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The titania pulp—a semi product received from the industrial production of titania white—was submitted for the thermal heating at 400–600 °C under Ar and H2 to obtain TiO2 with different structure and oxygen surface defects. Heating of titania in H2 atmosphere accelerated dehydration and crystallisation of TiO2 compared to heating in Ar. TiO2 prepared at 500 and 600 °C under H2 had some oxygen vacancies and Ti3+ centres (electron traps), whereas TiO2 obtained at 450 °C under H2 exhibited some hole traps centres. The presence of oxygen vacancies induced adsorption of atmospheric CO2. It was evidenced, that ethylene reacted with TiO2 after UV irradiation. Formic acid was identified on TiO2 surface as the reaction product of ethylene oxidation. Hydroxyl radicals were involved in complete mineralisation of ethylene. TiO2 prepared at 500 °C under H2 was poorly active because some active sites for coordination of ethylene molecules were occupied by CO2. The most active samples were TiO2 with high quantity of OH terminal groups. At 50 °C, the physically adsorbed water molecules on titania surface were desorbed, and then photocatalytic decomposition of ethylene was more efficient. TiO2 with high quantity of chemisorbed OH groups was very active for ethylene decomposition. The acidic surface of TiO2 enhances its hydroxylation. Therefore, it is stated that TiO2 having acidic active sites can be an excellent photocatalyst for ethylene decomposition under UV light.

We demonstrate amyloid fibril (AF) decomposition induced by NIR-active upconversion nanoparticles complexed with photosensitisers. The process is triggered by upconversion, which initiates a photochemical reaction cascade that culminates in the generation of the highly reactive singlet-oxygen product 1O2 close to the amyloid superstructures, resulting in AF decomposition.

This research was conducted in cooperation with the Ban San Bun Reung Community Enterprise Group, which produces and distributes common clay bricks throughout northern Thailand. The ongoing aim is to develop thermal–acoustic fired clay bricks. In this study, charcoal was selected as an additive during brick manufacture owing to the ease with which its particle size can be reduced and its tendency to burn out during firing. Four different sizes of charcoal, namely, large (2 mm), medium (1 mm), small (0.5 mm), and fine (0.04 mm), were investigated. The charcoals were added to the clay mixture in various amounts, such as 0, 5, 15, and 30 wt%. The extruded brick specimens were then fired at 900, 1000, or 1100 °C, and their physical, mechanical, thermal, and acoustic properties, mineralogical composition, and microstructure were examined. Subsequently, linear regression and multiple linear regression analyses were applied to model the relationships between the brick properties and one or more explanatory variables. The results obtained revealed that the mechanical properties of the fired clay bricks improved with increasing firing temperature owing to the formation of the mullite phase. However, the mechanical properties rapidly deteriorated as the proportion and size of the charcoal additive were increased. The linear and multiple linear regression analyses demonstrated that the physical properties were correlated with the other properties evaluated in this study. In terms of the physical and mechanical properties, the use of 15 wt% of small charcoal and firing temperature of 1100 °C were the optimal conditions for manufacturing clay bricks satisfying the Thai Industrial Standard. In contrast, the use of 30 wt% of large charcoal and firing temperature of 1100 °C afforded lower thermal conductivity and a higher sound absorption coefficient owing to the more porous nature of the resulting bricks. The current production cost and sale price of traditional clay bricks are 53.58 and 264 THB m−2, respectively. When added with charcoal, the price increases to 55.17, but we expect that thermal–acoustic bricks could attract a higher price.

This study focuses on the application of the ensemble averaging (EA) method that uses a pressure–velocity sensor (pu-sensor) to measure the sound absorption coefficient of porous clay bricks. It investigates factors including sample sizes, positions, and material properties of the porous clay bricks. The samples used in this study were produced from local red clay in Lampang, Thailand, whereby 2 mm charcoal was added to the mixture at a ratio of 30 wt%. Subsequently, the samples were formed by hydraulic pressing at 50 kN and were fired at 1100 °C. Testing was conducted in a reverberation room, whereby the selected frequency used was 100–3000 Hz. The validation found that the EA method with pu-sensor (EApu method) is applicable for the measurement of porous clay bricks. Samples of 30-cm square or larger are sufficient for the EApu method, and the optimum measurement position is at the center of the sample which presented small standard deviations. Sound absorption coefficients measured at positions far away from the center are in higher values. At 100–800 Hz, the sound absorption coefficient values are similar across every sample, despite the samples having different physical properties. On the other hand, the sound absorption coefficient, when observed with a frequency of over 1000 Hz, shows a clear difference. Moreover, the correlation indicates that the bulk density is an essential factor for porous clay bricks, as made evident by its high correlation value of 0.92.

We investigated the oxidative reforming (OR) of n -C 4 H 10 over Ni/CeO 2 catalysts with different amounts of Ni loading at ambient temperature by feeding a reaction mixture. The OR of n -C 4 H 10 was triggered rapidly over all the Ni/CeO 2 catalysts reduced at 1073 K. O 2 absorption at 323 K revealed that the support was composed of CeO 1.76 regardless of Ni loading after reduction. We concluded that the heat produced by spontaneous oxidation of CeO 1.76 to CeO 2 heated the catalysts to catalytic autoignition temperature. Among the catalysts, 1 wt% Ni/CeO 2 exhibited durability against carbon deposition as well as excellent catalytic activity for OR in a cyclic activity test.

The sulfated zirconia project was carried out in order to obtain a broad understanding of the preparation, characterization, and application of the solid superacids of sulfated zirconia. The sulfated zirconia catalysts were prepared by the equilibrium adsorption method and the ammonium sulfate kneading method using the reference catalysts JRC-ZRO-2, -3, -4, and -5, supplied by the Reference Catalyst Division of the Catalysis Society of Japan. The catalysts were characterized by elemental analysis, NH 3 -TPD, XRD, TG-DTA, CO 2 -TPD, Raman spectroscopy, and measurements of the surface area, pore size distribution, coverage (by the BAT method), and heat of Ar adsorption. In order to compare the catalytic activities, we used the prepared catalysts in the isomerizations of butane and n -heptane, hydroisomerization of heptane, aldol condensation, acylation, esterification, and cracking of cumene. The sulfated zirconia prepared using JRC-ZRO-2 by the equilibrium adsorption method showed the highest activity and larger surface area. On the other hand, the kneading method provided catalysts with high reproducibility.

