Accelerated Service Life Tests Research Articles

One-step synthesis of Pt-Nd co-doped Ti/SnO2-Sb nanosphere electrodes used to degrade nitrobenzene.

Ti/SnO2-Sb electrodes possess high catalytic activity and efficiently degrade nitrobenzene (NB); however, their low service life limits their wide application. In this study, we used one-step hydrothermal synthesis to successfully prepare Pt-Nd co-doped Ti/SnO2-Sb nanosphere electrodes. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were applied to characterize the surface morphology, microstructure, and chemical composition of the electrodes, respectively. The electrochemical activity and stability of the electrodes were characterized via linear sweep and cyclic voltammetry, electrochemical impedance spectroscopy, and an accelerated service life test; their performance for NB degradation was also studied. An appropriate amount of Pt-Nd co-doping refined the average grain size of SnO2 and formed a uniform and compact coating on the electrode surface. The oxygen evolution potential, total voltammetric charge, and electron transfer resistance of the Ti/SnO2-Sb-Nd-Pt electrodes were 1.88 V, 3.77 mC/cm2, and 11.50 Ω, respectively. Hydroxy radical was the main active radical species during the electrolytic degradation of nitrobenzene with Ti/SnO2-Sb-Nd-Pt. After Pt-Nd co-doping, the accelerated service life of the electrodes was extended from 8.0 min to 78.2 h (500 mA/cm2); although the NB degradation rate decreased from 94.1 to 80.6%, the total amount of theoretical catalytic degradation of NB in the effective working time increased from 17.4 to 8754.1 mg/cm2. These findings reveal good application potential for the electrodes and provide a reference for developing efficient and stable electrode materials.

Bimetal-oxide (Fe/Co) modified bagasse-waste carbon coated on lead oxide-battery electrode for metronidazole removal

Current study covers the preparation and application of a commercial modified lead oxide battery electrode (LBE) in electrochemical oxidation (ECO) of metronidazole (MNZ) in an aqueous phase. Modified electrode is prepared by doping of bimetal-oxide (Fe and Zn) nanoparticles (NPs) & single metal-oxide (Fe/Zn) on bagasse-waste carbon (bwc) which is further coated on LBE. The modified LBE electrode surface was examined for metal-oxide NPs through X-ray diffraction analysis (XRD). Different electrodes are prepared by varying combinations of two metal-oxide based on molar ratio and tested for electrochemical characterization and MNZ removal test. Based on large oxygen evolution potential in a linear sweep volumetry (LSV) analysis and high MNZ removal rate, the best electrode has been represented as Fe1:Co2-bwc/LBE which contains Fe & Co molar ratio of 1:2. Moreover, equilibrium attained at faster rate in degradation process of MNZ, where pseudo first order kinetics of 2.29 × 10−2 min−1 was obtained under optimized condition of (MNZ:100 mg/L, pH:7, CD: 30 mA/cm2 and electrolyte: 0.05 M Na2SO4). Maximum MNZ removal, total organic carbon removal (TOC), mineralization current efficiency (MCE) & energy consumption (EC) of 98.7%, 85.3%, 62.2% & 96.143 kW h/kg-TOC removed are found in 180 min of treatment time for Fe1:Co2-bwc/LBE electrode. Accelerated service life test confirms that the stability of modified electrode is enhanced by 1.5 times compared to pristine LBE. Repeatability test confirms that modified LBE (Fe1:Co2-bwc/LBE) can be utilized up to 3 times.

Fabrication of tubular porous titanium membrane electrode and application in electrochemical membrane reactor for treatment of wastewater

