Selective reduction of NO with methane over alumina-supported palladium catalysts

Article abstract of DOI:10.1246/nikkashi.2000.467

To lower the air pollution level caused by diesel engine exhaust gases and other sources, SCR of NO_x with methane in the presence of oxygen was studied over metal oxide-supported Pd catalysts. Effect of various metal oxides and conditions for c

Full text of DOI:10.1246/nikkashi.2000.467

ú»C2000, No. 7 îtEàcêEHcElcFA‹~iSp‰WE€G}Éæé^“ðÒ³ÜÆ·é NO IðÒ³
467
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2000 The Chemical Society of Japan
\
ê Ê _ ¶
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A‹~iSp‰WE€G}Éæé^“ðÒ³ÜÆ·é NO IðÒ³
i1999 N 12 Ž 9 úój
î t
mÞEàcêúEH c - ¾El c G º
à®_»¨Sp‰WE€G}ÉæéC^“ðÒ³ÜƵÄp¢½ NO IðÒ³½žðs¢CS
ÌÌíÞâp‰WE€SÊC²»ðÈÇÌe¿É¢ğ¢µ½DG}ˆ«ÍÅ谬ʽž•u
ðp¢Äªèµ½DA‹~iSÌżÌà®íðS³¹½G}âCp‰WE€SÅ¼Ìà®_»¨
SÌðp¢½G}ÆärµÄCA‹~iSp‰WE€G}Í NO IðÒ³½žÉ¨¢ÄÁÙIɂ
ˆ«ð¦µ½D‚·ÅÒ³EOˆðsÁ½A‹~iSp‰WE€G}ÅÍCˆ«ªáºµ½DLƒ
‰N^Š[[V‡“Ì‹ÊCA‹~iSÌÍÁÉÅÌ_«ª‚-Cܽp‰WE€ªUxà‚-ÈÁ
½D¯¶A‹~iSÌÅàC‚·ÅÒ³ðsÁ½àÌÍCp‰WE€ªUxªá-ÈÁ½D±êç̋
Ê©çCSÌÌÅÌ_«Æo‰WE€ªUxªCG}̈«É§ÚÉÖ^µÄ¢é±Æªí©Á½DÜ
½½žoHÍCp‰WE€ãŁ^“ª”ª_»³êC»Ì”ª_»¨ªA‹~iãÅ NOx ƽž·
éÆ¢¤oHªl¦çê½D
ÁÄ NO Ò³ˆ«ªÏ»µCA‹~iSp‰WE€Ìˆ«ª
A 
¾
Áɂ¢±Æð©¢¾µ½D³çÉCp‰WE€ªUxâSÌÌ
ÅÌ_«ªG}ˆ«É^¦ée¿É¢ğ¢µ½ÌÅC±êç
̋ÊÉ¢Äñ·éD
ßNCfB[[‹ÔÈÇ©çro³êé‚f_»¨(NO )Éæ
x
高õâlÌÖÌíQªâèÆÈÁĨèC»ÌḪ}±
ÆÈÁÄ¢éD»Ì½ßCfB[[‹G“W“âŠ[“o[“G
B À
±
“W“ÈÇ̂Zx_fðÜÞrKX†Ì NO 𜎷éG}
x
ZpJ-ªßçêÄ¢éD»Ý¤†³êÄ¢éLøÈ NO œ
x
B.A G } ² »
Ž@ÌêÂÉCY»ꢀfðÒ³ÜƵÄp¢½IðÒ³@ª
éD±êÜÅÒ³ÜƵÄÍCp‰tB“nCIŒtB“nCF
°nÈÇC³Ü´ÜÈY»ꢀfªp¢çêÄ«½1)–3)Dµ©
µC^“ÍRĵÉ-¢«¿Ì½ßCÒ³ÜƵÄ̘pÍ¢
à®_»¨Sp‰WE€G}ÍCà®_»¨SÌÉp‰WE
€–ntðÜZ³¹Ä²»µ½DG}²»Égpµ½à®_»¨
SÌÍCA‹~iCVŠJA‹~iC`^jACW‹RjACV
”
ŠJðp¢½DA‹~iSÌÍú{Pb`F“ò»
NK–16280
”
ïÅ éÆl¦çêÄ«½D^“ðÒ³ÜƵ½ NO IðÒ
x
(\ÊÏ 250 m2 g|1 )ÆG}»¬ò»
Ì 2 íÞðp¢½DVŠJA‹~iSÌÍA‹~iÜLʪ 60
CM–3
167 m2 g|1
CM–4
(\ÊÏ
228 m2 g|1
)
³G}ƵÄC[I‰CgnG}ÅÍCençÉæéC“WE
