Germanium-enriched double-four-membered-ring units inducing zeolite-confined subnanometric Pt clusters for efficient propane dehydrogenation

It is a great challenge to regulate the precise placement of confined metal species and assemble specific structures at the atomic level. Here we report the design and synthesis of a durable supported-metal-cluster catalyst, Pt@Ge-UTL, that features subnanometric Pt clusters encapsulated inside the extra-large pores of a stabilized UTL-type germanosilicate. Integrated differential phase contrast scanning transmission electron microscopy, in situ X-ray absorption fine structure, ¹⁹F magic-angle-spinning NMR, full-range synchrotron pair distribution function G(r) analysis and density functional theory calculations revealed that Pt clusters with an average of four atoms are firmly segregated within 14-membered-ring channels. This is achieved by selectively and directionally anchoring Pt, via Pt–O–Ge bonding, to the UTL zeolite’s unique secondary building units that feature a double-four-membered-ring (d4r) configuration and a Ge-enriched composition. The host–guest bimetallic structure (Pt₄-Ge₂-d4r@UTL) promotes propane dehydrogenation with high activity, high propylene selectivity and long-term stability. This research demonstrates the use of germanosilicates in the designed synthesis of high-performance propane dehydrogenation catalysts. [Figure not available: see fulltext.]