The role of H2 on the stability of the single-metal-site Ir1/AC catalyst for heterogeneous methanol carbonylation
| Autor: | Patrick Hemberger, Yunjie Ding, Zheng Jiang, Xiangsong Lin, Andras Bodi, Yang Liu, Xiangen Song, Feng Siquan |
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| Rok vydání: | 2020 |
| Předmět: |
inorganic chemicals
010405 organic chemistry Chemistry Inorganic chemistry chemistry.chemical_element 010402 general chemistry 01 natural sciences Catalysis Reductive elimination 0104 chemical sciences Metal Acetic acid chemistry.chemical_compound visual_art Atom visual_art.visual_art_medium Methanol Physical and Theoretical Chemistry Carbonylation Carbon |
| Zdroj: | Journal of Catalysis. 381:193-203 |
| ISSN: | 0021-9517 |
| DOI: | 10.1016/j.jcat.2019.10.032 |
| Popis: | Supported single-metal-site catalysts are well known for their 100% atom utilization efficiency, uniformly isolated active sites and well-defined coordination environment. Methanol carbonylation is a classic homogeneous reaction for acetic acid production. Here, we present the crucial role of H2 on the stability of single-metal-site Ir1/AC catalyst for heterogeneous methanol carbonylation. Metal leaching and carbon deposition are verified to be the main reasons of catalyst deactivation. Metal leaching is probably due to the formation of volatile [Ir(CO)3I] species, and carbon deposition is supposed to arise from the high energy barrier rate-determining step of CH3COI reductive elimination. However, hydrogenation of the surface intermediate species alleviates the carbon forming problem greatly and competitive adsorption of H2 with CO on active species inhibits the formation of [Ir(CO)3I]. Consequently, H2 is essential to avoid the activity decay of the Ir1/AC catalyst. |
| Databáze: | OpenAIRE |
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