全國中小學科展

化學

瓦斯熱水爐一氧化碳觸媒轉化器之研究

瓦斯熱水爐使用大火時廢氣的CO 濃度非常高是導致一氧化碳中毒事件的關鍵原因,要解決這個問題觸媒轉化是一種可行的方式。影響觸媒性能的因素中以活性中心的種類最為重要,我們發現對轉化一氧化碳為二氧化碳的反應而言鈷有最好的催化效果,其次分別為:鎳、銅、鐵。最好的載體是三氧化二鋁,鈷的含量使用10%,煅燒溫度使用300℃可兼顧性能與成本。 本研究中所研發的 Co/Al2O3 觸媒具備有實用的潛力,可以在空間速度高達1000min-1 的情況下將濃度14,632ppm 的CO 百分之百轉化為CO2,而僅需233℃的反應溫度。因此,應該可以應用在瓦斯熱水爐上以降低一氧化碳中毒的風險。 The incorrect usage of a natural gas powered water heater always generates high carbon monoxide concentration in a closed environment. The dangerous CO gas can be fatal to the careless user of the water heater. Catalytic conversion of CO to CO2 can be a convenient method to solve this problem. The effect of the support, the supported metal, loading of the metal, reaction temperature, gas concentration, and reactants flow rate on the performance of the CO oxidation catalysts have been investigated. X-ray diffraction, gas adsorption and Infrared spectroscopy were applied to study the characteristics of catalysts. A 100% conversion of CO to CO2 can be achieved when 1.46% CO/6% oxygen/N2 reactants was catalyzed by a 10% Co/Al2O3 catalyst at 233℃ with a space velocity of 1000min-1 . This reaction condition is sufficient to remove the entire CO generated by a family-sized natural gas water heater.

海格的爆尾釘蝦-鹼性電池的探討

鹼性電池使用的電解液均為強鹼,電池中的鋅極會與其發生腐蝕反應,使得電池放電壽命降低,並產生氫氣,而大量氫氣使得電池有爆裂的危險,為了改善上述問題,我們自行設計了氣體觀測儀器,用來檢測銀鋅電池充放電與靜置時之氣體產生量,更藉由探討影響變因的過程找出銀鋅電池較合適之使用條件,其中包含電解液種類及濃度之選擇、電極面積與充電電流對使用效果之影響,並改善電池腐蝕程度;我們將鋅極以浸鍍處理(Sn:Pb =1:1 )並搭配電解液添加物(KOH:Zn(OH)42 -= 2:1) 可效率地抑制氣體產生;更用氯化銀粉末取代傳統氧化銀極片為正極,發現氯化銀可代替氧化銀電極,且有不錯的放電效果。;As we know, the electrolyte solution used in an alkalinebattery is a concentrated alkaline solution, which corrodes the zinc electrode in a battery of this kind. The corrosive reaction not only reduces the lifespan of the battery but also produces hydrogen, causing the battery to explode. This study is intended to help us design a device to measure the quantity of hydrogen gas generated in the charging of a zinc-silver battery. We have studied several factors affecting zinc-silver battery, including the variety of electrolyte, the concentration of alkaline solution, the surface of electrode, and the density of charging current, etc. To reduce the corrosion of zinc electrode, we plate the zinc electrode by the immersion electroless plating method, using several kinds of low-polluting anti-corrosive additives (metallic compounds such as lead and tin). We also add zincate ion into electrolyte solution to further reduce the quantity of hydrogen produced. The experiments show a zinc-silver alkaline battery works most efficiently, if the powder of silver chloride is used instead of silver oxide.

