本研究以三氧化二鋁為主要擔體，採含浸法製備成複合擔體，複合物包括了：CuOx、ZnOx及MnOx，目的在進行表面改質，接著利用沈澱固著法製備成複合擔體奈米金觸媒，並進行甲醇部分氧化反應(POM reaction，CH3OH + 1/2O2 → 2H2 + CO2) 產製氫氣的程序，檢測儀器包括：感應耦合電漿質譜分析儀（ICP-AES）、熱重分析儀（TGA）、X射線繞射儀（XRD）、穿透式電子顯微鏡（TEM）、掃描式電子顯微鏡（SEM）、X射線光電子分析儀（XPS）等各項儀器與分析技術，分別對擔體及觸媒進行鑑定，藉以評估觸媒應用於質子交換膜燃料電池的可行性。由BET測試結果，發現不同擔體比表面積差異不大。ICP-AES結果顯示，不同擔體由於表面性質不同影響了金的擔載，以Au/Al2O3-MnOx觸媒的金附著率最高。TEM的分析結果發現，金顆粒的大小會因為擔體的不同而有所差異，複合擔體能提高金晶粒的分散度，金晶粒尺寸也較單一擔體觸媒小，Au/Al2O3-CuOx觸媒經473 K煅燒後Au粒徑約為4.97 nm，但經高溫673 K煅燒之後，呈現燒結現象粒徑達11.6 nm。由XPS的結果中發現，未煅燒過的觸媒中，金以氫氧狀態存在，而在573 K煅燒過的觸媒，則只有金屬態的金（Au0）存在。活性測試後發現，觸媒的活性與擔體複合物的選擇有關，其中以Au/Al2O3-CuOx觸媒活性最佳。觸媒未經煅燒時活性最佳，推測氧化態金能促進反應活性。隨著反應溫度的增加，甲醇轉化率與氫氣選擇率都會同時增加。金觸媒擔載在複合擔體上能有效降低燒結的現象，並且提供更多的活性點。未來可以研製不同複合擔體金觸媒朝向活性更佳並且能有更低的CO選擇率作研究，期望能產製高純度氫氣以提供甲醇燃料電池的氫氣來源。 The effect of binary support of gold catalysts is widely studied. We prepare the binary support via impregnation method(Al2O3-MOx, M=Cu, Zn and Mn). The gold catalysts is then prepared by deposition -precipitation method (Au/Al2O3-MOx). The catalysts were characterized by ICP-AES, TGA, XRD, TEM, and XPS analyses. BET results shows that the surface area does not differ much from the choose of the binary support. ICP-AES results shows the surface property effect of the ability of absorption, Au/Al2O3-MnOx has the greatest gold loading amount. TEM images show that the size of gold decreases because of the binary support, about half compare to the single support catalysts, 4.97 nm after 473 K calcination, but still sintering to 11.6 nm after 673 K calcination. From XPS data, gold exists in metallic state. Selective production of hydrogen by partial oxidation of methanol (CH3OH + 1/2O2 → 2H2 + CO2) over Au/Al2O3-MnOx catalysts, the activity depends strongly on the supports, but also on the state of gold. The activity is better than single support catalysts apparently. It shows the good activity while it goes without calcination, we believe that it is because of the state of gold. Increasing the reaction temperature, the methanol conversion and hydrogen selectivity increase either. Binary supports could lower the condition of sintering and provide more active site.
