Structural evolution induced by Au atom diffusion in Ag 2 S

Atom diffusion processes govern the structure and composition of core–shell nanomaterial, which play a crucial role in determining their properties. By using aberration-corrected high-resolution transmission electron microscopy and X-ray absorption near-edge structure spectroscopy in combination with in situ X-ray diffraction, we confirm that single-atom diffusion of Au to Ag 2 S occurs, and that the transition from the Au@Ag 2 S core–shell nanostructure to AuAgS–AuAg x or Ag 3 AuS 2 –AuAg x heterostructures was observed. Moreover, the phase of the ternary sulfide induced by Au single-atom diffusion in Ag 2 S is determined by the ratio of Au and Ag, thus exhibiting a significant difference in the photocatalytic activity performance.