€CKŠE€n[I‰CgnG}â4)–6) C䀶CAdelman,
Labree çÉæép‰WE€n[I‰CgnG}7)–11)ÈÇLøÈ
G}ªñ³êÄ¢éDêûCà®_»¨nG}É¢ÄÍCA
‹~iG}CRo‹gSA‹~iG}12)ªˆ«ð¦·±Æª
ñ³êÄ¢éªCˆ«ð¦··xÌ檂¢Æ¢¤‡_ª éD
^“Ì_»½žÅÍp‰WE€G}ª‚¢ˆ«ð¦·±Æª
ñ³êÄ¢éÌÅ13)–16)C{¤†ÅÍC^“ðÒ³ÜƵ½
³Ü´ÜÈà®_»¨Sp‰WE€G}Éæé NO IðÒ³
ˆ«É¢ğ¢µ½D_»¨Sp‰WE€G}ã́^“É
”
÷ÌG}»¬ò»
ASÌÍ_C„Lƒ^ŠXgò”» DC–3132(\ÊÏ 38 m2 g|1
DS–55
41 m2 g|1
(\ÊÏ
)ðp¢½D`^j
)
)
”
ðCW‹RjASÌÍúö»wò»
(\ÊÏ
CARIACT G–10
”
ðCVŠJSÌÍxmVŠVA»wò»
(\Ê
Ï 291 m2 g|1)ðp¢½D
¢¸êÌà®_»¨SÌàCÜZðs¤OÉóCĬOˆð
sÁ½DA‹~iCVŠJCVŠJA‹~iÍ600 ‹CÅĬµC
`^jAÆW‹RjAÍ520 ‹CÅĬµ½DȨCA‹~i
(CM–4)ÆVŠJA‹~iͲóÅ èCĬãC»ÌÜÜÌó
ÔÅgpµ½DA‹~i(NK–16280)C`^jACW‹RjAC
æé NO IðÒ³ÍCResasco çÉæé°_W‹RjASÌ17)
C
Ozkan çÉæé`^jASÌ18)ÈÇCÂÊÌSÌÉÖ·éñ
ªô© éªCSÌíCSÊC²»ðÌe¿ð‡Iɟ
¢µ½àÌͽ-È¢D{¤†ÅÍCSÌÌíÞâ²»ðÉæ
VŠJÍĬãCÓµÄÓé¢É©¯CbVꢀ20
850 mm)̱aÌàÌðp¢½D
p‰WE€´¿ÆµÄÍeg‰A“~“p‰WE€(Ü)É_–
\
32(500
\
nt([Pd(NH3)4](NO3)2soln.)ðp¢½DSÌÉntðÜZãC
110 ‹CÅö-íðp¢Ä£‡³¹½ãC´¥ÆµÄC200 cm3
¨¿HwHÆZp¤†ŠC305–8565 Â-ÎsŒ 1–1

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min|1 Ìꢀf¬ÊºÅ 400 ‹CÒ³µ½ãÉ}bt‹F†Å 500
‹CÅĬµ½DꔱÌððÏ»³¹éÀ±àsÁ½Dܽä
r̽ßC’àCCŠWE€CWE€CRo‹gSG}à¯
lÌû@Ų»µ½DSà®Ì´¿Í»ê¼êCeg‰A“~
“’à(Ü)É_–nt([Pt(NH3)4](NO3)2soln.)C–»CŠWE
€(Þ)(IrCl4EH2O)C–»WE€(Ý)(RhCl3E3H2O)C|_
Ro‹g(Ü)(Co(OAc)2E4H2O)ðp¢½D’àCCŠWE€C
WE€SÅÍCp‰WE€Ìê‡Æ¯lÉꢀf¬ÊºÅ 400
‹CÒ³µ½ãÉ}bt‹F†Å 500 ‹CÅĬµ½DRo‹gS
Å͂fÆ_f̬‡KX(4 : 1)¬ÊºÅ 500 ‹CĬµ½ãÉ}
bt‹F†Å 500 ‹CÅĬµ½D
·×Ä 0.1 wt÷Å éDNO Ì N2 ÖÌÒ³¦Æ^“Ì CO Ö
x
Ì_»¦ð Fig. 1 ɦ·D±ÌÆ«CN2O ̶¬ÍÙÆñÇÈ
-C^“Æ CO ̇vÅ éJ[{“o‰“XàÙÚ 100÷
x
Å
Á½Där̽ßCA‹~iPÆÅ̈«à¦µ½DA‹~
iPÆÅà500 ‹CÈã̂·ÅÍ NO Ò³ˆ«ª-»µC³çÉ
Ro‹gÌSÉæèá·Å̈«ªüã·é±Æªí©éDA
‹~iSMà®G}É¢ÄÍC’àCCŠWE€CWE€
ÅÍ NO Ò³ˆ«Íá©Á½ªCp‰WE€SG}ª NO Ò
³É¨¢ÄÁÙIɂˆ«Å èC^“_»É¨¢Äà¼ÌS
à®Éäׂˆ«Å é±Æªí©éD
ŸÉCp‰WE€G}ɨ¯é_»¨SÌÌ NO IðÒ³ˆ
«ÖÌe¿ð²×½Dp‰WE€SÊÍ0.1 wt÷Ƶ½D‹Ê
ð Fig. 2 ɦ·DA‹~i(NK–16280)ªSÌÌƫ͂¢ NO
Ò³ˆ«ª-»·éªCVŠJC`^jACW‹RjAªSÌÌ
Æ«ÍS-ˆ«ª-»µÈ©Á½D¯¶A‹~iÅà CM–4 Ì
ê‡Íˆ«ªá-CVŠJA‹~iÅÍ NO Ò³ˆ«ÍFßç
