The triggering of catalysis via structural engineering at atomic level: Direct propane dehydrogenation on Fe-N3P-C

The on-purpose direct propane dehydrogenation (PDH) has received extensive attention to meet the ever-increasing demand of propylene. In this work, by means of density functional theory (DFT) calculations, we systematically studied the intrinsic coordinating effect of Fe single-atom catalysts in PDH. Interestingly, the N and P dual-coordinated single Fe (Fe-N₃P-C) significantly outperform the Fe-N₄C site in catalysis and exhibit desired activity and selectivity at industrial PDH temperatures. The mechanistic origin of different performance on Fe-N₃P-C and Fe-N₄C has been ascribed to the geometric effect. To be specific, the in-plane configuration of Fe-N₄ site exhibits low H affinity, which results in poor activity in CH bond activations. By contrast, the out-of-plane structure of Fe-N₃P-C site exhibits moderate H affinity, which not only promote the CH bond scission but also offer a platform for obtaining appropriate H diffusion rate which ensures the high selectivity of propylene and the regeneration of catalysts. This work demonstrates promising applications of dual-coordinated single-atom catalysts for highly selective propane dehydrogenation.