由中间相炭微球一步合成多孔碳(英文全文)

Synthesis of porous graphitic carbon from mesocarbon microbeads by one-step route

Yu Lei •Zheng-Hong Huang •Wanci Shen •

Yongping Zheng •Feiyu Kang

Published online:4June 2013

ÓSpringer Science+Business Media New York 2013

Abstract We developed a one-step route to synthesize porous graphitic carbon (PGC)from mesocarbon micro-beads.The MCMB was ground with NaOH and FeCl 3in an agate mortar,and then the mixture was heated in an Argon flow.Finally the PGC was obtained after washing with acid and deionized water.The sample was characterized by nitrogen adsorption,X-ray diffraction,SEM,TEM and Raman spectroscopy.The results showed that NaOH acted as activation reagent to increase surface area,meanwhile FeCl 3worked as the catalyst to accelerate the graphitization.In order to balance the two effects,the orthogonal experimental design was used to optimize the experiment parameters including temperature,the amounts of NaOH and FeCl 3.The optimized result showed a surface area of 929m 2/g and a high degree of crystallization (L c =32.6nm).As a result,the combination of chemical activation and catalytic graph-itization upon MCMB created one kind of PGC with a sur-face graphitization structure which was helpful to contribute a conductivity network.

Keywords Porous graphitic carbon ÁOne-step route ÁChemical activation ÁCatalytic graphitization ÁMCMB Abbreviations MCMB Mesocarbon microbeads S BET Specific surface area obtained via brunauer-emmet-teller-equation

FWHM002Full width at half maximum of 002

1Introduction

Porous graphitic carbon (PGC)is a kind of carbon material that co-exists of pores and graphitic carbon structures [1].This multi-structural carbon has been paid considerable attention as catalyst supports in fuel cell,solid-phase extraction [2],and electrodes in electrochemical devices [3,4]since the following advantages:(a)Low cost,environmental friendly and versatile availability of carbon materials,(b)Large surface area and porous structure generating numerous reaction sites,(c)Partial graphitic structure engendering good conductivity [1,5].

The synthesis of PGC needs both the activation process and the graphitization process.The conventional activation process includes chemical and physical activations [6].NaOH,KOH,ZnCl 2,etc.are employed as the chemical activation reagents.And CO 2and steam are employed as the physical activation reagents to etch the carbon under thermal treatment.Since the chemical activation reagents may lead to the formation of cross-links which contributes to the formation of a rigid matrix,the carbon is less prone to volume contraction or volatile loss compared with physical activation [7].

The conventional graphitization usually requires tem-perature in excess of 2,500°C to obtain an ordered graphite framework [8,9].However the high temperature treatment will decrease the surface area and have severe damages to pore structures.Another method to increase the degree of crystallization is catalytic graphitization.In this way,graphitization reaction occurs under a moderate condition by the aid of catalysts (Fe,Co,Ni,etc.)[8].This method only requires an environment with a relative low temper-ature compared with the conventional one.However,the lower energy of catalytic graphitization is not capable to break down several cross-links so that the graphitization is

Y.Lei ÁZ.-H.Huang ÁW.Shen ÁY.Zheng (&)ÁF.Kang Lab of Advanced Materials,School of Materials Science

and Engineering,Tsinghua University,Beijing 100084,China e-mail:ypzheng@

J Porous Mater (2013)20:1323–1328DOI 10.1007/s10934-013-9717-z