In this study, tubular titanium membrane (TTM) /SnO2-Sb/SnO2-Sb-CeO2 porous anode was fabricated and used in continuous tubular membrane reactor for electrochemical treatment of dye wastewater. X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) were used to evaluate the morphology and microstructure of the different tubular titanium membrane. Linear sweep voltammetry (LSV) and accelerated service life test are employed to illustrate the performance of TTM/SnO2-Sb/SnO2-Sb-CeO2 porous membrane electrode. It is found that TTM/SnO2-Sb/SnO2-Sb-CeO2 active layer on titanium membrane has compact microstructure, high over-potential for oxygen evolution (2.10V vs saturated calomel electrode). The effects of pore diameter, applied voltage and flow rate on the electro-catalytic property of the tubular porous electrode were investigated. Study shows titanium membrane reactor with an optimized pore diameter of 10μm has the lowest energy consumption which is important for the practical application of electrochemical technology. The performance of titanium tubular membrane reactor is investigated by treating methylene blue (MB) wastewater under the cell voltage of 3.0–4.5V and the flow rate of 2.5–3.5Lmin−1. This continuous titanium membrane electrochemical reactor using solar cell show excellent performance in treating dye wastewater and the further potential application in electrochemical synthesis.

Effects of IrO2 interlayer on the electrochemical performance of Ti/Sb-SnO2 electrodes

Abstract In this work, the Ti/Sb-SnO2 and Ti/IrO2/Sb-SnO2 electrodes have been successfully fabricated by coating pyrolysis method. The effects of introducing IrO2 interlayer were analyzed systematically by X-ray diffraction (XRD), scanning electron microscopy (SEM), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and accelerated service life test. Our results showed that the presence of IrO2 interlayer on the Ti substrate promoted the electrodes' property effectively. In contrast with the traditional Ti/Sb-SnO2 electrode, Ti/IrO2/Sb-SnO2 electrode possesses smaller grains and more compact morphology structure. Then the changes of oxygen evolution potential (OEP) and charge transfer resistance (Rct) on the electrodes were discussed. Anodic stability test results showed that the introduction of IrO2 interlayer in the oxide coating produced a significant increase in stability. The accelerated service life of Ti/IrO2/Sb-SnO2 electrode was almost 30 times longer than that of Ti/Sb-SnO2 electrode.

Microwave synthesis of Ti/(RuO2)0.5(IrO2)0.5 anodes: Improved electrochemical properties and stability

Abstract The efficiency of electrochemical technology in treating water contaminated by complex organic pollutants has been widely investigated. Notwithstanding, it is still necessary to develop technologies capable of producing efficient and economically viable electrodes. In this context, the electrochemical oxidation using mixed metal oxide (MMO) anodes is a promisor alternative for wastewater treatment. However, the production of these anodes through thermal decomposition in electric furnaces demands a lot of production time. Here, we report an innovative method based on hybrid microwave irradiation to produce MMO anodes of Ti/(RuO2)0.5(IrO2)0.5 composition. The developed method uses simple apparatus and is faster than other conventional methods, thus decreasing the production costs. The anodes prepared at different calcination temperatures (300, 350, and 400 °C) using microwaves irradiation were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, cyclic voltammetry, electrochemical impedance spectroscopy, and accelerated service life tests. Besides, the results were compared with those obtained using the conventional heating method. The microwave-produced anodes calcined at 350 °C have the longest service lifetime, which is estimated as 15 years, which is 3.5-fold more than the conventionally made anodes. In addition, this anode has improved electrochemical performance when compared with the conventionally prepared anodes, showing the highest voltammetric charge (1.6-fold). Moreover, this anode removes 100% of color and 64% of TOC after 60 min of electrolysis of the model molecule methylene blue dye. Therefore, the developed method allows for producing materials with improved electrocatalytic properties and enhanced stability at short synthesis times.

Influence of the reactor configuration and the supporting electrolyte concentration on the electrochemical oxidation of Atenolol using BDD and SnO2 ceramic electrodes

Electrochemical oxidation of β-blocker atenolol (ATL, 100 ppm) at different applied current densities (33, 50 and 83 mA·cm−2) using a reactor divided by an ion-exchange membrane and an undivided one was investigated. Two types of anodes were used for this purpose: a boron-doped diamond (BDD) anode and new low-cost ceramic electrodes made of tin dioxide doped with antimony (Sb-doped SnO2). Degradation was assessed using a high performance liquid chromatography, while mineralization by measuring total organic carbon (TOC) dissolved in sample. Except for the lowest current density, ATL was completely degraded for both reactors and electrodes. The highest percentage of TOC eliminated (89%) was obtained at the highest applied current density with the BDD electrode in the divided reactor. The presence of the cation-exchange membrane prevented the reduction of both the electrogenerated oxidizing species and the oxidized organic compounds and enhances the electro-oxidation kinetic reaction.In order to study the influence of the supporting electrolyte, three different concentrations of sodium sulfate (0.014, 0.05 and 0.1 M) were tested in the undivided reactor with both electrodes. The results showed that an increase in the concentration of the supporting electrolyte improves the mineralization of ATL for the BDD electrode and, on the contrary, worsens for the ceramic electrode. Accelerated service life tests were carried out for the ceramic electrode at 100 mA·cm−2 in 0.5 M H2SO4. Ecotoxicity tests using marine bacteria (Vibrio Fischeri) revealed that no toxic by-products were formed in any case.

