大気圧酸素プラズマによる金ナノ粒子触媒の低温再生

ᄢ᳇࿶㉄⚛ࡊ࡜࠭ࡑߦࠃࠆ㊄࠽ࡁ☸ሶ⸅ᇦߩૐ᷷ౣ↢

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(2006 ᐕ 12 ᦬ 6 ᣣฃઃ㧘2006 ᐕ 12 ᦬ 27 ᣣฃℂ)

Low Temperature Regeneration of Gold Nanoparticle Catalyst Using

Atmospheric Pressure Oxygen Plasma

Hyun-Ha KIM,

_{Masakazu DATÉ,}

_{Susumu TSUBOTA,}

_{Atsushi OGATA}

and Shigeru FUTAMURA

(Received December 6, 2006; Accepted December 27, 2006)

Oxygen plasma was applied to the low temperature regeneration of the deactivated nanometer sized gold

(Au) supported on titanium dioxide (TiO

). The Au/TiO

catalyst, prepared by a deposition-precipitation method,

exhibited a very high catalytic activity for the oxidation of 1000 ppm CO in air. The initial activity completely

disappeared when the catalyst was used in the plasma-driven catalysis of 200 ppm benzene. Oxygen plasma

treatment of the deactivated Au/TiO

catalyst recovered catalytic activity up to 88% at 22000 h

.

1. ߪߓ߼ߦ ૐ᷷ࡊ࡜࠭ࡑᛛⴚࠍ↪޿ߚើ⊒ᕈ᦭ᯏൻว‛㧔એਅVOC㧕 ߩಽ⸃ߦ߅ߌࠆ⺖㗴ߩ৻ߟߣߒߡ㧘CO ߩ↢ᚑᛥ೙ߣ CO㧞 ߩ෼₸ะ਄߇᜼ߍࠄࠇࠆ㧚᳇⋧࡜ࠫࠞ࡞෻ᔕߦࠃࠆCO ㉄ ൻߪᲧセ⊛ㆃ޿ߚ߼㧘ૐ᷷ࡊ࡜࠭ࡑන⁛ߢCO ࠍ CO2ߦቢ ో㉄ൻߔࠆߩߪ࿎㔍ߢ޽ࠆ㧚Pt ߿ Rd ╬ߩ⾆㊄ዻ⸅ᇦߪ CO ㉄ൻ෻ᔕߦᵴᕈࠍ␜ߔ߇㧘200o_{C ⒟ᐲߩ㜞޿᷷ᐲ߇ᔅ} ⷐߢ޽ࠆ㧚⸅ᇦጀߩ೨Ბߢࠝ࠱ࡦࠍᷝടߔࠆߣ㧘100o_{C એ} ਅߢ߽CO ㉄ൻ෻ᔕ߇ଦㅴߐࠇࠆߎߣ߇ႎ๔ߐࠇߡ޿ࠆ1), 2)_{㧚৻ᣇ㧘㉄ൻ‛⴫㕙ߦᜂᜬߒߚ☸ᓘ10 nm એਅߩ㊄⸅ᇦ} ߪቶ᷷એਅߢ߽ಽሶ⁁㉄⚛ࠍ↪޿ߚ CO ㉄ൻ෻ᔕߦ㕖Ᏹ ߦ㜞޿ᵴᕈࠍ␜ߔ3), 4)㧚㊄࠽ࡁ☸ሶ⸅ᇦߪ☸ᓘଐሽᕈ߇ᄢ ߈ߊ㧘10 nm એਅߢߥ޿ߣᵴᕈࠍ⊒⃻ߒߥ޿ߚ߼㧘⸅ᇦౣ ↢ᤨߩಝ㓸ߦࠃࠆᄬᵴࠍ㒐ߋߦߪ㧘ടᾲߦࠃࠄߥ޿⸅ᇦౣ ↢ᛛⴚ߇ᦸ߹ࠇࠆ㧚ߎࠇ߹ߢᄬᵴߒߚ㊄࠽ࡁ⸅ᇦߩૐ᷷ౣ ↢ᛛⴚߣߒߡ⚡ᄖ✢ࠍᾖ኿ߔࠆᣇᴺ߇ႎ๔ߐࠇߡ޿ࠆ߇㧘 ಣℂᤨ㑆߇㐳ߊ㧘⸅ᇦߦኻߔࠆᾖ኿ߩဋ৻ᕈ╬ߦᡷༀ߇᳞ ߼ࠄࠇߡ޿ࠆ㧚 ᧄ⎇ⓥߢߪ㧘ᄬᵴߒߚ㊄࠽ࡁ☸ሶ⸅ᇦߩૐ᷷ౣ↢ᴺߣߒ ߡᄢ᳇࿶㉄⚛ࡊ࡜࠭ࡑߩㆡ↪น⢻ᕈߦߟ޿ߡᬌ⸛ߒߚ㧚ߎ ࠠ ࠠ࡯࡯ࡢࡢ࡯࡯࠼࠼㧦㉄⚛ࡊ࡜࠭ࡑ㧘㊄࠽ࡁ☸ሶ⸅ᇦ㧘CO ㉄ൻ 㧖 ↥ᬺᛛⴚ✚ว⎇ⓥᚲ㧔305-8569 ⨙ၔ⋵ߟߊ߫Ꮢዊ㊁Ꮉ 16-1 ↥✚⎇⷏㧕

