Metal Ni anchored to highly dispersed island-like CeO₂ on the TS-1 for catalyzing methane dry reforming by regulating Ni–O–Ce species

Metal Ni was deposited on the different island-like rare earth metal oxide/silica matrix composites. Among the rare earth metal oxides, CeO₂ was favorable for the metal Ni dispersion, leading to small-size Ni nanoparticle. For the silica matrices, they could affect the CeO₂ size, positively regulating the size of Ni nanoparticle. Among them, TS-1 (Titanium Silicalite-1) was beneficial to decrease the CeO₂ size, as well as the Ni nanoparticle size. The 10 wt %Ni-10 wt %CeO₂/TS-1 (NCT) catalyst consisting of CeO₂ and TS-1, exhibited the optimal catalytic performance, achieving 92 % CH₄ and 94 % CO₂ conversions, along with 0.98H₂/CO ratio within 50 h under 750 °C. This is mainly because small Ni nanoparticle could strengthen Ni–O–Ce species, increasing the surface charge density of metal Ni, which was conducive to CH₄ activation. Also, based on the similar Ni loading, small Ni particle could bring more Ni–O–Ce species, promoting the CO₂ activation. Furthermore, NCT catalyst also showed the best stability with 4.1 % CH₄ and 3.4 % CO₂ activity loss after 100 h, which was caused by the superior anti-sintering and anti-coking properties, because of the significant island barrier effect, and many strengthened Ni–O–Ce species. In-situ DRIFTS was performed to investigate reaction mechanism, revealing that significant amounts of strengthened Ni–O–Ce species were beneficial for the reactant activation processes, facilitating the DRM reaction.