Nanotubes TiO2 supported Pt catalyst for selective electrocatalytic oxidation of glycerol to glyceric acid

ABSTRACT Highly ordered nanotubes titanium dioxide (NTs-TiO2) array was fabricated and used as the support of Pt nanoparticles for the selective aqueous phase of glycerol (GLY) electrooxidation. The structure and morphology of the NTs-TiO2/Pt were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, etc. The electrooxidation GLY properties of NTs-TiO2/Pt were investigated by cyclic voltammetry, linear sweep voltammetry, and accelerated service life test. The results show that, compared with bulk Pt and nano-TiO2/Pt, the NTs-TiO2/Pt have the highest service life and electrooxidation activity and selection for GLY. At the reaction condition of 1.2 V potential, the NTs-TiO2/Pt catalyst afforded 67.1% selectivity for the glyceric acid.

Anodic oxidation of diuron using Co3O4/graphite composite electrode at low applied current

Economical and highly performed anode material is the critical factor affecting the efficiency of anodic oxidation toward organics. In this work, the graphite felt, a common carbonaceous electrode material, is etched by cobalt oxide to fabricated Co3O4/graphite composite anode to eliminate diuron in aqueous solution. The surface morphology, composition and structure of the Co3O4/graphite composite anode are characterized by scanning electron microscope, X-ray photoelectron spectroscopy and X-ray diffraction. Low-current degradation of diuron is achieved in an anodic oxidation process using Co3O4/graphite composite anode. The influence of the applied current density, initial pH value and initial concentration of diuron on the oxidation efficiency are investigated and optimized. The prepared Co3O4/graphite composite anode exhibited excellent activity for oxidation of 20 mg L−1 diuron, obtaining 100% removal efficiency within 14 min under the condition of applied current density 3 mA cm−2 and initial pH 2.0. The process is confirmed to possess a non-radical mechanism in which the diuron is oxidized at the catalytic sites of composite anode under the synergy effect of Co3O4/graphite composite and anodic current. The accelerated service life test proved good electrochemical stability of the prepared Co3O4/GF composite electrode. The low energy demand and use of cheap graphite substrate endow the anodic process based on Co3O4/graphite composite anode in this work with great application prospect to effective removal of diuron.

Corrected accelerated service life test of electrodeposited NiSn alloys and Ni as cathodes for industrial alkaline water electrolysis

The ?corrected accelerated service life test for hydrogen evolution reaction? (CASLT-HER), designed for application of certain electrode materials as cathodes in the cell for alkaline water electrolysis in 30 % KOH at 80 ?C, was performed at electrodeposited NiSn alloy and Ni 40 mesh electrodes. The Ni 40 mesh was slightly etched, while the NiSn alloy coating was electrodeposited from the bath containing pyrophosphate, glycine, SnCl2 and NiCl2 onto Ni 40 mesh to the thickness of approximately 40 ?m. It is shown that the NiSn cathode possess from maximum 0.77 V to minimum 0.30 V better overpotential than the Ni 40 mesh electrode during the 5 years of their exploitation at the conditions of industrial alkaline water electrolysis. It is also shown that both electrodes should be held at j = ?0.3 A cm-2 for at least 5 h in order to establish stable overpotential response. The limiting overpotential values for applying cyclic voltammetry (CVs, to mimic ?polarity inversion?) should be determined in a separate experiment before the CASLT-HER and should be adjusted during the application of CVs.

