全國中小學科展

化學

化學液相沉積法製作摻鋁氧化鋅奈米線於染料敏化太陽能電池之研究

研究使用化學液相沉積法製作摻鋁氧化鋅(Zn1-xAlxO,x=0、2%、4%、6%)奈米線於染料敏化太陽能電池上,研究摻鋁氧化鋅奈米線之晶體結構、光學及染料敏化太陽能電池特性。結果顯示摻鋁濃度4%之氧化鋅奈米線具有最佳(002)結晶相及奈米線直徑及長度,也具有最佳太陽能參數為:開路電壓0.683V、短路電流4.56mA、填充因子52.3及轉換效率1.62%。因為鋁離子取代鋅離子時,可改變氧化鋅晶格結構降低缺陷密度,使奈米線的直徑及長度增加,提升染料的吸附量,並降低能隙使電子與電洞復合機率降低,大幅提升光電轉換效率。然而摻雜過量的鋁離子6%時反而導致晶格產生扭曲,導致晶格內缺陷密度增加。從這研究可了解摻雜鋁元素對於氧化鋅奈米線之染料敏化太陽能電池影響,未來希望能研究其他參數進而改善染料敏化太陽能電池之發電效率。

探究螢光單體分子對激發複合體發光性質的影響及其應用

本研究設計與合成一系列的電子供體分子,以研究分子單體的化學結構對於所形成的激發複合體光物理性質的影響。 五個所設計的供體分子已被成功的合成並確定均具有分子內電子轉移的性質 其躍遷偶級距變化分布範圍在17.6-28.6D之間。 將此五個供體分子分別與兩種電子受體分子在溶液聚集在一起,利用在長波長處所新生的螢光發光,推測激發複合體的形成。研究的成果並顯示,具有類似三角形結構的供體分子將更容易形成激發複合體,而具有棒狀結構的分子則較不易形成之。此成果有效的提供有關於單體分子結構的設計對於所需激發複合體光物理性質的影響,形成可快速地提供各式不同發光波長的材料,將可作為在發光二極體發光層材料、螢光感測器、生物成像等領域需求時的分子設計藍圖與指引。

一價銠金屬催化肉桂胺衍生物進行不對稱氫芳基化反應 Rhodium(I)-Catalyzed Asymmetric Hydroarylation of Cinnamylamine Derivatives

一價銠金屬催化反應已經被廣泛應用於有機化學合成領域中。而本研究以具保護基之肉桂胺衍生物1與四芳基硼鈉試劑2a作為起始物進行銠金屬不對稱氫芳基化催化反應,得到具有保護基的掌性2,3-雙芳基丙胺衍生物3,並探討此反應的掌性雙烯配基對於反應的影響。本研究已完成使用Ts(對甲苯磺醯基)保護基之肉桂胺衍生物1a作為起始物進行反應,並改變與銠金屬錯合的配基,發現當配基使用2,5號位為芳基取代之配基L(掌性雙環[2,2,1]雙烯配基)時,反應有較好的位置選擇性,其中最佳的是芳基取代為苯基之配基L1,其位置選擇性比例為1:0:0.09。目前將進行改變起始物1之氮上的保護基,以L1作為配基進行反應,並與1a比較,優化反應性及產率。

