Controllable Conversion of Platinum Nanoparticles to Single Atoms in Pt/CeO 2 by Laser Ablation for Efficient CO Oxidation.

Downsizing metal nanoparticles to single atoms (monoatomization of nanoparticles) has been actively pursued to maximize the metal utilization of noble-metal-based catalysts and regenerate the activity of agglomerated metal catalysts. However, precise control of monoatomization to optimize the catalytic performance remains a great challenge. Herein, we developed a laser ablation strategy to achieve the accurate regulation of Pt nanoparticles (Pt NP ) to Pt single atoms (Pt 1 ) conversion on CeO 2 . Owing to the excellent tunability of input laser energy, the proportion of Pt 1 versus total Pt on CeO 2 can be precisely controlled from 0 to 100% by setting different laser powers and irradiation times. The obtained Pt 1 Pt NP /CeO 2 catalyst with approximately 19% Pt 1 and 81% Pt NP exhibited much-enhanced CO oxidation activity than Pt 1 /CeO 2 , Pt NP /CeO 2 , and other Pt 1 Pt NP /CeO 2 catalysts. Density functional theory (DFT) calculations showed that Pt NP was the major active center for CO oxidation, while Pt 1 changed the chemical potential of lattice oxygen on CeO 2 , which decreased the energy barrier required for CO oxidation by lattice oxygen and resulted in an overall performance improvement. This work provides a reliable strategy to redisperse metal nanoparticles for designing catalysts with various single-atom/nanoparticle ratios from a top-down path and valuable insights into understanding the synergistic effect of nano-single-atom catalysts.