CO oxidation catalyzed by Au nanoclusters

• Main Authors: Pei-shiuan Lin, 林佩萱
• Other Authors: Fu-Kwo Men
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/20387342561430558009

碩士 === 國立中正大學 === 物理所 === 96 === Gold nanoclusters supported on suitable oxide layers are active for carbon monoxide oxidation, which were discovered in 1987. Instead of employing oxide support, we have studied the catalytic activity of gold nanoparticles on highly oriented pyrolytic graphite (HOPG). HOPG surface is non-polar, inert, and easy to prepare. Gold atoms are deposited onto HOPG via molecular beam epitaxy. Atomic force microscopy is used to observe the morphology and the size of gold clusters on HOPG. After gold deposition, the HOPG substrate is heated to a range of temperatures to obtain Au nanoclusters of desired sizes. Oxygen gas and carbon monoxide gas are then leaked into the chamber. Residual gas analyzer is used to measure the partial pressures of carbon monoxide, oxygen, and carbon dioxide. For gold clusters larger than 10 nm, which are prepared by heating the HOPG substrate to above 320K, we find there is no catalytic activity for gold clusters on the oxidation of carbon monoxide. For gold clusters with an average size less than 5 nm, prepared by heating the substrate to 303K, we detect an increase in the partial pressure of carbon dioxide, a clear indication of catalytic effect by gold clusters. We have also observed the increase in carbon dioxide partial pressure as the density of the gold clusters increase.