静电纺丝基碳纤维载纳米钯催化剂的制备及应用

doi:10.15541/jim20130556

摘要/Abstract

摘要：

采用静电纺丝、化学还原及高温碳化方法制备了碳纳米纤维螯合钯纳米粒子复合催化剂。实验详细考察了三种还原剂 (硼氢化钠、水合肼、氢气)在催化剂制备过程中对钯纳米粒子及碳纤维形貌的影响。通过固体紫外、X射线粉末衍射、红外、扫描电镜、场发射透射电镜等测试方法对已制备的一系列催化剂进行表征。结果表明选择氢气为还原剂时, 碳纤维上获得了7 nm左右、粒子分布均匀的钯纳米粒子, 催化剂相对柔韧, 继而将此催化剂应用于Heck偶联反应测试其催化及循环利用特性。催化结果证实此方法制备的催化剂具有优异的稳定性、底物耐受性、可回收性。

关键词: 静电纺丝, 钯纳米粒子, Pd NPs/CNFs, Heck反应

Abstract:

Carbon nanofibers-supported palladium nanoparticle catalysts were prepared by electrospinning, chemical reduction and the subsequent high temperature carbonization methods. The experiments were carried out to investigate the influence of different reducing agents (sodium borohydride, hydrazine hydrate and hydrogen gas) on morphology of palladium nanoparticles and carbon nanofibers in detail. Catalysts were characterized by UV-Vis spectra, X-ray diffraction, fourier transform infrared spectrum, scanning electron microscope, field emission transmission electron microscope. Results show that the palladium nanoparticles are distributed uniformly on the carbon nanofibers with dimension of about 7 nm, and the catalyst is relatively flexible by using hydrogen gas as reducing agent. Then it was applied to the Heck coupling reaction to test catalytic properties and recyclability. Results indicate that the catalyst possesses excellent stability and recyclability.

Key words: electrospinning, palladium nanoparticles, Pd NPs/CNFs, Heck reaction

中图分类号:

O643

郭丽萍, 白杰, 梁海欧, 李春萍, 孙炜岩, 孟庆润. 静电纺丝基碳纤维载纳米钯催化剂的制备及应用[J]. 无机材料学报, 2014, 29(8): 814-820.

GUO Li-Ping, BAI Jie, LIANG Hai-Ou, LI Chun-Ping, SUN Wei-Yan, MENG Qing-Run. Preparation and Application of Carbon Nanofibers-supported Palladium Nanoparticles Catalysts Based on Electrospinning[J]. Journal of Inorganic Materials, 2014, 29(8): 814-820.

图/表 9

图 1 Pd NPs/PAN纳米纤维膜被不同还原剂还原前后的紫外可见吸收光谱固体紫外表征结果

Fig.1 UV-vis diffuse reflection spectra of Pd NPs/PAN reduced by different reducing agents (A) Sodium borohydride; (B) Hydrazine hydrate; (C) Hydrogen gas

图 2 不同还原剂制备的Pd NPs/CNFs催化剂的XRD图谱

Fig. 2 XRD patterns of Pd NPs/CNFs catalysts prepared with different reducing agents (A) Sodium borohydride; (B) Hydrazine hydrate; (C) Hydrogen gas

图3 PdCl2/PAN 纳米纤维膜(A)和不同还原剂制备的Pd NPs/CNFs(B、C、D)的FT-IR图谱

Fig.3 FTIR spectra of PdCl2/PAN nanofibers (A) and Pd NPs/CNFs catalysts (B, C, D) prepared with different reducing agents (B) Sodium borohydride; (C) Hydrazine hydrate; (D) Hydrogen gas

图 4 PdCl2/PAN纳米纤维膜(a)和不同还原剂制备的Pd NPs/PAN纳米纤维膜(b、c、d)的SEM照片

Fig. 4 SEM images of PdCl2/PAN nanofibers(a) and Pd NPs /PAN nanofibers (b, c, d) prepared with different reducing agents (b) Sodium borohydride; (c) Hydrazine hydrate; (d) Hydrogen gas

