製備氧化鋅/鐵酸鋅層次級奈米結構與其本質催化性質之研究

Fabrication of ZnO/ZnFe2O4 hierarchical nanostructures with improved intrinsic peroxidase-like activity

楊智傑(Jhih-jie Yang)

指導教授 ： 李勝偉

國立中央大學/工學院/材料科學與工程研究所/碩士(2014年)

摘要

近年來鐵酸鋅被發現具有類似過氧化酶催化活性 (peroxidase activity)，可將過氧化氫分解為氫氧自由基。過氧化氫通常會在有機物分解過程中產生，例如葡萄糖可被葡萄糖氧化酶 (GOx) 氧化為葡萄糖酸以及過氧化氫。由於鐵酸鋅有優異的本質過氧化酶活性，且於大多催化反應中具有良好的抗腐蝕能力以及結構穩定性，因此鐵酸鋅相當有潛力可應用於葡萄糖檢測及染料降解。由於鐵酸鋅的本質催化活性與其形貌及維結構有關，降低材料維度可有效地增加比表面積，因此能顯著的提升其催化性質。
本研究中共分兩大方向去提升鐵酸鋅催化活性。首先我們結合靜電紡絲技術與溶膠凝膠法製備氧化鋅/鐵酸鋅玉米穗棒狀奈米複合材料，鐵酸鋅奈米顆粒源自金屬鹽類前驅液中的Fe(OH)3晶核熱分解。由於鐵酸鋅奈米顆粒可提供額外的反應面積，故展現出優異的催化活性與葡萄糖檢測能力。
第二部分則是利用選擇性蝕刻方式製備氧化鋅/鐵酸鋅介孔複合奈米纖維。於SEM影像中顯示在經過化學蝕刻後的樣品表面出現許多微小孔洞，這些孔洞性質可藉由氮氣吸附-脫附儀分析，結果顯示蝕刻過後可將比表面積由30.1 m2/g 增加至38.3 m2/g，平均孔洞直徑由7.9 nm增加至12.2 nm，總孔洞體積由0.082 cm3/g增加至0.157 cm3/g。綜合SEM、XRD、BET及BJH量測結果顯示選擇性蝕刻能有效提升複合奈米纖維比表面積以及孔洞體積。由於蝕刻後的複合奈米纖維具有較大的比表面積，因此展現出較優異的催化活性。

關鍵字

鐵酸鋅 ； 靜電紡絲 ； 選擇性蝕刻 ； 過氧化氫酶物質

並列摘要

Recently, extensive research has shown that zinc ferrite possessed intrinsic peroxidase-like activity and it can catalyze H2O2 into hydroxyl radical. It is known that H2O2 is the main product of the glucose oxidase (GOx)-catalyzed reaction. Since it can be catalyzed by ZnFe2O4 to produce the color signal, the colorimetric detection of glucose can be realized. The peroxidase-like activity of zinc ferrite is strongly dependent on its morphology and microstructure. Thus, reducing the dimension of material can effectively enhance the catalytic ability.
This thesis contains two sections. First, we combined the electrospinning technique and sol gel method to fabricate ZnO/ZnFe2O4 composite nanocobs. The appearance of zinc ferrite NPs is due to the decomposed Fe(OH)3 nuclei in the metal salt precursor at annealing processes. Because zinc ferrite NPs can provide extra surface area, it possesses outstanding catalytic ability of glucose detection and degradation of dye.
Second, we utilized the selective etching method to fabricate mesoporous composite nanofiber. SEM images showed that a large number of mesopoles appeared at the surface after etching. The structural information of the etched sample were obtained by BET and BJH. The measurement results presented that the surface area, average pore diameter and total pore volume of the sample after etching were increased from 30.1 to 38.3 m2/g, 7.9 to 12.2 nm and 0.082 to 0.157 cm3/g, respectively. In summary, the result of SEM, XRD, BET and BJH indicated that the selective etching is an effective method to fabricate mesoporous nanofiber. Owing to the larger surface area, the sample after etching shows a better intrinsic peroxidase-like activity.

並列關鍵字

zinc ferrite ； electrospinning ； selective etching ； peroxidase mimic

參考文獻

[2] C. H. Kim, Y. Myung, Y. J. Cho, H.S. Kim, S. H. Park, J. Park, J. Y. Kim, B. Kim, "Electronic Structure of Vertically Aligned Mn-Doped CoFe2O4 Nanowires and Their Application as Humidity Sensors and Photodetectors," The Journal of Physical Chemistry C, vol. 113 (2009) pp. 7085-7090.

[3] Z. Zhou, Y. Zhang, Z. Wang, W. Wei, W. Tang, J. Shi, R. Xiong, "Electronic structure studies of the spinel CoFe2O4 by X-ray photoelectron spectroscopy," Applied Surface Science, vol. 254 (2008) pp. 6972-6975.

[4] S. Xuan, F. Wang, J. M. Y. Lai, K.W. Y. Sham, Y. X. J. Wang, S. F. Lee, J. C. Yu, C.H.K. Cheng, K.C.-F. Leung, "Synthesis of Biocompatible, Mesoporous Fe3O4 Nano/Microspheres with Large Surface Area for Magnetic Resonance Imaging and Therapeutic Applications," ACS Applied Materials & Interfaces, vol. 3 (2011) pp. 237-244.

[5] W. Pon-On, N. Charoenphandhu, I. M. Tang, P. Jongwattanapisan, N. Krishnamra, R. Hoonsawat, "Encapsulation of magnetic CoFe2O4 in SiO2 nanocomposites using hydroxyapatite as templates: A drug delivery system," Materials Chemistry and Physics, vol. 131 (2011) pp. 485-494.

[6] F. Liu, X. Li, Q. Zhao, Y. Hou, X. Quan, G. Chen, "Structural and photovoltaic properties of highly ordered ZnFe2O4 nanotube arrays fabricated by a facile sol–gel template method," Acta Materialia, vol. 57 (2009) pp. 2684-2690.