êÈ©Á½D±Ì‹Ê©çC{¤†ÌÍÍàÅÍCA‹~iªB
êøÊIÈSÌÅ èC¼ÌSÌÅ͈«ª-»µÈ¢±ÆCA
‹~iÉVŠJª¡‡·é±ÆÉæÁĈ«ªÙÚ®SÉÁ¸·
é±Æª¾ç©ÆÈÁ½DܽCG}ˆ«Ígpµ½A‹~iÌ
B.B G}ˆ«]¿
G}ˆ«ÍCÅè°í³¬Ê½ž•uðp¢Äªèµ½D
NO IðÒ³ˆ«ÌªèÅÍC½žKXÍ´¥ÆµÄCNO
(1000 ppm), O2(10÷)C^“(3000 ppm)ðÜÞwŠE€ðp
¢CÚGžÔ(W/F)Í0.18 g s cm|3 Ƶ½D½žã̶¬KX
ÍKXN}gO‰tB[Ū͵½DJ‰€Í Molecular
Sieve 5A Æ Porapak Q Ì 2 íÞðp¢COÒÅ N2 Æ CO Ɓ
^“ðèʵCãÒÅ N2O Æ CO2 ðèʵ½Dˆ«ÍCNO Ì
N2 ¨æÑ N2O ÖÌ]»¦Æ^“Ì CO (CO{CO2)ÖÌ]»¦
x
Å®µ½D
íÞÉà˶µ½DêûÅC^“Ì CO ÖÌ_»ˆ«ÍW‹
x
êûCNO ©ç NO2 ÖÌ_»ˆ«à]¿µ½ªC±Ìê‡C
½žKXÍ NO(1000 ppm)Æ O2(10÷)ðÜÞwŠE€ðp¢C
RjASÌÌê‡ÁÉá¢Ù©ÍCSÌÉæÁÄÙÆñÇÏ»µ
È¢±Æ͍ڳêéD
ÚGžÔ(W/F)Í 0.2 g s cm|3 Ƶ½D¶¬KX†ÌNO (NO
ŸÉCp‰WE€SA‹~i(NK–16280)ɨ¯ép‰WE
€SÊÌe¿ð²×½DSÊÍ0.05÷©ç1.0÷ÌÔÅÏ»
³¹½D‹Êð Fig. 3 ɦ·DNO Ò³ˆ«Íp‰WE€SÊ
ª 0.1 wt÷ÌÆ«ÉÅà‚ˆ«ð¦µC‚SÊÅÍ NO Ò³
¦ªáºµ½Dêû^“_»ˆ«ÍCp‰WE€SÊªÁ
x
{NO2)ZxÍ»w-õ@ NO ªÍvÅ힂j^[µ½D±Ì
x
žCNO¨NO2 R“o[^[ðoRµÈ¢æ¤ÉoHðØèÖ¦
é±ÆÉæÁÄCNO †Ì NO ÌèÊðsÁ½D
x
B.C Lƒ‰N^Š[[V‡“
G}ÌLƒ‰N^Š[[V‡“ƵÄCCO zꢀÉæép‰W
E€ÌªUxªèÆCA“‚jA TPD ÉæéSÌÌÅÌ_«Ì
ªèðsÁ½D
B.C.A p‰WE€ªUxªèFŽ¿ÌÊÍ0.2 g Ƶ½Dꢀf
C¬†Åº·©ç350 ‹CÜÅ 30 ªÅ¸·µÄ350 ‹CÅ 30 ªÒ³
ˆµC»Ìã 50 ‹CÜÅ 60 ª©¯Ä~·µ½D50 ‹CɞBã
¬ÊKXðꢀf©çwŠE€ÉØèÖ¦½DÈãÌOˆðsÁ
½ãC20÷CO/He ðp¢½p‹X@ÉæÁÄzꢀ CO Êð
ßC»Ìl©çp‰WE€ÌªUxðß½D±ÌÆ« CO 1 ª
qª Pd 1 ´qÉzꢀ·éàÌƼ赽D
”
B.C.B A“‚jA TPDFåq¤ò»¸·E£•u
Model
ATD 700A ðp¢Äªèµ½DŽ¿ÌÊÍ0.5 g Ƶ½DÎpZ
‹†ÌŽ¿ð500 ‹CÅ 1 h rCˆµ½ã 100 ‹CÉâpµC100
Torr ÌA“‚jAðZ‹†É±üµÄ 1 h zꢀ³¹C»ÌãC
ŠÌA“‚jAðrCµ½D±êçÌOˆðsÁ½ãC10 ‹C
min|1 ̬xŸ·µÄªèµ½DE£µ½A“‚jAÍM`±
¦Ÿoí(TCD)ðp¢ÄªÍµ½D
Fig. 1 Catalytic activities of alumina and 0.1÷ alumi-
na–supported various metals.
C ‹ÊÆl@
›, œ: Pd/Al2O3, ¢, £: Pt/Al2O3, , ¡: Ir/Al2O3,
ž, : Rh/Al O , ¤, ¥: Co/Al O , no symbol: Al O .
C.A Sp‰WE€G}Ì NO Ò³ˆ«
}
2
3
2
3
2
3
A‹~i(NK–16280)Ép‰WE€C’àCCŠWE€CW
E€CRo‹gðSµ½G}ðp¢C^“Éæé NO Ið
Ò³½žÉ¨¯éG}ˆ«ÖÌà®íÌe¿ðŸ¢µ½D^“
Éæé NO IðÒ³½žÉη鈫ð²×½Dà®SÊÍ
Solid line: NO conversion, dashed line: CH4 conversion.
