Nature of cobalt sites in Single-Atom Co1/Silicalite-1 Catalysts for Enhanced Propane Dehydrogenation

This project focuses on the development of single-atom cobalt catalysts (Co1@S1) supported on silicalite-1 zeolites for propane dehydrogenation (PDH), a more sustainable route to produce propylene compared to conventional steam or catalytic cracking. These catalysts exhibit outstanding performance, surpassing state-of-the-art noble metal systems, with high conversion, selectivity, and long-term stability. The catalytic activity is strongly influenced by the concentration of silanol nests in the zeolite: low concentrations generate highly active and stable sites, while high concentrations lead to inactive materials. Conventional and ex situ characterization techniques fail to explain these differences, as all samples appear structurally similar. Therefore, the project proposes in situ X-ray Absorption Spectroscopy (XAS) under reaction conditions, enabled by synchrotron radiation. This approach will track in real time the structural and electronic evolution of cobalt species during pretreatment and PDH, clarifying changes in oxidation state, coordination, and local geometry. The data will be integrated with complementary techniques such as NMR, operando IR, STEM, and kinetic studies. The expected outcome is a fundamental understanding of how the microenvironment of silanol nests governs the nature and performance of single-atom cobalt sites, providing a rational basis for designing next-generation non-noble catalysts for PDH and related reactions.