Efficient rhodamine B degradation using electro‐fenton process with PbO2‐coated titanium as the anode

To replace the high cost Pt anode, Ti based PbO2 electrode (PbO2‐Ti) and Ti based SnO2 doped with Sb electrode (SnO2/Sb‐Ti) were fabricated and compared for treating 0.1 mM Rhodamine B (RhB) in Electro‐Fenton (EF) process. Scanning electron microscopy, energy dispersive X‐ray, X‐ray diffraction spectrometry were carried out to study the surface morphology, element composition, and substance composition of the anodes (PbO2‐Ti and SnO2/Sb‐Ti). Linear Sweep Voltammetry, cyclic voltammetry, Tafel, and electrochemical impedance spectroscopy were conducted to examine the electrochemical properties of the anodes (Pt, PbO2‐Ti, SnO2/Sb‐Ti, and Ti). These assessments showed that PbO2‐Ti had the best performance. Then, the influence of varied parameters (pH, types of anodes, current density, and electrolyte) were explored. Almost complete decolorization (99.01%) was reached at pH 3, current density 50 A/m2, 0.05 M Na2SO4 using PbO2‐Ti as the anode after 20 min electrolysis. Under these conditions, 90.48% of total organic carbon was removed after 180 min. Finally, the durability of PbO2‐Ti was evaluated via accelerated service life test and exhibited long service lifetime (∼4000 h). © 2018 American Institute of Chemical Engineers Environ Prog, 38: 189–197, 2019

Accelerated service life test of electrodeposited NiSn alloys as bifunctional catalysts for alkaline water electrolysis under industrial operating conditions

Electrodeposited NiSn alloy coatings onto Ni 40mesh substrate were tested for application as cathodes and anodes in the cell for alkaline water electrolysis in 30wt% KOH at 80°C. The “accelerated service life test” (ASLT) was performed for the hydrogen evolution reaction (HER), as well as for the oxygen evolution reaction (OER), and compared to that recorded for the Ni coating (Ni-dep) and Ni-mesh for both reactions. The morphology and chemical compositions of the NiSn and Ni coatings were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), while their surface composition was investigated by X-ray photoelectron spectroscopy (XPS) before and after the ASLT for both reactions, respectively. By measuring the potential at j=0.3Acm−2 it was shown that during the ASLT the NiSn alloy coating catalytic activity for the HER decreases (about 24mV after 25cycles), while the catalytic activity for the OER increases (about 50mV after 25cycles), so that the cell voltage decreases for about 26mV. The Ni-dep and Ni-mesh electrodes catalytic activity was found to increase for the HER (for about 103mV), as well as for the OER (for about 52mV) during the ASLT. Hence, the cell voltage for the Ni-dep and Ni-mesh electrodes decreased from 2.402V to 2.245V during the ASLT, while that for the NiSn electrode decreased from 1.967V to 1.941V. The cell voltage saving with the NiSn electrodes amounts to about 435mV before the ASLT and about 304mV after the ASLT. SEM results showed that no changes in the morphology of as prepared samples could be detected after the ASLTs for both reactions. EDS analysis confirmed that some changes occurred during the ASLT, particularly for the oxygen content in the surface layer. Similar conclusions were made from the XPS analysis.

Effect of SnO2 intermediate layer on performance of Ti/SnO2/MnO2 electrode during electrolytic-manganese process

SnO2 intermediate layers were coated on the titanium (Ti) substrate by thermal decomposition. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that uniform SnO2 intermediate layers with rutile crystal structure were successfully achieved. According to the results of linear sweep voltammetry (LSV), oxygen evolution potential (OEP) of the Ti/SnO2/MnO2 electrodes decreases with increasing SnO2 content, indicating that the electro-catalytic oxidation activity of the electrode increases. Accelerated service life tests results demonstrate that SnO2 intermediate layer can improve the service life of the Ti/SnO2/MnO2 electrode. As the content of SnO2 intermediate layer increases, the cell voltage and the energy consumption decrease apparently.