開發回收PET合成UiO-66並應用於催化合成羥甲香豆素

本研究利用乙二醇處理後的聚對苯二甲酸(PET)及氯氧化鋯,以創新的無溶劑方式”solvent-free PET-to-MOF conversion”合成一類金屬有機框架材料(MOF) ── UiO-66(Zr),並發現此材料可用於催化Pechmann condensation、以間苯二酚和乙醯乙酸乙脂合成羥甲香豆素。於190℃之環境下,乙二醇處理6小時的EG-PET可合成出晶型最接近模擬模型的UiO-66晶體;而我們開發的合成方法中,最佳的反應條件為反應物質量比(氯氧化鋯:PET)= 2:1、130℃合成24小時。 對於合成出的UiO-66(Zr),我將其進行了XRD、FTIR、BET、SEM檢測,結果符合UiO-66(Zr)的特徵;唯比表面積僅有約900 平方公尺/克,推測此方法合成出的材料之有機linker數量和一般UiO-66(Zr)有所差異。 對於催化合成羥甲香豆素之反應,我們首先發現UiO-66(Zr)可作為非勻相催化劑參與此反應;且實驗結果顯示,相較於溶劑熱合成的UiO-66(Zr),以本研究的方法所得之UiO-66(Zr)作為催化劑可得到更高產率的羥甲香豆素。

Greenhouse Gases Reduction: Conversion of Methane and Carbon Dioxide into Clean Energy

In the upcoming years, both population and energy consumption are expected to increase dramatically [1]. Industrialization has led to a dramatic shift in the energy environment [2], with predictions of a 57% increase in demand for energy between 2002 and 2025 [3]. In addition to organic materials like trees and solid waste, fossil fuels like coal, natural gas, and oil provide more than 90% of the world's energy needs. Their overuse has resulted in the release of climate-altering greenhouse gases like carbon dioxide (CO2) and methane (CH4) into the atmosphere [4]. Scientists and other stakeholders are putting more emphasis on finding solutions to global warming, increasing energy production in order to meet increasing demands, and decreasing emissions of greenhouse gases. Using greenhouse gasses to make useful chemicals or fuels is one solution to both problems [5]. This motivated researchers to investigate the potential of CO2 and CH4 as clean energy sources. The process of dry reforming of methane (DRM) has been identified as a potentially successful strategy for transforming CO2 into marketable syngas with a balanced H2/CO composition [6], [7], [8], [9]. The economic viability of DRM, the reactor type, the availability of raw materials, and the intended use of the produced syngas are all-important considerations. Though DRM is gaining popularity, maintaining its long-term stability is difficult due to carbon accumulation from CO disproportionation and methane degradation [10], [11]. The catalyst used, as well as other parameters like as pressure, temperature, feed concentration, and reactor size, are critical to the process's effectiveness. In this scenario, a nickel catalyst on a La2O3/SiO2 substrate with microspheres and a core-shell structure will be developed to improve the conversion of greenhouse gases into profitable syngas. This catalyst is projected to improve the efficiency and performance of the DRM process significantly.

Utilization of Nano cellulose from date palm waste for improvement of thermal stability in epoxy composite

Nano additives is becoming popular trends nowadays due to its nanosize (1-100 nm). Incorporating nano additives in polymer could increase different properties such as mechanical, physical, electrical and thermal stability (1, 2). Different nano additives has been used such as nano copper oxide, nano silica, nano zinc oxide, nano titanium dioxide but most of these come from synthetic or metal oxides that considered as non-environmentally friendly and harmful to human when exposed or inhaled (3). One of the green materials that become attention by researchers is nano cellulose. Nano cellulose can be extracted in different methods and sources such as from wood, and non-woody resources such as kenaf, jute, bamboo as well as from bacteria such as Acetobacter species(4). This making nano cellulose abundantly available in resources. Nano cellulose can be in the form of nano crystalline cellulose (CNC) or NCC or can be in form of nano fibrillated cellulose (NFC) and bacterial nanocellulose (BNC)(5). This nanocellulose has many advantages that can give improvement in different applications such as mechanical, physical, thermal and improving the biodegradation when added together in different matrices (6, 7). Polymers have a problem in thermal stability while processing. It hard to control and maintain the thermal stability of polymer during processing and most polymers considered to have low in thermal stability except for thermosetting polymers such as epoxy. Epoxy has been widely used in many fields such as coating, adhesive, laminates, castings and many more (8). But the drawbacks of epoxy while using is hard to maintain and controll the thermal properties when processing of this materials and used for long period due to aging and attack by free radicals causing by UV radiation (9, 10). In this study we are incorporating nano additives into epoxy as polymer matrix to enhance and improve the thermal stability of composite by crosslinking the polymer chains with the nano additives. Furthermore, the nano additive used is come from nano cellulose extracted from date palm waste and thus to create an environmentally friendly and sustainable nano additives products.

