在本研究中，採用沉積-沉澱法(deposition-precipitation method)製備金承載針狀二氧化鈰(Au/N-CeO2)奈米微粉作為CO氧化觸媒。首先，以兩階段沉澱法製備奈米針狀CeO2擔體，接著，以氯金酸(HAuCl4)溶液作為前驅鹽將奈米金粒子沉積於CeO2上。文中探討金前驅鹽溶液pH值及濃度對所得觸媒之金含量、形態、晶相結構以及觸媒比表面積等特性之影響，並以一氧化碳之氧化進行觸媒活性分析。另外，以顆粒狀CeO2 (P-CeO2)作擔體製備Au/P-CeO2觸媒以探討擔體晶形對其催化活性之影響，並輔以TPR、FTIR及XPS等分析，進一步解析各觸媒之金粒子與CeO2間之交互作用。
　　實驗結果顯示，金前驅鹽溶液之pH值影響金粒子於N-CeO2上之沉積量及分散性甚鉅。pH 6所得之Au/N-CeO2觸媒擁有最大之金含量，以及最高之CO轉化率。然而，隨著金前驅鹽pH值之上升，金粒子之粒徑減小，且其分散性愈佳。比較Au/N-CeO2與N-CeO2觸媒發現，金之承載可明顯提高催化活性，此外，由TPR、FT-IR及XPS等分析結果顯示，Au與CeO2間明顯存在一作用力，即Au4f之電子部分轉移至Ce上造成CeO2氧缺陷數目之增加，有助於反應活性之提昇。
　　當金前驅鹽濃度由1wt%增加至3wt%時，雖然金含量增加，但當前驅鹽濃度大於2wt%時，由於金粒子之聚集現象，導致催化活性下降。比較Au/N-CeO2與Au/P-CeO2之觸媒活性發現，Au/N-CeO2擁有較高活性，此乃因N-CeO2擔體具有較多之高活性晶面所致。

　　In this study, gold supported cerium oxide nanoneedles (Au/N-CeO2) were synthesized by the deposition-precipitation method for the catalytic CO oxidation. Nanocrystalline CeO2 needles were firstly prepared by the two-stage precipitation method. Then, Au nanoparticles were deposited on the prepared CeO2 nanoneedles starting from the HAuCl4 solution. The effects of pH value and concentration of Au precursor on properties of the resulting Au/N-CeO2 including gold content, morphology, crystalline structure and surface area were investigated. Furthermore, the catalytic oxidation of carbon monoxide over the Au/N-CeO2 was employed as the model reaction for analyzing the activities of catalysts. In order to study the effect of support morphology on catalytic activity, the particulate CeO2 (P-CeO2) was used as the support for preparing Au/P-CeO2. Moreover, the interaction between Au and CeO2 support were characterize by using TPR, XPS and FTIR.
　　The results showed that the pH value of the precursor solutions played an important role on the deposited amount and dispersion of Au nanoparticles. The sample prepared at pH value of about 6 exhibited the largest deposition amount and thus showed a maximum conversion on CO oxidation. However, with increasing the pH value of precursor solution, the Au particle size decreased, and the Au dispersion became higher. As compared the Au/N-CeO2 with N-CeO2 catalysts, it demonstrated that the loading gold would obviously lead to enhance the catalytic activity. Furthermore, from results of TPR, XPS and FT-IR analysis, it revealed that electrons were partially transferred from Au to Ce and then caused the increasing of oxygen defects and promoting the catalytic activity.
　　With increasing the Au precursor concentration from 1 wt% to 3 wt%, the gold content was increased. However, when the Au precursor concentration was higher than 2 wt%, the catalytic activity decreased due to the aggregation of Au grains. In addition, the Au/N-CeO2 catalysts exhibited higher activity than Au/P-CeO2 ones. This was obviously attributed from having more active facets for the N-CeO2 support.

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