Novel preparation method for supported metal catalysts with high resistance to sintering

高抗烧结负载型金属催化剂的制备新方法

• 批准号: 12450328
• 负责人: KISHIDA Masahiro
• 金额: $ 8.45万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450328/
• 关键词: Alumina-supported Pt Catalyst; Silica-coated Rh particle; Microemulsion; Sintering; NO-CO reaction; マイクロエマルション法; アルミナ担持白金触媒; シリカ包接白金微粒子; シリカ包接ロジウム微粒子; 包接微粒子; 担持貴金属触媒

1. We have developed a novel preparation method for supported metal catalysts using water-in-oil microemulsion, an ME method. In this method, Rh particles are partially embedded in SiO_2 supports because the SiO_2 supports are formed by hydrolysis of TEOS around the Rh precursor particle before being synthesized in the reverse micelle. In this work, sintering behaviors of Pt particles were investigated in Pt/Al2O3 catalysts prepared by different preparation method (ME, sol-gel and impregnation method (IMP). Pt/Al2O3 catalysts prepared by ME and sol-gel method possessed high resistance to sintering compared with the catalyst prepared by IMP method, because Pt particles were embedded in the support. Furthermore, resistance to the sintering of Pt particles was improved by pressing the catalysts at 156 MPa. For the endurance test under air flow at 700 ℃ for 12 h, the catalyst prepared using microemulsion and then pressed, the pressed ME catalyst, had greater resistance to sintering of Pt particles than the sol-gel and impregnation catalysts. The pressed ME catalyst exhibited higher activity in NO-CO reaction and maintain the high activity.2. We successfully synthesized Rh nanoparticles wholly coated by a nanometer-scale SiO2 layer ring a specific microemulsion system. The thermal stability and the catalytic activity of CO-CO reaction of SiO2-coated Rh catalyst were compared with those of the catalysts prepared by ME, sol-gel and IMP methods. In the SiO2-coated Rh catalyst, all the Rh particles were covered by the SIO2 layer and remained small even after the thermal treatment at 900 ℃ for 12 h. It is concluded that migration of Rh particles of the SiO2-coated Rh catalyst was restrained by the SiO2 layer, resulting in the highest resistance to sintering. As a result, this catalyst had the highest activity in NO reduction by CO after thermal treatment at 900 ℃ for 12 h.

1.我们开发了一种新的制备负载型金属催化剂的方法，即微乳液法。在该方法中，Rh颗粒部分嵌入SiO_2载体中，因为SiO_2载体是在反胶束中合成之前由Rh前体颗粒周围的TEOS水解形成的。本文研究了不同制备方法（ME法、溶胶-凝胶法和浸渍法）制备的Pt/Al_2O_3催化剂中Pt颗粒的烧结行为。与IMP法制备的催化剂相比，ME法和溶胶-凝胶法制备的Pt/Al 2 O3催化剂具有更好的抗烧结性，这是因为Pt颗粒嵌入到载体中。此外，通过在156 MPa下压制催化剂，提高了Pt颗粒的抗烧结性。在700 ℃空气流下12 h的耐久性测试中，采用微乳液制备后压制的ME催化剂比溶胶-凝胶和浸渍催化剂具有更好的抗Pt颗粒烧结性能。压制后的ME催化剂在NO-CO反应中表现出较高的活性，并保持了较高的活性.在特定的微乳液体系中，我们成功地合成了表面包覆有纳米SiO2层的Rh纳米粒子。比较了SiO_2包覆Rh催化剂与ME法、Sol-gel法和IMP法制备的催化剂的热稳定性和CO-CO反应活性。在SiO2包覆的Rh催化剂中，所有Rh颗粒均被SiO2层覆盖，即使在900 ℃热处理12 h后，Rh颗粒仍然很小。它的结论是，迁移的Rh颗粒的SiO2涂层的Rh催化剂被抑制的SiO2层，导致在最高的抗烧结性。结果表明，该催化剂在900 ℃热处理12 h后，CO还原NO的活性最高。