Glass Coloring by the production of Colloidal Hydroxide

When doing an experiment to produce colloidal ferric hydroxide, the bottom of the beaker used was colored in yellow-brown with thin film interference. This phenomenon is well-known, but the cause has not been clearly studied. As a result of the research, the coloration on the bottom of the beaker is caused by β-FeOOH forming a thin film which is chemically bonded with Si-OH on the glass surface. Also, the amount of β-FeOOH depends on the number of experiments, the area of the bottom of the beaker, and the concentration of FeCl3 aq. We found that it can be possible to determine the amount of β-FeOOH from the formula m=knsc and the adhesion constant was found to be 6.8✕10-3 (L/m2). In addition, from machine learning we predicted that the thin film thickness becomes thicker as it moves away from the center.

ZIFs與釩氧化物作為鋅電池陰極材料之應用與性能研究

本研究旨在優化鋅離子電池陰極材料的性能,選用沸石咪唑酯骨架材料(ZIFs)與釩氧化物(V6O13)進行複合材料的合成與應用。隨著鋰電池成本的上升,鋅離子電池因其安全性與成本效益逐漸受到重視。ZIFs 具有高比表面積及良好的離子導電性,而V6O13則因多價態和優良導電性而成為潛力材料。通過結合這兩種材料,我們開發了具有多孔結構和優異穩定性的複合陰極材料,再使用 PXRD、SEM 及 EDX 對材料進行結構表徵,並使用此新材料製作鋅離子電池進行電化學性能測試。結果顯示,熱裂解後的 PY-VxOy@ZIF-Zn/Co具有最佳的克容量及穩定性,且在500次循環後保持良好的穩定性。本研究展示了ZIFs和V6O13結合在鋅離子電池中的應用潛力,為低成本、高效能的儲能解決方案提供了新的方向。

探討手性有機硒催化劑合成與性質

研究指出⼿性有機硫催化劑能催化反應合成出⾼立體選擇性的產物,並有相關的研究指出以同族的硒取代⽽成的催化劑也有類似的性質,我們好奇兩者之間催化能⼒的差異處。本研究探討⼿性有機硒催化劑THSeOBn的合成,並將其應用催化形成氮環丙烷化物及環氧化物以探討其性質。本研究發現相較⼿性有機硫催化劑THTOBn催化,其催化形成氮環丙烷反應的dr 值及反應速率皆有顯著的上升,但其催化形成環氧化物的反應儘管反應速率有上升,但是dr值卻下降。最後本研究提出了關於THSeOBn催化形成氮環丙烷及環氧化物的反應機構。

一價銠金屬催化肉桂胺衍生物進行不對稱氫芳基化反應 Rhodium(I)-Catalyzed Asymmetric Hydroarylation of Cinnamylamine Derivatives

一價銠金屬催化反應已經被廣泛應用於有機化學合成領域中。而本研究以具保護基之肉桂胺衍生物1與四芳基硼鈉試劑2a作為起始物進行銠金屬不對稱氫芳基化催化反應,得到具有保護基的掌性2,3-雙芳基丙胺衍生物3,並探討此反應的掌性雙烯配基對於反應的影響。本研究已完成使用Ts(對甲苯磺醯基)保護基之肉桂胺衍生物1a作為起始物進行反應,並改變與銠金屬錯合的配基,發現當配基使用2,5號位為芳基取代之配基L(掌性雙環[2,2,1]雙烯配基)時,反應有較好的位置選擇性,其中最佳的是芳基取代為苯基之配基L1,其位置選擇性比例為1:0:0.09。目前將進行改變起始物1之氮上的保護基,以L1作為配基進行反應,並與1a比較,優化反應性及產率。