Reaction conditions: NO1000 ppm, CH43000 ppm,
O210÷,
W/F0.18 g s cm|3
.

ú»C2000, No. 7 îtEàcêEHcElcFA‹~iSp‰WE€G}Éæé^“ðÒ³ÜÆ·é NO IðÒ³
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Fig. 2 Catalytic activities of 0.1÷ palladium supported on
metal oxides.
Fig. 4 Catalytic activities of 0.1÷ palladium supported on
alumina reduced or/and calcined under various condi-
tions.
›, œ: SiO2, ¢, £: Al2O3(NK–16280), , ¡: TiO2,
ž, : ZrO , ¤, ¥: Al O (CM–4), ~, {: SiO –Al O .
}
›, œ: 300 ‹C red. –500 ‹C calc., ¢, £: 300 ‹C red. –600
‹C calc.,
, ¡: 400 ‹C red. –500 ‹C calc., ž, : 600 ‹C red. –500
2
2
3
2
2
3
Solid line: NO conversion, dashed line: CH4 conversion.
Reaction conditions: NO1000 ppm, CH43000 ppm,
O210÷,
}
‹C calc.,
¤, ¥: 500 ‹C calc. –500 ‹C calc., ~, {: 500 ‹C calc.
–600 ‹C calc.
W/F0.18 g s cm|3
.
Solid line: NO conversion, dashed line: CH4 conversion.
Reaction conditions: NO1000 ppm, CH43000 ppm,
O210÷,
W/F0.18 g s cm|3
.
min|1 Ìꢀf¬ÊºÅ 300 ‹CÒ³µ½ãÉ}bt‹F†Å 500
Q300 C
‹CĬCò ‹Ò³ÌãÉ
R400 C
500
‹Ä¬Cò
600 C
‹Ò³ÌãÉ
S600 C
‹CĬCò ‹Ò³ÌãÉ
500 C
T100 cm3 min|1
‹Ä¬Cò
̂
fÆ_f̬‡KX(4 : 1)¬ÊºÅ 500 ‹CĬÌãÉ500 ‹CĬC
U500 C
600 C
ò
‹Ä¬ÌãÉ ‹Ä¬CÌ íÞÌðÅÒ³EĬð
6
s¢CG}ˆ«É^¦ée¿ð²×½D‹Êð Fig. 4 ɦ·D
600 ‹CÒ³ðʼnÉsÁ½àÌÍ NO Ò³ˆ«ªá-ÈÁ½ªC
»êÈOÌðÅÍCNO Ò³ˆ«ÉÍÙÆñÇÏ»ÍÈ©Á
½DܽC^“_»ˆ«Í±êçÌÒ³EĬðÌe¿ðÙ
ÆñÇó¯È©Á½D
C.B G}ÌLƒ‰N^Š[[V‡“
C.B.A SÌÌÅÌ_«F{G}Ì NO Ò³ˆ«Ée¿·éö
qƵÄCܸSÌÌÅÌ_«ªl¦çêéÌÅCA“‚jA
TPD ÉæéSÌÌÅÌ_«ÌªèðsÁ½DTPD XyNg‹ð
Fig. 5 ɦ·D¢¸êÌSÌà200 ‹CßÓÉs[Nª èC_-
x É Í å « È · Í F ß ç ê È © Á ½ D ê û Å C A ‹ ~ i
(NK–16280)ÌÅÌ_ʪÁɽ-CA‹~i(CM–4)àÙÚ¯
öxÌÅÌ_ÊðL·é±Æªí©Á½DܽVŠJA‹~i
ÍCA‹~iÜL¦ÌáºÉºÁÄÅÌ_Êà¸-µ½DêûC
`^jAÆW‹RjAÌ_ÊÍ-È-CVŠJÍÙÆñÇ_«ð
LµÄ¢È¢±Æªí©éD
Fig. 3 Catalytic activities of alumina–supported palladium
with various loadings.
›, œ: 1.0÷, ¢, £: 0.5÷, , ¡: 0.2÷, ž, : 0.15÷,
}
¤, ¥: 0.1÷, ~, {: 0.05÷, no symbol: 0.0÷.
Solid line: NO conversion, dashed line: CH4 conversion.
Reaction conditions: NO1000 ppm, CH43000 ppm,
O210÷,
W/F0.18 g s cm|3
.
·éÙÇüã·é±Æªí©éD
C.B.B p‰WE€ªUxF{G}Ì NO Ò³ˆ«Ée¿·é
öqƵÄCp‰WE€ªUxªl¦çêéÌÅCp‰WE€S
³çÉC0.1 wt÷p‰WE€SA‹~i(NK–16280)ɨ¯
P200 cm3
éÒ³EĬðÌe¿ðŸ¢µ½DÜZC£‡ãCò
0.1 CO
÷ÌG}É¢ÄC zꢀÉæéªUxªèðsÁ½D
Ê

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Fig. 5 Results of NH3–TPD measurements.
›: Al2O3(NK–16280), œ: SiO2, ~: TiO2, ¢: ZrO2, {: Al2O3(CM–4), : SiO2–Al2O3.
Fig. 6 Dispersion of palladium of impregnated 0.1÷ metal oxide– supported palladium obtained from CO adsorption.
: 400 C red., ‚: Al O NK–16280 .
