A Ni/ZnO system was prepared by coprecipitation and characterized after reduction at different temperatures (350, 400, 450 and 500 °C) using TG-MS, H₂-TPR, N₂ physisorption, XRD, SEM, H₂ and CO chemisorption, TEM, EPR and XPS. H₂ and CO chemisorption experiments combined with XRD, SEM and TEM analyses showed evidence for strong metal–support interactions (SMSI) between Ni and ZnO particles, and the degree of SMSI strengthened as the reduction temperature rose. TEM, EPR and XPS studies revealed that the generation of SMSI was attributed to the geometric decoration of Ni particles by ZnO and electron transfer from ZnO to Ni atoms as well as the chemical interaction between Ni and ZnO leading to the formation of a NiZn alloy. Methanation of CO was used as a probe reaction to characterize the effect of SMSI on the catalytic performance of Ni/ZnO. The results showed that SMSI in general had a remarkable suppression effect on the methanation activity, but a light-degree SMSI state facilitated enhancement of the selectivity and stability of CO methanation. Interestingly, the suppressed activity can also be restored with different degrees via re-oxidization and re-reduction treatments under mild conditions. The discovery of SMSI between Ni and ZnO gives a new understanding of the interaction between Ni and supports, and provides a way to tune the interaction between Ni and supports as well as a way to regulate the methanation performance of the Ni/ZnO catalyst or Ni-based catalysts.

中文翻译：

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Ni和ZnO颗粒之间强大的金属-载体相互作用及其对Ni / ZnO的甲烷化性能的影响

通过共沉淀制备Ni / ZnO系统，并在不同温度（350、400、450和500°C）下还原后使用TG-MS，H ₂ -TPR，N ₂物理吸附，XRD，SEM，H ₂和CO化学吸附进行表征，TEM，EPR和XPS。高₂CO化学吸附实验以及XRD，SEM和TEM分析表明，Ni和ZnO颗粒之间存在很强的金属-载体相互作用（SMSI），并且随着还原温度的升高，SMSI的程度也增强了。TEM，EPR和XPS研究表明，SMSI的产生归因于ZnO对Ni颗粒的几何修饰以及电子从ZnO转移到Ni原子，以及Ni和ZnO之间的化学相互作用导致形成NiZn合金。使用CO的甲烷化作为探针反应来表征SMSI对Ni / ZnO催化性能的影响。结果表明，SMSI通常对甲烷化活性具有显着的抑制作用，而轻度SMSI状态则有助于提高CO甲烷化的选择性和稳定性。有趣的是，通过在温和的条件下进行再氧化和再还原处理。Ni和ZnO之间的SMSI的发现使人们对Ni与载体之间的相互作用有了新的认识，并提供了一种调整Ni与载体之间的相互作用的方法以及调节Ni / ZnO催化剂或Ni的甲烷化性能的方法。基催化剂。