Improvement of electrochemical performance of tin dioxide electrodes through manganese and antimony co-doping

Manganese (Mn) and antimony (Sb) co-doping tin dioxide (SnO2) electrodes with low impedance and high electrochemical stability were successfully fabricated by coating pyrolysis method. The electrodes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), linear sweep voltammetry (LSV), and accelerated service life test. The Ti/Mn-Sb-SnO2 electrodes with 6at.% Mn doped exhibited the best stability in accelerated service life test. The accelerated service life of Ti/Mn-Sb-SnO2 electrode was 7 times longer than that of Ti/Sb-SnO2 electrode. We also calculated the optimal geometry structure and bandstructure of Mn-doping SnO2 by using the first principle method, and the bandgap of SnO2 was narrowed after introducing Mn ion. The X-ray diffraction patterns (XRD) showed the deterioration of crystallinity and crystal lattice shrinkage with increasing in Mn-doping concentration. Furthermore, we provided some different coating models for preparing of Ti/Sb-X electrodes or other double dopants coating techniques.

Microrod structure and properties of Sb-doped Ti/SnO2 anodes prepared by magnetron sputtering

Cyclic voltammetry and chronopotentiometry have been used to study the Sb-doped Ti/SnO2 anodes prepared by magnetron sputtering. The results showed that magnetron sputtering condition influenced the surface morphology and the properties of the anodes. After the Ti substrate was tempered in Ar at 600 °C for 1h, TiH1.5 on the surface generated from the acid etching was replaced by needle-like TiO2. The SnO2 coating on the above Ti substrate by magnetron sputtering with post-annealing was comprised of microrod and different with the traditional Ti/SnO2 anode. The accelerated service life test showed that the microrod SnO2 anode gained the longest service time. The anode exhibited oscillations in the chronopotentiometry curves, and the microrod SnO2 coating almost dissolved after the life test. A model of layer-by-layer degradation mechanism for the anode was proposed.

Effect of electrolysis temperature on surface morphology and stability of Ti/RuO2–IrO2–SnO2 anode

The effect of electrolysis temperature on the surface morphology and stability of a Ti/RuO2–IrO2–SnO2 anode was studied using scanning electron microscopy, energy dispersed X-ray spectroscopy and an accelerated service life test. It has been shown that when the electrolysis temperature is 5 and 10°C, almost no active coating exists in the edge of the deactivated anode, but a few active components remain in the centre area, and the cell voltage is very high in the initial stages of electrolysis, resulting in worse stability. With the increasing electrolysis temperature, the anode coatings wear down uniformly, and the stability is improved when comparing to the results obtained with a low electrolysis temperature (5 and 10°C).

Preparation and characterization of carbon nanotube and Bi co-doped PbO2 electrode

A novel carbon nanotube and Bi co-doped PbO2 electrode (CNT-Bi-PbO2) was prepared by thermal deposition and electrodeposition technologies. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were used to characterize the surface morphology and crystal structure of the electrodes. In contrast with PbO2, Bi-PbO2, and CNT-PbO2 electrodes, the CNT-Bi-PbO2 electrode had smaller crystal particles and more compact structure. The linear voltammetry was utilized to determine the oxygen evolution overpotential of electrodes. The electro-catalytic activity of electrodes was investigated by cyclic voltammetry. The yield of ·OH and electro-catalytic oxidation degradation of p-nitrophenol (p-NP) at four kinds of electrodes were tested. Besides, the stability of electrodes was also determined by accelerated service life tests. The results show that the prepared CNT-Bi-PbO2 electrode had higher oxygen evolution overpotential and more excellent electrochemical oxidation performance than other three kinds of electrodes. The reaction rate constant of p-NP on the CNT-Bi-PbO2 electrode was 1.69 times and the mineralization current efficiency at 180min on CNT-Bi-PbO2 electrode was 1.36 times that on PbO2 electrode. Moreover, the service lifetime of CNT-Bi-PbO2 electrode was 4.16 times as much as that of PbO2 electrode.