純粋なAlPO4は通常の沈殿法で調製すると1000°Cで空気焼成してもアモルファスで130 m2/g程度の大きな比表面積を持っている．これの焼成温度を上げてゆくと，1100°Cでは結晶子サイズが16 nm程度にやや結晶化して反応活性は向上し，1200°Cで焼成するとさらに結晶化が進行して活性は低下した．一方10 mol%のCeを添加したAlPO4触媒は，1000°Cで焼成したものが最高活性を示し，1100°Cで焼成した純粋なAlPO4と同程度に結晶化した．Ce添加触媒は1100°Cで焼成すると成分リン酸塩結晶がシンタリングし，活性は低下した．助触媒のCeはAlPO4の三次元networkを適度な大きさに切断することによって，純粋なAlPO4より100°C低い焼成温度でAlPO4の最適な結晶化状態を作り出していると結論した．両者をフロン濃度を高くして800°C，900°Cで加速劣化させたところ結晶化が進行してSSAは低下し，反応活性も低下した．比表面積ゼロに補外した活性（転化率50%になる温度）はAlPO4で587°C，Ce添加AlPO4触媒で467°Cであった．後者は比表面積が低下しても550°C程度で転化率100%となり，非常に長寿命な触媒であることが推定された．1000°Cで空気焼成したAlPO4を水蒸気で900°Cで処理すると，1100°Cで空気焼成したものと同程度に結晶化し，反応活性は上昇した．一方，Ceを添加したAlPO4触媒は1000°Cで8 h水蒸気処理してもCePO4の結晶のみがシンタリングし，AlPO4の結晶のシンタリングは抑制され，反応活性はやや上昇した．水蒸気処理はこれらの触媒の結晶化を少しだけ促進した．水蒸気処理すると長時間使用後は水蒸気処理を行わなかった場合に比べて活性が低下する可能性があることがわかった．塩素だけを含むCCl4，フッ素だけを含むCF4と両者を含むCCl2F2でAlPO4の加速劣化処理を行ったところ，CCl2F2の場合が最も結晶化が進行した．これはCCl2F2の分解ではAlとPの両元素について，昇華性を持つ塩化フッ化物が生成可能であることに起因すると推定した．

We report n -C 4 H 10 autothermal reforming over MgO-supported base metal catalysts at 723 K. Catalytic performance was investigated not only after H 2 treatment at 1073 K (reductive treatment) but also after subsequent O 2 /Ar treatment at the reaction temperature (oxidative treatment) to mimic the shutdown and startup of a domestic fuel cell system. After reductive treatment, both Ni/MgO and Co/MgO exhibited high n -C 4 H 10 conversion and hydrogen formation activity; the stability of Ni/MgO was better than that of Co/MgO. The reaction route was investigated by measuring activity at various contact times. The results revealed that n -C 4 H 10 autothermal reforming over Ni/MgO is a multi-step reaction composed of combustion, steam reforming, water gas shift reaction, and methanation. In contrast, Cu/MgO and Fe/MgO did not show reforming activity but cracking and combustion of n -C 4 H 10 . Ni/MgO and Co/MgO catalyzed H 2 formation even after the oxidative treatment. However, the initial activity of Co/MgO after the oxidative treatment was lower than that after the reductive treatment and a decrease in H 2 formation rate was again observed after 6 h in Co/MgO, similar to the measurements after the reductive treatment.

Lanthanum phosphate was prepared in the presence of citric acid and stearic acid under methanolic conditions at pH 4.5 and pH 7, respectively. The samples obtained were intensively characterized using X-ray diffraction, nitrogen adsorption-desorption isotherm study, transmission electron microscopy (TEM), thermal gravimetric and differential thermal analysis, and Fourier transform infrared (FTIR) analysis. The as-synthesized samples prepared at pH 4.5 showed lamellar mesostructured form with high crystallinity. Results showed that the pore size and pore volume changed when the materials were prepared under different pH conditions. Morphology of the samples was observed by using TEM, which showed that the samples possessed relatively small particles closely packed together. The as-synthesized samples were investigated using FTIR, and the mesopore formation mechanism was discussed.

Oxidative steam reforming of n -butane over supported Ni catalysts at relatively low temperature, 723 K, is reported. Among all the supported 20 wt% Ni catalysts studied, only Ni/MgO was able to convert n -butane directly after O 2 oxidation. Additionally, when the Ni/MgO was prepared from an aqueous Ni(NO 3 ) 2 solution with pH 7, H 2 formation rate of Ni/MgO (pH 7) at a high SV (1660 l(h · g) −1 ) was 2.3 times as high as that of conventional Ni/MgO. The higher activity of Ni/MgO (pH 7) was ascribed to stronger resistance against oxidation of Ni 0 due to the formation of relatively large Ni 0 particles.

The oxygen storage capacity including OSC, OSCC and dynamic OSC was measured for Ce–Pr oxides using a temporal analysis of products (TAP) reactor system. The exact features of reduction and re-oxidation were obtained by accurately measuring the uptake of CO and O, and the production of CO 2 . It was found that the reduction temperature of Ce–Pr oxides was lowered 50–100 °C in comparison to that of CeO 2 . The substitution of cerium by praseodymium in the Ce 1− x Pr x O 2− δ oxides enhanced both OSC and OSCC. However, OSCC was much influenced by the increase of praseodymium content more than OSC. It was interpreted that the addition of Pr significantly increased the amount of oxygen migrating from bulk to surface while the migration rate of bulk oxygen was slightly accelerated. On the basis of analyses of the Ce 3d, Pr 3d and O 1s X-ray photoelectron spectra, the promotion effect of Pr on oxygen storage capacity could be attributed to the Ce 4+ /Ce 3+ , Pr 4+ /Pr 3+ redox behaviour and the enrichment of oxygen vacancies in Ce 1− x Pr x O 2− δ .

Oxidative steam reforming of n -butane over supported Ni catalysts at relatively low temperature, 723 K, is reported. Catalytic performance was investigated not only after H 2 treatment at 1073 K “reductive treatment” but also after subsequent O 2 /Ar treatment at the reaction temperature “oxidative treatment” to mimic the shutdown and startup of the domestic fuel cell system. After the reductive treatment, n -butane conversion attained 100% for all the catalyst at a lower space velocity (SV) of 67 L(h g) −1 . Differences in catalytic activity were emphasized at a higher SV of 667 L(h g) −1 , and were attributed to corresponding differences in metal surface area. Since a fraction of Ni in some catalysts was oxidized during the reaction at the higher SV, the reaction at the higher SV was indicated to be kinetically more oxidative condition. Although Ni/Al 2 O 3 was inactive at the lower SV after the oxidative treatment, n -butane conversion of the other catalysts attained 100%. In contrast, only Ni/MgO was able to convert n -butane at the higher SV after the oxidative treatment. Therefore it was revealed that nickel oxide species on the catalyst were reduced by n -butane in the reactant even under severe oxidative conditions.

