25 7 2004 7 Vol 25 No 7 Chi nese Jou rnal of Catalysis J uly 2004 : 025329837 (2004) 0720523206 : 523 528 CuZnAl Zr 1 2, (1, 200237 ; 2, 200092) : CuZnAlZr, XRD TPR,, (Cu 7 Zn 3 ) 7 (Al 6 Zr 4 ) 3, 200, 91 %, CO 0112 % Cu,Zn Cu, Al Zr Cu 2 + :,,,,, : O643 : A Investigation on Oxidative Steam Ref orming of Methanol over CuZnAl Zr Catalyst Optimization of Catalyst Formulation YU Liting 1, MA J ianxin 2 3 ( 1 Institute of Indust rial Catalysis, East China U niversity of Science and Technology, S hanghai 200237, China ; 2 Clean Energy A utomotive Engineering Center, Tongji U niversity, S hanghai 200092, China) Abstract : Low2temperat ure steam reforming of met hanol is a relevant technique for on2board supply of hydrogen for f uel2cell vehicles Recently, much attention was paid on oxidative steam reforming of met hanol due to it s quick response and auto2t hermal properties This paper deals wit h t he optimization of catalyst formulation of CuZnAlZr composite oxide system The catalyst was prepared by co2precipitation f rom aqueous solutions of Cu, Zn, Al and Zr nitrates and Na 2 CO 3 (p H = 716) at 65 The influence of the catalyst composition, such as the ratios of n (CuZn) / n (AlZr), n (Cu) / n (Zn) and n (Al) / n (Zr), on its catalytic performance for oxidative steam re2 forming of methanol to hydrogen was investigated The optimized composition of the catalyst was ( Cu 7 Zn 3 ) 7 2 (Al 6 Zr 4 ) 3 Over this catalyst, the methanol conversion reached 91 % at 200, while the (CO) was only as low as 0108 % The dispersion of CuO species and it s occupation on t he catalyst surface are t he determining fac2 tors for the catalyst activity The component Zn is responsible for the dispersion of CuO, while the components Al and Zr give assistance to stabilize the existence of Cu species on the catalyst surface Key words : copper oxide, zinc oxide, alumina, zirconia, composite oxide, oxidative steam reforming of met hanol,,, : 2003209222 :,, 1978, : Tel : (021) 65985422 ; E2mail : jxma @fcv2sh com
524 25 2 h, 110, CuZnAlZr,, 5 7 MPa, 0145 019, mm 1 2, 12 mm, 250 mm 3 ml [1 3 ], 200 300, ( 300 ) H 2 2N 2 ( V ( H 2 ) / V (N 2 ) = 2, q V = 120 ml/ min), 350,, 10 h, 2 [4 ] (2 h), [5 ],, H 2 102 CO, (, TCD), [6 ] ; CO CO 2 GC2910,, CO, (, FID) [7,8 ],H 2 GDX2401 GC2, 910 ( FID) 1 3 CuZn D/ max2rb X (Rigaku ), Cu K, = 01154 08 nm,, 40 kv, 60 ma, 4 / min 0103 g,, He 500 2 h, 10 %H 2 290 %He (20 ml/ min) [9 ], Zr CuZn (10 / min) [10 ] 2 [11 ], CuZnAlZr, 2 1 n( CuZn) / n( AlZr),Cu 9 Zn 1 Al 8 Zr 2 [11 ], 1 n (Cu) / n (Zn) n (Al) / n (Zr) 1 1 n (CuZn) / n (AlZr) (Cu 9 Zn 1 ) x (Al 8 Zr 2 ) 102 x Zr (NO 3 ) 2 6H 2 O (AR,, n (Cu 9 Zn 1 ) / n (Al 8 Zr 2 ) ),Al (NO 3 ) 3 9H 2 O (AR, 200 ),Cu (NO 3 ) 2 3H 2 O (AR, ) Zn (NO 3 ) 2 6H 2 O (AR, ), 1, n (Cu 9 Zn 1 ) / n (Al 8 Zr 2 ) Na 2 CO 3 (AR, ),, n (Cu 9 Zn 1 ) / n (Al 8 Zr 2 ) = 7/ 3,, p H 716, 65, ( 70 %),, H 2