魂「縈」夢「牽」-談重金屬污染

近年來重金屬污染問題日益嚴重,因此檢測地下水、工業廢水中的重金屬含量為一重要課題。本實驗即是利用錄音機中的零件-石英振盪器作為電化學分析偵測的工作電極,在0.1 M KNO3(pH = 3)溶液中利用循環伏安法以50 mV/s 的掃描速度從 – 100 到 – 700 mV 持續掃描 10 圈,來穩定電極表面。 以方波陽極剝除伏安法(SWASV)模式設定預濃縮電位– 700 mV、預濃縮時間60 秒偵測重金屬的鉛離子。掃描電位範圍由 – 700 到 – 100 mV vs. Ag/AgCl 往氧化方向掃描。偵測鉛離子濃度範圍為200-600 ppb,之後可針對各種條件作最佳化的條件探討可降低偵測濃度及實際運用於地下水及工業廢水的檢測。 Heavy metal pollution becomes very serious. Lead (Pb) determination is a continuous research interest in clinical, environmental, and industrial application. The main causes for living biological media are mutagenic, carcinogenic, and teratogenic activity. The determination of trace metal in the ground and industrial waste water will be a important project. Here, we report a simple system which using quartz crystal microbalance (QCM) (use in radio machine) for working electrode. The QCM was first equilibrated in 0.1 M KNO3(pH = 3)base electrolyte for about 1 min before electrochemical experiments. It was then pretreated by continuous scans in the window from – 100 to – 700 mV at a scan rate of 50 mV/s until a stable background current obtained. The amount of Pb2+ was detected quantitatively using square-wave anodic stripping voltammetry(SWASV). The potential range was set from – 100 to – 700 mV in the cathodic direction for most cases. The standard addition method concentration range is from 200 to 600 ppb. Analytical conditions were systematically optimized and extended to practical applications aslo.

甲醇氧化物對直接甲醇燃料電池發電效能的影響

The purpose of this paper is to study the roles of formic acid and formaldehyde playing in the Direct Methanol Fuel Cells(DMFCs).The assumption is now widely accepted that the Oxidation-reduction intermediate of cell like formic acid and formaldehyde will hinder the reaction of DMFCs. At first, we recorded data which measured the efficiency of DMFCs working under the different temperature of fuel, then we recorded data which measured the efficiency of DMFCs working under the different consistency. In the end, we compared the data we recorded before and chose the best reaction environment as standard environment for the future experiment. Then we discover intermediate has positive effect on DMFCs. we separately put formic acid and formaldehyde into fuel, and we discover the efficiency is better than\r before. For example, the volt stability and volt intensity of DMFCs are better. The above conclusion is mainly based on open current volt, equally volt and electric current density which is the standard of evaluation.本實驗主要探討甲酸、甲醛等雜質在直接甲醇燃料電池中扮演的角色,一般認為甲酸等是甲醇在電池中反應的中間產物,大多數人認為這些中間產物會阻礙燃料電池的反應。而我們先針對了甲醇在各種溫度下電池的效能先做出了圖表,並使用不同濃度的甲醇燃料來測量電池的效能並與之前溫度的圖表做比較,選出最合適的直接甲醇燃料電池反應環境作為添加雜質實驗的標準環境。接下來我們在研究過程中發現,其實中間產物可能對電池有正面的效果,我們發現甲酸、甲醛等對直接甲醇燃料電池的電源輸出有正面的影響,例如電壓穩定性與電壓強度的增強。在研究中,我們將甲酸等加入燃料電池的燃料(甲醇)內,模擬甲醇因不當保存而產生的雜質,針對添加物的濃度做些調整,以電池的開路電壓(OCV)、平均輸出電壓、以及單位面積的電流密度作為評比電池效能的標準,並找出甲酸等對燃料電池效能的影響,並進一步找出最適合的電池燃料配置。

分子篩與過氧化氫感測器

目前市面上缺乏簡單而精準的過氧化氫檢測法,我們參考Fenton Reaction 中,鐵離子對過氧化氫分解的催化模式,利用鐵、鈷、鎳、錳、鋅分子篩,測試他們催化過氧化氫分解反應的效率,從成本、毒性、活化能的多方考量下,選擇以分子篩來固定金屬催化離子,作為我們後續實驗的研究主軸。實驗的初步,我們選擇過氧化氫作為自由基,並著重於過氧化氫的分解反應。利用濃差電池的原理,設計出一套濃度檢測系統,由分子篩作為電極。鑒於粉末狀的分子篩容易流失,我們製備出陶土鐵分子篩,以陶土固定分子篩,並以此作為電極,搭配白金絲,透過能士特方程式,測出過氧化氫的濃度,且藉由電路調控放大倍率,可以直接控制檢測範圍。從實驗結果得知,鐵分子篩在處理過氧化氫的時候,不會有鐵離子溶出的現象,且其催化性在酸性液中可以維持,能不斷的使用,長時間來看,分子篩相當有經濟與環境保護上的價值。We attempted to provide a system for quickly determining the concentration of free radicals. The existing methods or techniques are inefficient or need expensive equipment, therefore, an inexpensive system is being sought for. As a preliminary study, we focused on the decomposition of hydrogen peroxide. Taking the Fenton reaction as reference, we designed a measuring system. This system includes a catalyst containing Fe or Pt ions for catalyzing hydrogen peroxide decomposition reaction. The Fe- and Pt-zeolite were prepared to hold Fe and Pt ions to avoid losing. Because the electrically induced potential would decrease with the decrease in the concentration of hydrogen peroxide, we could measure the concentration of hydrogen peroxide by monitoring the electrical potential. We determined the initial concentration of hydrogen peroxide in water from the initial electrical potential measured through the equation obtained from the calibration line. The practicability of this system has been assured after a series of experiments. We will further develop the technique for measuring other free radicals. We anticipate that this technique will be further developed for measuring other free radicals. Although there are several problems and limitations to be solved and conquered, one thing is for sure: this system is an environment-friendly and cost-effective facility for determining the concentration of free radicals in an aqueous solution.

