| 掺杂La3+对纳米Au/TiO2催化剂结构和性能的影响 |
| Effect of La3+ Doping on the Structures and Performance of Nano-structured Au/TiO2 Catalysts |
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| 摘要: 采用三嵌段共聚物聚乙醚-聚丙醚-聚乙醚EO20PO70EO20(P123)为有机模板剂分别合成了纯的和掺杂少量La3+的介孔TiO2载体，用沉积-沉淀法制得负载金催化剂。运用N2 吸附-脱附(BET)、X射线衍射(XRD)、X射线光电子能谱(XPS)、高分辨电镜技术(HR-TEM)和X射线能量分散谱(EDX)对催化剂的结构与形貌进行了表征。BET结果表明，采用P123为模板剂 |
| 关键词: 纳米金催化剂 一氧化碳氧化 介孔二氧化钛 P123模板剂 掺杂 La3+ |
| 基金项目: |
| Abstract: The mesoporous TiO2 and La-TiO2 were synthesized by using P123 as an organic template， and the supported gold catalysts were prepared by using deposit-precipitation method. The N2 adsorption-desorption， XRD， XPS， HR-TEM and Energy Dispersive X-ray (EDX) analysis techniques were employed to characterize the structures of the catalysts. The results of N2 adsorption-desorption show that the synthesized TiO2 possesses high surface area (103 m2·g-1) and uniform mesoporous structure with the pore size mainly centered at ～4.1 nm. With the doping of La3+， the surface area and the pore size of La3+ doped mesoporous TiO2 increase to 122 m2·g-1 and ～4.9 nm， respectively. After calcination at 450 ℃， the mesoporous structure of Au/TiO2 has collapsed partly， while that of Au/La-TiO2 is well maintained. The gold in Au/TiO2 calcined at 450 ℃ exists as Au0， but in La3+ doped catalyst there is a small portion of Au2O3 in addition to Au0. The results of HR-TEM show that after calcination at 400 ℃， the crystallite sizes of Au in Au/TiO2 and Au/La-TiO2 are 6～8 nm and ～5 nm， respectively. After calcination at 450 ℃， the Au crystallites in Au/TiO2 increase to above 20 nm， while in Au/La-TiO2 they still keep very small size of ～9 nm. For ambient CO oxidation， all the catalysts calcined at 400 ℃ or below exhibit excellent activity. After calcination at 450 ℃， the temperature for the full conversion of CO over Au/TiO2 reaches 86 ℃， while the temperature is only 53 ℃ over Au/La-TiO2. The doping of a small amount of La3+ effectively inhibits the sintering of Au crystallites， and therefore， makes the catalyst possess good activity and high thermal stability. |
| Keywords: nano-structured gold catalyst carbon monoxide oxidation mesoporous titania P123 template doping La3+ |
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| 侯凯军,孟 明,邹志强,吕 倩.掺杂La3+对纳米Au/TiO2催化剂结构和性能的影响[J].无机化学学报,2007,23(9):1538-1544. |
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