Comparison of electrocatalytic characterization of boron-doped diamond and SnO2 electrodes

Boron-doped diamond (BDD) and SnO2 electrodes were prepared by direct current plasma chemical vapor deposition (DC-PCVD) and sol–gel method, respectively. Electrochemical characterization of the two electrodes were investigated by phenol electrochemical degradation, accelerated service life test, cyclic voltammetry (CV) in phenol solution, polarization curves in H2SO4. The surface morphology and crystal structure of two electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The results showed a considerable difference between the two electrodes in their electrocatalytic activity, electrochemical stability and surface properties. Phenol was readily mineralized to CO2 at BDD electrode, favoring electrochemical combustion, but its degradation was much slower at SnO2 electrode. The service life of BDD electrode was 10 times longer than that of SnO2. Higher electrocatalytic activity and electrochemical stability of BDD electrode arise from its high oxygen evolution potential and the physically absorbed hydroxyl radicals (OH) on electrode surface.

Modelling of conditions for accelerated lifetime testing of Humidity impact on PV-modules based on monitoring of climatic data

Water is considered as an important degradation factor for PV-modules by causing hydrolysis of polymeric components, corrosion of glass and of metallic components like grids and interconnectors. The type approval testing of PV-modules according to the IEC standards takes water into account by means of the so called Damp-Heat test and the Frost-Thaw test. The test-conditions were designed long time ago and initially meant to reflect the service life of a module, but the type approval testing is not applicable for prediction of long-term durability behaviour, but a qualification test for the assurance of a minimum quality level.Basically absorption and mass transport of water into and within the module has to be considered. These phenomena depend on the ambient climate of the PV-module in use, the design (back-sheet, glass-glass, all polymer, e.g.), the operation conditions (rack-mounted, on rooftop, building integrated) and the material composition. We try to evaluate test conditions that are primarily based on the stresses occurring during the operation at specific locations by using monitored climatic data and applying phenomenological models for the estimation of the moisture load at the surfaces of PV-modules as function of the module temperature. A simple time transformation function was used for the design of appropriate damp-heat tests as accelerated service life tests. The evaluated testing times differ up to an order of magnitude for different climatic locations, depending on the kinetics of the dominant degradation processes.

Preparation and characterization of TiO 2-NTs/SnO 2-Sb electrodes by electrodeposition

The novel Sb-doped SnO 2 electrodes (TiO 2-NTs/SnO 2-Sb) have been prepared by anodization, electrodeposition and annealing. TiO 2 nanotubes (TiO 2-NTs) after Sb and Sn electrodeposited were characterized using field-emission scanning electron microscopy (FE-SEM). In contrast with the traditional Sb-doped SnO 2 coating prepared by thermal decomposition, the Sb-doped SnO 2 coating prepared by electrodeposition processes show more compact. X-ray diffraction (XRD) analysis indicates that the Sb-doped SnO 2 coating prepared by electrodeposition processes are firmly combined with the TiO 2-NTs formed on the Ti substrate. Accelerated service life tests reveal that the electrodeposition processes enhance the electrochemical stability of the Sb-doped SnO 2 electrode. The cyclic voltammetry analysis shows that TiO 2-NTs/SnO 2-Sb electrodes have higher overpotential for oxygen evolution and higher electrochemical porosity. Besides, the enhanced stabilization mechanism of the TiO 2-NTs/SnO 2-Sb electrode prepared by electrodeposition processes has been studied.

Study on the service life and deactivation mechanism of Ti/SnO2-Sb electrode by physical and electrochemical methods

The Sb doped tin dioxide electrode (Sb-doped SnO2) inter-layer was prepared using electroposition layer-by-layer onto a titanium plate, and the Sb-doped SnO2 surface catalytic layer (Ti/SnO2-Sb) was prepared using thermo-decomposition method. Accelerated service life tests were carried out in 0.5 M H2SO4 solution and 1.0 M NaOH solution, respectively. The deactivation mechanism of the electrodes is studied using oxygen evolution reaction (OER) as the reaction mode. Cyclic voltammetry test showed that the electrodes after accelerated life tests had no catalytic-oxidizing activity upon phenol. Electrochemical impedance spectroscopy (EIS) analysis exhibited that the membrane resistance of the deactivated electrode increases obviously in 0.5 M H2SO4 solution and 1.0 M NaOH solution, with the values of 1231 and 90.6 Ω, respectively. The structure, morphology and the content of the fresh and deactivated electrode were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray detector (EDX). This suggested that the Ti content on the electrode surface increases after deactivation, and TiO2 membrane with poor conductivity is grown on the electrode surface.