Oxygen storage capacity of CuMO2 (M=Al, Fe, Mn, Ga) with a delafossite-type structure

Kato, Sumio; Fujimaki, Ryu; Ogasawara, Masataka; Wakabayashi, Takashi; Nakahara, Yuunosuke; Nakata, Shinichi

doi:10.1016/j.apcatb.2008.11.033

Cited by 90 publications

(65 citation statements)

References 11 publications

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“…It suggests that the reduction from Mn 4+ to Mn 3+ may occur in the low temperature region to increase the hydrogen consumption of peak a of CuCMn(500). However, manganese oxide is much harder to be reduced than copper oxide because the free energy of formation of manganese oxide is lower than copper oxide [31,32], which results in the slight increase of the reduction temperature of peak a for CuCMn(500). Moreover, hydrogen consumption of peak c for CuCMn(500) catalyst is also higher than that of CuC(500), 299 and 224 lmol/g cat , respectively, which means that the peak c should also include the reduction of MnO x species.…”

Section: Redox Property Of Catalystsmentioning

confidence: 99%

Catalytic performance of manganese doped CuO–CeO 2 catalysts for selective oxidation of CO in hydrogen-rich gas

Guo

Zhou

2016

Fuel

116

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Section: Redox Property Of Catalystsmentioning

confidence: 99%

Catalytic performance of manganese doped CuO–CeO 2 catalysts for selective oxidation of CO in hydrogen-rich gas

Guo

Zhou

2016

Fuel

116

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“…In this respect, the delafossite CuMO 2 , where M denotes a trivalent metal, is thermodynamically stable phases crystallizing in a two-dimensional lattice and has received growing attention over the last decade [2][3][4]. They occupy an important place in various fields by virtue of the diversity of physical properties and have a great promise in the solar energy conversion [5][6][7] and environmental protection [8,9]. However, the lifetime of the photocarriers is short because they move in a narrow Cu-3d band (*2 eV width) with a small diffusion length and a low hole mobility (*10 -5 cm 2 V -1 s -1 ) [10]; this inhibits considerably the light-to-energy conversion and leads to low efficiencies.…”

Section: Introductionmentioning

confidence: 99%

Sol–gel synthesis and characterization of the delafossite CuAlO2

Benreguia

Barnabé

Trari

2015

J Sol-Gel Sci Technol

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Nanocrystalline CuAlO 2 is synthesized by solgel method using ethylene glycol as solvent. The stages of formation are followed by thermal analysis. The X-ray diffraction pattern of the powder heat-treated at 1100°C shows a single phase, indexed in a rhombohedral symmetry (R 3 m). The apparent crystallite size (57 ± 8 nm) is determined from the Williamson-Hall plot. The direct optical transition (=3.69 eV), evaluated from the diffuse reflectance spectrum, is attributed to the charge transfer (O 2-: 2p ? Cu ? : 4s). The oxide is p-type semiconductor, and the conduction occurs predominantly by small polaron hopping between mixed valences Cu 2?/? , due to oxygen insertion in the layered crystal. The photoelectrochemical characterization gives a flat band of 0.20 V SCE and a hole density of 1.13 9 10 18 cm -3 . The semicircle centered on the real axis, in the electrochemical impedance spectroscopy (EIS), is due to the absence of constant phase element with a pure capacitive behavior. The straight line at 35°at low frequencies is attributed to the diffusion in the layered structure. Graphical Abstract Temperature dependence of the electrical conductivity for CuAlO 2 synthesized by sol-gel method. Inset: the variable range hopping at low temperatures. The sol-gel method has been successfully employed for the preparation of CuAlO 2 . The thermal variation of the conductivity indicates a semiconducting behavior which is frequency independent. At low temperature, a variable range hopping involves electrons jump over large distances according to the Mott law r ¼ r 0 exp T 0 T À Á 0:25 .

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“…[1][2] Nowadays, CuFeO2 is a p-type semiconductor of delafossite oxides and it has attracted much attention as a p-type TCO (Transparent Conducting Oxide) used for several applications such as transparent diodes, photocatalysts, photovoltaics, ferroelectrics and so on. [3][4][5][6][7] Generally, the CuFeO2 powders could be synthesized through high temperature solid state reactions under an inert gas environments (Ar or N2) at 900-1200°C , because of Cu + is more stable than Cu 2+ at high temperature. However, the solid state reaction or sol-gel method need an posttreatment at high temperature, [8][9] and the high temperature is a serious defect for these preparation methods.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal synthesis of delafossite CuFeO₂ crystals at 100 °C

Xiong

et al. 2015

RSC Adv.

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In this work, we first report a fast, facile hydrothermal method to synthesize delafossite CuFeO2 crystals through lowtemperature (100-160 °C) reaction. In detail, CuFeO2 crystals with submicron-sized (100-300 nm) could be obtained based on hydrothermal reaction from the starting materials of Cu(NO3)2, FeCl2 and NaOH at 100 °C for 12h. Furthermore, the TG curve of CuFeO2 is similar to other copper based delafossite oxides, and CuFeO2 tend to be oxidized by O2 in air at a higher sintering temperature (> 400°C ). The obtained CuFeO2 film has an optical transmission of 50-60% in visible region, and the optical bandgap for the direct band transition was estimated to be 3.18 eV. Finally, the magnetic hysteresis loops measured at room temperature show CuFeO2 crystals exhibit antiferromagnetic behavior, the Néel temperature (TN) about 11 K and the biggest magnetic susceptibility around 0.168 emu g -1 . This quick and facile method maybe opens a new route for preparation of CuFeO2 crystals, due to the low reaction temperature and short reaction time.

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Oxygen storage capacity of CuMO2 (M=Al, Fe, Mn, Ga) with a delafossite-type structure

Cited by 90 publications

References 11 publications

Catalytic performance of manganese doped CuO–CeO 2 catalysts for selective oxidation of CO in hydrogen-rich gas

Catalytic performance of manganese doped CuO–CeO 2 catalysts for selective oxidation of CO in hydrogen-rich gas

Sol–gel synthesis and characterization of the delafossite CuAlO2

Hydrothermal synthesis of delafossite CuFeO₂ crystals at 100 °C

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Oxygen storage capacity of CuMO2 (M=Al, Fe, Mn, Ga) with a delafossite-type structure

Cited by 90 publications

References 11 publications

Catalytic performance of manganese doped CuO–CeO 2 catalysts for selective oxidation of CO in hydrogen-rich gas

Catalytic performance of manganese doped CuO–CeO 2 catalysts for selective oxidation of CO in hydrogen-rich gas

Sol–gel synthesis and characterization of the delafossite CuAlO2

Hydrothermal synthesis of delafossite CuFeO2 crystals at 100 °C

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Product

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Hydrothermal synthesis of delafossite CuFeO₂ crystals at 100 °C