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.我们开发了一种新型的油包水微乳液制备负载金属催化剂的方法，即ME法。在该方法中，Rh颗粒部分嵌入SiO_2载体中，因为SiO_2载体是通过Rh周围的TEOS水解形成的。在反胶束中合成之前的前驱体颗粒在这项工作中，研究了 Pt 颗粒在不同制备方法（ME、溶胶-凝胶和）制备的 Pt/Al2O3 催化剂中的烧结行为。浸渍法(IMP)制备的Pt/Al2O3催化剂与IMP法制备的催化剂相比，由于Pt颗粒嵌入载体中，因此具有较高的抗烧结性。改进了催化剂在156 MPa、700 ℃、12 h空气流动下的耐久性试验，采用微乳液制备催化剂，然后进行压制。 ME催化剂比溶胶-凝胶催化剂和浸渍催化剂具有更好的抗Pt颗粒烧结能力，在NO-CO反应中表现出更高的活性，并保持了高活性。 2． SiO2包覆Rh催化剂与ME制备的催化剂的热稳定性和CO-CO反应催化活性进行了比较。溶胶-凝胶和IMP方法中，SiO2包覆的Rh催化剂中，所有Rh颗粒都被SIO2层覆盖，并且即使在900℃热处理12小时后仍然很小，因此得出结论，Rh颗粒发生了迁移。 SiO2包覆Rh催化剂受到SiO2层的约束，具有最高的抗烧结性，因此，该催化剂在900 ℃热处理后具有最高的CO还原NO活性。 12 小时。