Enabling highly efficient ambient-temperature formic acid dehydrogenation over ultrafine Pd–Ir alloy nanoclusters supported on aminated dealuminated Beta zeolite

Palladium-based zeolite catalysts are promising candidates for formic acid dehydrogenation (FAD), enabling on-demand hydrogen release and utilization. Achieving uniform dispersion of Pd-based alloy nanoparticles on zeolites through defect-engineering strategies remains a significant challenge. In this study, the acidity of Beta zeolite was modulated by dealumination, which simultaneously created structural defects known as “silanol nests.” Subsequently, the zeolite was functionalized with amino groups using 3-aminopropyltriethoxysilane, followed by co-reduction to successfully generate highly dispersed metal species with an average size of approximately 1.5 nm. The as-prepared Pd–Ir/NH 2 -deAlBeta catalyst exhibits abundant exposed active sites and excellent formic acid adsorption ability. The optimized Pd 0.75 Ir 0.25 /NH 2 -deAlBeta catalyst demonstrates an initial turnover frequency (TOF) of 3521 ± 150 h⁻ 1 at 298 K. Kinetic isotope effect measurements indicate that C–H bond cleavage is the rate-determining step, and further mechanistic studies reveal that the HCOO* species is the key surface intermediate on the Pd–Ir/NH 2 -deAlBeta catalyst.