The stability of nanosized platinum catalyst in direct propane dehydrogenation reaction is one of most critical challenges,which hinders the further improvements of catalytic performance.The cokes from side reaction covering the active site seriously undermine the catalyst stability.In this work,first principles calculations are performed to explore the catalytic properties of supported subnanometer platinum cluster on carbon nanotube support and focus is put on the inhibition of deep dehydrogenation.The reactivities of metal,interface,and tin promoter are investigated at the same footing.The whole reaction pathway from propane adsorption to propene desorption is revealed for different sites.It turns out that the C-H bond activation in propane is not the catalytic step with the largest barrier.Instead,the desorption of propene is more difficult.The comparison between different sites indicates that the interface between metal and support and Sn promoter is helpful to curb the propene deep dehydrogenation.Moreover,a descriptor is proposed to screen the potential effective propane direct dehydrogenation catalyst.The current work provides important insights on the development of new dehydrogenation catalyst.