Dehydrogenation\nof <i>n</i>‑Butane\non Metal Cobalt Sites Confined within Ceria Nanoislands

Preparation of highly efficient alkane dehydrogenation\ncatalysts\nworking at high temperatures is still a great challenge due to the\nsintering property of metal components under reducing atmospheres.\nTo improve the thermal stability of cobalt on the support, we propose\na confinement strategy using ceria nanoislands located on the silicalite-1\nsupport, which improves the resistance to sintering of cobalt species.\nUnlike the coke-coated cobalt particles and carbon nanotubes observed\non 1Co/S-1, ceria nanoislands on 1Co6CeO<sub><i>x</i></sub>/S-1 restrain the overaggregation of metallic cobalt, preventing\nthe occurrence of side reactions such as cracking and coking induced\nby large metallic cobalt particles. Comprehensive analysis results\nshow that active lattice oxygen species within ceria participate in\nthe oxidative dehydrogenation reaction in the initial stage of the\nreaction, boosting the deep dehydrogenation of <i>n</i>-butane\nto 1,3-C<sub>4</sub>H<sub>6</sub>. During the transition from Ce(IV)\nto Ce(III), the depletion of active lattice oxygen lowers oxidative\ndehydrogenation activity, triggering the reduction of cobalt species\nand shifting the reaction pathway from oxidative dehydrogenation to\ndirect dehydrogenation. The proposed confinement strategy using ceria\nnanoislands on silicalite-1 support offers a promising solution to\nthe challenge of sintering in metal catalysts.