Applied Surface Science 320 (2014) 218–224 Contents lists available at ScienceDirect Applied Surface Science journal h om epa ge: www.elsevier.com/locate/apsusc Preparation of flexible zinc oxide/carbon nanofiber webs for mid-temperature desulfurization Soojung Kim a , Bharat Bajaj a , Chang Ki Byun b , Soon-Jin Kwon b , Han-Ik Joh a , Kwang Bok Yi b,∗ , Sungho Lee a,c,∗∗ a Carbon Convergence Materials Research Center, Institute of Advanced Composite Materials, Korea Institute of Science and Technology, San 101, Eunha-ri, Bongdong-eup, Wanju-gun, Jeollabuk-do 565-905, Republic of Korea b Department of Chemical Engineering Education, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea c Department of Nano Material Engineering, University of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea a r t i c l e i n f o Article history: Received 17 July 2014 Received in revised form 12 September 2014 Accepted 14 September 2014 Available online 22 September 2014 Keywords: Electrospinning Carbon nanofibers Zinc oxide Hydrogen sulfide Desulfurization a b s t r a c t Polyacrylonitrile (PAN) derived carbon nanofiber (CNF) webs loaded with zinc oxide (ZnO) were synthe- sized using electrospinning and heat treatment at 600 ◦ C. Uniformly dispersed ZnO nanoparticles, clarified by X-ray diffraction and scanning electron microscopy, were observed on the surface of the nanofiber composites containing 13.6–29.5 wt% of ZnO. The further addition of ZnO up to 34.2 wt% caused agglom- eration with a size of 50–80 nm. Higher ZnO contents led the concentrated ZnO nanoparticles on the surface of the nanofibers rather than uniform dispersion along the cross-section of the fiber. The flexible composite webs were crushed and tested for hydrogen sulfide (H 2 S) adsorption at 300 ◦ C. Breakthrough experiments with the ZnO/CNF composite containing 25.7 wt% of ZnO for H 2 S adsorption showed three times higher ZnO utilization efficiency compared to pure ZnO nano powders, attributed to chemisorption of the larger surface area of well dispersed ZnO particles on nanofibers and physical adsorption of CNF. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Zinc oxide (ZnO) has been widely used to remove hydrogen sulfide (H 2 S), which is one of toxic gases to degrade industrial facilities and pollute environment. Even though various adsor- bents such as metal oxides [1], metal oxide modified alumina [2,3], and zeolites [4,5] were applied to remove H 2 S at relatively high temperature range from 500 to 800 ◦ C, ZnO is recognized to be the most effective adsorbent under hot gas stream con- dition [6–8]. The volatility of Zn at reducing environment over 600 ◦ C has been known as a serious drawback so that the effort to reduce the reaction temperature using ZnO nanoparticles has been studied because they are much more reactive due to the increased surface area and enhanced gas diffusion character- istics [9–11]. However, it is known that aggregations of ZnO ∗ Corresponding author at: Department of Chemical Engineering Education, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea. Tel.: +82 42 821 8583; fax: +82 42 821 8864. ∗∗ Corresponding author at: Carbon Convergence Materials Research Center, Insti- tute of Advanced Composite Materials, Korea Institute of Science and Technology, San 101, Eunha-ri, Bongdong-eup, Wanju-gun, Jeollabuk-do 565-905, Republic of Korea. Tel.: +82 63 219 8134; fax: +82 63 219 8269. E-mail addresses: cosy32@cnu.ac.kr (K.B. Yi), sunghol@kist.re.kr (S. Lee). nanoparticles can be formed even at 300 ◦ C due to relatively unsta- ble characteristics of ZnO, which reduces efficient surface area for adsorption of H 2 S [9]. Therefore, ZnO nanoparticles on stable supports such as Al 2 O 3 , silica, and carbon have been investigated to increase the thermal durability of ZnO nanoparticles [10–14]. Desulphurization takes place on ZnO as following well-known reaction [6]. ZnO(s) + H 2 S(g) → ZnS(s) + H 2 O(g) (1) Fang et al. reported activated carbon (AC) supported metal oxides as H 2 S adsorbents [15]. Metal precursors (1 wt%) were impregnated into commercial AC in solution, and heat treatment at 300–450 ◦ C for 4 h led to the adsorbents, showing as high as 125 min in breakthrough time. Even though similar ex situ loadings of metal oxides on carbon materials were studied, there was a limitation on uniform dispersion of a large amount of metal nanoparticles, which is critical to minimize the fixed cost on facilities [16,17]. Pre- viously, we reported well dispersed ZnO nanoparticles, loaded on reduced graphene oxide, showing significantly high breakthrough time in H 2 S adsorption test at 300 ◦ C without any aggregation of ZnO nanoparticles [9]. In this study, we report in situ preparation of ZnO nanoparticles dispersed on nanofibers using simple and fast electrospinning for http://dx.doi.org/10.1016/j.apsusc.2014.09.093 0169-4332/© 2014 Elsevier B.V. All rights reserved.