The CO/O 2 and CO 2 pulse experiments were carried out to acquire useful information about oxygen release/storage and CO 2 adsorption on ceria and Pt–Rh/ceria. In the CO pulse experiments at 500 °C, ca. 60% of CO uptake was released as CO 2 while the rest of CO uptake was retained as carbon residuals on the surfaces of both samples. The carbon residuals could be removed when O 2 was provided. In the CO 2 pulse experiments, the adsorption of CO 2 was found to relate to the temperatures and the oxidation states of surface cerium. The reduced Ce 3+ sites (O vacancies) were responsible for the adsorption of CO 2 at the temperature of 500 °C. In addition, the molar ratios of CO 2 adsorption to O vacancies (38–39%) were in agreement with the ratios of carbon residuals to CO uptake ( ca. 40%) measured in the CO pulse experiments. Quantitative analyses of oxygen release/storage and CO 2 adsorption implied that in the process of oxygen release, carbon residuals were possibly in the form of a carbonate-like species due to the adsorption of CO 2 onto the reduced Ce 3+ sites.

A series of lanthanide (LA) phosphate were prepared by using N-(2-hydroxyethyl) ethylenediane-N,N′,N′-triacetic acid (H3hedtra) as a chelating agent. The obtained samples were characterized by using X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm, thermal analysis (TG-DTA), transmission electron microscope (TEM) and TPD-ammonia desorption. The results showed that samples prepared through chelating agent route possessed smaller particle size which led to higher specific surface area with increased acidic sites compared with the reference samples prepared free of H3hedtra. It was also found that the acidic strength increased gradually from the light lanthanide phosphate to heavy lanthanide phosphate. Besides, pore size of the samples could be controlled by altering the mole ratio of the lanthanide(LA): H3hedtra. Pore size distribution of the samples became narrower through synthesis in the presence of H3hedtra. The precursor sol complex was investigated by FTIR and XRD and mesopore formation mechanism had been discussed.

A synthesis of molybdenum incorporated mesoporous aluminophosphate with long-chain n-alkylamine as template material had been prepared under non-aqueous condition. These materials were extensively characterized by using X-ray diffraction (XRD), nitrogen sorption isotherms, nuclear magnetic resonance of 27Al and 31P (NMR), inductive coupled plasma (ICP), electron spin resonance (ESR), Fourier transform infrared (FTIR) and thermogravimetric–differential thermal analysis (TG–DTA). Morphology of the materials had been observed by using transmission electron microscope (TEM) that revealed the mesoporous materials possessed wormhole-like structures. Alkaline solvent extraction using n-butylamine/ethanol had been efficiently removed the n-alkylamine from the mesoporous samples which yielded BET surface areas around 550–730 m2/g. BJH analysis showed a narrow pore size distribution which increased with increasing of the carbon chain length of alkylamine (template). Valence state and coordination of the molybdenum in the obtained samples were investigated by using ESR and FTIR where it was found that Mo4+ and Mo6+ molybdenum species existed in the molybdenum incorporated mesoporous aluminophosphate in tetrahedral coordination.

A considerably high surface area of nanocrystalline mesoporous cerium phosphate with controllable pore size has been obtained by using N-(2-hydroxyethyl)-ethylenediane-N,N′,N′-triacetic acid (H3hedtra) as chelating agent. By varying the mole ratio of H3hedtra/Ce during synthesis, the surface area and average pore size of the materials as well as narrow pore size distribution can be controlled properly. The highest surface area of the obtained cerium phosphate is 145 m2 g−1 with average pore size at 8.54 nm, which is significantly higher than that of the reference sample prepared without H3hedtra. The morphology of the samples was observed by using TEM where sample prepared in the presence of H3hedtra possessed relatively smaller particle size compared with the reference sample prepared without H3hedtra. Besides, higher amount of acidic sites was found for samples prepared in the presence of H3hedtra compared with the sample prepared free of H3hedtra. Although the acid strength remained unchanged, the surface concentration of acidic sites had increased at mole ratio of H3hedtra/Ce above 0.5.

In order to obtain useful information about the effect of Sr, Pd promotion and calcination temperature on the reducibility of La1−xSrxFe(Pd)O3±δ perovskites, CO-TAP in combination with XRD, BET, TG-DTA, and SEM were employed to characterise the perovskite oxides prepared by the method of sol–gel auto-combustion. Reducibility of the perovskites was studied by means of the oxygen release capacity measurement in which a TAP reactor system was used to perform the CO pulse or alternate CO–O2 pulse experiments. Partial substitution of La3+ by Sr2+ in LaFeO3 significantly enhanced the reducibility and La0.6Sr0.4FeO3±δ showed the highest reducibility among the La1−xSrxFeO3±δ perovskites. An incorporation of Pd in replacement of 5 mol% of Fe into La0.6Sr0.4FeO3±δ caused a significant decrease of reduction temperature and an enhancement of reducibility. Moreover, the thermal stability was improved in the presence of Pd. It was found that the reducibility was strongly affected by the calcination temperatures. Extremely high reducibility (ca. 650 μmol-CO2 g−1 of OSC and ca. 800 μmol-CO2 g−1 of OSCC) was observed on the 1000 °C calcined La0.6Sr0.4Fe0.95Pd0.05O3±δ although its BET specific surface area was very low. We concluded that calcination of La0.6Sr0.4Fe0.95Pd0.05O3±δ at relatively high temperatures was favourable of creating more lattice defects and the lattice defects instead of surface area were mainly responsible for the reducibility.

