3080 (Wuli Huaxue Xuebao) Acta Phys. -Chim. Sin., 2010, 26(11): November [Article] * (,,, ) : HNO 3 (CNT) Ni-MgO,,.

Size: px

Start display at page:

Download "3080 (Wuli Huaxue Xuebao) Acta Phys. -Chim. Sin., 2010, 26(11): November [Article] * (,,, ) : HNO 3 (CNT) Ni-MgO,,."

甚崇吕
5 years ago
Views:

1 3080 (Wuli Huaxue Xuebao) Acta Phys -Chim Sin, 2010, 26(11): November [Article] wwwwhxbpkueducn * (,,, ) : HNO 3 (CNT) Ni-MgO,, Boehm X (XRD) (TPD) (FTIR) X (XPS) HNO 3 : 70 mol L K 24 h CNT ; 3, > > : ; ; ; : O647 Purification of Multiwalled Carbon Nanotubes and Characterization of Their Oxygen-Containing Surface Groups ZHOU Jin-Mei LI Hai-Yan LIN Guo-Dong ZHANG Hong-Bin * (College of Chemistry and Chemical Engineering, State Key Laboratory of Physical Chemistry for Solid Surfaces, National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters, Xiamen University, Xiamen , Fujian Province, P R China) Abstract: We conveniently removed the Ni-MgO catalyst components from an as-grown multiwalled carbon nanotube (CNT) using an aqueous HNO 3 solution with strong acidity and oxidizability as a purifying reagent Some oxygen-containing surface groups were generated at the CNT surface, which converted the hydrophobic surface into a hydrophilic surface The phase composition and the oxygen-containing surface groups of the CNTs treated by nitric acid were determined and characterized using Boehm s neutralizing titration method and X-ray powder diffraction (XRD), temperature-programmed desorption (TPD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) techniques The results indicated that the total content of the formed oxygen-containing surface groups was the highest for the CNTs treated with 70 mol L -1 aqueous HNO 3 at 378 K for 24 h The content of the three major oxygen-containing surface groups was: carboxyl>lactonic carboxyl>phenolic hydroxyl Key Words: Multiwalled carbon nanotubes; Purification; Oxygen-containing surface group; Surface modification (CNT) sp 2 -C [1] CNT sp 2 -C H 2,, Received: May 17, 2010; Revised: July, 24, 2010; Published on Web: September 13, 2010 * Corresponding author hbzhang@xmueducn The project was supported by the National Key Basic Research Program of China (973) (2009CB939804) and Fujian Provincial Key Scientific & Technical Project, China (2009HZ0002-1) (973) (2009CB939804) (2009HZ0002-1) 鬁 Editorial office of Acta Physico-Chimica Sinica

2 No : [2-5] CNT, ( 12 CNT treated ) ( Fe Co Ni ), CNT( CCVD ), [2] CNT, (NaHCO 3 Na 2 CO 3 CCVD CNT ( CNT as-grown ) ; ( ) 10 g( 0001 g) CNT treated, 100 ml, 25 ml 01 CNT as-grown, mol L -1 (NaHCO 3 Na 2 CO 3 NaOH), (, 60 min,, 250 ), CNT as-grown ml, 01 mol L -1 CCVD CNT, CNT treated CNT as-grown, 13 CNT treated, CNT treated ( ), ;, CO 2, CO, CNT as-grown, Boehm (temperature-programmed desorption, [6-7] (XRD TPD-MS(or TCD) FTIR XPS ) HNO 3 CNT ( (TPD), ) 1 11 CNT CNT CNT, CH 4, Ni x Mg 1-x O, CCVD, TPD CO 2 CO [8] 50 g CNT as-grown, TPD (CO 2 CO) ml (mmol ), ( 6 ml g -1 ) HNO 3, (500 r min -1 ) 4 HNO K, ma,, CNT, CNT treated,, NaOH) Boehm [6-7], TPD) Micromeritics Auto Chem II+Qic-20, (GC) (TCD) TPD He( Ar) ( 35 ml min -1 ) 10 K min -1, H 2 O CO 2 CO TPD, TEM HRTEM Technai F30 (USA) N 2 -BET Micromeritics Tristar-3000 (Carlo Erba) mol L -1, h XRD X Pert PRO X, K (PANalytical, The Netherlans), Cu K α (λ=,, nm), 40 kv, 30 FTIR AVATAR 360 CNT treated, FTIR (Nicolet, USA) CNT, 5 K min KBr 1 ( ) ; K, 300 min, 13 mm, 1 mm, N m -2 ;

3082 Acta Phys -Chim Sin, 2010 Vol26 4000-400 cm -1, 16 XPS VG ESCA LAB MK-2 X-, Mg K α (10 kv, 20 ma, hν=12536 ev), UHV (1 10-7 Pa), Al 2p (E B =733 ev) 2 21 CNT as-grown 1(a) CNT as-grown TEM CNT