图 5 不同还原剂制备的Pd NPs/CNFs催化剂的SEM照片

Fig. 5 SEM images of Pd NPs/CNFs catalysts prepared with different reducing agents (a) Sodium borohydride; (b) Hydrazine hydrate; (c) Hydrogen gas

图 6 不同还原剂制备的Pd NPs/CNFs催化剂的TEM照片

Fig. 6 TEM images of Pd NPs/CNFs catalysts prepared with different reducing agents (a) Sodium borohydride; (b) Hydrazine hydrate; (c) Hydrogen gas

表1 不同还原剂制备的Pd NPs/CNFs催化剂催化性能对比

Table 1 Comparative product yields for iodobenzene with methyl acrylate under series of catalysts

Catalyst	Temperature /℃	Reaction time /h	Catalyst /g	Conversion rate /%	Selectivity /%
a	150	10	0.0305	100	97.50
b	150	10	0.0307	100	96.09
c	150	10	0.0301	100	94.56

表2 Pd NPs/CNFs催化剂在碘代苯/丙烯酸甲酯体系中的循环使用性能研究

Table 2 Recycling experiments using Pd NPs/CNFs catalyst in the Heck coupling reaction of iodobenzene and methyl acrylate

Run	Temperature /℃	Reaction time /h	Catalyst /g	Conversion rate /%	Selectivity /%
1	150	10	0.0301	100	94.56
2	150	10	0.0300	100	96.24
3	150	10	0.0298	100	98.21
4	150	10	0.0296	100	98.43
5	150	10	0.0297	100	98.25

图7 反应五次后Pd NPs/CNFs催化剂的TEM照片及反应前(A)和反应后(B)钯纳米粒子粒径分布柱形图

Fig. 7 TEM image and particle diameter distribution histograms of Pd NPs before (A) and after (B) being catalyzed the Heck reaction five times

