized by utilizing two nanoporous Pt (npPt) electrodes and a copolyelectrolytic junction. One nanoporous Pt electrode was to measure the pH as an indicating electrode (pH-IE) and the other assembled with copolyelectrolytic junction was to maintain constant open circuit potential ($E_{oc}$) as a solid-state reference electrode (SSRE). The copolyelectrolytic junction was composed of cationic and anionic polymers immobilized by photo-polymerization of N,N'-methylenebisacrylamide, making buffered electrolytic environment on the SSRE. It was expected to make. The nanoporous Pt surrounded by a constant pH excellently worked as a solid state reference electrode so as to stabilize the system within 30 s and retain the electrochemical environment regardless of unknown sample solutions. Combination between the SSRE and the pH-IE commonly based on nanoporous Pt yielded a complete solid-state pH sensor that requires no internal filling solution. The solid state pH sensing chip is simple and easy to fabricate so that it could be practically used for disposable purposes. Moreover, the solid-state pH sensor successfully functions in calibration-free mode in a variety of buffers and surfactant samples.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.57-58
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• 2022

Reinforced concrete (RC) structures play a significant role in the construction industries. An embeddable solid-state reference electrode (ESSRE) was used to evaluate the corrosion status of steel rebar in the concrete of various cover thicknesses that exposed to the maritime environment (3.5 % NaCl) in this study. From the open circuit potential measurement (OCP), the passive state, the corrosion uncertainty, and the 90% probability of corrosion state of the steel rebars in the concrete were monitored by ESSRE. From the electrochemical impedance spectroscopy (EIS) method, severe corrosion was observed at the exposure period of 1510, 1847, 2350, and 3020 h for C10, C15, C20, and C30 concrete, respectively. The results confirm that the ESSRE can be useful to identify the corrosion occurrence and severe corrosion of steel rebar embedded in different cover depth concrete structures.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.50-57
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• 2016

According to the urban gas business legislation, cathodic protection systems should be applied for buried steel gas pipelines to prevent corrosion. In advanced countries including United States, the criteria for Cathodic Protection Potential is at least -850mV with respect to a saturated copper/copper sulfate electrode(CSE) when the CP applied, and the IR drops must be considered for valid interpretation. However, the IR drop through the pipe to soil boundary has been neglected in Korea. According to KGS code, a reference electrode must be placed in proximity to gas pipelines possible when measuring the CP potential. In this study, we have installed several solid reference electrodes around the buried pipeline(1.2m depth), lower surface(0.5m depth), and the surface individually in order to measure the CP potentials through the each reference electrode and find out the IR drops according to the location of each reference electrode. We have found the IR drop is the greatest when measuring the CP potential through the electrode placed on the ground and the IR drop is the smallest through the electrode installed near pipeline. Therefore, we have suggested the solid reference electrode should be installed as close as possible to buried pipeline in order to measure the correct CP potential without IR drop. We have also suggested the amendment of CP criteria considering IR drop.

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.11a
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• pp.69-71
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• 1993

Fluoride compound potentiometric cell oxygen sensors were fabricated for the measurement of oxygen pressure in the low temperature range (300。K-500。K). The disk type sensors consist of a reference Air(0$_2$):Ag, a solid electrolyte SrF$_2$, and a sensing metel Ag electrode. And the buried reference electrode type sensor have a NiO/Ni reference electrode. The open circuit emf of the cell showed high sensivity to oxygen gas (60mv) at the measuring temperature 20$0^{\circ}C$. Also, The buried reference electrode type sensor showed 30mv from 1% to 10% oxygen pressure range.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.177-180
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• 2006

This study is to make a basic study if solid zinc (Zn) can be used for buried reference electrode, so we examined the adequacy of zinc as reference electrode by using zinc which showed regular electrode for buried period. The deference of electric potential if zinc electrode for corrosion factor such as soil resistivity or pH didn't show fixed trend and there was no clear trend on the change of measurement period. From field test, it is known that the natural electric potential difference of CSE electrode and zinc electrode is 1,100mV, but the electric potential of zinc electrode for CSE electrode in the natural soil and copying soil was 1,094~1,158mV. There was no fixed trend on the change of measurement period and electric potential difference of zinc electrode for corrosion factors such as soil resistivity or pH. Consequently, there was 40~60mV of electric potential difference in every copying soil during the experiment measurement.