3 3082 Acta Phys -Chim Sin, 2010 Vol cm -1, 16 XPS VG ESCA LAB MK-2 X-, Mg K α (10 kv, 20 ma, hν=12536 ev), UHV ( Pa), Al 2p (E B =733 ev) 2 21 CNT as-grown 1(a) CNT as-grown TEM CNT Ni 2 CNT, treated XRD Ni x Mg 1-x O Fig2 XRD patterns of the CNT treated by HNO 3 with CNT varying treating-conditions and the reference systems, Ni NiO/ MgO, XRD ( 2(b)),, ; (70 mol L -1 ) 378 K 24 h ( 2(f)) 1 1(b) CNT treated TEM CNT, Ni, CNT as-grown NiO MgO 90% 53%(,,, ); 70 mol L CNT treated 378 K 24 h, NiO MgO 2 XRD 2θ 261, % CNT, [8-10] (002), (100) (004) ; Ni 2θ ; 2θ 371, CNT 024% 005%, C (S BET ) 87 m 2 g m 2 g -1 ( 1) 70 mol L K 432, 625, NaCl 24 h CNT as-grown [8,11] Ni x Mg 1-x O, ( ) 2,, CNT, Ni, Ni x Mg 1-x O Liu [12] HNO 3 -H 2 SO 4 ; 35 mol L -1 K 2 Cr 2 O 7 -H 2 SO 4 CNT, 378 K 24 h, Ni x Mg 1-x O CNT ( 6 h, 40%; 1 (a) CNT as-grown TEM ; (b) CNT treated TEM ; (c) CNT treated HRTEM Fig1 (a) TEM image of CNT as-grown ; (b) TEM image of CNT treated ; (c) HRTEM image of CNT treated

4 No : 1 CNT ) CNT ;, Table 1 Ash content and surface area of the CNT CNT treated under varying conditions 5 (a-e) HNO 3-treated conditions No S BET/(m 2 g -1 ) Ash mass fraction (%) C HNO3 /(mol L, ) t/h T/K (a) CNT treated (b) (a) CNT as-grown TPD-MS (c) (d) H 2 O, CO 2 CO (e) (f) , CNT CH 4 (g) un-treated CNT H 2, 24 h, 100%); XPS CNT Ni 0 [8-9] x NiO MgO, 363 K 22 CNT treated HNO 3,, Ni, CNT C ( CNT( 1(c)) C [12-15] ),,, ( ), Boehm [6-7], (NaOH Na 2 CO 3 NaHCO 3 ), 2 CNT treated, CNT, 6, 70 mol L K 24 h (f) ( 0391 mmol g -1 ) 3 Fig3,,,, Table 2 treating conditions: 70 mol L -1 HNO 3 aqueous solution, 378 K for 24 h; ( MS: mass spectrometry 2 (a) CNT as-grown (b) CNT treated TPD-MS TPD-MS profiles of (a) CNT as-grown and (b) CNT treated CNT Surface acidic functional groups and TPD-species as well as their content of the CNT treated with varying treating conditions No HNO 3-treated conditions Amount of surface acid (mmol g -1 ) Amount of TPD-species (mmol g -1 ) C HNO3 /(mol L -1 ) t/h T/K carboxy COOH lactonic COOH phenolic OH CO 2 CO (a) (b) (c) (d) (e) (f) (g) un-treated

5 3084 Acta Phys -Chim Sin, 2010 Vol26 H 2 O H 2 O ; (II)( K) CNT 588 K H 2 O CNT CO 2, 953 K - NiO (III)( K) CO, NiO/MgO -(II) -(III) CO 2,, 598 CO 2 CO K CO 2 ( ( CNT CO 2 CO, K, mmol g -1 ), 2 CO K) 773 K 1273 K : (f)>(e)>(c)>(a)>(d)>(b); CO, CNT Boehm CNT ( C ( 2) C ) 773 K,, TPD NiO, Ni CO [16] 3(b) CNT treated TPD-MS,, CNT, NiO MgO CO 03%( 1(f)),, Boehm ( 2(f)), H 2 O, CO 2 CO, CNT 24 CNT treated FTIR, 5(a) CNT FTIR [17-18], CNT CH 4 Ni x Mg 1-x O CO 2,, ( 1(c)) CNT CO, 3(b), 338 K H 2 O H 2 O, 553 K CO 2 CNT H- [10], CNT MgO -, 1013 K CO NiO, - 4 CNT, 2920 cm cm -1 TPD-GC TPD 3 TPD, [21] TPD-MS 3 O H ; : 393 K -(I)( K) H 2 O, 593 K K, CO C,, CH 4 H 2, sp 2 -C H, Mg(OH) 2 Ni(OH) 2 [19-20] CH 3 CH 2 ; 3430 cm cm -1 CNT sp 2 -C E 1u 4 Fig4 CNT TPD-GC TPD-GC profiles of CNT treated by HNO 3 with varying treating-conditions GC: gas chromatography 5 Fig5 (a) (b) CNT FTIR FTIR spectra of (a) CNT as-grown and (b) CNT treated treating conditions: 70 mol L -1 HNO 3 aqueous solution, 378 K for 24 h

