nanostructured electrochemical reactors for control nano-scale control cell current (ma) nox...

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  • Ceramic electrochemical reactors are expected for their high performance on conversions of energy and substances; for examples, electric power generation (solid oxide fuel cells: SOFCs), synthesis of hydrogen, and decomposition and purification of environmental pollutants.

    Development of novel electrochemical modules for deNOx/PM reactor by nanostructure control

    Combination with thermoelectric ceramic module for harvesting of waste heat energy

    Nanostructured electrochemical reactors for NOx/PM decomposition and micro SOFCs

    Masanobu Awano Institute of Advanced Industrial Science and Technology(AIST)

    Nagoya 463-8560, JAPAN

    OECD Conference on Potential Environmental Benefits of Nanotechnology: Fostering Safe Innovation-Led Growth, Session 3. Clean Car Technology Paris, July 15-17, 2009

    New type MicroSOFC development of high performance APU unit for vehicles by nano-micro structure control as clean energy source

  • Various applications of electrochemical reactor (O2--conducting ceramics )

    e-

    e-

    O2-

    Air

    ① H2 H2O (SOFC) ② CH4 H2O + CO2 (SOFC)

    e-

    e-

    ③ NO N2 (de-NOX) ④ H2O H2 (H2 generation)Air

    O2- O2-

    O2 ⑤ CH4 CO + H2 (Syngas) ⑥ O2 pumping ⑦ CH4 CH3OH (GTL) ⑧ C CO2

  • 6th Pacific Rim Conference on Ceramic and Glass Technology, September 15th 2005, Hawaii, USA

    Nitrogen oxides ( NOx ) in exhaust gas are known - to cause air pollution problems (acid rain, photochemical smog) - to give damage to human nerves and respiratory organs

    The reduction of NOX emission has become one of the greatest challenges in environment protection.

    % 100

    NO2

    50

    0

    A/F

    14.3 14.5 14.7

    C O

    H C

    % 100

    NO2

    50

    0

    A/F

    14.3 14.5 14.7

    C O

    H C

    Active at higher PO2 atmosphere

    % 100

    NO2

    50

    0

    A/F

    14.3 14.5 14.7

    C O

    H C

    % 100

    NO2

    50

    0

    A/F

    14.3 14.5 14.7

    C O

    H C

    Active at higher PO2 atmosphere

    Japanese regulation

    near zero- emission

  • Environment purifying / Saving energy

    NO x → N 2 +O 2

    NANOSTRUCTURED DE-NOx REACTOR

    NOx/PM DECOMPOSITION

    ELECTROCHEMICAL/THERMO ELECTRIC MODULE

  • Contents

    1. Ceramic electrochemical reactor for NOx decomposition

    2. Ceramic electrochemical reactor for PM (particulate matter) decomposition

    3. Thermoelectric ceramic module for enhanced deNOx property by using waste heat energy

  • 1. Ceramic electrochemical reactor for NOx decomposition

  • O 2熱電変換による電力供給

    NO x

    N 2

    高温排ガス クリーンガス

    ガス分子吸着サイト

    多孔質触媒電極層

    固体電解質

    (酸素イオン 伝導体)

    多孔質電極

    O 2

    O 2-

    高温におけるNO x高選択性

    e

    e

    O 2熱電変換による電力供給

    NO x

    N 2

    高温排ガス高温排ガス クリーンガスクリーンガス

    ガス分子吸着サイト

    多孔質触媒電極層

    固体電解質

    (酸素イオン 伝導体)

    固体電解質

    (酸素イオン 伝導体)

    多孔質電極

    O 2

    O 2-

    高温におけるNO x高選択性

    ee

    ee

    Oxygen as an inhibitor to

    de-NOx reaction

    Large amount of electrical current supply is required →difficulty to the application

    Porous Cathode

    Solid Electrolyte Oxygen ion conductor

    Porous Anode

    Catalytic Activation Site

    Example: scheme of NOx purifying by an electrochemical cell (under excess oxygen coexistence such as diesel engine exhaust gas)

  • TEM image of an NiO and YSZ interface, and reaction model of selective NO molecule decomposition. The expected mechanism of the absorption and decomposition of N to Ni, and oxygen capturing and pumping in the region of high defects concentration is also displayed

    nano redox-reaction zone

    nano pores

    2nm O-N

    nano particles

    O-ion →O2

    YSZ

    Exhaust gas N2

    e-

    Ni←NiO NiOYSZ

    nano-spacenano-space

    Ni nano particles

    high conc. oxygen defects layer

    NOx m olecules

    O2-(→O2) N2

    NiOYSZ

    nano-space TEM image of an NiO and YSZ interface, and reaction model of selective NO molecule decomposition. The expected mechanism of the absorption and decomposition of N to Ni, and oxygen capturing and pumping in the region of high