Anaerobic oxidation of isobutane was studied using MgV 2 O 6 , Mg 2 V 2 O 7 and Mg 3 V 2 O 8 . Isobutene, a small amount of CO x , and trace amount of oxygen containing compounds were formed. CO 2 was formed mainly at the beginning of the reaction and decreased with reaction time. Catalytic activity of Mg 2 V 2 O 7 was slightly higher than that of MgV 2 O 6 but the CO x formation over MgV 2 O 6 was more than over Mg 2 V 2 O 7 . Mg 3 V 2 O 8 was the least active. Therefore, Mg 2 V 2 O 7 is the most suitable for oxidative hydrogenation of isobutane under the anaerobic reaction conditions. The equilibration between 16 O 2 and 18 O 2 over MgV 2 O 6 was faster than over Mg 2 V 2 O 7 or Mg 3 V 2 O 8 at 673 K. The rate of equilibration between 18 O 2 and lattice oxygen over MgV 2 O 6 was similar to that over Mg 2 V 2 O 7 , which was faster than over Mg 3 V 2 O 8 . Highest yield of isobutene formation over Mg 2 V 2 O 7 would come from the character of Mg 2 V 2 O 7 , in which mobility of the lattice oxygen is great but surface reaction of isobutane was not so fast. Higher activity for isobutene formation may come from the nature of Mg 2 V 2 O 7 , of which mobility of the lattice oxygen is great but surface reaction of isobutane was not so much fast. Mn, Cr, Fe, Ni and Co can be introduced into Mg 2 V 2 O 7 to give a single phase. Substitution of Co, Cu and Cr for Mg increased the activity of Mg 2 V 2 O 7 for isobutane oxidation and substitution of Ni and Mn scarcely affected the activity but substitution of Fe and Zn decreased the activity. Substitution of all the metal ions slightly increased the isobutene selectivity. MgO, MgV 2 O 4 and Mg 3 V 2 O 8 were observed in the sample after the anaerobic oxidation of isobutane. Cu containing catalyst was reduced to give Cu metal.

A new reforming process was studied using Ni/SiO2 with a hydrogen-permeating membrane reactor. Nickel catalyst supported on SiO2 is highly active for CH4−H2O−O2 reaction in membrane reactor and the reaction close to CH4+0.35O2+1.3H2O→CO2+3.3H2 proceeds at 873 K. Since the selectivity to carbon and CO2 increased and decreased with decreasing contact time respectively, it is considered that the reaction was started by decomposition of CH4 followed by oxidation of C and water shift reaction. Therefore, the reaction mechanism was different from so-called autothermal reforming (ATR) reaction.

The catalytic conversion of chlorobenzene (CB) over some metal phosphates and sulfate was studied in the presence of water vapor and oxygen. The conversion of CB proceeded in the order of AlPO 4 , Zr 3 (PO 4 ) 4 , CePO 4 -AlPO 4 , and La 2 (SO 3 ) 3 above 673 K. The major products were CO, CO 2 , and HCl. The reaction proceeded in the absence of water vapor; however, the activity was greatly reduced in the absence of oxygen. Even in the presence of oxygen, 30 mol % of water vapor inhibited the reaction. No intermediate hydration products were observed. There was no correlation between each of the catalytic activity, the acidity, and the concentration of the surface hydroxys of the catalysts. These results suggest that the essential reaction for CB conversion is oxidation. The specific surface area (SSA) of the catalysts was not changed during the CB conversion.

Among rare earth phosphates, only CePO4 and LaPO4 exhibit very high activity for oxidative dehydrogenation (ODH) of isobutane. This phenomenon was studied in comparison with the corresponding oxides. Isobutene was formed over NdPO4, which was used as a representative of inactive phosphate catalysts, by simple dehydrogenation with 30–32% selectivity, C3H6 and CO2 were formed with a selectivity of 25–33% and 20–30%, respectively. Isobutene was obtained at a higher selectivity of 79–86% over CePO4 and LaPO4. No H2 formation suggests that the essential reaction was the ODH of isobutane. In the oxidation over metal oxides, isobutene selectivity was relatively high: 60–70% over CeO2; however, the essential reaction was considered to be a simple dehydrogenation. Isobutene was formed at 40–47% selectivity, but simple dehydrogenation of isobutane would proceed over Nd2O3 and La2O3. La2O3, Nd2O3, and NdPO4 have only weak acidic sites. CeO2 has weak acidic sites and those with intermediate strength; LaPO4 and CePO4 have relatively strong acidic sites in addition to the weak acidic sites and those of intermediate strength. Oxidative dehydrogenation activity was correlated with strong acidic sites. ODH of isobutane occurred in the reaction between lattice oxygen of CePO4 and isobutane. Introduction of NH3 into the reaction system reduced both ODH of isobutane and CO2 formation; and stopping the NH3 supply led to a resumption of the activity, which suggests the participation of acidic sites. CePO4 catalyst contained 2% excess Ce to P; in the prepared CePO4 sample, Ce4+ was detected by XPS. We conclude that acidic sites and redox between Ce4+ and Ce3+ play important roles in the ODH of isobutane.

Sodium aluminate has been used as the aluminium precursor in the synthesis of mesoporous aluminophosphate where cetylpyridinium chloride (CTPC) was used as structure directing agent. Synthesis of the materials was performed in a broad range of pH from 3 to 10. The obtained materials were characterized by using XRD, TEM, ICP, nitrogen sorption isotherms, solid state NMR, TG-DTA and FTIR. The samples prepared at pH 5–8 were thermally stable up to 450 °C and presented specific surface areas in the range of 420–640 m2 g−1 after calcination for removal of the surfactant material. TEM image revealed the obtained mesoporous aluminophosphate possessed disordered porous structures. DH analysis derived from the adsorption branch showed that the average pore size of the sample was 2.6 nm in the 5–8 pH range.

Direct oxidation of hydrogen by gaseous oxygen was studied on Au/SiO2 catalyst without addition of a halogen compound. It was found that Au supported on SiO2 exhibits the high activity to H2O2 formation by direct oxidation of H2 by O2. Although the same Au catalyst is used, the H2O2 formation rate is strongly dependent on the support oxide. When the acidic oxides such as SiO2 or zeolite are used for support, reasonably high formation rates of H2O2 were achieved. In particular, the H2O2 formation rate is at a maximum on the SiO2 support. The high H2O2 formation rate observed with the SiO2 supported catalyst can be explained by the low activity for H2O2 decomposition. H2O2 formation rate on Au/SiO2 catalyst increased with increasing hydrogen partial pressure with P H 2 1.05 , however, it decreased with oxygen partial pressure with P O 2 − 0.505 . Therefore, activation of hydrogen on the catalyst seems to be the key step for H2O2 formation by direct oxidation of H2 by O2. Effects of additives on Au/SiO2 catalyst were further studied and it was found that the addition of a small amount of Pd is effective for increasing the H2O2 formation rate. The formation rate and the selectivity for H2O2 at initial 2 h were achieved to a value of 3.2 μmol/h and 30% under the optimized condition of Au–Pd/SiO2 catalyst.