ò
‹
ò
(
3
)
2

ܸSÌÌe¿É¢IJ׽‹Êð Fig. 6òɦ·D±êç
ÌG} Í Fig. 2 É Îž· éàÌ Å éD‚ ˆ«Ì A‹ ~i
(NK–16280)SÌÉSµ½p‰WE€ÍªUxª‚-C»Ì¼
ÌSÌÉSµ½p‰WE€ÍSÌIɪUxªá¢±Æªí©
éDµ©µCW‹RjASp‰WE€ÍÙÆñÇ NO Ò³ˆ
«ªÈ©Á½Éà©©í縪UxªärI‚©Á½D
‹Êð
òɦ·D¯¶‚ˆ«A‹~i( )Sp
Fig. 6‚ NK–16280
‰WE€ÅàC600 ‹Ĉ·ÅꢀfÒ³ˆ·é±ÆÅCp‰W
E€ªUxªå«-ặé±Æªí©Á½D
C.C NO Ò³ˆ«-»Ìvö
ÈãÌÀ±‹Ê©çCSp‰WE€G}Ì NO Ò³ˆ«É
e¿ð^¦éöqðl@µ½DA‹~i(NK–16280)CA‹~i
(CM–4)CVŠJA‹~iC`^jACW‹RjACVŠJ»ê
¼êðSÌƵ½Sp‰WE€G}ÌSÌÌÝÌÅÌ_ÊCp
³çÉC‚ˆ«ÌA‹~i(NK–16280)Sp‰WE€G}É
¨¢ÄCp‰WE€ªUxÖÌÒ³EĬðÌe¿ð²×½D

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471
Table 1 Summary of catalytic activity measurement and characterization of metal oxide–supported palladium catalysts
TOF of NO conv.i450‹CjTOF of CH4 conv.i450‹Cj Amount of solid acid
I10|3 s|1
Pd dispersion
I÷
Metal oxide support
I10|3 s|1
I10|6 mol
Al2OiNK–16280ji400‹C red.j .72
3
8.15105 482.16 6.14
5
i600‹C red.j
10.63
6.73
0.00
0.00
0.00
0.00
193.07
228.88
285.65
684.53
33.36
482.16
461.09
328.36
171.59
194.08
28.28
18.05
15.20
8.78
Al2OiCM–4j
3
SiO2–Al2O3
TiO2
ZrO2
36.19
SiO2
978.66
39.153.82
‰WE€ªUxÌÙ©C450 ‹Cɨ¯é NO ©ç N2 ÖÌÒ³¨
æс^“©ç CO ÖÌ_»Ì^[“I[o[pxð Fig. 2 ©
x
çßCTable 1 ÉÜÆß½DA‹~i(NK–16280)SÌÌê‡
ÍC600 ‹CÅÒ³µ½G}É¢Ä঵½D
Table 1 ɨ¢ÄC400 ‹CÅÒ³²»µ½G}É¢Äär·
éÆCÅÌ_ʪ½¢àÌÙÇp‰WE€ªUx͂¢Xüª©
çêéDAli çÍCPd–H–ZSM–5 ɨ¯é EXAFS Éæ韢
©çCp‰WE€Íà®ÅÍÈ-_»¨ é¢ÍJ`I“ƵÄ
¶Ý·é±Æð¾ç©ÉµÄ¢éª19)C{¤†Ìê‡àp‰W
E€Í_»¨ÆµÄ¶ÝµÄ¨èCÅÌ_«ª-¢Æp‰WE€
ÆSÌÆ̊Ýìpª--ÈèªU«ªüã·éÆl¦çêéD
½¾µC2 íÞÌA‹~iðär·éÆÅÌ_ÊÉÙÆñÇ·ª
FßçêÈ¢Éà©©íç¸Cp‰WE€ªU«Í NK–16280
Ìûª CM–4 æèà‚¢D±Ì‹ÊÍCp‰WE€ªU«ªP
É_ʾ¯ÅˆÜéÌÅÍÈ-¼Ìöqà¶ÝµÄ¢é±Æð¦
´µÄ¢éD
^“Ì CO ÖÌ_»½žÍp‰WE€ªUxÆ-¢ŠÖª
x
Fig. 7 Catalytic activities of various metal oxides.
›, œ: SiO2, ¢, £: Al2O3(NK–16280), , ¡: TiO2,
ž, : ZrO , ¤, ¥: Al O (CM–4), ~, {: SiO –Al O .
èCp‰WE€ªUxªá¢ÙDZ̽žÌ^[“I[o[p
x͂-ÈÁ½DA‹~i(NK–16280)Sp‰WE€G}ð
600 ‹CÅÒ³·éÆCċÉæÁÄp‰WE€ªUxª¼ªÉá
º·éªC»êɺÁā^“_»Ì^[“I[o[pxÍ{
µÄ¨èCµ½ªÁÄC±ÌG}́^“_»ˆ«Í‚·Ò³ˆ
ÉæÁÄÏ»µÈ¢Dp‰WE€G}ã́^“_»É¨¯é
p‰WE€G}Ì\¢q´«É¢ÄÍ·ÅÉñª èC_»
p‰WE€±qªå«-ÈéÙǁ^“_»Ì^[“I[o[p
}
2
2
3
2
2
3
Solid line: NO conversion, dashed line: CH4 conversion.
