Fig. 3: Selective oxidation of Ag nanocrystals with different planar defect configurations.
From: Defect-driven selective metal oxidation at atomic scale
a–d Preferential oxidation of an Ag nanocrystal with an isolated SF. a, b Two oxide embryos formed preferentially at the SF-surface junctions on both sides (indicated by the light blue arrows), while the TB-surface junctions remained intact. Inset in a shows the atomistic structure of the surface near the SF, which consists of atomically flat (11\(\bar 2\)) plane and several (11\(\bar 1\)) kink steps. c, d Subsequent SF-assisted fast inward and lateral growth of Ag2O island. Meanwhile, oxide nucleation and growth was initiated at the TB3-surface junction away from the SF. e–h Preferential oxidation in an Ag nanocrystal with unevenly spaced planar defects. e Multiple parallel TBs (#1–6) and a SF (indicted by the white arrow) pre-existed in the as-fabricated Ag nanocrystal with a clean surface. f Oxide embryo nucleated preferentially at the SF-surface junction. g Inward growth of the Ag2O island along the SF plane. h Integrated inward and lateral growth of the Ag2O oxide with the annihilation of the SF. No evident oxidation was observed at the TB-surface intersection sites nearby. Insets in e, f are zoomed-in snapshots presenting the atomistic nucleation processes of the oxide embryo at the SF-(111) surface facet junction. Scale bars in a and e: 5 nm.