Effects of dopant and coating carbon nanotube on anodic performance of Si were studied for metallic anode Li ion rechargeable battery with large capacity. Although the large Li intercalation capacity higher than 1500 mAh g −1 is exhibited on pure Si, it decreased drastically with increasing cycle number. Increasing the electrical conductivity by doping Cr or B is effective for increasing the initial capacity and the cycle stability of Si for Li intercalation. Coating semiconductive Si with the carbon nanotube by decomposition of hydrocarbon is effective for increasing the cycle stability, though the initial Li intercalation capacity slightly decreased. Conducting binder is also important for increasing the cycle stability and it was found that Li intercalation capacity higher than 1500 mAh g −1 can be sustained by using poly vinyliden fruolide. Consequently, reversible Li intercalation capacity of 1500 mAh g −1 was successfully sustained after 10th cycles of charge and discharge by doping Cr and coating with carbon nanotube.

Improvement in the rate properties of orthorhombic LiVOPO 4 was investigated and it was found that making a fine powder of LiVOPO 4 by the mechanical milling pretreatment is effective for increasing the de-intercalation capacity of Li from LiVOPO 4 . The electrochemical de-intercalation capacity at high current density can further increase by optimizing the acetylene black amount as a conducting binder. The optimized acetylene black amount was 15 wt.% and intercalation capacity of Li was achieved a value of 100 and 60 mAh g −1 at high rate condition of C/5 (0.4 mA cm −2 ) and 1C (2 mA cm −2 ), respectively.

Emission of hydrocarbon at low temperature, especially in the cold start condition of the automobile engine, has attracted attention these days. For the first time an electrochemical sensor based on LaGaO 3 with iron doping was demonstrated to have very high sensitivity to propene (C 3 H 6 ) at low temperature (423–573 K). In the amperometric mode, the output current signal was found to increase linearly with the C 3 H 6 concentration (500–2000 ppm) in logarithm scale. Effect of iron doping at the gallium site was found to influence the sensing properties greatly and the electrolyte composition La 0.7 Sr 0.3 Ga 0.7 Fe 0.3 O 3 showed the highest sensitivity of 976 μA/decade at 473 K. The sensors were fast, reproducible and highly selective to hydrocarbons.

Metal fluorides are more stable than metals and metal oxides; therefore, no oxides can be applied as catalyst supports for the reactions in which hydrogen fluoride is involved. The authors observed that metal phosphates are not reactive to HF at higher reaction temperatures such as 973 K. Hence, the decomposition of CClF 2 CClF 2 was studied over Pt-supported SiO 2 , Al 2 O 3 , and AlPO 4 -based catalysts. Hydrodehalogenation proceeded and CHF 2 CClF 2 and C 2 H 6 were formed as major products, small amounts of CHF 2 CHF 2 , CH 2 FCClF 2 , CH 2 FCF 3 , and CH 4 were also formed. Pt/SiO 2 was the most active; however, SiO 2 reacted with HF and the SiF 4 formed sublimated. Following these, Al 2 O 3 was the most active; however, it reacted with HF to form AlF 3 and was deactivated. Similar hydrodehalogenation proceeded over Pt/AlPO 4 and Pt/(CePO 4 AlPO 4 ). The crystal structure of these catalysts did not change during the catalytic reaction, although the reduction of specific surface areas (SSA) was observed. Therefore, AlPO 4 and Ce containing AlPO 4 are suitable as catalyst supports in reactions in which HF is involved. XPS showed that the electronic effects of AlPO 4 lie between that of SiO 2 and Al 2 O 3 . A good linear relationship is found to exist between the initial reaction rates per unit surface area of Pt metal supported on the supports and the binding energy of supported Pt. This suggests that the more cationic the Pt, the more easily it could abstract Cl − from CClF 2 CClF 2 .

Effects of various additives to Ni anode on SOFC using La 0.9 Sr 0.1 Ga 0.8 Mg 2 O 3 based oxide electrolyte were investigated in this study for increasing the surface activity. Among the examined additives, it was found that the addition of small amount of Fe is highly effective for increasing the anodic activity. When 5 wt% Fe was added to Ni anode, the anodic overpotential was as small as 34 mV at 873 K, 0.1 A/cm 2 , which is almost half of pure Ni anode. Since the estimated activation energy for anodic reaction decreased, addition of Fe to Ni seems to be effective for increasing the activity of Ni for anodic reaction. XRD measurement after power generation measurement suggests that added Fe formed alloy with Ni. Addition of third element to Ni-Fe bimetallic anode was also studied and it was found that addition of small amount of Pt is effective for further increasing the activity of Ni anode. Consequently, this study reveals that Ni-Fe-Pt is highly active for anodic reaction of SOFCs at decreased temperatures.

Hydrogen storage into multi-walled carbon nanotubes obtained by the decomposition of hydrocarbons using Ni-Li/SiO2 was investigated. The optimized reaction conditions for the synthesis of carbon nanotubes were 873K and W/F=40 g-cat.h/mol, and carbon nanotubes obtained by C2H6 decomposition were found to exhibit fairly large H2 storage capacity of 1 wt% at room temperature. The storage capacity increased with decreasing temperature and a capacity of 5 wt% was achieved at 77K, with 66% of adsorbed hydrogen being desorbable. Hydrogen adsorption by pi orbital in C-C bond coordination is proposed, observing both weakened Raman adsorption C-C peaks and the thermal release of CH4 after H2 storage.

A yttria-stabilized zirconia (YSZ) thin film on an La0.8Sr0.2MnO3 porous cathode substrate was prepared, using electrophoretic deposition (EPD) to fabricate a solid oxide fuel cell (SOFC). The electrical conductivity of an La0.8Sr0.2MnO3 substrate is satisfactorily high at room temperature; therefore, YSZ powder could be deposited electrophoretically onto an La0.8Sr0.2MnO3 substrate without any extra surface treatment, such as a metal coating. Successive repetition of EPD and sintering was required to obtain a film without gas leakage, because of the thermal expansion coefficient mismatch between the YSZ and the La0.8Sr0.2MnO3 substrate. On the other hand, the electromotive force of the oxygen concentration in the cell that used YSZ film prepared via EPD increased and attained the theoretical value when the number of deposition and calcination cycles was increased. Six or more successive repetitions were required to obtain a YSZ film without gas leakage. A planar-type SOFC was fabricated, using nickel as the anode and YSZ film (∼10 μm thick) that had been deposited onto the La0.8Sr0.2MnO3 substrate as the electrolyte and cathode. The cell exhibited an open circuit voltage of 1.0 V and a maximum power density of 1.5 W/cm2. Thus, the EPD method could be used as a colloidal process to prepare YSZ thin-film electrolytes for SOFCs.

