Atomically dispersed Ir/α-MoC catalyst with high metal loading and thermal stability for water-promoted hydrogenation reaction

Atomically dispersed Ir/alpha-MoC catalyst with high metal loading exhibits remarkable activity, selectivity and stability for quinoline hydrogenation reaction through water-promoted hydrogenation mechanism. Synthesis of atomically dispersed catalysts with high metal loading and thermal stability is challenging but particularly valuable for industrial application in heterogeneous catalysis. Here, we report a facile synthesis of a thermally stable atomically dispersed Ir/alpha-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 alpha-MoC substrate enables high dispersion of Ir on the alpha-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/alpha-MoC catalyst exhibits remarkable reactivity, selectivity and stability, for which the presence of high-density isolated Ir atoms is the key to achieving high metal-normalized activity and mass-specific activity. We also show that the water-promoted quinoline hydrogenation mechanism is preferred over the Ir/alpha-MoC, and contributes to high selectivity towards 1,2,3,4-tetrahydroquinoline. The present work demonstrates a new strategy in constructing a high-loading atomically dispersed catalyst for the hydrogenation reaction.

Automated summary

The atomically dispersed Ir/alpha-MoC catalyst with high metal loading shows remarkable activity, selectivity, and stability for quinoline hydrogenation through a water-promoted hydrogenation mechanism. The strong interaction between Ir and alpha-MoC substrate enables high dispersion of Ir on the surface, leading to high reactivity and selectivity. The synthesis of high-loading atomically dispersed catalyst is a new strategy for efficient hydrogenation reactions.