以溶膠-凝膠法製備Al/ZnO和其特性研究

Preparation and characterization of Al/ZnO by sol-gel process

郭硌(Kuo, Luo)

指導教授 ： 張莉毓

國立屏東科技大學/工學院/機械工程系所/碩士(2015年)

https://doi.org/10.6346/NPUST.2015.00243

摘要

當光觸媒的粒徑縮小至「奈米」尺寸時，材料因量子效應會使得半導體材料能隙變大，提高電子電洞對的氧化還原能力。且光觸媒體積變小，電子電洞對遷移至觸媒表面的機率變大，降低遷移途中進行再結合的機率。此外，對ZnO進行摻雜能夠有效改變光催化劑的比表面積、晶粒大小和光催化活性等性質。

本研究利用三嵌段兩性共聚物F127作為天然模板，以硝酸鋅為前驅物，摻雜不同比例Al2O3，本實驗使用溶膠-凝膠法，經由550℃、600℃和650℃煆燒後而生成ZnO。經X-ray繞射分析、掃描式電子顯微鏡、穿透式電子顯微鏡和可見光-紫外光光譜儀分析該材料之微結構與性質，並探討不同的煆燒溫度及不同掺雜比例對ZnO結構與性質之影響。

由XRD分析得知，純ZnO及Al/ZnO均為六方纖鋅礦結構，由XRD計算晶粒尺寸，可以知道摻雜Al能夠抑制ZnO晶粒成長。由SEM觀察ZnO表面型態，煆燒溫度在600℃時有較明顯的晶粒形貌。可由TEM分析得知，ZnO晶粒尺寸及結晶形貌，並藉由EDS成份分析得知晶粒成份。最後光催化活性測試得知，當Al/ZnO比例為0.02/0.98時，經煆燒600℃後，為此研究之光催化效果最好的。

關鍵字

溶膠-凝膠法 ； ZnO ； 摻雜

並列摘要

When the particle size of photocatalyst down to ''nano'' size, the material due to quantum effects will make semiconductor band gap increase, and improve the redox ability of electron hole pairs. If the particle size of photocatalyst become small,the probability of electron hole pairs migrate to the catalyst surface will become larger to reduce the probability of recombination of electron hole pairs. In addition, element doping could effectively change the specific surface area, particle sizes, and photocatalytic activity of ZnO.

In this study, a triblock copolymer (F127) and zinc nitrate were used respectively as a template and as a precursor and doped with Al2O3 at different ratios. This experiment employed the sol-gel process, in which ZnO was prepared by calcination temperatures at 550℃, 600℃, and 650℃. Then, the effects of doping and calcination temperatures on the properties of ZnO were examined using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photocatalyst activity testing.

By the XRD analysis showed that pure ZnO and Al/ZnO are wurtzite structure. The results of grain size calculations in the XRD further indicated that doping with Al could suppress the growth of ZnO grains. The SEM observations of the surface morphology of ZnO powder showed that calcination temperature at 600℃ has obvious grain morphology. The TEM analysis and EDS composition analysis revealed that the size of ZnO grains and crystal topography as well as grain composition. Finally, the photocatalytic activity testing revealed that when Al/ZnO was at the ratio of 0.02/0.98 and calcined at 600℃, performed the best photocatalytic efficiency in this study.

並列關鍵字

sol-gel method ； ZnO ； doping

參考文獻

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