National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba West, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan

 [email protected] ߩ㉄⚛ࡊ࡜࠭ࡑߦࠃࠆౣ↢ᴺߪേ૞᷷ᐲ߇ቶ᷷ߢ޽ࠆ ߚ߼㧘ᾲߦࠃࠆ㊄࠽ࡁ☸ሶߩಝ㓸ࠍ㒐ߋߎߣ߇ᦼᓙߢ߈ࠆ㧚 2. ታ㛎 ᧄ⎇ⓥߢߪ㧘㉄ൻ࠴࠲ࡦ㧔TiO2㧕ࡍ࡟࠶࠻ߩ㧔ᐔဋ☸ᓘ 1.8 mm㧕਄ߦᨆ಴ᴉᲚᴺ (deposition-precipitation method㧘 એਅDP ᴺ)ߦࠃࠅ㊄࠽ࡁ☸ሶࠍᜂᜬߐߖ㧘CO ㉄ൻࠍᜰᮡ ෻ᔕߣߒߡ⸅ᇦᵴᕈࠍ⹏ଔߒߚ㧚㊄ߩᜂᜬ㊂ߪ2wt%ߣߒ ߚ㧚㊄࠽ࡁ☸ሶ⸅ᇦߩᒻ⁁߅ࠃ߮ࠨࠗ࠭ߪ㧘TEM (Hitachi Co., H9000NAR)ߦࠃࠅⷰኤߒߚ㧚࿑ 1 ߦ෻ᔕེߩ᭎⇛࿑ࠍ ␜ߔ㧚ౝᓘ13 mm,᦭ല㐳 200 mm ߩ⍹⧷▤ߩਛߦ㜞㔚࿶ 㔚ᭂߣߒߡࠦࠗ࡞⁁ߩࠬ࠹ࡦ࡟ࠬࡢࠗࡗ࡯ࠍᝌ౉ߒߚ㧚㉄ ⚛ࡊ࡜࠭ࡑߪᄬᵴߒߚ⸅ᇦߩౣ↢ߩ㓙ߦߩߺශടߒ㧘CO ߩ㉄ൻ෻ᔕߪࡊ࡜࠭ࡑࠍශടߖߕߦቶ᷷ߢⴕߞߚ㧚෻ᔕེ ߦలႯߒߚAu/TiO2⸅ᇦߩ㊂ߪ߅ࠃߘ25 cm3ߢ޽ࠆ㧚㉄⚛ ࡊ࡜࠭ࡑߩ᡼㔚㔚ജߣಣℂᤨ㑆ߪߘࠇߙࠇ10. 9 W ߣ 30 ಽߣߒߚ㧚ࡊ࡜࠭ࡑߩ⊒↢ߦߪ㧘AC 㜞㔚࿶㧔30 kVp-p, 300 Hz㧕ࠍ૶↪ߒߚ㧚᡼㔚㔚ജߪ㧘V-Q ࡝ࠨ࡯ࠫࡘࡊࡠࠣ࡜ ࡓ㧔ࠗࡦࠨࠗ࠻␠㧘Ver. 1.72㧕ࠍ↪޿ߡ⸘▚ߒߚ5)_㧚ࠟࠬ ᵹ㊂ߪ4~24 L/min ߩ▸࿐ߢᄌൻߐߖ㧘ⓨ㑆ㅦᐲߩᓇ㗀ࠍ ⺞ߴߚ㧚㉄⚛ߣCO ࠟࠬߩỚᐲߪߘࠇߙࠇ 20㧑ߣ 1000 ppm ߣߒߚ㧚FTIR (Perkin Elmer, Spectrum One)ࠍ↪޿ߚ CO ߩ ቯ㊂ಽᨆߢߪ㧘ࠝ࠱ࡦߦࠃࠆᐓᷤࠍㆱߌࠆߚ߼ᵄᢙ 2162 cm-1_{ߩCO ๆ෼ࡇ࡯ࠢࠍ↪޿ߚ㧚}

, 31, 2 (2007) 78 79 J. Inst. Electrostat. Jpn.

