Ru/CeO2催化剂对CO2甲烷化的活性位点依赖反应机理,Journal of the American Chemical Society

当前位置： X-MOL 学术 › J. Am. Chem. Soc. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Ru/CeO2催化剂对CO2甲烷化的活性位点依赖反应机理
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2016-05-06 , DOI: 10.1021/jacs.6b02762
Fei Wang ₁ , Shan He ₁ , Hao Chen ₁ , Bin Wang ₂ , Lirong Zheng ₃ , Min Wei ₁ , David G. Evans ₁ , Xue Duan ₁

Affiliation

金属氧化物表面的氧空位是最重要的缺陷之一，在各种催化反应中充当反应位点。本工作采用操作谱方法研究了分别由 Ru/CeO2（CeO2 中存在氧空位）和 Ru/α-Al2O3（无氧空位）催化的 CO2 甲烷化反应，以期对活性物质的活性有更深入的了解。位点依赖性反应机制。在 Ru/CeO2 催化剂中，使用原位 XANES、IR 和拉曼来揭示 Ce(3+)、表面羟基和氧空位的生成过程及其在实际反应条件下的结构演变。稳态同位素瞬态动力学分析 (SSITKA) 型原位漂移红外光谱无疑证实了 CO2 甲烷化在 Ru/CeO2 催化剂上经历甲酸盐路线，氧空位催化甲酸解离为甲醇是决速步骤。相比之下，CO2 甲烷化在 Ru/α-Al2O3 中在 Ru/α-Al2O3 的 Ru 表面经历 CO 路线，没有氧空位，证明了对 CO2 甲烷化的活性位点依赖性催化机制。此外，Ru/CeO2 催化剂上的催化活性评估和振荡反应进一步证明，与 Ru/α-Al2O3 中的 Ru 表面相比，氧空位催化速率决定步骤的活化温度要低得多（125 vs 250 °C ）。

"点击查看英文标题和摘要"

Active Site Dependent Reaction Mechanism over Ru/CeO2Catalyst toward CO2Methanation

Oxygen vacancy on the surface of metal oxides is one of the most important defects which acts as the reactive site in a variety of catalytic reactions. In this work, operando spectroscopy methodology was employed to study the CO2 methanation reaction catalyzed by Ru/CeO2 (with oxygen vacancy in CeO2) and Ru/α-Al2O3 (without oxygen vacancy), respectively, so as to give a thorough understanding on active site dependent reaction mechanism. In Ru/CeO2 catalyst, operando XANES, IR, and Raman were used to reveal the generation process of Ce(3+), surface hydroxyl, and oxygen vacancy as well as their structural evolvements under practical reaction conditions. The steady-state isotope transient kinetic analysis (SSITKA)-type in situ DRIFT infrared spectroscopy undoubtedly substantiates that CO2 methanation undergoes formate route over Ru/CeO2 catalyst, and the formate dissociation to methanol catalyzed by oxygen vacancy is the rate-determining step. In contrast, CO2 methanation undergoes CO route over Ru surface in Ru/α-Al2O3 with the absence of oxygen vacancy, demonstrating active site dependent catalytic mechanism toward CO2 methanation. In addition, the catalytic activity evaluation and the oscillating reaction over Ru/CeO2 catalyst further prove that the oxygen vacancy catalyzes the rate-determining step with a much lower activation temperature compared with Ru surface in Ru/α-Al2O3 (125 vs 250 °C).

更新日期：2016-05-06

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南