2008-10-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/700681摘要：本計畫是台荷雙邊合作研究，目標是利用光能高效率地將CO2和H2O轉成燃料，例如CH4、CH3OH或類似 Fisher Tropsch 反應的產物。由能源和環保的觀點，利用太陽光能將CO2轉成碳氫再生能源，是永久解決溫室氣體CO2和再生能源的最佳策略。其反應歸納如下， CO2 + 2 H2O → CH4 + 2 O2 CO2 + 2 H2O → CH3OH + 3/2 O2 x CO2 + &frac12; y H2O → CxHy + (x+ 2y) O2 研究內容包括光觸媒的發展和光反應器的設計，期望可得高效率的光能收穫目標。在執行上 (1)台灣大學吳紀聖教授將由溶凝膠法製備高效能光觸媒，包括Cu, Ag, Pt負戴TiO2以及Ta2O5/Nb2O5複合光觸媒，在光纖光反應器進行流動式穩態CO2 光催化還原反應；(2) 荷蘭 Delft University of Technology 的 Guido Mul 教授合成3-D Ti-Base中孔洞的觸媒，和Cu和Zr結合發展可見光觸媒，應用於CO2光催化還原，使用原位紅外線光譜儀和拉曼光譜儀，可在反應條件下分析動態光催化的表面成分；(3) 台灣大學和 Delft University of Technology 經由光觸媒和光催化的機理的研究成果，雙邊合作設計改進光反應器的光能轉換效率，最終達到具實用價值的太陽光能轉成再生能源的光反應系統。<br> Abstract: The present proposal is aimed at an efficient use of photons to improve efficiency in the highly desired conversion of CO2 and H2O into fuel molecules, such as CH4, CH3OH, or even Fisher Tropsch-like products. From the viewpoint of energy and environment, the conversion of CO2 to hydrocarbons by solar energy is the ultimate solution for CO2 emission and renewable energy. The reactions can be summarized as follows: CO2 + H2O → CH4 + O2 CO2 + H2O → CH3OH + O2 x CO2 + &frac12; y H2O → CxHy + (x+ 2y) O2 The proposed research comprises catalyst development and practical reactor design, both aiming at highly efficient light harvesting. The photocatalysts should have well designed characteristics, such as large absorption of, preferably, visible light photons, a long lifetime of activated states, a good adsorption of reactants CO2 and H2O, and a relatively easy desorption of products (the fuel molecules). Various novel materials will be investigated including : i) Copper modified titanias, which have been demonstrated by the group of Prof. Wu to be promising candidates for further optimization, especially if made through sol-gel procedures. Novel approaches include various other transition-metals loaded TiO2, such as Pt and Ag, to further promote charge separation of photogenerated holes and electrons, as well as non-titania photo catalysts, such as Ta2O5 and Nb2O5 composite oxides. ii) Ti-based mesoporous catalysts based on TUD-1. Ti-based mesoporous materials (e.g. MCM-41) have been reported in the literature to be more efficient in the CO2 reduction reaction than dense phase TiO2 particles, while combinations of Cu and Zr, or Cu and Ti induce visible light sensitivity through a metal to metal charge transfer. The relatively easy synthesis procedure (one pot) of TUD-1 allows a combinatorial investigation of the potential combinations of metals to further optimize visible light sensitivity and CO2 reduction rates. The open 3-D structure of TUD-1 ensures mass transport limitations do not occur. iii) Various reports of nano-structured TiO2 have appeared in the literature recently, and appear to be interesting candidates for CO2 photoreduction due to their high surface area and open structure limiting transport phenomena. Modification of these structures with Cu2O might further enhance the visible light sensitivity and performance. Extensive screening is proposed to propel the discovery of novel formulations. The ultimate goal is to develop catalysts with an improved photon efficiency in the range of two orders of magnitude. At the same time, a rational approach will be followed by determination of the rate limiting step in the conversion of water and CO2 over the most promising catalysts, which leads to a rational further improvement of these candidates. The use of (ATR)-FT-IR spectroscopy and Raman spectroscopy is proposed to be used to analyze the dynamics of the surface composition of the catalysts as a function of reaction conditions. Another challenge is to design an optimized photoreactor: illumination of the active sites and desorption of products need to be maximized. Light transmitting reactor modules with parallel channels, combined with so-called Taylor flow operation (guaranteeing high mass transfer, and ideal plug flow reactor behavior, such as the absence of extended stagnant volumes close to the light source) might provide the optimal reaction environment in liquid phase (water) conversion of CO2. The application of a coating on the optical fibers is another approach that might lead to the optimum use of reactors for CO2 conversion.光催化CO2 還原碳氫燃料奈米結構材料光反應器PhotocatalysisCO2 reductionhydrocarbon fuelnanostructured materialsphoto reactors