6 No : D- [10,22-23], CNT FTIR, 5(b) CNT sp 2 -C E 1u O (1620 cm -1 ) D- (1380 cm -1 ) CNT treated O 1s C 1s XPS CNT CH 3 CH 2 6(b) 6(c), ( cm -1 ), O 1s-XPS 3 O NiO/MgO ( 03% ), [25], : C 襒 O C OH IR C O C, O 1s 5310, ev CNT, C 1s-XPS C 1s- Figueiredo [18], XPS ( 6(c)), 6 IR, C 1s 2838, 2846, 2860,, ( TPD [24] ) 2870, ev 2838 ev, Figueiredo [18] Szymanski [19], CNT treated (2843 ev), CNT IR : [9] 2846 ev cm -1 CNT C 1s O H ; , ev cm -1 CNT C OH / C O C, C 襒 O, cm ev C O Fig6 25 CNT treated XPS 6(a) CNT as-grown CNT treated XPS 532 ev 6 CNT XPS XPS spectra of CNT before and after HNO 3 treatment (a) CNT as-grown and CNT treated, (b) O 1s of CNT treated, (c) C 1s of CNT treated; treating conditions: 70 mol L -1 HNO 3 aqueous solution, 378 K for 24 h C 1s, C 襒 O, C( 襒 O) O C 1s p π-π * [26] XPS CNT treated O 1s-XPS XPS, CNT O/C 3 79% 186%, O ( : HNO 3 235, CNT ), CNT, 70 mol L -1

7 3086 Acta Phys -Chim Sin, 2010 Vol K 24 h M Langmuir, 2002, 18: Toebes, M L; van Heeswijk, E M P; Bitter, J H; van Dillen, A CNT, HNO 3 J; de Jong, K P Carbon, 2004, 42: 307 CNT (Ni 0 x, NiO MgO) 14 Peng, D; Yu, H, Peng, F; Wang, H J; Yang, J Chin J Catal,, C 2009, 30: 570 [,,,, C, 2009, 30: 570], 70 mol L Yu, H; Zeng, K; Fu, X B; Zhang, Y; Peng, F; Wang, H J; K 24 h CNT Yang, J J Phys Chem C, 2008, 112: Fu, R W; Baumann, T F; Cronin, S; Dresselhaus, G; ; 3, Dresselhaus, M S; Satcher Jr, J H Langmuir, 2005, 21: 2647 > > 17 Moreno-Castilla, C; Ferro-Garcia, M A; Joly, J P; Bautisfa- References 1 Iijima, S Nature, 1991, 354: 56 2 De Jong, K P; Geus, J W Catal Rev-Sci Eng, 2000, 42: Serp, P; Corrias, M; Kalck, P Appl Catal A-Gen, 2003, 253: Zhang, H B; Lin, G D; Yuan, Y Z Curr Topics Catal, 2005, 4: 1 5 Zhang, H B; Liang, X L; Dong, X; Li, H Y Lin, G D Catal Surv Asia, 2009, 13: 41 6 Boehm, H P Carbon, 2002, 40: Boehm, H P Carbon, 1994, 32: Chen, P; Zhang, H B; Lin, G D; Hong, Q; Tsai, K R Carbon, 1997, 35: Eklund, P C; Holden, J M; Jishi, R A Carbon, 1995, 33: Chen, P; Zhang, H B; Lin, G D; Tsai, K R Chem J Chin 23 Branca, C; Frusteri, F; Magazu, V; Mangione, A J Phys Chem Univ, 1998, 19: 765 [,,, B, 2004, 108: 3469, 1998, 19: 765] 24 Dandekar, A; Baker, R T K; Vannice, M A Carbon, 1998, 36: 10 Zhang, H B; Lin, G D; Zhou, Z H; Dong, X; Chen, T Carbon, , 40: Biniak, S; Szymanski, G; Siedlewsk, J; Swiatkowski, A Carbon, 11 XRD data bank attached to X Pert PRO X-ray diffractometer 1997, 35: 1799 The Netherlands: PANalytical, Zeng, Y; Ying, Z; Du, J H; Cheng, H M J Phys Chem C, 12 Liu, Z L; Lin, X H; Lee, J Y; Zhang, W D; Han, M; Gan, L 2007, 111: Toledo, F Langmuir, 1995, 11: Figueiredo, J L; Pereira, M F R; Freitas, M M A; Orfao, J J M Carbon, 1999, 37: Szymanski, H A IR theory and practice of infrared spectroscopy New York: Plenum Press, 1964: Tang, H T Spectroscopic identification of organic compounds Beijing: Peking University Press, 1992: [ :, 1992: ] 21 Nakamoto, K Infrared and Raman spectra of inorganic and coordination compounds 3rd ed Trans Huang, D R; Wang, R Q Beijing: Chemical Industry Press, 1986: [Nakamoto, K,, :, 1986: ]

Supporting information Combination of N-Arylstilbazolium Organic Nonlinear Optical Chromophores with Iodoargentates: Structural Diversities and Optica

Supporting information Combination of N-Arylstilbazolium Organic Nonlinear Optical Chromophores with Iodoargentates: Structural Diversities and Optical Properties Yu-Kang Wang, Li-Ming Zhao, Yu-Qing Fu,