通过丙烯加氢等技术探讨 TiO2 结构对 Rh/TiO2 催化剂中金属-载体相互作用的影响,Applied Surface Science

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通过丙烯加氢等技术探讨 TiO2 结构对 Rh/TiO2 催化剂中金属-载体相互作用的影响
Applied Surface Science ( IF 6.3 ) Pub Date : 2024-01-14 , DOI: 10.1016/j.apsusc.2024.159389
Hanqin Zhao , Li-Yin Hsiao , Nicholas G. Rudawski , Bochuan Song , Po-Chien Kuan , Lauren Hullender , Hagelin-Weaver

研究了铑与平均粒径相似的锐钛矿 (ANP)、金红石 (RNP) 和板钛矿 (BNP) TiO 纳米颗粒之间的金属-载体相互作用。低铑负载量（按重量计 0.4%）产生 1.5–2.0 nm Rh 颗粒，并确保最大的 Rh-TiO 相互作用。在这些密切匹配的条件下，铑的氧化态随着 TiO2 结构、粒径和还原条件的变化而变化。在 200 °C 还原后，与板钛矿或金红石 TiO 或较小的锐钛矿 TiO 纳米颗粒上的 Rh 相比，具有较大粒径 (15 nm) 的锐钛矿 TiO 载体表面存在更多的金属铑，这可能解释了为什么Rh/TiO-ANP 是丙烯加氢中最活跃的催化剂。高温还原（500°C）导致 TiO2 迁移到锐钛矿和板钛矿上的铑上，但不会迁移到金红石 TiO2 载体上，而金红石 TiO2 载体上的电子相互作用占主导地位。这项研究揭示了在研究金属-载体相互作用时考虑 TiO2 结构和粒径、活性金属粒径以及 TiO2 载体的形状和稳定性的重要性。 Rh 的电子特性敏感地取决于 TiO2 结构、粒径和稳定性，并且随预处理条件的不同而显着变化。

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Influence of TiO2 structure on metal-support interactions in Rh/TiO2 catalysts probed by propylene hydrogenation and other techniques

Metal-support interactions between rhodium and nanoparticles of anatase (ANP), rutile (RNP), and brookite (BNP) TiO with similar average particle sizes were investigated. The low rhodium loading (0.4 % by weight) yielded 1.5–2.0 nm Rh particles and assured maximum Rh-TiO interactions. Under these closely matched conditions, the oxidation state of rhodium was shown to vary with TiO structure plus particle size and reducing conditions. After reduction at 200 °C, more metallic rhodium was present at the surface of the anatase TiO support with the larger particle sizes (15 nm) compared with Rh on brookite or rutile TiO, or smaller anatase TiO nanoparticles, and this likely explains why the Rh/TiO-ANP is the most active catalyst in the hydrogenation of propene. A high temperature reduction (500 °C) resulted in migration of TiO over rhodium on anatase and brookite, but not on rutile TiO supports where instead strong electronic interactions dominated. This study reveals the importance of considering TiO structure and particle size, active metal particle size, as well as shape and stability of the TiO support when investigating metal-support interactions. The electronic properties of Rh depend sensitively on the TiO structure, particle size and stability, and vary significantly with pretreatment conditions.

更新日期：2024-01-14

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