Identification and localization of Pt species in Pt-NaA zeolite catalysts prepared by direct synthesis

MARTÍNEZ GALEANO, YOHANA; MORENO, SERGIO; RAMALLO-LÓPEZ, JOSÉ M.; TARDITI, ANA M.; MIZRAHI, MARTÍN; CORNAGLIA, LAURA

CATALYSIS COMMUNICATIONS

ELSEVIER SCIENCE BV

Año: 2022 vol. 172 p. 106558 - 106570

1566-7367

Several characterization techniques were employed to elucidate the Pt species present in the structure of Pt-NaA catalysts. Three types of Pt particles were identified: nanoparticles located at the surface of the crystals (with a higher size and flattened form), 1?2 nm particles inside the structure, and sub-nanometric particles, lower than 1 nm, confined in the pores. The low Pt?Pt coordination number (EXAFS) is compatible with both flattened dihedral-like morphology, as well as the presence of sub-nanometric particles. The Pt0.6_NaA catalyst exhibited higher activity (in the WGS) than the other catalysts, which could be related to the presence of small particles.