簡易方法合成石墨烯-氧化鋅複合物及其光催化特性應用之研究

A facile synthesis of Graphene-ZnO hybrids and its application in photocatalysis

馮氏鶯(Phung Thi Oanh)

指導教授 ： 呂志鵬

國立交通大學/工學院/材料科學與工程系所/碩士(2019年)

摘要

在本文中，我們開發了一種高效、簡便且一步合成的方法，結合了石墨超音波電化學剝離法及 Zn(NO3)2 超音波輔助沉澱法生產石墨烯-氧化鋅複合物（G-ZnO）。經由X光繞射儀、拉曼光譜儀、FT-IR、X光電子能譜儀（XPS）、SEM、TEM，對石墨烯-氧化鋅複合物之結構及表面形貌進行了全面地分析量測，以及進一步利用紫外光光光譜儀( UV )及PL測量其應用於光催化降解亞甲基藍水溶液之能力。研究並比較剝離時間和Zn（NO3）2濃度對G-ZnO生成及其光催化性能的影響。
結果證實 : 石墨烯與氧化鋅的相互作用可以通過反應時間和Zn（NO3）2的濃度來控制。根據拉曼光譜分析，較高的ID / IG比和連帶出現的D' 峰對應於氧化鋅和石墨烯之間的強鍵結，這可能有利於半導體的光催化活性。其複合物對亞甲基藍 (MB) 的光催化活性在室溫26 ℃於氙燈下所測得。在Langmuir-Hinshel-wood pseudo-first-order kinetic model中良好地描述且擬合了G-ZnO的降解反應（R2 > 0.95）。濃度1M的Zn(NO3)2 經60分鐘電化學剝離後，G-ZnO於氙燈的照射下展現極高程度降解亞甲基藍的光催化活性，反應速率常數k = 2.23.10-2 min-1，且能幾乎完全去除。其增強的光催化活性可歸因於更高的光吸收強度、電荷載子的重組、易於分離的電荷載子以及縮小的G-ZnO複合物能隙所造成的綜合效應。

關鍵字

超音波輔助合成 ； 超音波電化學剝離法 ； 石墨烯-氧化鋅複合物 ； 亞甲基藍 ； 光催化降解

並列摘要

In this thesis, we have developed an efficient, facile one-step-approach to fabricate graphene-ZnO hybrids (G-ZnO) by combining sonoelectrochemical exfoliation of graphene and ultrasonic-assisted synthesis using Zn(NO3)2. The formation, structure, and morphology of graphene-ZnO hybrids were confirmed by X-ray diffraction, Raman, Fourier-transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microcopy (TEM). Furthermore, ultraviolet spectroscopy (UV) and photoluminescence (PL) were employed for studying its photocatalytic degradation of methylene blue in an aqueous solution. The effects of reaction time and Zn(NO3)2 concentration on the formation of G-ZnO and their photocatalytic performance were examined and compared.
The results show that the interaction of graphene and ZnO can be controlled by the factor of the reaction time and concentration Zn(NO3)2. Based on Raman analysis, a higher ID/IG ratio in conjunction with the appearance of D’ peak corresponds to a strong bonding between ZnO and graphene, which enhance photocatalytic activity of semiconductor. The photocatalytic activity of the G-ZnO hybrids for methylene blue (MB) were tested under Xenon light at room temperature of 260C. The degradation reaction of G-ZnO of MB can be well described and fitted by Langmuir-Hinshelwood pseudo first-order kinetic model (R2>0.95). Under 1M Zn(NO3)2 and 60-minute reaction time, G-ZnO hybrid exhibits an exceptionally high photocatalytic activity for degrading MB, with a reaction rate constant of k =2.23.10-2 min-1 and approximately complete removal efficiency. The enhanced photocatalytic activity is attributed to the synergistic effect of reduced recombination of charge carrier, enhanced light absorption intensity, and narrower bandgap of G-ZnO hybrids.

並列關鍵字

Ultrasonic-assisted synthesis ； sonoelectrochemical exfoliation ； graphene-ZnO hybrids ； methylene blue ； photocatalytic degradation

參考文獻

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