7 : CuZnAlZr 525 1 n( CuZn) / n( AlZr) CuZnAl Zr Fig 1 Catalytic performance of CuZnAlZr oxide with different n (CuZn) / n (AlZr) ratios (1) X (CH 3 OH), (2) S ( H 2 ), (3) S (CO 2 ), (4) (CO) ( n (Cu) / n (Zn) = 9/ 1, n (Al) / n (Zr) = 8/ 2 Reaction conditions : n ( H 2 O) / n (CH 3 OH) = 1, n (O 2 ) / n (CH 3 OH) = 01204, q V (feed) = 0125 ml/ min, = 200, and the same below) 9914 %, CO 2 9813 % ; CO (014 %), AlZr Cu ; AlZr, n (Cu 9 Zn 1 ) / n (Al 8 Zr 2 ) = 7/ 3,Cu Cu, Cu 2, 2 (1) CuO 3, (Cu 9 Zn 1 ) x (Al 8 Zr 2 ) 102 x, CuAl ( 2 = 120 29136 ) n (Cu 9 Zn 1 ) / n (Al 8 Zr 2 ), CuAl ( ) 200 ( ), 2 (4) Cu 2 + Cu 2 + [12 ], 3 (1), n (CuZn) / n (AlZr),CuO 150 ( ) Cu 2 + Cu 2 +, Cu, XRD CuAl 3 (1) Cu Cu 2 +, ( 420 ), CuAl 3 (2) 2 CuZnAl Zr XRD Fig 2 XRD patterns of different CuZnAlZr oxide samples (1) (Cu 9 Zn 1 ) 4 (Al 8 Zr 2 ) 6, (2) (Cu 9 Zn 1 ) 5 (Al 8 Zr 2 ) 5, (3) (Cu 9 Zn 1 ) 6 (Al 8 Zr 2 ) 4, (4) (Cu 9 Zn 1 ) 7 (Al 8 Zr 2 ) 3, (5) (Cu 9 Zn 1 ) 8 (Al 8 Zr 2 ) 2 3 CuZnAl Zr TPR Fig 3 TPR profiles of different CuZnAlZr oxide samples (1) (Cu 9 Zn 1 ) 4 (Al 8 Zr 2 ) 6, (2) (Cu 9 Zn 1 ) 5 (Al 8 Zr 2 ) 5, (3) (Cu 9 Zn 1 ) 6 (Al 8 Zr 2 ) 4, (4) (Cu 9 Zn 1 ) 7 (Al 8 Zr 2 ) 3, (5) (Cu 9 Zn 1 ) 8 (Al 8 Zr 2 ) 2
526 25 Cu 2 +, n (Cu 9 Zn 1 ) / n (Al 8 Zr 2 ), n (Cu) / n (Zn) ( Cu x Zn 102 x ) 7 (Al 8 Zr 2 ) 3 Cu 2 + XRD, 200 n (Cu) / n (Zn) n (Cu 9 Zn 1 ) / n (Al 8 Zr 2 ) 8/ 2, Cu 2 +, Cu 2 + 4, n (Cu) / n (Zn),, AlZr Cu 2 + H 2 CO 2, AlZr, Cu 2 +, CO, n (Cu) / n (Zn) = 7/ 3, Cu 2 + 8216 %, H 2 9917 %,CO 2 2 2 n( Cu) / n( Zn) 9910 % ; (CO) = 0108 %, n (CuZn) / n (AlZr) n (Al) / n (Zr), n (Cu) / n (Zn) = 7/ 3 4 n( Cu)/ n( Zn) CuZnAl Zr Fig 4 Catalytic performance of CuZnAlZr oxide with different n (Cu) / n (Zn) ratios (1) X (CH 3 OH), (2) S ( H 2 ), (3) S (CO 2 ), (4) (CO) ( n (CuZn) / n (AlZr) = 7/ 3, n (Al) / n (Zr) = 8/ 2) 5, 5 (1) CuO n (Cu) / n (Zn),CuO, CuO, Zn Cu, CuO 6, TPR ( ), Cu 2 +, Cu 2 + n (Cu) / n (Zn) 7/ 3, n (Cu) / n (Zn), ; n (Cu) / n (Zn),, 6 (3) Cu 2 + Cu 2 +, n (Cu) / n (Zn) 7/ 3,Cu 2 + Cu 2 + ; n (Cu) / n (Zn) 7/ 3, Cu 2 +,, Cu 2 + 5 CuZnAl Zr XRD Fig 5 XRD patterns of different CuZnAlZr oxide samples (1) (Cu 5 Zn 5 ) 7 (Al 8 Zr 2 ) 3, (2) (Cu 6 Zn 4 ) 7 (Al 8 Zr 2 ) 3, (3) (Cu 7 Zn 3 ) 7 (Al 8 Zr 2 ) 3, (4) (Cu 8 Zn 2 ) 7 (Al 8 Zr 2 ) 3, (5) (Cu 9 Zn 1 ) 7 (Al 8 Zr 2 ) 3
7 : CuZnAlZr 527 6 CuZnAl Zr TPR Fig 6 TPR profiles of different CuZnAlZr oxide samples (1) (Cu 5 Zn 5 ) 7 (Al 8 Zr 2 ) 3, (2) (Cu 6 Zn 4 ) 7 (Al 8 Zr 2 ) 3, (3) (Cu 7 Zn 3 ) 7 (Al 8 Zr 2 ) 3, (4) (Cu 8 Zn 2 ) 7 (Al 8 Zr 2 ) 3, (5) (Cu 9 Zn 1 ) 7 (Al 8 Zr 2 ) 3 2 3 n( Al) / n( Zr), n (Cu) / n (Zn) n (CuZn) / n (AlZr) n (Al) / n (Zr) (Cu 7 Zn 3 ) 7 (Al x Zr 102 x ) 3, 200 n (Al) / n (Zr) 7, n (Al) / n (Zr) = 10/ 0 6/ 4, (81 % 91 %) ; n (Al) / n (Zr) = 4/ 6 0/ 10, (43 % 53 %), ( 100 %) CO ( 0107 % 0113 %), n (Al) / n (Zr), n (Al) / n (Zr) > 6/ 4, n (Al) / n (Zr) < 6/ 4, 8, n (Al) / n (Zr), 8 (4) ZrO 2,,ZrO 2 7 n( Al) / n( Zr) CuZnAl Zr Fig 7 Catalytic performance of CuZnAlZr oxide with different n (Al) / n (Zr) ratios (1) X (CH 3 OH), (2) S ( H 2 ), (3) S (CO 2 ), (4) (CO) ( n (CuZn) / n (AlZr) = n (Cu) / n (Zn) = 7/ 3) 9, TPR,, CO Cu 2 +, Cu 2 +, Zr, XRD, Zr ZrO 2, ( n (Al) / n (Zr) 6/ 4), Zr, Zr Cu, Cu 2 +,Zr Cu,, Cu 2 + Cu 2 + [13 ],Zr
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