【摘要】 分别以空气和氮气焙烧的ZrO₂圆形纳米片（标记为ZrO₂-Air和ZrO₂-N₂）为载体,采用沉积-沉淀法制得1%Au/ZrO₂催化剂（标记为Au/ZrO₂-Air和Au/ZrO₂-N₂）.考察了富氢气氛下上述催化剂的水煤气变换反应（WGSR）催化性能,发现Au/ZrO₂-Air的催化活性明显高于Au/ZrO₂-N₂,且显著优于Au负载量较高的Au/Fe₂O₃和Au/CeO₂催化剂.采用XRD、AAS、N₂物理吸脱附、TEM、UV-Vis DRS及EPR等手段研究了两种气氛焙烧的ZrO₂载体和相应Au/ZrO₂催化剂的结构及表面性质.结果表明,两种ZrO₂载体的晶相结构及织构性能无明显差异,但两种ZrO₂载体上表面缺陷种类和浓度分布差别较大.相较于ZrO₂-N₂,ZrO₂-Air的表面具有较多的配位不饱和Zr3+,这些位点有助于提高负载Au的分散度,使得Au/ZrO₂-Air具有较高的催化活性.更多还原

【Abstract】 The ZrO₂ nanodisks were calcined in air and N₂ atmosphere to obtain ZrO₂-Air and ZrO₂-N₂,respectively. Then,the gold was deposited on different ZrO₂ to produce 1% Au/ZrO₂ catalysts（ denoted as Au/ZrO₂-Air and Au/ZrO₂-N₂,respectively） by a deposition-precipitation method. The catalysts were evaluated in the water-gas shift reaction（ WGSR） under H2-rich reformate atmosphere.It is found that the Au/ZrO₂-Air shows much higher catalytic activity than Au/ZrO₂-N₂. Importantly,the catalytic activity of Au/ZrO₂-Air is also significantly higher than that of the previously reported Au/Fe2 O3 and Au/CeO₂ catalysts. The structural and surface properties of ZrO₂ calcined in air and N₂ atmosphere were studied by XRD,AAS,N₂-physisorption,TEM,UV-Vis DRS and EPR characterizations. The results show that the calcination atmosphere has a great influence on the type and concentration distribution of surface defects on ZrO₂. The ZrO₂-Air possesses more surface coordinatively unsaturated Zr3+centers,which have strong interaction with supported Au species,resulting in an increased Au dispersion and a higher catalytic activity of Au/ZrO₂-Air.更多还原