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 Co-1 species to afford the sintering-resistant Co SAs/SiO2 NMs catalyst. The as-obtained Co SAs/SiO2 NMs with unsaturated Co-O-3 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-O-3 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.

Automated summary

This study presents a catalyst for propane dehydrogenation with low cost, environmental friendliness, and high activity. The catalyst, constructed using SiO2 nanomeshes with ultrashort three-dimensional channels, effectively immobilizes Co single atoms. The catalyst exhibits outstanding catalytic performance and long-term stability, making it significant for the design of high-efficiency single-atom catalysts.