摘要
从同一 ZrO(OH)2 出发制备了三种不同尺寸的 ZrO2 纳米颗粒(ZrO2-CP: 40～200 nm, ZrO2-AN: 18～25 nm,ZrO2-AD: 10～15 nm), 采用沉积-沉淀方法制备了相应的 Au/ZrO2 催化剂. 用 XRD, XRF, TEM 和低温 N2 吸附对 ZrO2和 Au/ZrO2进行了表征. XRD 和 TEM 分析表明 Au/ZrO2样品中 Au 粒子的平均尺寸为 4～5 nm, 而 ZrO2的晶相和颗粒大小没有因为“负载”Au 粒子而发生变化. CO 催化氧化反应的结果表明, Au/ZrO2催化活性随着 ZrO2纳米粒子尺寸的减小活性明显增加. TEM/HRTEM结果表明, Au/ZrO2催化剂中Au粒子与ZrO2颗粒接触界面随ZrO2颗粒尺寸的减小而明显增加, 这很可能是含有更小尺寸 ZrO2纳米粒子的 Au/ZrO2催化剂具有更高催化活性的重要原因.
This work explores the size-effect of zirconia nanoparticles on the catalysis of Au/ZrO2 for CO oxidation. Zirconia particles with different sizes (ZrO2-CP: 40similar to200 nm; ZrO2-AN: 18similar to25 nm; ZrO2-AD: 10similar to15 nm) was prepared from a single source of ZrO(OH)(2) and the deposition-precipitation method was employed to prepare the Au/ZrO2 catalysts. The samples were characterized with XRD, TEM, XRF and nitrogen adsorption measurements. While the Au particles in all the Au/ZrO2 catalysts appeared to show similar sizes (4similar to5 nm), the catalytic activity order of Au/ZrO2-AD>Au/ZrO2-AN>Au/ZrO2-CP revealed clearly that smaller zirconia nanoparticles led to Au/ZrO2 catalyst with higher catalytic activity. The activity improvement by reducing zirconia nanoparticle size seems attributable to the increased Au-zirconia junctions in the catalysts.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2005年第1期86-90,F009,共6页
Acta Chimica Sinica
基金
国家杰出青年基金(No. 20125310)
国家 973 计划(No. 2003CB615804)资助项目.