奈米微粒現形記~化學反應速率的探索

In order to facilitate a paradigm shift from traditional high volume chemical experiments to an environmentally friendly microdose experiment; I had to innovate and overcome a lot of difficulties. After six generations of experiment design I successfully reduced the volume of the combined reactants to a single drop. I utilized many recycled components to build my apparatus including a vintage computer, a simple CD disk, optical sensors and a transistor from a common computer mouse. By using a CCD monitor with an external camera feed, the single drop chemical reaction can be observed in real time and a recording of the event can be made. I chose the focus of the experiment to be the reaction of sodium thiosulfate and hydrochloric acid to create a colloidal solution of sulfonium nanoparticles. By employing a custom-made transparency target to achieve a higher precision of measurement I have also conducted deeper research into the reaction order and the rate constants. 為了將傳統高劑量的化學實驗順利的推向顯微液滴的化學實驗上,今年我們更是創新突破了很多困難的關卡。 儀器設計由第一代減量研究到第六代的減量設計,目前已能成功的運用報廢的光碟片、報廢的電腦、報廢滑鼠內的感光二極體元件及電晶體來自製設計出兩反應物各一滴溶液做自動偵測反應的記錄。透過顯微鏡加裝的CCD電子螢幕目視觀看、拍成電子影片檔由電腦播放的目標。 因此,我選定了硫代硫酸鈉溶液和鹽酸溶液反應可產生硫奈米微粒的膠態溶液作為實驗的主軸及設計可較精確定量的投影片載液面,我們也企圖對其反應速率式的級數及反應速率常數做更深入的探討。

綠色能源-天然微生物燃料電池之開發

本研究開發以天然資材為原料之綠色微型微生物燃料電池。電池以碳紙為陰陽極,陽極槽以酵母菌對葡萄糖之厭氣氧化反應,陰極則塗佈有葉綠素鐵傳遞電子,以催化氧氣的還原反應,使電之進行,成功的以修飾中心金屬離子後的葉綠素取代傳統微生物燃料電池使用的金屬卟啉類化合物。實驗發現,陽極以每克酵母菌溶以1.5mL的葡萄糖液進行氧化,將葉綠素鐵0.1g塗佈於陰極,並加入純水,曝於自然光,即可有效增加微生物燃料電池電壓,電壓可達0.62 V,與典型的燃料電池在全額負載下可產生的 0.5 - 0.8 V 相當,顯示出所開發的微型微生物燃料電池是具有應用潛力。為了提升所開發電池的實用性,將微生物燃料電池微型化設計便於攜帶及未來直接結合植物光合作用之組合,同時發展不需使用具毒性之電子傳遞介質的陽極反應,使能連續從植物光合作用取得葡萄糖作為燃料的可行性。本研究所開發的微型微生物燃料電池構造簡單,所使用的酵母菌、葡萄糖、葉綠素及氧氣等資材皆可於自然界取得,符合永續經營與綠色能源的目的。未來結合直接採用植物光合作用產生之葡萄糖為燃料來發電,更可發展為就地使用完全無污染的綠色植物太陽能源。

防鏽小尖兵(分子自組薄膜的探索)

