2007-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/696427摘要：太陽能是地球生物的終極能源，植物光合作用從古到今提供或儲存人類絕大多數使用的化石能源，利用太陽光能，進行光催化還原CO2，碳源將循環來自CO2，因此不會增加CO2的淨排放，可以根本解決CO2排放和再生能源的問題。本研究構想在過去3年度已成功地用TiO2光觸媒進行光催化還原CO2生產碳氫化合物，結果在水溶液及氣相中，通入CO2，以紫外光照射進行光催化反應，成功地將CO2轉成甲醇，類似模擬植物光合作用。另外在空污研究中，NOx可被TiO2光觸媒光分解，但效率不高，原因在於光催化反應機理並未深入探討，以致無法有效顯著提升光催化轉換效率。本計畫目標將在兩年內，以"原位散反射傳立葉紅外光譜"(in situ Diffuse-Relfectance Infrared Fourier Transform spectroscopy, DRIFT)的方式，在光催化反應的同時，監測有機化合物等中間產物的變化消長，瞭解光催化還原的機理。第1年使用TiO2或M/TiO2 (M=Cu, Pt, V等過渡金屬)光觸媒，搜尋定位包括NO、NO2、CO2、CO及CxHy的波長數(wavenumber)，第2年進行非TiO2新型光觸媒，如Ta2O5，Nb2O5等系列新型複合氧化物光觸媒，進行相同的光催化反應，瞭解不同型態光觸媒的中間產物的變化消長。另外將配合分析光觸媒之特性變化，進行SEM、TEM、XPS、XANES、XRD和UV-Vis等檢測，包括光觸媒晶相、粒徑等，建立其活性與光催化之關係，從根本改良光觸媒和反應條件的控制操作，才可能提升NO和CO2的光催化還原的效率，預期完成之成果，有助於暸解光催化機理，促使光觸媒提升活性具有商業化實用價值。<br> Abstract: Sun is the ultimate energy source for mankind. The photo reduction of CO2 using solar energy can eventually solve the problem of CO2 emission and the need of renewable energy. Nitric oxide (NOx) is one of air pollutants, which is emitted from the industrial boilers and the engines of automobiles. The increased ozone is due to NOx in air and causes health as well as environmental problems. In the past 3 years, our team successfully developed the photo reduction of CO2 to generate hydrocarbons, mainly methanol, using Cu/TiO2. In other air pollution research, the photo decomposition of NO was carried out using TiO2. However, the efficiency of photo conversion is too low to be practiced. The photo activity cannot be intrinsically improved because the photo mechanism is not known clearly. The objective of 2-year project is to apply in situ Diffuse-Reflectance Infrared Fourier Transform (DRIFT) spectroscopy to investigate the chemical intermediates of NO and CO2 during the photo catalytic reactions. Thus the photo reaction mechanism can be revealed. In year 1, TiO2 and M/TiO2 (M=Cu, Ag, Pt transition metals) catalysts will be used. The wavenumbers of NO, NO2, CO2, CO2 and any CxHy will be identified and located. In year 2, non-titania photo catalysts, such as Ta2O5, Nb2O mixed oxides will be studied using the same in situ DRIFT spectroscopy under the same photo reactions. Thus, different intermediates of photo reactions on different catalysts can be studied and compared. The characterization of photo catalysts will be performed using SEM, TEM, XPS, XANES, EXAFS, XRD and UV-Vis. The photo activity and characteristics of photo catalysts, thus, can be well correlated. Therefore, the efficiency of NO and CO2 photo reactions can be significantly improved by the modification of photocatalyst and photo reaction conditions. The results is expected to show the photo kinetic mechanism, and to increase photoactivity of catalysts having commercial potential.光催化反應原位紅外線光譜二氧化碳氧化氮光催化反應動力Photocatalysisin situ IR spectroscopyCO2Nitric oxidePhoto Kinetics