The focus of this study is to assess the reaction rate-based kinetics of three NiO-based oxygen transfer materials (OTMs) supported on ZrO₂, Al₂O₃ and SiO₂ under CH₄ reduction. Both NiO weight change data and gaseous phase composition from TGA-MS tests are utilized for the elucidation of the reaction scheme. We show that mainly CH₄, as well as CO and H₂ (primary NiO reduction products by CH₄), are involved in the reduction process under a varying extent that depends on the support used. The developed kinetic model is first order dependent on the concentration of the main reductant at each reaction and a function of the NiO/Ni concentration. On ZrO₂, NiO is exclusively reduced by CH₄ via both total and partial oxidation. On the other hand, in addition to CH₄, CO and H₂ also contribute to NiO reduction on Al₂O₃ and SiO₂. Still, total and partial CH₄ oxidation are the dominant routes. In the case of SiO₂ in particular, the reduction rate of NiO by CO and H₂ is the highest among all OTMs. The CH₄ decomposition reaction, catalyzed by the metallic nickel sites, also takes place via the Langmuir-Hinshelwood mechanism after the completion of the NiO reduction. The rate of this reaction correlates with the surface area of the materials due to the higher population of active metallic nickel sites on the surface, leading to carbon deposition in the order NiO/Al₂O₃ > NiO/SiO₂ > NiO/ZrO₂.

这项研究的重点是评估在CH ₄还原下负载在ZrO ₂，Al ₂ O ₃和SiO ₂上的三种基于NiO的氧转移材料（OTM）的基于反应速率的动力学。来自TGA-MS测试的NiO重量变化数据和气相组成均用于阐明反应方案。我们发现主要是CH ₄以及CO和H ₂（通过CH ₄还原的主要NiO还原产物）在不同程度上取决于所使用的支持物而参与还原过程。建立的动力学模型是一阶的，取决于每个反应中主还原剂的浓度以及NiO / Ni浓度的函数。在ZrO _2上，NiO仅通过全部和部分氧化被CH ₄还原。另一方面，除了CH _4之外，CO和H ₂还有助于在Al ₂ O ₃和SiO ₂上还原NiO 。尽管如此，全部和部分CH ₄氧化仍是主要途径。特别是在SiO ₂的情况下，CO和H ₂对NiO的还原率是所有OTM中最高的。NiO还原完成后，通过金属镍位点催化的CH ₄分解反应也通过Langmuir-Hinshelwood机理发生。由于表面上活性金属镍位的数量增加，该反应的速率与材料的表面积相关，从而导致碳沉积的顺序为NiO / Al ₂ O ₃ > NiO / SiO ₂ > NiO / ZrO ₂。