    nano-spacenanonanonanonano -space-space decomposition of N to Ni, and oxygen capturing and pumping in the region of high

    space decomposition of N to Ni, and oxygen capturing and pumping in the region of high

    space decomposition of N to Ni, and oxygen capturing and pumping in the region of high

    space decomposition of N to Ni, and oxygen capturing and pumping in the region of high

    spacespacespacespacespacenano-space

    Ni nano particles

    high conc. oxygen defects layer

    NOx m olecules

    O2-(→O2) N2

    Proposed Mechanism of Selective DeNOx Reaction

  • Improvement of de-NOx / current efficiency

    0 50 100 150 200 250 0

    10

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    80 oxygen 2% t=7000C

    1000ppm-NO Pt-13000C Ag-8000C Pd-8000C Pd-13000C Pd-Pt-13000C

    Literature

    t=6000C oxygen 2% 1000ppm-NO

    EC electrode

    N O

    x C

    on ve

    rs io

    n (%

    )

    Current (mA) 0 50 100 150 200 250

    0

    10

    20

    30

    40

    50

    60

    70

    80

    0 50 100 150 200 250 0

    10

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    80 oxygen 2% t=7000C

    1000ppm-NO Pt-13000C Ag-8000C Pd-8000C Pd-13000C Pd-Pt-13000C

    Literature

    t=6000C oxygen 2% 1000ppm-NO

    EC electrode

    N O

    x C

    on ve

    rs io

    n (%

    )

    Current (mA) 0 50 100 150 200 250

    0

    10

    20

    30

    40

    50

    60

    70

    80 oxygen 2% t=7000C

    1000ppm-NO Pt-13000C Ag-8000C Pd-8000C Pd-13000C Pd-Pt-13000C

    Literature

    t=6000C oxygen 2% 1000ppm-NO

    EC electrode

    N O

    x C

    on ve

    rs io

    n (%

    )

    Current (mA) 0 50 100 150 200 250

    0

    10

    20

    30

    40

    50

    60

    70

    80

    0 50 100 150 200 250 0

    10

    20

    30

    40

    50

    60

    70

    80 oxygen 2% t=7000C

    1000ppm-NO Pt-13000C Ag-8000C Pd-8000C Pd-13000C Pd-Pt-13000C

    Literature

    t=6000C oxygen 2% 1000ppm-NO

    EC electrode

    N O

    x C

    on ve

    rs io

    n (%

    )

    Current (mA)

    Energy efficiency of

    ordinary catalyst system

    previous results

    meso- scale

    control

    nano- scale

    control

    C ell current (m A)

    N O

    x de

    co m

    po si

    tio n

    (% )

    @2001

    @2003

    0 50 100 150 200 250 0

    10

    20

    30

    40

    50

    60

    70

    80 oxygen 2% t=7000C

    1000ppm-NO Pt-13000C Ag-8000C Pd-8000C Pd-13000C Pd-Pt-13000C

    Literature

    t=6000C oxygen 2% 1000ppm-NO

    EC electrode

    N O

    x C

    on ve

    rs io

    n (%

    )

    Current (mA) 0 50 100 150 200 250

    0

    10

    20

    30

    40

    50

    60

    70

    80

    0 50 100 150 200 250 0

    10

    20

    30

    40

    50

    60

    70

    80 oxygen 2% t=7000C

    1000ppm-NO Pt-13000C Ag-8000C Pd-8000C Pd-13000C Pd-Pt-13000C

    Literature

    t=6000C oxygen 2% 1000ppm-NO

    EC electrode

    N O

    x C

    on ve

    rs io

    n (%

    )

    Current (mA) 0 50 100 150 200 250

    0

    10

    20

    30

    40

    50

    60

    70

    80 oxygen 2% t=7000C

    1000ppm-NO Pt-13000C Ag-8000C Pd-8000C Pd-13000C Pd-Pt-13000C

    Literature

    t=6000C oxygen 2% 1000ppm-NO

    EC electrode

    N O

    x C

    on ve

    rs io

    n (%

    )

    Current (mA) 0 50 100 150 200 250

    0

    10

    20

    30

    40

    50

    60

    70

    80

    0 50 100 150 200 250 0

    10

    20

    30

    40

    50

    60

    70

    80 oxygen 2% t=7000C

    1000ppm-NO Pt-13000C Ag-8000C Pd-8000C Pd-13000C Pd-Pt-13000C

    Literature

    t=6000C oxygen 2% 1000ppm-NO

    EC electrode

    N O

    x C

    on ve

    rs io

    n (%

    )

    Current (mA)

    Energy efficiency of

    ordinary catalyst system

    previous previous previous resultsresultsresults

    previous results

    meso- scale

    control

    nano- scale

    control

    C ell current (m A)

    N O

    x de

    co m

    po si

    tio n

    (% )

    @2001

    @2003

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