Surface Intermediates in In-Based ZrO2-Supported Catalysts for Hydrogenation of CO2 to Methanol
| Autor: | Tsoukalou, Athanasia, Bushkov, Nikolai S., Docherty, Scott R., Mance, Deni, Serykh, Alexander I., Abdala, Paula M., Copéret, Christophe, Fedorov, Alexey, Müller, Christoph R. |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry C, 136 (4) |
| ISSN: | 1932-7455 1932-7447 |
| Popis: | The influence of the phase of the ZrO2 support (monoclinic, tetragonal, and amorphous, referred to as m-, t-, and am-, respectively) on the nature of the surface species involved in methanol synthesis and the rates of their formation on ZrO2-supported, In-based catalysts for CO2 hydrogenation has been investigated. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) at 300 degrees C and 20 bar (H-2:CO2:N-2 = 3:1:1 volume ratio) on m-ZrO2:In, In2O3/t-ZrO2, and In2O3/am-ZrO2 catalysts (m-ZrO2:In is a solid solution) shows that formate species (HCOO*) appear prior to methoxy species (*OCH3), and both intermediates form faster on the more active m- ZrO2:In catalyst. Only formate bands are detected for the In2O3/t-ZrO2 catalyst. For these materials, indium sites are essential for the formation of HCOO* and *OCH3 species as only carbonate species are observed on m-, t-, and am-ZrO2 supports under CO2 hydrogenation conditions. The nature of the reaction intermediates is confirmed by ex situ solid-state nuclear magnetic resonance (NMR), where both methoxy and formate species are detected in m-ZrO2:In and In2O3/am-ZrO2, respectively, but only a weak formate peak is observed for In2O3/t-ZrO2. The presence of a major methoxy peak and only a very minor formate signal in unsupported In2O3 indicates that an india-zirconia interface is required for the effective stabilization of formate species. Catalytic tests in a fixed bed reactor are consistent with both CO and Me0H being primary products of CO2 hydrogenation; the tests also show that the methanol selectivity and space time yield decrease in the following order: m-ZrO2:In > In2O3/t-ZrO2 > In2O3/am-ZrO2 for all of the contact times tested. ISSN:1932-7455 ISSN:1932-7447 |
| Databáze: | OpenAIRE |
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