這次所提出的三年期科技部計畫之目的，是以理論計算方法探討在不同的金屬或雙 金屬以及ZSM-5 等表面之催化下，如何將現存於環境大氣中比較影響人類生活的氣體， 做一些可能的化學轉換，以利未來人類的永續生活。其中第一個子計畫之設計是關於消 減空氣污染之研究，我們將試著尋找活性較高的純金屬或合金雙金屬之觸媒表面，來與 大氣中有害之含氮的有毒氣體NOx 作用，並詳細觀察其吸附行為。我們隨後將再運用 通入氫氣的方式，讓該吸附物-NO(a)進行氫化反應，希望其能有效地轉換成有價值的氨 氣(NH3)和無污染性之水氣(H2O)。至於了解何種金屬或雙金屬合金可以達到預期的最佳 效果及可能的化應機制與微觀原因分析，那將是本第一個子計畫所要探討的目標。 再者，鎳(Ni)和銅(Cu)催化劑可利用於許多非均相之催化反應，尤其是其有很高的 活性能夠當作電化學反應之氧化或還原電極。不幸的是，常有硫化物雜質會快速的將上 述電極毒化並嚴重地使該催化劑失去其原有的活性。因此我們第二個子計畫的主要目 的，是想藉由乙炔(HC=CH)分子去處理硫在貴金屬的毒化現象，我們期待此方法能有效 地去再生貴金屬的催化活性。關於乙炔分子與硫原子在上述表面的吸附過程，以及相關 反應中C-S 鍵的形成、C-C 鍵的斷裂和C4H4S(噻吩)的脫附，都是我們要仔細計算與研 究的部分。我們希望能夠藉由理論計算的方法，去預測出最好的反應途徑並能詳細地提 供實驗家更微觀的物理化學現象，這也將是我們在此第二個子計畫最主要的執行任務。 最後，我們將嘗試把目前環境生活中常見的廢棄塑膠袋，利用化學催化方法來進行 回收利用。例如：聚合物之有機分子-聚乙烯(polyethylene)是生活中常見的PE 塑膠袋， 若能經過回收再利用並轉換成有價值的產物，將是非常重要的研究主題。在最近的文獻 調查，我們發現高矽鋁比之矽酸鋁沸石(ZSM-5)具有明顯的孔洞結構，此特殊的結構特 性已經被許多研究學者發現其不但具有高效率的催化能力，並能當作載體材料。此外， 它還能夠讓一些具高分子量的有機分子有足夠的吸附與反應空間，例如：低密度聚乙烯 (LDPE)將可以藉由ZSM-5 表面被催化與裂解。故此第三個子計畫，我們希望能透過理 論計算的方式去找到更環保且更節能的方法來轉換這些塑膠廢料，期許能將之再回收利 用並成為有價值的產物。 The purpose of this three years project is to study the possible catalytic effect by applying the metallic/bimetallic and ZSM-5 (Zeolite Socony Mobil-5) surfaces on the chemical reactions in which the reactants are those gases from the environment that related to the daily-life of mankind. There are three sub-projects, each of which correlates to one of the practical chemical reactions; such as by applying the highly active metallic and bimetallic as catalysts to effectively adsorb the exhausted NOx gases in the air and then converted into the useful and benign NH3 and H2O gases by hydrogenation reactions. Our goal in this first project is to find the possible reaction mechanisms in each reaction in reaching the optimal catalytic effect provided by these highly active metallic/bimetallic surfaces. Secondly, nickel and copper-based catalysts can be employed for many heterogeneous catalytic reaction due to its high activity for electrochemical reaction. Unfortunately, trace amounts of sulfur in the natural gas feed severely deactivate the above catalysts. Therefore, the purposes of this second year project is to address the fully picture for the regeneration of precious-metal catalysts by acetylene (HC=CH). As to which capture processes of surface, such as C-S bond formation, C-C bond broken and C4H4S (thiophene) desorption, could do the best favorable pathway, as well as the understanding of the complicated reaction mechanisms will be the main task that we have to overcome completely in this second year project. At last, larger size surfaces of ZSM-5 is an aluminosilicate zeolite showing well defined pores and channels and has been used as a support material for catalysis. It provides larger reaction platform for larger organic molecules, such as low density polyethylene (abbreviated LDPE) polymer, for carrying out the catalytic degradation reactions, will be also considered. We hope this third year project can be use as an alternative recycling method for converting plastic waste to more valuable energy sources.