Reaction conditions: NO1000 ppm, CH43000 ppm,
O210÷,
W/F0.18 g s cm|3
.
ÅÌ_«ð½È¢SÌÌê‡Éä×ÄC^“_»ˆ«ªáº
·éÆàq×Ä¢é21)
x͂-Èé±ÆªmçêÄ¢é20)
D
D
W‹RjASp‰WE€G}ÅÍáOIÈf[^ª¾çê
½DW‹RjAÆ`^jAÅÍÅÌ_ÊÍÙÚ¯ÊÅ éªCp
‰WE€ªUxÍW‹RjASÌûª‚¢D³çÉC^“_
»Ì^[“I[o[pxÍA‹~iSp‰WE€Æä×Äá-
ÈÁ½D±Ìæ¤È‹Êª¾çê½´öƵÄCp‰WE€ÆW
‹RjASÌÆÌÔÌÁÊȊÝìpªl¦çêéªC{¤†Å
ͻ̝R;ç©ÉÅ«È©Á½D
µ©µC{¤†É¨¢ÄÍCA‹~iÈOÌSÌÉSµ½p
‰WE€G}ÅÍ NO Ò³ˆ«ªÙÆñÇFßçêÈ©Á½D
±Ì–ÀÍCÅÌ_Êâp‰WE€ªUxÈOÉÒ³ˆ«ðxz
·éöq̶Ý𦴵ĢéD±êÉ¢ğ¢·é½ßCS
ÌPǼ^“Éæé NO Ò³ˆ«à²×½D‹Êð Fig. 7 É
¦·DA‹~i(NK–16280)ÆA‹~i(CM–4)ÍC450 ‹CÈã
ÅärI‚¢ NO Ò³ˆ«Æ^“_»ˆ«ð¦µ½D¼ÌS
ÌÅÍCW‹RjAª 450 ‹CÈãÅÍ NO Ò³ˆ«ª-»µ½
ªCVŠJA‹~iC`^jACVŠJSÌÅÍCNO Ò³ˆ«
ðS-¦³È©Á½D±Ì–ÀÍCp‰WE€SÉæÁÄ NO
Ò³ˆ«ªÁ¸µ½W‹RjAðœ¢ÄCS̩̪ˆ«ð¦³
È¢àÌÍp‰WE€ðSµÄà NO Ò³ˆ«ðLµÈ¢±
ÆðÓ¡µÄ¢éD䀶çÍCH–ZSM–5 ª^“Éæé NO
IðҳɈ«ð¦·ªCNa–ZSM–5 ÍS-ˆ«ªÈ¢±ÆC
¯lÉ Pd/H–ZSM–5 ͂¢ˆ«ð¦·ª Pd/Na–ZSM–5 ÍS
NO ÌÒ³ˆ«É¢ğ¢·éÆCSÌÌÅÌ_ʪ½-C
p‰WE€ªUxª‚¢ÙÇ NO Ò³ˆ«ª‚-ÈéXüªF
ßçêéDAli çÍ H–ZSM–5 ™uŒ“Xebh_«ðL·éS
Ìðp¢½ê‡CSµ½p‰WE€ª Pd2{ ÖÆ_»³êÄ
NO IðÒ³ˆ«ª-»µCÅÌ_«ð½È¢SÌÌê‡Íp
‰WE€ª PdO N‰X^[ð`¬µCNO IðÒ³ˆ«Í¸í
ê^“_»ˆ«ÌÝÉÈéÆq×Ä¢é19)DAli çÍCܽC
uŒ“Xebh_«ðL·éSÌÅC©Â NO ̶ݺÅÍC

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-ˆ«ªÈ¢±ÆðñµÄ¢éª7)8)C{¤†Ì‹ÊÆÉßÄ
æ-êvµÄ¢éD±Ì±ÆÍS̩̪ NO IðÒ³½žÉ
å«-Ö^µÄ¢é±Æ𦴷éàÌÆl¦çêéD
Table 1 ÉLÚµ½OÂÌA‹~iSp‰WE€G}Ì NO
Ò³ˆ«É¢Äär·éÆCNO Ò³Ì^[“I[o[pxÍ
p‰WE€ªUxÉæÁÄ ÜèÏ»µÈ¢±Æªí©éDµ½
ªÁÄCp‰WE€ªUxª‚¢ÙÇG}SÌÌ NO Ò³ˆ«
ª‚-ÈÁÄ¢é±Æªí©Á½D
ÅÍC[I‰Cg__ãÅÌ NO ©ç NO2 wÌ_»ª^“
ðp¢½ NO IðÒ³½žÌæêiKÅ éÆq×çêÄ¢
é
7)–9)D{¤†Åà NO ©ç NO2 wÌ_»ªæêiKÆÈÁÄ
¢é±Æªl¦çêéDܽ{¤†ÅÍCp‰WE€ÌSÉæ
è NO Ò³Ì᷈«ªåÉüãµÄ¢é±Æ©çCæêi
KÌ NO _»ªåƵÄp‰WE€ãÅiÝC³çÉA‹~i
ãŁ^“ƽžµÄ¢éCÆ¢¤¼àªl¦çêéD±Ì¼à
ðŸØ·é½ßCNO ¹É NO2 ðp¢ÄCA‹~iSÌPÆÅ
x
ÈãÌl@ðÜÆßéÆCŸÌæ¤ÉÈéD
̈«ð²×½D‹Êð Fig. 8 ɦ·Dp‰WE€SA‹~
P
ò
NO 500 C
Ò³ÌûªC ‹ÈºÅ‚¢Ò³¦ð^¦½D»ê
Sp‰WE€Í_»¨Ì`ŶݵĢéƄè³êC
iãÌ
SÌÌÅÌ_«ª-¢ÙÇCSÌÆp‰WE€ÌŠÝìpª-
-CS_»p‰WE€ÌªUx͂©Á½D
ä¦Cp‰WE€Ìð„Í NO ©ç NO2 ÖÌ_»ð£i·é±
ÆÅÍà¾Å«È¢D
Q
CO
NO
_»ˆ«É¢ğ¢·é½ßCp‰
ò
p‰WE€ªUxªá¢Ùǁ^“Ì
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NO
x ÖÌ_»Ì
