本研究是利用桃園縣之廢棄稻殼，經酸洗、碳燒跟熱解處理後的稻殼灰份(rice husk ash，RHA )，採用初濕含浸法先製備出ZnO、RHA的複合擔體，再以沈澱固著法製備出不同Si/Zn原子比的Cu/ZnO-RHA複合擔體觸媒。催化反應測試方面，利用甲醇在常壓下進行氧化性蒸氣重組反應(oxidative steam reforming of methanol, ORSM)，由於反應物中包含了水與氧，同時具備了甲醇蒸氣重組反應(steam reforming of methanol, SRM)和甲醇部份氧化反應(partial oxidation of methanol, POM)的優點，擁有較高的氫氣產率也能有效降低一氧化碳選擇率，減少燃料電池Pt電極的毒化。在觸媒與擔體特性分析方面，利用感應耦合電漿原子發射光譜儀(ICP-AES)、X射線繞射儀(XRD)、程式升溫還原(TPR)、N2O分解吸附(dissociative adsorption of nitrous oxide)、穿透式電子顯微鏡(TEM)、掃描式電子顯微鏡(SEM)等技術，進一步了解各種不同操作變數對觸媒的影響。 由XRD的結果可得知Zn含量越多，Cu0的繞射峰就越明顯也越高。在TPR圖譜中，Zn含量越多Cu的還原溫度也越高。由N2O分解吸附結果顯示Zn含量越多反而造成粒徑變大、分散度變差的問題。但是在活性測試中，擔體中的Si/Zn的原子比為9/1的反應性最好，可以瞭解到加入少量的ZnO能增加觸媒活性，而N2O分解吸附結果對於不同煅燒溫度探討，煅燒溫度在673 K時有最佳的分散度與最小粒徑。在TEM與SEM顯微圖中可得知粒徑大小，其與N2O分解吸附計算出來的結果相似。在氧化性蒸氣重組反應中，可得知在Si/Zn原子比9/1、進料莫耳比O2/CH3OH=0.3與H2O/CH3OH=1及反應溫度為523 K時，觸媒擁有最佳甲醇轉化率、氫氣產率與最低的一氧化碳選擇率。 Cu/RHA-ZnO catalysts were studied for oxidative steam reforming of methanol (OSRM, CH3OH + 0.5H2O + 0.25O2 → 2.5H2 + CO2) to produce hydrogen. Rice husk ash (RHA) was used to prepare RHA-ZnO binary supports by incipient wetness impregnation method and the catalysts were prepared by deposition-precipitation method with the binary support. The catalysts and supports were characterized by ICP-AES, XRD, TPR, N2O titration, TEM and SEM analyses. The average diameter of Cu particles was determined by TEM and N2O titration. XRD was used to study the crystallinity of the catalysts. The TPR results stated that redox properties of catalysts depended on the RHA/ZnO molar ratios. From N2O titration, TEM and SEM results, it was concluded that ZnO played minor role on controlling particle size of copper. However, the appropriate amount of Zn in catalysts is beneficial for activity. The effects of several experimental parameters of this study such as Si/Zn ratio, calcination temperature, reduction temperature, composition of feeding and reaction temperature had been discussed. The Cu/RHA-ZnO catalyst with Si/Zn atomic ratio at 9/1, calcined at 673 K and reduced at 573 K exhibits the optimum CH3OH conversion, H2 production rate and CO selectivity. The most suitable reaction temperature is 523 K with the feed ratio of H2O/CH3OH/O2 = 1/1/0.3 for OSRM reaction.
