Extended Data Fig. 5: Changes of Pt atoms on SiO2 or CeO2 supports under various treatment conditions.
From: Functional CeOx nanoglues for robust atomically dispersed catalysts
a,b, Single Pt atoms (yellow circles) and small Pt clusters (yellow squares) were present in the as-synthesized Pt/SiO2 (synthesized by the SEA method using Pt(NH3)42+ ions in alkaline solution). c,d, After H2 reduction of the as-synthesized Pt/SiO2 at 300 °C for 1 h, Pt sintered to form various sizes of nanoparticles (c) although some small Pt clusters were observable (d). e,f, After calcination of the as-synthesized Pt/SiO2 at 500 °C for 1 h, larger Pt agglomerates (e) and many Pt nanoparticles (e,f) were formed. g,h, Atomic-resolution HAADF images of a 0.3 wt% Pt/CeO2 catalyst prepared by the SEA method. The Pt single atoms (yellow circles) on flat facets of CeO2 nanoparticles are clearly distinguishable. i,j, HAADF images of a 0.3 wt% Pt/CeO2 after reduction treatment (10 ml min−1 of H2/He at 300 °C for 1 h), clearly reveal formation of small Pt nanoparticles. During the H2-activation process, Pt atoms became mobile on CeO2 surfaces and sintered to form Pt clusters/nanoparticles (yellow squares). k, CO-DRIFTS spectrum of the reduced 0.3 wt% Pt/CeO2 indicates presence of Pt clusters/nanoparticles.