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NO Fig. 9
ɦ·ªCp
R
ò
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Pƒ
_»ˆ«É¢IJ׽D‹Êð
Á½D±êÍSÌ©ÌÌ NO Ò³ˆ«ÆŠÖª èCSÌ©Ì
ª NO IðÒ³ÉÏÉIÉÖ^µÄ¢é±Æ𦴵ĢéD
‰WE€Í’àÙÇ NO _»ˆ«ª‚-È¢±Æªí©Á½D
±Ì‹Ê©çCp‰WE€Ìð„Í NO _»ÅÍÈ-^“_
»Ì£iÅ ë¤Æl¦çê½D
S
ò
NO
Ò³Ì^[“I[
A‹~iSp‰WE€Ìê‡C
QNO
ðp¢½ê‡Cò 2ðp
o[pxÍCp‰WE€ªUxÉæÁÄ ÜèÏíç¸C»Ì‹
Ê NO Ò³ˆ«Íp‰WE€ªUxª‚¢ÙÇå«-ÈÁ½D
C.D ½ ž o H
Fig. 8 ÉÍC³çÉò
PNO
¹É
NO
x
¢½ê‡CÌ 2 íÞÌP[Xɨ¯é NO Ò³¦Æ^“_»
x
RNO
¦C³çÉCò
x ðYÁµÈ©Á½ê‡Ì^“_»¦ð\
Lobree çÉæéCH–ZSM–5 Sp‰WE€G}ðp¢½ñ
ÅÍCNO ªp‰WE€Ézꢀ³êC^“ƽžµÄ CN í
𶬵C»êª³çÉ NO ƽžµÄ N2 𶬷éÆq×ç
êÄ¢é11)D
¦µ½DNO ¹ª NO Å ÁÄà NO2 Å ÁÄàC»ÌÒ³ˆ
x
«ÉÍå«È·Í»êÈ©Á½D±Ì±ÆÍCNO Ò³Ìê‡
NO2 ª†ÔÌÆÈÁĢȢ©C é¢ÍCNO ©ç NO2 _»
ªÉßĬ¢iKÅ é©CÇ¿ç©Å é±Æð¦µÄ¢éD
ܽ¢¸êÌê‡àC^“_»ˆ«Éàå«È·Í»ê¸C³
êûC䀶çÉæép‰WE€[I‰CgnG}ðp¢½ñ
çÉ NO ðYÁµÈ©Á½ê‡àC^“_»ˆ«ÉÏíèÍ
x
È©Á½D±êç̋ʩçC{½žÅÍC_fÉæé^“Ì
_»ªæêiKÉÈÁÄ¢éƄè³êéD
Fig. 8 Catalytic activities of alumina and 0.1÷ palladium
supported on alumina for various reactions.
›, œ: Pd/Al2O3(NO–CH4–O2), ¢, £: Pd/Al2O3(NO2
–CH4–O2),
Fig. 9 Catalytic activities of alumina and 0.1÷ platinum
and palladium supported on alumina for NO oxidation.
›: Pd/Al2O3, ¢: Pt/Al2O3, ~: Al2O3, no symbol:no
catalyst.
, ¡: Al O (NO –CH –O ), : Pd/Al O (CH –O ).
}
Solid line: NO conversion, dashed line: CH4 conver-
2
3
2
4
2
2
3
4
2
x
sion.
Reaction conditions: NO(NO2)1000 ppm, CH4
3000 ppm, O210÷,
Reaction conditions: NO1000 ppm, O210÷,
W/F0.2 g s cm|3
.
W/F0.18 g s cm|3
.

ú»C2000, No. 7 îtEàcêEHcElcFA‹~iSp‰WE€G}Éæé^“ðÒ³ÜÆ·é NO IðÒ³
473
ÝÅ Á½D»Ìê‡CA‹~iÌíÞâ²»ðÉæÁÄ_»
p‰WE€ªUxÍÏ»µ½ªCNO Ò³½žÌ^[“I[o[
pxÉÍå«Èϻͩçê¸C‹ÊƵÄC_»p‰WE€ª
Uxª‚¢ÙÇ NO Ò³ˆ«ª‚-ÈÁ½D
R
ò
NO
IðÒ³½žÍC
A‹~iSp‰WE€G}ãÅÌ
_»p‰WE€ãŁ^“ª”ª_»³êC»Ì”ª_»†ÔÌ
ªA‹~iãÅ NOx ƽžµÄ N2 𶬷éCÆ¢¤oHª„
è³ê½D»ÌÛC_»p‰WE€ªUxª‚¢ÙÇA‹~iS
ÌÆÌÚGÊϪ¦C_»p‰WE€ã́^“”ª_»¨ª
A‹~iSÌãÉÚ®µâ·-ÈèCNO Ò³ˆ«ªüã·éÆ
l¦çê½D_»p‰WE€±qãÅ»ÌÜܔª_»†ÔÌÌ
_»ªißÎCNO Ò³ªN±é±ÆÈ-^“Í_»³êéà
ÌÆl¦çê½D
Scheme 1 Presumed reaction pathway.