• Journal of the Korean Ceramic Society
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• v.37 no.8
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• pp.817-823
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• 2000

A solid-state electrochemicall cell for sensing CO2 gas was fabricated using a solid electrolyte of Li2CO3-Li3PO4-Al2O3 mixture and a reference electrode of LiMn2O4. The e.m.f. (electromotive force) of sensor showed a good accordance with theoretical Nernst slope (n=2) for CO2 gas concentration range of 100-10000 ppm above 35$0^{\circ}C$. The e.m.f. of sensor was constant regardless of oxygen partial pressure at the high temperature above 0.1 atm. It was, however, a little depended on oxygen partial pressure as the pressure decreased below 0.1 atm. The oxygen-dependency of our sensor gradually disappeared as the operating temperature increased. The sensing behavior of our CO2 sensor was affected by the presence of water vapor, but its effect was small comparing with other sensors.

• Journal of Sensor Science and Technology
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• v.5 no.4
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• pp.25-34
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• 1996

A SOx sensor using NASICON electrolyte was developed for monitoring of air pollution. The following galvanic cell with $Na_{2}SiO_{3}(Pt)$ reference electrode was assembled : Pt | $Na_{2}SiO_{3}$ | NASICON | $Na_{2}SO_{4}$ | Pt, $SO_{2}$, air $Na_{2}SO_{4}$ was used as an indicator electrode to protect NASICON electrolytes from chemical reaction with $SO_{2}$. The EMFs were measured after injecting $SO_{2}$ in the initial concentrations range of $5{\sim}95ppm$ at $400{\sim}550^{\circ}C$. The measured and calculated potentials were in good agreement above $500^{\circ}C$. However, the cells were unstable below $500^{\circ}C$, most likely due to incomplete attainment of chemical equilibrium. Response time was within 10 min. Based on the stability and response time of this cell, the NASICON solid electrolyte with $Na_{2}SiO_{3}(Pt)$ as the reference electrode and $Na_{2}SO_{4}$ (Pt)as the indicator electrode showed the possibility of a reliable, inexpensive commercial solid-state SOx sensor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.912-917
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• 2007

Many electrochemical power devices such as solid state batteries and solid oxide fuel cell have been studied and developed for solving energy and environmental problems. An amperometric gas sensor usually generates sensing signal of electric current along the proportion of the concentration of target gas under the condition of limiting current. For narrow variations of gas concentration, the amperometric gas sensor can show higher precision than a potentiometric gas sensor does. In additional, cross sensitivities to interfering gases can possibly be mitigated by choosing applied voltage and electrode materials properly. In order to improve the sensitivity to $NO_2$, the device was attached with Au reference electrode to form the amperometric gas sensor device with three electrodes. With the fixed bias voltage being applied between the sensing and counter electrodes, the current between the sensing and reference electrodes was measured as a sensing signal. The response to $NO_2$ gas was obviously enhanced and suppressed with a positive bias, respectively, while the reverse current occurred with a negative bias. The way to enhance the sensitivity of $NO_2$ gas sensor was thus realized. It was shown that the response to $NO_2$ gas could be enhanced sensitivity by changing the bias voltage.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.281-282
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• 2023

The solid-state reference electrodes made of polyaniline-coated MnO₂ (SSRE-PAM) and their electrochemical characteristics were studied in simulated concrete pore solutions (SCPS) containing 0 and 3.5% NaCl. Saturated calomel electrodes (SCE) have been used to conduct electrochemical studies on the stability behavior of SSRE-PAM. Open circuit potential (OCP) and potentiodynamic polarization techniques were used to assess the corrosion performance of steel rebar exposed in SCPS with 0 and 3.5% NaCl using SSRE-PAM. The results demonstrate that the SSRE-PAM was capable of identifying steel rebar in a concrete environment that was either passive or active. Potentiodynamic polarization parameters such as E_corr and I_corr for steel rebar in SCPS containing 0 and 3.5%)NaCl are greater than that of the passive condition (0% NaCl). All the studies validate the importance of using SSRE-PAM for corrosion monitoring applications in concrete structures.