自組薄膜(SAMs, self-assembled monolayers)乃是具有特定官能基的化合物在不需外力作用 下自動吸附到基質表面上而自行排列成有自序規則之結構。SAMs技術因製備容易且穩定,在 應用上深具潛力。目前此方法中,以硫醇接在Au上的研究最為廣泛。本作品希望藉著SAMs 方法將硫醇分子吸附於鐵片或其他金屬表面上,以達成防鏽與抗酸目的。我們分別透過接觸 角量測研究正十二硫醇在鐵片上形成分子薄膜的可能性;利用酸與金屬產生氣體的速率研究 分子薄膜抗酸蝕的情況;測試分子薄膜的耐熱性;根據鐵片生銹時pH值變化、重量變化與[Fe2+] 含量差異來探究分子薄膜能否防鏽;最後找出適合形成分子薄膜的濃度與溫度效應。由實驗 結果我們發現SAMs薄膜確實能吸附於鐵(及鎳、銅、鋅等金屬)的表面上並增加抗酸與防鏽蝕 能力,薄膜對熱的穩定性極佳,35℃時結合效果較佳,而濃度的提高有助於SAMs的效用。 Self-assembled monolayers(SAMs) are elements which have specific functions.SAMs,ordered molecular aggregates can automatically adhere to the surface of substrate without any force.The applcation of SAMs’technique has high potential not only because ther are easy to make but also because they are stable.Exposing molecules such as alkyl thiols to an Au(0) surface is now in widespread use. In this work,we apply the thiols chemisorb onto the Fe or other metal surface to make it rust-resistant and acid-resistant.We study the following issues to find the appropriate conditions of forming monolayers in varying concentration and temperture: I. The possibility of forming n-dodecanthiol molecular monolayers on Fe surface by measuring the contact angles. II. The ability of antiacid corrodibility by comparing the rates of producing gas from acid and metal. III. The heat-resistant of molecular monolayers. IV. Whether it’s antirust by detecting the changes of pH,weight,and the concentrations of Fe2+ during the iron rust. According to the results,we conclude SAMs do adhere to the surface of Fe(and other matal like Ni,Cu,Zn), which increases the ability of antiacid and antirust.Besides they are stable to heat, have good combining effect at 35℃, and it is beneficial to the effect of SAMs through raising their concentration.

燃起新契機-燃料電池電極材料性質之探討

Based on environmental protection and new energy development, the energy containing low pollution and having high efficiency becomes more popular. The fuel cell is an emerging technology, which is the reason why it is considered as Green energy. However, high-price membrane electrode assembly (MEA) inhabits the development of fuel cell. Among these components in MEA, platinum-based electrode leads the most cost. We select the multi-walled carbon nanotubes (MWNTs) as catalyst support to improve electrode material performance and reduce Pt utilization. But the particle size and dispersion of platinum as well as character of catalyst support may significantly affect the efficiency of electrode.燃料電池因為具備低排放污染、低噪音及高轉換效率等環保特性,故被稱為綠色能源,可取代內燃機作為發電之能源系統。然而燃料電池中觸媒粒徑大小、分散情形以及使用不同的觸媒載體,均有可能會影響其電觸媒的催化效能,所以我們以「觸媒粒徑大小」、「觸媒分散情形」為主軸,著手以下的研究。本實驗在不同的酸鹼值下製備燃料電池的電極材料,並以電子顯微鏡等器材,觀察已披覆在電極上白金觸媒的特性,探討不同酸鹼環境對白金觸媒粒徑大小的影響,並探究白金觸媒粒徑大小與其發電效率的關係。

蟹殼幾丁凝膠應用在金屬氧化物奈米顆粒的製備與燒結

筆者利用自製的幾丁質與不同金屬的混合溶液而燒結出的奈米顆粒成效極佳,不但粒徑大小符合,在燒結的過程中也不需經過物理研磨及介面活性劑的輔助,並且在低溫下即可燒結,可以增加實用性以及商業價值。此外,在分解亞甲藍方面也有不錯的效率,並進一步從金屬氧化物之奈米膠體混合溶液比例的不同,決定其粗糙度(以AFM測定)及能隙改變,在陽光下有更高的應用效率。而在實驗的延伸研究上,希望應用在防菌、除污、甚至光電池。 We make use of self-made chitin with the mixed solutions of different metals to solder nano particles, and the result is excellent. The particle radius not only matches up to the size, but in the process of soldering nano particles, it doesn’t need any physical pulverizing or surfactant assistance. Also, it can solder in low temperature. And we could raise its practicality and the business value. What’s more, there is a good efficiency in decomposing Methylene Blue. We can further decide the roughness (measured with AFM) and the variation of the band gap from nano colloid of different metal oxide mixed ratios.Our experiment in the extending research aims to apply it to the defense of bacteria and pollution, and even photoelectric cell.