Single Co Sites in Ordered SiO2 Channels for Boosting Nonoxidative Propane Dehydrogenation

Searching for low-cost, environmentally friendly, and highly active catalysts for C–H bond activation in propane dehydrogenation (PDH) reaction remains a great challenge. Herein, SiO2 nanomeshes (NMs) with ultrashort three-dimensional (3D) channels were constructed to effectively confine the Co single atoms (Co SAs/SiO2 NMs). The ultrashort 3D channels were formed by gasifying carbon in the self-assembled SiO2@polymer composites under the air atmosphere. The carbon removal process resulted in abundant oxygen (O*) defects in the channel windowsill that immobilized the dissociative Co1 species to afford the sintering-resistant Co SAs/SiO2 NMs catalyst. The as-obtained Co SAs/SiO2 NMs with unsaturated Co–O3 sites exhibited an outstanding PDH catalytic behavior (95% selectivity and 196 h–1 turnover frequency), superior to Co SAs/SiO2 commerce (83%, 49 h–1), Co NPs/SiO2 NMs (87%, 13 h–1), and most non-noble metal-based catalysts. Furthermore, Co SAs/SiO2 NMs showed high long-term stability with no significant deactivation during 24 h of reaction. Theoretical and experimental analysis indicated that these unsaturated Co–O3 sites could selectively activate the first and second C–H bonds and limit the further splitting of C–H (C) bonds during PDH. This work paves a way for designing high-efficiency single-atom catalysts for PDH.