以壳聚糖为介质的Ni2B非晶态合金/ 膨胀石墨的制备 ... - 李伟教授课题组

28 4 2007 4 Vol. 28 No. 4 Chi nese Journal of Catalysis April 2007: 025329837 (2007) 0420351206: 351356Ni2B / 1 ,2 , 1 , 1 , 1(1 , 300071 ; 2 , 037009): ,Ni2B . X Ni2B . ,Ni2B,. ,,,. . Ni2B .: ; 2; ; ; : O643 : APreparation of Chitosan2Mediated Expanded Graphite2SupportedAmorphous Ni2B Alloy Catalysts and Their CatalyticHydrogenation PerformanceWU Meixia 1 ,2 , L I Wei 1 3 , ZHANG Minghui 1 , TAO Keyi 1( 1 Institute of New Catalytic M aterials Science , College of Chemist ry , N ankai U niversity , Tianjin 300071 , China ;2 Depart ment of Chemist ry , S hanxi Datong U niversity , Datong 037009 , S hanxi , China)Abstract : A series of chitosan2mediated expanded graphite2supported amorphous Ni2B alloy catalysts were suc2cessfully prepared by a silver2catalyzed electroless plating method in an aqueous solution. The effects of chitosanon the structure , composition , surface texture , and dispersion of Ni2B particles on expanded graphite were char2acterized by X2ray powder diffraction , inductively coupled plasma analysis , transmission electron microscopy ,selected area electron diffraction , and scanning electron microscopy. The characterization results show that theamorphous structure of Ni2B particles is not influenced by chitosan. The activity of as2prepared catalysts wastested by the hydrogenation of sulfolene to sulfolane and the selective hydrogenation of p2chloronitrobenzene top2chloroaniline. In comparison with the catalyst without chitosan , the presence of a proper amount of chitosanin the catalyst leads to homogeneous dispersion of Ni2B particles , small size of Ni2B particles , and high catalyticactivity.Key words : chitosan ; nickel2boron amorphous alloy ; sulfolene ; p2chloronitrobenzene ; catalytic hydrogenation, [1 ] . [2 ,3 ] . : 2006210227. : , , 1977 , , .: . Tel : (022) 23508662 ; E2mail : weili @nankai. edu. cn.: (20403009) ; (105045) .

352 28 Ni2B [47 ] , .(chitosan , 1 ,42222222 2D2,CS) ,,. C 2,C 3 ,,,. , , [811 ] ,.,Ni2B , [1214 ] . ,( EG) [15 ] . ,,,Ni2B ,X ( XRD) ( ICP) ( SEM) ( TEM) (SAED) Ni2B ,.1 1. 1 Ni2B2CS ,45 ,152 ml Ni2B (515 g/ L KBH 4 ,12 g/ L NiSO 4 6H 2 O , 1616 g/ L N H 2 CH 2 CH 2 N H 2 ,40 g/ L NaOH) 5 ml 011 mol/ L AgNO 3 (Ag + 1 1) ,015 h , ,,Ni2B2CS. Ni2B ,.Ni2B/ CS2EG ,1 %() , 4mol/ L NaOH p H 7 , ,,NaOH p H 13 , . p H = 8 , ,,CS2EG . CS2EG AgNO 3 (Ag 012 %) , , ,Ag2CS2EG. Ag2CS2EGNi2B,45 30 min ,Ni2B/ CS2EG. ,,. ,Ni2B/ EG.1. 2 XRD ,Rigaku D/ Max22500 X , Cu K(= 01154 05 nm) . Philips Tacnai F20 ( 200 kV ) L EO 1530 VP . IRISIntrepid . Micromeritics ASAP2010 .1. 3 WDF2011 () . GC27800 () .,100 ml 012 g 30 g 30 g ,H 2 ,H 2 215 MPa , 45 , ,800 r/ min. ,,10 min .,100 ml 018 g 8 g 48 ml ,H 2,H 2 115 MPa , (95 ) , ,800 r/ min. .2 2. 1 XRD 1 Ni2B2CS , EG Ni2B/ CS2EG

4 : Ni2B / 3531 Ni2B XRD Fig 1 XRD patterns of expanded graphite ( EG) anddifferent Ni2B samples(1) Ni2B2CS , (2) EG , (3) Ni2B/ CS2EG(CS Chitosan. )XRD . , Ni2B2CS XRD 245,Ni2B ,,. 1 (2) (3) ,. ,1(3) 245,Ni2B [13 ] .2. 2 TEM SEM TEM SEM Ni2B . 2 TEM ,SAED . Ni2B TEM ,Ni2B ,,,300 nm ; Ni2B2CS ,,,65 nm . SAED,Ni2B. Ni2B ,Ni2B ,Ni2B/ EGNi2B 5080 nm , Ni2B/ CS2EG22 (1) Ni2B 20 nm .2 Ni2B TEM SAED Fig 2 TEM images and SAED patterns (inset) of different Ni2B samples(a) Ni2B , (b) Ni2B2CS , (c) Ni2B/ EG , (d) Ni2B/ CS2EG22 (see Table 1)

