Investigation into the coking-related key reaction steps in dry reforming of methane over NiMgOx catalystстатьяИсследовательская статья
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Дата последнего поиска статьи во внешних источниках: 20 февраля 2024 г.
Авторы:
Jianyue Wang,
Jiawei Wang,
Sheng Wei,
Yiwen Zhang,
Fuhou Tian,
Dan Yang,
M Kustov Leonid,
Yanhui Yang,
Yihu Dai
Аннотация:With pre-reduced NiMgOx catalyst, the structure evolution, catalytic performance, surface species and coking-related reaction steps are investigated in methane dry reforming (DRM) at selected temperatures. Satisfactoryconversion of CH4 and CO2, H2/CO ratio, and anti-coke stability are achieved in long-term (78 h) reaction at 650◦C as a proper temperature. The characterizations evidence co-existence of metallic Ni0 and solid solution phasesin the working catalysts. Combined catalytic evaluation and coke analysis reveal that, at 650 ◦C, endothermicCO2-free CH4 decomposition shows a high initial rate for H2 production but severe coke deposition for rapiddeactivation, serving as the primary coking process. In contrast, exothermic CO disproportionation exhibits alower reaction rate and a higher coke graphitization degree. The in-situ DRIFT spectra demonstrate that carbonatesand bicarbonates serve as the primary adsorbates during CO2 dissociation process, whereas formateintermediates dominate in DRM reactions. Such evolution of the surface species verifies facile dissociation