Transition metal-doped aluminum nitride catalysts for propane dehydrogenation

Nonoxidative propane dehydrogenation (PDH) offers a greener alternative to traditional petroleum-based cracking processes. Metal nitrides, such as AlN, are promising PDH catalysts due to their Lewis acid-base functionalities that can activate the C-H bond of alkanes. In this work, Density Functional Theory (DFT) calculations, microkinetic modeling (MKM), and proof-of-concept experiments have been carried out to examine the PDH activity of transition metal-doped AlN catalysts. Through an initial catalyst screening approach using reactivity and selectivity descriptors, Mn- and Zn-doped AlN catalysts were identified as promising candidates for PDH. Detailed DFT-based MKM demonstrated that the kinetically preferred mechanism follows a reverse Horiuti-Polanyi mechanism which entails two successive C-H bond scission steps. Additionally, MKM revealed that Zn-doped AlN outperforms pristine AlN in catalytic activity and propylene selectivity due to lower energy barriers along the dominant reaction pathway. Proof-of-concept experiments confirmed that both catalysts are active and selective for PDH, with Zn/AlN showing higher intrinsic reaction rate, significantly lower apparent activation energy (by similar to 60 kJ mol(-1)), and slightly higher propane conversion (by 4.5 %) compared to pristine AlN. The propylene selectivity of Zn/AlN was marginally reduced compared to AlN. Overall, this work integrates DFT, MKM, and proof-of-concept experiments to advance the development of active and selective PDH catalysts, offering insights into the catalytic performance of previously untested metal nitride catalysts for PDH.