AC high voltage

Au/TiO

Ground electrode

࿑1 ෻ᔕེߩ᭎⇛࿑ Fig. 1 Schematic diagram of the reactor.

3. ⚿ᨐߣ⠨ኤ ࿑2 ߦ㧘㊄࠽ࡁ☸ሶ⸅ᇦߦࠃࠆ CO ㉄ൻ෻ᔕߩᵴᕈࠍ␜ ߔ㧚DP ᴺߢ⺞⵾ߒߚ㊄࠽ࡁ☸ሶߩ☸ᓘߪ⸅ᇦᵴᕈ߇㜞޿ ߣߐࠇߡ޿ࠆ3 nm ߆ࠄ 7 nm ߦಽᏓߒߡ޿ߚ㧚⺞⵾⋥ᓟߩ ㊄࠽ࡁ☸ሶ⸅ᇦߪ CO ㉄ൻ෻ᔕߦኻߔࠆᵴᕈ߇㕖Ᏹߦ㜞 ߊ㧘ⓨ㑆ㅦᐲ130,000 h-1_{߹ߢ98㧑એ਄ߩォൻ₸ࠍ␜ߒߚ㧚} ෻ᔕߒߚCO ߪ 100㧑ߩ෼₸ߢ CO2ߦォ឵ߐࠇߚ㧚ߒ߆ߒ㧘 10 ᤨ㑆߶ߤࡊ࡜࠭ࡑࠍශടߒߥ߇ࠄࡌࡦ࠯ࡦಽ⸃෻ᔕߦ ૶↪ߔࠆߣ㧘CO ㉄ൻᵴᕈߪቢోߦᄬࠊࠇߚ㧚ᄬᵴߩේ࿃ ߣߒߡߪ㧘ࡌࡦ࠯ࡦಽ⸃෻ᔕߩਛ㑆↢ᚑ‛╬߇㊄࠽ࡁ☸ሶ ߩ⴫㕙ߦၸⓍߒ㧘⸅ᇦᵴᕈࠨࠗ࠻߇Ⴇ߇ࠇߚߚ߼ߣ⠨߃ࠄ ࠇࠆ㧚ߎߩೋᦼᵴᕈࠍቢోߦᄬߞߚAu/TiO2⸅ᇦࠍቶ᷷ߢ ㉄⚛ࡊ࡜࠭ࡑ㧔᡼㔚㔚ജ10.9 W㧕ࠍ↪޿ߡ 30 ಽ㑆ಣℂߔ ࠆߎߣߦࠃࠅ㧘⸅ᇦᵴᕈ߇㗼⪺ߦ࿁ᓳߐࠇࠆߎߣ߇⏕⹺ߐ ࠇߚ㧚㉄⚛ࡊ࡜࠭ࡑߢౣ↢ߒߚ Au/TiO2⸅ᇦߦౣ߮ 1000 ppm ߩ CO ࠟࠬࠍᵹߔߣ㧘ⓨ㑆ㅦᐲߦࠃࠅ⇣ߥࠆ߇ 22,000 h-1_{ߢߪCO ォ឵₸ 88㧑߹ߢᵴᕈ߇࿁ᓳߒߚ㧚ߎࠇߪ㧘ᵴ} ᕈὐࠍⷒߞߡ޿ߚ᦭ᯏ‛߇㉄⚛ࡊ࡜࠭ࡑߦࠃࠅಽ⸃㒰෰ ߐࠇߚߚ߼ߣᕁࠊࠇࠆ㧚ⓨ᳇ਛߦ߅ߌࠆૐ᷷ࡊ࡜࠭ࡑߦᲧ ߴ㉄⚛ࡊ࡜࠭ࡑߢߪ㧘⓸⚛㉄ൻ‛߇↢ᚑߖߕ㧘⸅ᇦ⴫㕙਄ ߩVOC ߿ਛ㑆↢ᚑ‛ࠍࠃࠅല₸ࠃߊ㉄ൻಽ⸃น⢻ߢ޽ࠆ 6)_{㧚ಝ㓸ߦࠃࠅ㊄࠽ࡁ☸ሶߩ☸ᓘ߇ᄢ߈ߊߥࠆߣCO ㉄ൻ} ᵴᕈߪ⊒⃻ߒߥ޿ߎߣ߆ࠄ㧘㉄⚛ࡊ࡜࠭ࡑߦࠃࠆౣ↢ಣℂ ᓟߩᵴᕈὐ᭴ㅧߪ଻ߚࠇߡ޿ࠆߣ⠨߃ࠄࠇࠆ㧚㉄⚛ࡊ࡜࠭ ࡑߩ᡼㔚㔚ജ߿ಣℂᤨ㑆ࠍᄢ߈ߊߔࠆߣ㧘⸅ᇦᵴᕈߩ࿁ᓳ ᐲว޿߇ᄢ߈ߊߥࠆߎߣ߇ࠊ߆ߞߡ޿ࠆ㧚੹ᓟ㧘㉄⚛ࡊ࡜ ࠭ࡑߩ೑↪ᴺࠍ♖ᩏߔࠆߎߣߦࠃߞߡ㧘㊄࠽ࡁ☸ሶ⸅ᇦߩ ૐ᷷ౣ↢ᴺࠍߐࠄߦᦨㆡൻߢ߈ࠆߣ੍ᗐߐࠇࠆ㧚 0 30000 60000 90000 120000 C O ox id at io n ef fic ie nc y (% ) Space velocity (h-1₎ Fresh Au/TiO₂ 0 20 40 60 80 100 Deactivated Au/TiO₂ Regenerated Au/TiO₂