354 28 ,Ni2B Ni2B .EG , Ni2B/ EG Ni2B/ CS2EG22 BET ,5517 , 519 3213 m 2 / g. ,Ni2B ,Ni2B . Ni , Ni2B/ CS2EG22 Ni2B/ EG 5 ,,Ni2B ,TEM .SEM (3) ,Ni2B/ EG , Ni2B EG . Ni2B/CS2EG22 , Ni2B EG,Ni2B ,2 TEM ; Ni2B ,Ni2B ,, Ni2B .Ni2B . 4 (a)(b) Ni2B/ CS2EGTEM . , Ni2B/CS2EG26 Ni2B 40 nm ,, , Ni2B/ CS2EG27 Ni2B 25 nm . Ni2B . ,, Ni2B .4 Ni2B TEM Fig 4 TEM images of Ni2B samples prepared with water2solublechitosan with different molecular weight(a) Ni2B/ CS2EG26 , (b) Ni2B/ CS2EG273 Ni2B SEM Fig 3 SEM images of different Ni2B samples(a) Ni2B/ EG , (b) Ni2B/ CS2EG22,,.,100 000 1 000 ,2. 3 Ni2B ,Ni Ni2B ,,(1610 %) (1410 %) ,,,.

4 : Ni2B / 355,.1 . ,,Ni2B . 20 %,Ni2B/ CS2EG25 Ni2B/ EG1/ 5 , Ni B . ,Ni2B ,,Ni2B Ni B ,.1 Ni2B Table 1 Effect of CS/ EG mass ratio on the compositionof Ni2B samplesSampleCS/ EGmassratio ( %)Platingtime(min)Loadingof Ni( %)Composition ( %)Ni2B/ EG 0 30 14. 2 69. 5 30. 5Ni2B/ CS2EG21 1 20 14. 0 70. 9 29. 1Ni2B/ CS2EG22 5 12 14. 2 70. 8 29. 2Ni2B/ CS2EG23 10 10 14. 4 70. 6 29. 4Ni2B/ CS2EG24 15 8 14. 6 70. 1 29. 9Ni2B/ CS2EG25 20 6 14. 6 70. 1 29. 9NiB,. TEM 2 Ni2B/ CS2EG ,. ,Ni2B Ni2B ,,,15 min . . ,Ni . : B ,,Ni2B Ni2B , Ni B ,,,.,,,2 Ni2BTable 2 Effect of molecular weight of soluble chitosan on thecomposition of Ni2B samplesSampleMolecularweight ofchitosanPlatingtime(min)Loadingof Ni( %)Composition ( %)Ni2B/ CS2EG26 100000 15 13. 9 51. 2 48. 8Ni2B/ CS2EG27 1000 15 13. 6 51. 5 48. 52. 4 Ni2B Ni2B . 3 Ni2B. ,NiB,1 %10 %,Ni2B/ CS2EGNi2B/ EG.3 Ni2B Table 3 Effect of CS/ EG mass ratio on catalyst activity forhydrogenation of sulfolene and para2chloronitrobe2nzene ( p2CNB)SampleSulfolene hydrogenation aConversion ofsulfolene ( %)p2CNB hydrogenation bConversion Selectivity forof p2CNB ( %) p2CA ( %)Ni2B/ EG 53. 1 95. 1 99. 9Ni2B/ CS2EG21 88. 5 96. 5 99. 8Ni2B/ CS2EG22 98. 6 100 99. 9Ni2B/ CS2EG23 67. 9 98. 8 99. 4Ni2B/ CS2EG24 48. 6 41. 2 100Ni2B/ CS2EG25 39. 4 30. 6 100Ni2B/ CS2EG26 87. 4 100 98. 1Ni2B/ CS2EG27 96. 8 100 99. 9a Reaction conditions : 012 g catalyst , 30 g sulfolene , 30 gwater , 215 MPa H 2 , 45 , 800 r/ min.b Reaction conditions : 018 g catalyst , 8 g p2CNB , 48 mlethanol , 115 MPa H 2 , 95 , 800 r/ min.p2CA : para2chloroaniline.,,; ,, Ni2B ,Ni2B ,; ,, Ni2B ,,, [16 ] .3 Ni2B/CS2EG26 Ni2B/ CS2EG27 . ,,,, Ni2B/ CS2EG27

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