For the first time, an amperometric electrochemical sensor based on LaGaO3 was demonstrated as highly sensitive to detect hydrocarbon (C3H6) at low temperature (423−773 K). At this temperature range, it is very important to estimate hydrocarbon pollution of automobile exhaust gas (the cold start condition). In the present study, using La0.5Sr0.5MnO3 as the oxygen reduction electrode, various hydrocarbon (C3H6) oxidation electrodes of Pt-based alloy systems were investigated. Addition of Co and subsequently cermet LDC [(CeO2)0.8(LaO1.5)0.2] produced very high sensor response and improved the performance of the sensor with respect to that using only Pt paste as the electrode. The sensors were hardly influenced by the oxygen concentration variation (0.5−5%). At the best operating temperature (623 K) the C3H6 sensitivity was above 800 μA/decade, and the lowest temperature of detection was 423 K. The sensors were fast, highly selective in the presence of coexisting gases, e.g., NO, NO2, CO, and H2, in the exha...

Partial electronic and oxide ion conductivity in La 0.7 Sr 0.3 Ga 0.6 Fe 0.4 O 3 (LSGF) was investigated in this study by the ion blocking method. It was seen that LSGF stably exhibits the electronic hole conduction over wide oxygen partial pressure. The estimated oxide ion conductivity decreased with decreasing P O2 and this seem to be caused by decreasing amount of V O ¨ which is balanced with Fe valence number. The estimated transport number of oxide ion is reasonably agreed with those estimated by oxygen concentration cell. It was found that the theoretical oxygen permeation rate in LSGF is much larger than that of observed value. Therefore, it is expected that the oxygen permeation rate could be improved by increasing activity of surface catalyst.

Partial electronic conduction in Ni-doped LaGaO3-based oxide was investigated by using the ion-blocking method. It was seen that the hole and the electronic conduction originated from doped Ni becomes dominant with decreasing temperature and also with increasing Ni content. PO2 dependences of hole and electronic conduction decrease with increasing Ni content and it becomes almost PO21/12 and PO2−1/12, respectively, at 1073 K when 10 mol% Ni is doped to Ga site. The estimated transport number of oxide ion in Ni-doped LaGaO3 is always higher than 0.95 in PO2 range from 1 to 10−21 atm, which is the important PO2 range for fuel cell application. Therefore, the main charge carrier is still oxide ion in Ni-doped LaGaO3. Comparing with the partial electronic conduction in Co-doped sample, the electrolyte domain is wider on Ni-doped sample.

Thermally stable hexagonal zirconium phosphate has been synthesized by a two-step method in which hexagonal zirconium sulfate surfactant composite is first produced by surfactant-assisted method and then subsequently treated in H3PO4 for long term. The 31P MAS NMR spectra show that the connectivity of phosphorus atoms increases from one ((Zr-O)PO3) or two ((Zr-O)2PO2) to three ((Zr-O)3PO) or four (P-O-P) upon calcination. There exists a significant number of surface Bronsted acid sites (Zr-O)3POH on calcined sample. The high thermal stability of hexagonal zirconium phosphate is due to (Zr-O)3PO and P-O-P connections, which build a network of zirconium phosphate.

Oxide ion conductivity in doped LaOXF3-2X was investigated. It was found that oxygen doped into LaF3 can be mobile through introduced anion vacancy and LaO0.6F1.8 exhibits the high oxide ion conductivity, which is comparable with those in doped Bi2O3-based oxides. The oxide ion conductivity in LaO0.6F1.8 was further improved by simultaneous doping of SrO, SrF2, and NaF. The highest conductivity is achieved with the composition La0.9Sr0.1Na0.05O0.4F2.0 in the present study. La0.9Sr0.1Na0.05O0.4F2.0 is chemically stable in oxygen partial pressure from 1 to 10-21 atm, and almost the theoretical electromotive force is exhibited in the oxygen gas-concentration cell. The conductivity of oxygen-doped LaF3 was further confirmed by the dc polarization method. No polarization in conductivity was observed over 24 h, and also no segregation of F- ion at positive electrode was noticed. Furthermore, desorption of F2 from lattice was not observed. Therefore, it was confirmed that oxygen-doped LaF3 exhibits oxide ion con...

Reversibly and irreversibly adsorbed water on AlPO 4 and CePO 4 AlPO 4 (Ce/Al = 1/9) were determined by a TPD method and an electro-balance. The amounts of reversible and irreversible adsorption over AlPO 4 were larger than that of CePO 4 AlPO 4 . However, the surface concentration of surface hydroxyls on AlPO 4 was smaller than that on CePO 4 AlPO 4 . Catalytic activity for CCl 2 F 2 decomposition of AlPO 4 is smaller than that of CePO 4 AlPO 4 . To explain these results, a surface intermediate, O surface CF 2 O surface , is proposed. The stabilization energy was calculated for the surface species; CCl 2 F 2 interacting with surface hydroxyls and the OCX 2 O (X = Cl or F) type surface species. The calculations suggest that PO surface H⋯ClCF 2 Cl⋯HO surface P species and AlO surface CF 2 O surface Al species are the most stable. To clarify the reaction mechanism, trace amounts of by-products in the decomposition of CH 2 FCF 3 which is hydrofluorocarbon with two carbon atoms were analyzed and found the formation of HOCH 2 CF 2 OH which may be derived from the surface intermediate, O surface CH 2 CF 2 O surface . This strongly supports the formation of bidentate surface intermediates.

Partial electronic and oxide ionic conductivity in Co doped LaGaO 3 was investigated with a polarization method and it was seen that the partial electronic conductivity became significant with increasing temperature. P O 2 dependences of the partial electron and hole conductivities at 1173 K are almost proportional to P O 2 −1/4 and P O 2 1/4 , respectively, in accordance to Wagner's theory. On the other hand, P O 2 dependences of electron and hole conductivities deviate from those of Wagner's theory and became much smaller as temperature decrease. The small P O 2 dependence of the partial electronic conductivity could be explained by extrinsic electrons or holes originating from oxidation or reduction of cobalt. In order to explain the small P O 2 dependence, average valence numbers of Co were measured by redox titration. It was seen that the P O 2 dependence of the Co valence number is similar to those of partial electron and hole conduction. Consequently, the small P O 2 dependence of partial electronic conduction could be assigned to the small P O 2 dependence of the valence number of Co.