Èã̋ÊÈçÑÉ NO Ò³ÉÍS̪ÏÉIɽžÉÖ^
µÄ¢éÆ¢¤±Æ©çCScheme 1 ɦ·æ¤ÉC_»p‰W
E€ãŁ^“ª”ª_»³êC»Ì”ª_»¨ªA‹~iãÅ
NOx ƽž·éCÆ¢¤½žoHªl¦çêéD±ÌÛC_»
p‰WE€ªUxª‚¢ÙÇA‹~iSÌÆ̊Ýìpª¦C
_»p‰WE€ã́^“”ª_»¨ªA‹~iSÌãÉÚ®µ
â·-ÈéÆl¦çêéDܽCNOx Ɓ^“”ª_»¨ÆÌ
½žÉæé N2 ¶¬ÍCêÊIÉSÌÌÅÌ_ʪ½¢ÙÇ£i
³êéªCSÌPÆ̈«âSÌÆp‰WE€Æ̊ÝìpÈÇ
Ìe¿àó¯Ä¢éƄè³êéDêûC^“Ì_f_»Í_
»p‰WE€ãÌÝÅis·éÆl¦çêCªUxÌe¿ðÙÆ
ñÇó¯È¢Dp‰WE€ªUxª¬³¢ê‡^“_»½žÌ
^[“I[o[pxªå«-ÈéªC±êÍCOqÌæ¤ÉC_
»p‰WE€ÌªUxª¬³-_»p‰WE€±qÌ\ÊϪ¬
³¢Æ«ÉÍCPÊ\Êϖ½è́^“_»ˆ«ª‚-ÈéC
\¢q´«Ì½ßÅ éÆl¦çê½20)D
ÅãÉCp‰WE€ªUxªèÉÛµ²¦Íðº³Á½CRX
‚‡¤†ŠÌc¨õIÉC´ÓÌÓð\µÜ·D
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(
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5) ]ꎥC¬ì ²Cªè®FCenpêCæ 72 ñG}
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D ‹
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^“Éæé NO IðÒ³½žÉηéà®_»¨Sp‰
WE€G}̈«É¢Ĥ†ðsÁ½‹ÊCŸÌæ¤È‹_ª
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¾çê½D
(
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SÌƵ𢵽A‹~iCVŠJA‹~iCW‹R
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jAC`^jAÍÅÌ_-xÉå«È·Í©çêÈ©Á½ªCÅ
Ì_ÊÍA‹~iªÅཀྵÁ½Dp‰WE€Í_»p‰WE€
ƵÄSÌãɶݵĢéÆl¦çêCÅÌ_ʪ½¢ÙÇ_
»p‰WE€ÌªUx͂-ÈéXüª Á½DêûC_»p‰
WE€ªUxªá¢Ùǁ^“_»½žÌ^[“I[o[pxª
‚-ÈéXüª èC‹ÊƵā^“_»ˆ«ÍSÌÌíÞâ
_»p‰WE€ªUxÌe¿ð Üèó¯È©Á½D±ế^
“_»ª_»p‰WE€±qãÅisµC»Ì\¢q´«Ì½ß
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Å
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Ò³½žªis·éÌÍCíXÌ
{¤†ÌÍÍÅÍC
à®_»¨SÌ̤¿A‹~iÉp‰WE€ðS³¹½ê‡Ì

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2000
No. 7
474
Selective Reduction of NO with Methane over Alumina–Supported
Palladium Catalysts
Megumu INABAÞ, Yoshiaki KINTAICHI, Masaaki HANEDA and Hideaki HAMADA
National Institute of Materials and Chemical Research; 1–1 Higashi, Tsukuba–shi 305–8565 Japan
Selective reduction of NO with methane in the presence of oxygen using metal oxide–supported pal-
ladium catalysts was explored. EŠect of various metal oxides and the conditions for catalysts preparation
on the catalytic activity was investigated. Alumina–supported palladium exhibited especially highest
catalytic activity for the selective reduction of NO among the other alumina–supported metal catalysts;
alumina was found to be most eŠective as the support among several metal oxides. Although most of
preparation conditions did not aŠect the activity of Pd/Al2O3, reduction at high temperature resulted in
the decrease of deNOx activity. Result for catalyst characterization indicated that alumina support had
strong solid–acidity and that the Pd dispersion for Pd/Al2O3 having high deNOx activity was high. The
reduction at high temperature led to low dispersion of palladium supported on the same alumina. These
results indicate that the solid acidity of the support and the dispersion of palladium are essential for the
high catalytic activity. Concerning the reaction pathway, it was presumed that methane was ˆrst oxi-
dized on palladium particles to partially oxidized compounds, which then reacted with NOx on alumina
support to give N2, COx and H2O.
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