参考文献 25

[1]	SUH WON H, SUH YOO H, STUCKY, et al. Multifunctional nanosystems at the interface of physical and life sciences. Nano Today, 2009, 4(1): 27-36.
[2]	SKHANNA A V, BAKSHI B R. Carbon nanofiber polymer composites: evaluation of life cycle energy use. Environ. Sci. Technol., 2009, 43(6): 2078-2084.
[3]	MOSTOﬁZADEH A, LI Y W, SONG B, et al. Synthesis, properties, and applications of low-dimensional carbon-related nanomaterials. J. Nanomater., 2011, 2011(2011): 1-21.
[4]	QIN Y, XIA J H, STAEDLER T, et al. Effects of ion bombardment on the morphology and microstructure of carbon nanomaterials grown by microwave plasma chemical vapor deposition. Appl. Phys. Lett. , 2007, 90(24): 243109-1-3.
[5]	NI Y H, GE X W, XU X L, et al. Developments in preparation of nano-scale materials. Journal of Inorganic Materials, 2000, 15(1): 9-15.
[6]	WANG Y Z, YANG Q B, DU J S, et al. Electrospinning a high effect and low cost technique for nanofibers. New Chemical Materials, 2005, 33(6): 12-14.
[7]	YANG Q B, LI D M, HONG Y L, et al. Preparation and Characterization of a PAN Nanofibre Containing Ag Nanoparticles via Electrospinning. Proceedings of the 2002 International Conference on Science and Technology of Synthetic Metals, 973-974.
[8]	DEMIR M M, GULGUN M A, MENCELOGLU Y Z. Palladium nanoparticles by electrospinning from Poly (acrylonitrile-co- acrylic acid)-PdCl2 solutions. relations between preparation conditions, particle size, and catalytic activity. Macromolecules, 2004, 37(5): 1787-1792.
[9]	BAI J, LI Y X, YANG S T, et al. Synthesis of AgCl/PAN composite nanofibres using an electrospinning method. Nanotechnology, 2007, 18(30): 305601-1-5.
[10]	LI D, XIA Y N. Fabrication of titania nanofibers by electrospinning. Nano Lett., 2003, 3(4): 555-560.
[11]	WU H, HU L B, ROWELL M W, et al. Electrospun metal nanoﬁber webs as high-performance transparent electrode. Nano Lett. , 2010, 10(10): 4242-4248.
[12]	ZHU J, ZHAO T J, KVASNDE I, et al. Carbon nanofiber-supp-orted palladium nanoparticles as potential recyclable catalysts for the Heck reaction. Chin. J. Catal., 2008, 29(11): 1145-1151.
[13]	OKUMURA K, NOTA K, YOSHIDA K, et al. Catalytic performance and elution of Pd in the Heck reaction over zeolite-supported Pd cluster catalyst. J. Catal., 2005, 231(1): 245-253.
[14]	HUAN C Y, MA L, LV D Y, et al. Preparation and formation mechanism of a new kind PdHx-Pd/C catalyst through hydrazine-reducing method under atmospheric pressure and H2-free conditions. Journal of Inorganic Materials, 2013, 28(10): 1072-1078.
[15]	ZHAN K, YOU H H, LIU W Y, et al. Pd nanoparticles encaged in nanoporous interpenetrating polymer networks: A robust recyclable catalyst for Heck reactions. React. Funct. Polym., 2011, 71(7): 756-765.
[16]	TAKASAKI M, MOTOYAMA Y, HIGASHI K, et al. Chemoselective hydrogenation of nitroarenes with carbon nanofiber-suppo-rted platinum and palladium nanoparticles. Org. Lett., 2008, 10(8): 1601-1604.
[17]	MOUSSA S, SIAMAKI A R, GUPTON B F, et al. Pd-partially reduced graphene oxide catalysts (Pd/PRGO): laser synthesis of Pd nanoparticles supported on PRGO nanosheets for carbon-carbon cross coupling reactions. ACS Catal., 2012, 2(1): 145-154.
[18]	ZHU J, ZHOU J H, ZHAO T J, et al. Carbon nanofiber-supported palladium nanoparticles as potential recyclable catalysts for the Heck reaction. Appl. Catal. A-Gen., 2009, 352(1): 243-250.
[19]	MAIYALAGAN T, SCOTT K. Performance of carbon nanofiber supported Pd-Ni catalysts for electro-oxidation of ethanol in alkaline medium.J. Power Sources, 2010, 195(16): 5246-5251.
[20]	TSE K Y, ZHANG L Z, BAKER S E, et al. Vertically aligned carbon nanofibers coupled with organosilicon electrolytes: electrical properties of a high-stability nanostructured electrochemical interface. Chem. Mater., 2007, 19(23): 5734-5741.
[21]	HU Y, GAO X H, YU L, et al. Carbon-coated CdS petalous nanostructures with enhanced photostability and photocatalytic activity. Angew Chem. Int. Ed., 2013, 52(21): 5636-5639.
[22]	LÜ R J, SHI K Y, ZHOU W, et al. Highly dispersed Ni-decorated porous hollow carbon nanoﬁbers: fabrication, characterization, and NOx gas sensors at room temperature. J. Mater. Chem., 2012, 22(47): 24814-24820.
[23]	YANG Y, CENTRONE A, CHEN L, et al. Highly porous electrospun polyvinylidene ﬂuoride (PVDF)-based carbon ﬁber .Carbon, 2011, 49(11): 3395-3403.
[24]	AYKUT Y. Enhanced field electron emission from electrospun Co-loaded activated porous carbon nanofibers. ACS Appl. Mater. ,Interfaces, 2012, 4(7): 3405-3415.
[25]	BAI J, YANG Q B, LI M Y, et al. Synthesis of poly (N-vinylp-yrrolidone)/β-cyclodextrin composite nanofibers using electrospinning techniques. J. Mater. Process Tech., 2008, 208(1): 251-254.