Activity for hydrolysis of CCl2F2 (CFC12) on various metal sulfate was investigated. Zr(SO4)2 was found to be the most active while FeSO4, Cr2(SO4)3, Al2(SO4)3, La2(SO4)3 and Ce2(SO4)3 had intermediate activity. MnSO4, CoSO4, and MgSO4 showed low activity and SrSO4, CaSO4, and BaSO4 had even less activity. The major carbon containing product was CO2 and small amount of CClF3 and CO were formed over several sulfates. The crystal structure of the sulfates was stable during decomposition of CCl2F2, and the conversion reached a steady state after initial decrease at 275 °C over Zr(SO4)2 catalyst. The concentration of surface hydroxyl was larger than that over AlPO4-based catalysts and a reaction mechanism similar to that over AlPO4-based catalysts was proposed.

Effects of Co doping to Ga sites of a LaGaO 3 based oxide on the oxide ion conductivity was investigated. Oxide ion conductivity increased by doping with Co and it was found that usage of a LaGaO 3 -based perovskite type oxide, doped with Sr for the A site and Co and Mg for the B site (La 0.8 Sr 0.2 Ga 0.8 Mg 0.115 Co 0.085 O 3 denoted as LSGMC), for the electrolyte of the fuel cell gave a notably large power density at an intermediate temperature of 873 K on a cell using H 2 and O 2 as fuel and oxidant, respectively. The power density increased as the thickness of the electrolyte was decreased. The maximum power density was attained at values of 1.4 and 0.5 W/cm 2 at 1073 and 873 K, respectively, when 0.18 mm thick LSGMC was used for the electrolyte. Electrical conductivity in the LSGMC was also estimated using polarization methods. Electrical conductivity was also increased by doping with Co, resulting in an increased amount of chemically leaked oxygen. Consequently, the theoretical calculation demonstrated that the highest energy conversion efficiency would be achieved when the thickness of the LSGMC electrolyte was 100 μm.

Although LaMnO 3 perovskite oxide has been reported to exhibit low activity in NO direct decomposition into N 2 and O 2 , doping Ga or In at the Mn site of La(Ba)MnO 3 has been found effective of increasing the activity for NO direct decomposition into N 2 and O 2 . The activity of NO decomposition increased in the order Ba>Sr>Ca for the La site dopant, and In>Ga for the Mn site. Among the investigated dopants and compositions, the highest N 2 yield was achieved with La 0.7 Ba 0.3 Mn 0.8 In 0.2 O 3 . On this catalyst, NO conversion increased with increasing reaction temperature, and at 1123 K, NO conversion into N 2 and O 2 attained values of 75 and 41%, respectively. The high yield of N 2 and O 2 was maintained for 12 h. Coexistence of oxygen decreased the N 2 yield with P O 2 −0.53 ; however, a N 2 yield of 15% could be sustained even at 10% coexisting O 2 at 1073 K. The NO decomposition rate increased with increasing NO partial pressure and obeyed with P NO 1.31 . O 2 temperature-programmed desorption measurements showed that oxygen desorption was greatly enhanced by In doping at the Mn site. NO TPD also showed that the amount of NO adsorbed greatly increased with In doping. Therefore, improved activity of NO decomposition with In substitution seems to be caused by the weakening adsorption of oxygen and the increased adsorption of NO. IR measurements of adsorbed NO also suggest that the major adsorption species at high temperature was NO 3 − and it seems likely that NO decomposition proceeds after removal of NO 3 − and/or oxygen. N 2 O direct decomposition on La 0.7 Ba 0.3 Mn 0.8 In 0.2 O 3 was further studied. It was found that La 0.7 Ba 0.3 Mn 0.8 In 0.2 O 3 is highly active in the direct decomposition of N 2 O even under the coexistence of O 2 . Therefore, decomposition of NO on La 0.7 Ba 0.3 Mn 0.8 In 0.2 O 3 may proceed via N 2 O as the intermediate species.

The oxygen storage capacity of CeO2, Ce0.9Pr0.1O2, Pt−Rh/CeO2 and Pt−Rh/Ce0.9Pr0.1O2 was investigated by conventional GC pulse method and transient pulse techniques. It is shown that incorporation of PrOy into CeO2 matrix strongly promotes oxygen storage capacity (OSC) measured using the transient pulse technique. The improvement of OSC at low temperature is observed in Pt−Rh loaded onto CeO2 and Ce−Pr catalysts.

Effects of the addition of various manganese compounds on anodic performance of carbon nanotube were investigated. It was seen that the Li intercalation capacity decreased drastically by the addition of most manganese compounds. However, addition of Mn(CH3COO)2 greatly improved the capacity for Li intercalation. Li intercalation capacity increased with increasing Mn(CH3COO)2 concentration and the largest capacity of 360 and 330 mAh/g for the insertion and reversible Li intercalation was achieved when 1 wt.% Mn(CH3COO)2 was added. The increased capacity was sustained after 50 times of charge and discharge cycles. X-ray absorption near edge spectra (XANES) suggests that the state of added Mn ion is close to MnO2 and so the added Mn(CH3COO)2 decomposed during preparation. The surface organic layer formed by the acetic acid appears to give a superior solid electrolyte interface (SEI). The positive effects of Mn(CH3COO)2 are obtained only when manganese ion and acetic acid coexist. Therefore, it is believed that the coexisting Mn ion works as a catalyst for the decomposition of acetic acid.

Seven phases of VOPO 4 were synthesized and their Li intercalation properties were investigated. Li can be reversibly intercalated into all phases of VOPO 4 and potential plateaus for Li intercalation and de-intercalation exist at 3.7 and 3.9 V, respectively, except for the β- and e-phases. β- and e-phases of VOPO 4 exhibit slightly higher flat potentials of 3.9 and 4.1 V. The capacity for Li intercalation is strongly affected by the crystal structure of VOPO 4 and the Li intercalation capacity increases with increasing average valence of V. Among the VOPO 4 crystal phases, it was found that the δ-phase exhibits the largest reversible capacity of ca. 130 mAh/g. The capacity for Li de-intercalation in δ-phase VOPO 4 hardly decreased over 35 charge and discharge cycles. On the other hand, the Li intercalation capacity in δ-phase VOPO 4 decreased with increasing current density for charge and discharge and temperature. However, even at a current density of 0.4 mA/cm 2 , corresponding to C /5, fairly large capacity of ca. 60 mAh/g was sustained, and at a operating temperature or 323 K, a capacity of 110 mAh/g was exhibited at 0.04 mA/cm 2 .