using oxygen plasma

࿑2 ㊄࠽ࡁ☸ሶ⸅ᇦߩ CO ㉄ൻ෻ᔕߦኻߔࠆᵴᕈ㧔ቶ᷷㧘 ㉄⚛ࡊ࡜࠭ࡑߦࠃࠆᄬᵴ⸅ᇦߩౣ↢㧧10.9 W, 30 ಽಣℂ) Fig. 2 CO oxidation by Au nanoparticle catalyst (room temperature, Regeneration of deactivated catalyst using oxygen plasma; 10.9 W, 30 min). 4. ߹߹ߣߣ߼߼ ㉄ൻ࠴࠲ࡦ਄ߦᨆ಴ᴉᲚᴺߦࠃࠅ⺞⵾ߒߚ☸ᓘ 10 nm એਅߩ㊄࠽ࡁ☸ሶ⸅ᇦߦࠃࠆ CO ㉄ൻ෻ᔕߦߟ޿ߡᬌ⸛ ߒߚ㧚ᧂ૶↪ߩAu/TiO2⸅ᇦߪቶ᷷㧘ⓨ㑆ㅦᐲ130,000 h-1 ߩ᧦ઙߢ߽98%એ਄ߩ㜞޿ CO ㉄ൻᵴᕈࠍ␜ߒߚ㧚৻ᣇ㧘 CO ㉄ൻᵴᕈࠍቢోߦᄬߞߚ Au/TiO2⸅ᇦߦ㉄⚛ࡊ࡜࠭ࡑ ࠍශടߔࠆߎߣߦࠃࠅ㧘ቶ᷷ߢ⸅ᇦߩౣ↢߇น⢻ߢ޽ࠆߎ ߣࠍ᣿ࠄ߆ߦߒߚ㧚ᒰ⹥ᛛⴚߪ㊄࠽ࡁ☸ሶ⸅ᇦߩߺߥࠄߕ㧘 ৻⥸ߩ⸅ᇦߦኻߒߡ߽⸅ᇦᵴᕈὐߩഠൻࠍᦨዊ㒢ߦߔࠆ ߎߣ߇ߢ߈ࠆౣ↢ᛛⴚߣߒߡᦼᓙߐࠇࠆ㧚 ෳ⠨ᢥ₂

1) A. Naydenov, R. Stoyanova, D. Mehandjiev: J. Molecular Cat. A: Chemical, 98 (1995) 9

2) M. Petersson, D. Jonsson, H. Persson, N. Cruise, B. Andersson: J. Catal., 238 (2006) 321

3) M. Haruta, N. Yamada, T. Kobayashi, S. Iijima: J. Catal.,

115 (1989) 301

4) M. Daté, Y. Ichihashi, T. Yamashita, A. Chiorino, F. Boccuzzi, M. Haruta: Catal. Today, 72 (2002) 89

5) H. H. Kim, A. Ogata, S. Futamura: IEEE Trans. Plasma Sci.,

34 (2006) 98

6) ㊄⾫ᄐ㧘ᧉᱜᣩ㧘ፕℙ◪㧘๓ᕈᣱ㧘የᒻᢕ㧘ੑ㩊᧛᫪㧦

㕒㔚᳇ቇળ⹹㧘29 (2005) 32