Peripheral P doping in Zn1/NC single-atom catalyst to enhance propane dehydrogenation reaction

Abstract

Although Zn-based catalysts are widely used for propane dehydrogenation (PDH), the positively charged Zn is susceptible to reduction to metallic state under harsh conditions, which ultimately leads to its vaporization and thus irreversible deactivation. Moreover, the understanding of the structure-performance relationship of Zn-based catalysts in PDH remains limited. In this work, the effect of peripheral P doping on PDH over atomically dispersed Zn catalysts with different N/C coordination numbers (Zn1-NnC4-n-P, n = 2–4) is investigated by density functional theory (DFT) calculations. The results show that the peripherally P-doped Zn1-N2C2 catalyst exhibits improved performance and stability compared to the undoped Zn1-N2C2. It is revealed that there is a linear relationship between the energy barrier of the first dehydrogenation step of C3H8 and the H affinity of the active site. Furthermore, the peripheral P doping contributes to the stabilization of the tetra-coordination structure of Zn during catalysis, which in turn lowers the energy barrier for the second dehydrogenation step of C3H8. The experimental results are in good agreement with theoretical predictions. This work provides useful insights for the rational design of efficient SACs for PDH via doping strategy.