title: Dual role of CO in the stability of subnano Pt clusters at the Fe3O4(001) surface.
abstract: Interactions between catalytically active metal particles and reactant gases depend strongly on the particle size, particularly in the subnanometer regime where the addition of just one atom can induce substantial changes in stability, morphology, and reactivity. Here, time-lapse scanning tunneling microscopy (STM) and density functional theory (DFT)-based calculations are used to study how CO exposure affects the stability of Pt adatoms and subnano clusters at the Fe3O4(001) surface, a model CO oxidation catalyst. The results reveal that CO plays a dual role: first, it induces mobility among otherwise stable Pt adatoms through the formation of Pt carbonyls (Pt1-CO), leading to agglomeration into subnano clusters. Second, the presence of the CO stabilizes the smallest clusters against decay at room temperature, significantly modifying the growth kinetics. At elevated temperatures, CO desorption results in a partial redispersion and recovery of the Pt adatom phase.
authors.affiliation: Institute of Applied Physics, TU Wien, 1050 Vienna, Austria;
authors.forename: Roland
authors.initials: R
authors.lastname: Bliem
authors.affiliation: Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials, Utrecht University, NL-3584 CG Utrecht, The Netherlands;
authors.forename: Jessi E S
authors.initials: JE
authors.lastname: van der Hoeven
authors.affiliation: Institute of Applied Physics, TU Wien, 1050 Vienna, Austria;
authors.forename: Jan
authors.initials: J
authors.lastname: Hulva
authors.affiliation: Institute of Applied Physics, TU Wien, 1050 Vienna, Austria;
authors.forename: Jiri
authors.initials: J
authors.lastname: Pavelec
authors.affiliation: Institute of Applied Physics, TU Wien, 1050 Vienna, Austria;
authors.forename: Oscar
authors.initials: O
authors.lastname: Gamba
authors.affiliation: Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials, Utrecht University, NL-3584 CG Utrecht, The Netherlands;
authors.forename: Petra E
authors.initials: PE
authors.lastname: de Jongh
authors.affiliation: Institute of Applied Physics, TU Wien, 1050 Vienna, Austria;
authors.forename: Michael
authors.initials: M
authors.lastname: Schmid
authors.affiliation: Institute of Materials Chemistry, TU Wien, 1040 Vienna, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Blaha
authors.affiliation: Institute of Applied Physics, TU Wien, 1050 Vienna, Austria;
authors.forename: Ulrike
authors.initials: U
authors.lastname: Diebold
authors.affiliation: Institute of Applied Physics, TU Wien, 1050 Vienna, Austria; parkinson@iap.tuwien.ac.at.
authors.forename: Gareth S
authors.initials: GS
authors.lastname: Parkinson
keywords: Fe3O4; adsorbate induced sintering; nucleation and growth; redispersion; single-atom catalysis