Microsoft Word-nwab026.docx

Synthesis of atomically dispersed catalysts with high metal loading and thermal stability is challenging but particularly valuable for industrial applications in heterogeneous catalysis. Here, we report a facile synthesis of a thermally stable atomically dispersed Ir/α-MoC catalyst with metal loading as high as 4 wt%, an unusually high value for carbide supported metal catalysts. The strong interaction between Ir and the α-MoC substrate enables high dispersion of Ir on the α-MoC surface, and modulates the electronic structure of the supported Ir species. Using quinoline hydrogenation as a model reaction, we demonstrate that this atomically dispersed Ir/α-MoC catalyst exhibits remarkable reactivity, selectivity, and stability, for which the presence of high-density isolated Ir atoms is the key to achieve high metal-normalized activity and mass-specific activity. We also show that water-promoted quinoline hydrogenation mechanism is preferred over the Ir/α-MoC, which contributes to high selectivity towards D ow naded rom http/academ ic.p.com /nsr/advance/doi/10.1093/nsr/nw ab026132277 by N aonal Sience nd Tenology Lrary -R ot user on 28 Feruary 2021 O R IG IN A L U N E D IT E D M A N U S C R IP T 1,2,3,4-tetrahydroquinoline. The present work demonstrates a new strategy to construct high-loading atomically dispersed catalyst towards hydrogenation reaction.