The stability of catalysts in dry reforming of methane (DRM) is a known issue. In this paper an encapsulation strategy has been employed to improve the stability compared with conventional impregnation methods. Herein, nickel nanoparticles encapsulated in silicalite-1 were prepared using a range of methods including post treatment, direct hydrothermal and seed-directed methods to investigate the effect of synthesis protocol on the properties of catalysts, such as degree of encapsulation and Ni dispersion, and anti-coking/-sintering performance in DRM. The Ni@SiO₂-S1 catalysts obtained by the seed-directed synthesis presented the full encapsulation of Ni NPs by the zeolite framework with small particle sizes (∼2.9 nm) and strong metal-support interaction, which could sterically hinder the migration/aggregation of Ni NPs and carbon deposition. Therefore, Ni@SiO₂-S1 showed stable CO₂/CH₄ conversions of 80% and 73%, respectively, with negligible metal sintering and coking deposition (∼0.5 wt.%) over 28 h, which outperformed the other catalysts prepared. In contrast, the catalysts developed by the post-treatment and ethylenediamine-protected hydrothermal methods showed the co-existence of Ni phase on the internal and external surfaces, i.e. incomplete encapsulation, with large Ni particles, contributing to Ni sintering and coking. The correlation of the synthesis-structure-performance in this study sheds light on the design of coking-/sintering-resistant encapsulated catalysts for DRM.

甲烷干重整 (DRM) 中催化剂的稳定性是一个已知问题。在本文中，与传统的浸渍方法相比，采用封装策略来提高稳定性。在此，使用一系列方法（包括后处理、直接水热法和种子导向法）制备了包封在硅质岩 1 中的镍纳米粒子，以研究合成方案对催化剂性能的影响，例如包封度和镍分散，以及DRM 中的抗焦化/烧结性能。Ni@SiO ₂-通过种子定向合成获得的-S1催化剂将Ni NPs完全包裹在具有小粒径（~2.9 nm）和强金属-载体相互作用的沸石骨架中，这可能在空间上阻碍Ni NPs和碳的迁移/聚集沉积。因此，Ni@SiO ₂ -S1 在 28 小时内表现出稳定的 CO ₂ /CH ₄转化率分别为 80% 和 73%，金属烧结和焦化沉积（~0.5 wt.%）可忽略不计，优于其他制备的催化剂。相比之下，后处理和乙二胺保护水热法开发的催化剂显示出Ni相在内外表面共存，即封装不完全，Ni颗粒大，有助于Ni烧结和结焦。本研究中合成-结构-性能的相关性为设计用于 DRM 的抗结焦/烧结包封催化剂提供了启示。