Catalytic performance and the surface character of the Ga 2 O 3 supported Bi-Mo complex oxides were studied to achieve direct formation of methacrolein from isobutane. Bi 2 Mo 3 O12 (a phase) and Bi 2 Mo 1 O 6 (γphase) showed higher catalytic activity than Bi 2 Mo 2 O 9 β phase) for isobutane partial oxidation. Supporting Ga 2 O 3 , which is an active catalyst for dehydrogenation of hydrocarbons, onto the oxides, enhanced the catalytic activity. The optimum amount of supported Ga 2 O 3 on Bi 2 Mo 3 O 12 was about 3 wt% for methacrolein formation. In the presence of oxygen, a remarkable amounts of hydrogen over Ga 2 O 3 during the isobutane oxidation but no hydrogen was formed over Ga 2 O 3 /Bi 2 Mo 3 O 12 . It is confirmed from TPR that Ga 2 O 3 and Bi 2 Mo 3 O 12 were not reduced until 550°C but the reduction of Ga 2 O 3 /Bi 2 Mo 3 O 12 started at 350-380°C. The on-set temperature in TPR of the Bi-Mo complex oxides decreased to 350-380°C from 500°C by the supporting Ga 2 O 3 onto the oxides, and the catalysts after TPR measurement are composed of BiO, Bi, and Mo0 2 in addition to B1 2 Mo 3 O 12 . These results suggest that the hydrogen spillover took place over supported catalyst. Ga 2 O 3 /Bi 2 Mo 3 O 12 catalyst showed higher activity and high selectivity for methacrolein at 450°C. The improvement in the selectivity for methacrolein of the Ga 2 O 3 /Bi 2 Mo 3 O 12 may be explained as following. Isobutane is adsorbed on the surface of Ga 2 O 3 to form hydrogen atom and t-butyl fragment and both formed species migrates to Bi 2 Mo 3 O 12 surface. Migrated hydrogen may modify the Bi 2 Mo 3 O 12 surface property by the reaction with oxide ions, which is active for the deep oxidation resulting in high selectivity for methacrolein. In the non-aerobic oxidation of isobutane over the Ga 2 O 3 /Bi 2 Mo 3 O 12 catalyst, the formation rate of CO x significantly reduced, and methacrolein and isobutene were selectively obtained when the reduction degree of the catalyst was lower than 0.3% at 450°C.

水産業, 畜産業からは貝殻, 卵殻, 鶏骨等のCaを含有する廃棄物が発生する。一方で石炭石油などの化石燃料を使用する産業では酸化還元工程でCOが, 脱窒工程でNH3が発生する。これらの中には利用されないで廃棄物となるものがある。そこで, Ca化合物とNH3, COの反応により, 窒素肥料として最も有用であるCaCN2を合成できれば, 産業廃棄物の発生を低減できる。この観点から貝殻, 卵殻, 鶏骨のNH3, COによる白色CaCN2の合成を試みた。その結果, 600℃で, 数時間の反応により, 貝殻, 卵殻からは約20重量%のCaCN2が生成した。鶏骨からは8.0重量%のCaCN2が生成した。CaCN2合成反応は6CaO+6NH3+6CO→4CaCO3+2CaCN2+9H2+N2のように近似できた。

Partial electronic and hole conductivity in Co doped LaGaO3 based perovskite oxide was investigated with the ion-blocking method. Typical S-shaped polarization curves were observed on La0.8Sr0.2Ga0.8Mg0.2−XCoXO3 (0

The oxidation of isobutane was investigated over various complex vanadium oxide catalysts. Mg 2 V 2 O 7 , MgV 2 O 6 , and Mg 3 V 2 O 8 are effective catalysis for isobutene formation at >300°C. Cu 2 V 2 O 7 and CaV 2 O 6 showed intermediate activity and BiVO 4 and Ca 7 V 4 O 17 were slightly active. The active catalysts had relatively strong acidic sites, and H abstraction from the t-carbon of isobutane by acidic site was considered to be the initial and rate-determining step because a linear relationship was observed between the amount of acidic sites and the catalytic activity of the catalysts. The introduction of transition metals into the Mg sites of the Mg 2 V 2 O 7 crystal lattice formed Mg 1.8 V 2 M 0.2 O 7 (M =Mn, Cr, Fe, Co, Ni) catalysts. This substitution significantly promoted the catalytic activity without changing the selectivity for isobutene. Introduction of these transition metals increased the reactivity of lattice oxygen in Mg 1.8 V 2 M 0.2 O 7 catalysts. Decreased W/F, increased the selectivity for isobutene to approaching 100%, suggesting that the initial reaction is the oxidative dehydrogenation of isobutane without parallel CO x formation.

Effects of water addition to oxidant on the cathodic overpotential of La-doped BaCoO 3 electrode were investigated. It was found that the overpotential of La-doped BaCoO 3 decreased by addition of H 2 O to oxygen. In particular, the decrease in overpotential by addition of H 2 O was significant with decreasing operating temperature of the cell. Therefore, it became clear that the maximum power density increased by addition of H 2 O to oxidant. The improved cathodic activity by addition of H 2 O was further studied by using 18 O tracer exchange measurement. Although the diffusion coefficient was independent of the coexisting water, the surface exchange coefficient increased greatly by addition of water. 18 O- 16 O isotopic exchange reaction under coexisting H 2 16 O demonstrated that the surface oxygen exchange reaction through H 2 O is very fast and the coexisting water catalytically accelerates the dissociation reaction of gaseous oxygen molecule into oxide ion. The positive effects of humidified oxidant were stable over 50 hours of testing.

The power-generating property of direct dimethyl ether- (DME-) fueled SOFCs using a LaGaO 3 -based electrolyte was investigated in this study. The performance of a single Ni/La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 /Sm 0.5 Sr 0.5 O 3 cell fueled with DME was comparable to that of the cell fueled with hydrogen at 1073 K. However, the power density of the DME cell decreased dramatically with decreasing temperature and showed a lower maximum power density than H 2 cell at 973 K due to the high anodic overpotential. DME-fueled cells based on cobalt-doped LSGM (1 to 9 mol%) electrolyte showed much higher power density compared with the cell using LSGM electrolyte, and the power density increased with increasing concentration of cobalt doping for LaGaO 3 . The maximum power density attained a value of 1.4 W/cm 2 at 1073 K. Because the deposition of carbon was not significant, this study demonstrated that DME is an attractive fuel for SOFCs, in particular, for intermediate-temperature SOFCs.