甲醇氧化/蒸汽重組複合式反應觸媒之設計-CuO/ZnO/CeO2/ZrO2/Al2O3; Oxidative steam reforming of methanol over CuO/ZnO/CeO2/ZrO2/Al2O3 catalysts

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Title:	甲醇氧化/蒸汽重組複合式反應觸媒之設計-CuO/ZnO/CeO2/ZrO2/Al2O3;Oxidative steam reforming of methanol over CuO/ZnO/CeO2/ZrO2/Al2O3 catalysts
Authors:	張丞鈞;Cheng-chun Chang
Contributors:	化學工程與材料工程研究所
Keywords:	氧化鈰;銅基觸媒;氧化鋯;甲醇氧化/複合式蒸汽重組反應;Oxidative steam reforming of methanol;Cerium oxide;copper catalyst;Zirconium oxide
Date:	2009-06-15
Issue Date:	2009-09-21 12:31:49 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	複合式甲醇蒸汽重組反應(OSRM)，一般觸媒成分以CuO/ZnO/Al2O3為主，有研究者指出添加CeO2、ZrO2可提升觸媒的性能。雖然許多研究者對CeO2與ZrO2所扮演的角色做了不同的闡述，但觸媒成分比例探討的範圍是在較低CuO負載量及較高Al2O3含量的成分下做探討，不符合實際應用。本研究以商業觸媒G66B(CuO/ZnO/Al2O3 = 30/60/10)成份作為參考，以共沉澱法製備不同比例的CuO/ZnO/CeO2/ZrO2/Al2O3觸媒，進行OSRM反應，探討CeO2、ZrO2、Al2O3及CuO負載量對OSRM反應的影響，以期設計OSRM反應的理想成份觸媒。　　CeO2可增加CuO、ZnO的無序度及增進觸媒還原能力，但對反應活性為負面效果。ZrO2可提升觸媒的分散性及還原能力，增加觸媒零價銅表面積及表面一價銅的百分比，ZrO2添加必須在不過量取代ZnO時方有明顯的促進效果，觸媒理想的CuO/ZnO比值應小於0.8，添加10~20 wt% ZrO2，CuO/ZnO/Al2O3(20/70/10)觸媒的CuO/ZnO比值由0.29增至0.4，CuO/ZnO/Al2O3(30/60/10)觸媒的CuO/ZnO比值則由0.5增至0.75，皆能有效的促進觸媒活性，CuO/ZnO/Al2O3(40/50/10)觸媒引入ZrO2，CuO/ZnO比值大於0.8，觸媒活性反下降。Al2O3可增加觸媒的無序度，但降低觸媒的還原能力，且抑制銅裸露於觸媒表面，減少觸媒的活性位置，對反應活性為負面影響，適當引入量應小於10 wt%。　　不同CuO負載量觸媒中，CuO/ZnO/Al2O3(40/50/10)觸媒有最佳活性，其CuO/ZnO比值為0.8，引入10 wt% ZrO2，CuO/ZnO比值大於0.8，對活性的促進效果無法顯現，但能增進觸媒的穩定，CuO/ZnO/ZrO2/Al2O3(40/40/10/10)仍為一理想比例觸媒。 The oxidative steam reforming of methanol (OSRM) was usually studied over CuO/ZnO/Al2O3-based catalysts. Numerous researchers announced that introducing CeO2 and ZrO2 could improve the performance of catalysts. Previous studies have reported the adventages of CeO2 and ZrO2 under low loading amount of CuO or high amount of Al2O3, their composition was limited. In this research, commercial catalysts G66B (Nisson-Gridler) with weight ratio of 30/60/10 (CuO/ZnO/Al2O3) was used as a starting reference for designing CuO/ZnO/CeO2/ZrO2/Al2O3 catalysts which were prepared by co-precipitation method for OSRM. Introducing CeO2 improved the dispersions of CuO and ZnO and increased the reducibility of catalysts; however CeO2 has a negative effect on the OSRM reaction. ZrO2 not only increased the dispersions, reducibility and Cu0 surface area of catalysts but also induced Cu+ formation. Only if CuO/ZnO ratio of catalysts smaller than 0.8, the advantage of ZrO2 can be revealed. Introducing 10~20 wt% ZrO2 increased CuO/ZnO ratio of CuO/ZnO/Al2O3 (20/70/10) catalyst from 0.29 to 0.4 and CuO/ZnO/Al2O3 (30/60/10) catalyst from 0.5 to 0.75, the activity of catalysts were promoted effectively. Nevertheless introducing ZrO2 into CuO/ZnO/Al2O3 (40/50/10) catalyst increased the CuO/ZnO ratio to exceed 0.8 instead inhibited the activity of catalyst. Al2O3 enhanced the dispersions of catalysts but reduced the reducibility and restraind copper exposing to the surface of catalysts therefore decreased the active site. Al2O3 has a negative effect to the reaction activity; the adaptable introducing amount should be less than 10 wt%. CuO/ZnO/Al2O3 (40/50/10) catalyst showed best activity. Introducing 10 wt% ZrO2 into CuO/ZnO/Al2O3 (40/50/10) catalyst increased the CuO/ZnO ratio to exceed 0.8 therefore the advantage of ZrO2 to the activity of catalyst could not be revealed but the stability of catalyst was improved, consquently CuO/ZnO/ZrO2/Al2O3 (40/40/10/10) catalyst was considered to be an ideal catalyst.
Appears in Collections:	[National Central University Department of Chemical & Materials Engineering] Electronic Thesis & Dissertation

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