Supporting information

Transcription

1 Supporting information Hierarchical Macro-meso-microporous ZSM-5 Zeolite Hollow Fibers With Highly Efficient Catalytic Cracking Capability Jia Liu, a Guiyuan Jiang,* a Ying Liu, a Jiancheng Di, b Yajun Wang, a Zhen Zhao,* a Qianyao Sun, a Chunming Xu, a Jinsen Gao, a Aijun Duan, a Jian Liu, a Yuechang Wei, a Yong Zhao,* b Lei Jiang b a State Key Laboratory of Heavy Oil Processing China University of Petroleum, Beijing Beijing , P. R. China jianggy@cup.edu.cn zhenzhao@cup.edu.cn b Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University Beijing , P. R. China zhaoyong@buaa.edu.cn 1

2 Materials Aqueous tetrapropylammonium hydroxide (TPAOH, 25 wt%) as the structure directing agent, tetraethyl orthosilicate (TEOS, SiO %) as Si source, aluminium iso-propoxide (Al(O-i-Pr) 3, 98%) as Al source were purchased from Sinopharm Chemical Reagent Co.,Ltd. Polyvinylpyrrolidone (PVP, M w 1,300,000) was supplied by Sigma-Aldrich. Iso-butane (C 4 H 10, 99.9%) was used as a reactant to test catalytic cracking performance of ZSM-5 fibers. Catalyst characterization: The crystallinity of the samples was determined on a powder X-ray diffractometer(shimadzu XRD 6000), using CuKα radiation (λ= nm) at 40 kv and 30 ma with a scanning rate of 2 o /min. The BET specific surface area and pore volume of the catalysts were measured with linear parts of BET plot of nitrogen adsorption isotherms, using a Micromeritics TriStar II 2020 porosimetry analyzer at 77 K. Quanta 200F scanning electron microscpy (SEM) was used to observe morphology of the catalysts, and it was also employed for EDX line scan. Prior to the measurement, the samples were adhered to carbon belt attached to a aluminous pad and suttered with gold to get the necessary conductivity. TEM images were obtained by a JEOL JEM 2100 electron microscope equipped with a field emission source at an accelerating voltage of 200 kv. Acidic amounts of the zeolite were measured by temperature-programmed desorption of ammonia (NH 3 -TPD) method. 0.2 g sample was pretreated in nitrogen at 600 C for 1 h, cooled to 100 C and adsorbed NH 3 for 30 min. After flushing by pure nitrogen gas at 100 C for 45 min, temperature-programmed desorption started at a rate of 10 C/min from 100 C to 600 C, and the signal was monitored with a thermal conductivity detector (TCD). Catalytic activity measurement: The catalytic reaction was carried out in a fixed-bed flow reactor by passing a gaseous of iso-butane (2 ml min -1, 99.9%) in a N 2 flow at a flow rate 38 ml min -1 over 200 mg catalyst (total pressure of 1 atm). The products were analyzed on-line using a gas chromatograph (SP-2100) equipped with a 30 m GS-ALUMINA capillary 2

3 column and a FID detector. Figure S1. Schematic illustration of the setup for the fabrication of ZSM-5 zeolite hollow fibers. The spinneret was fabricated from two coaxial stainless steel capillaries, through which paraffin oil acted as inner liquid and an ethanol solution containing PVP and ZSM-5 nanocrystals were simultaneously ejected to form a continuous coaxial jet. Figure S2. (a) SEM image and (b) XRD pattern of as-synthesized ZSM-5 nanoparticles. 3

4 Figure S3. TEM and high resolution TEM images of ZSM-5 hollow fibers, showing the mesopores created from the stacking of ZSM-5 nanoparticles. Figure S4. SEM images of ZSM-5 hollow fibers before (a) and after ultrasonic treatment, (b) for 10 min, (c) for 20 min. It indicates that the as-fabricated hollow fibers are of good structural stability. 4

5 Figure S5. SEM images of as-prepared hollow fibers under the condition of the inner fluid rates of (a) 0.4, (b) 1.0, and (c) 1.2 ml h -1 during preparation. 5

6 Figure S6. SEM image of the solid fibers that were electrospun from ZSM-5/PVP in ethanol solution before (a) and after (b) calcination at 550 C, the composite fibers are converted to nanoparticle fibers after calcinations.(c) The magnified SEM image of the hollow fibers after calcination at 550 C. (d) XRD pattern of the fibers after calcination, indicating the MFI structure of the fibers. (e) Nitrogen adsorption/desorption isotherms and BJH pore size distribution of the ZSM-5 solid fibers (inset). 6

7 Figure S7. (a) SEM image and (b) XRD pattern of Conventional ZSM-5. Figure S8. The coking carbon distribution of the conventional ZSM-5 particle (a) and ZSM-5 hollow fiber (b) after 16h continuous reactions at 625 C via EDX line scans. 7

8 Table S1 Textual parameters of the conventional ZSM-5 (Conv-ZSM-5), Nano-ZSM-5 and as-prepared ZSM-5 fibers Sample BET t-method Total pore t-method surface micropore suface volume/ml.g -1 micropore area/m 2.g -1 area / m 2.g -1 volume/ml.g -1 Conv-ZSM Nano-ZSM ZSM-5 solid fibers ZSM-5 hollow fibers