Registered charity number: 207890 As featured in: See Shouguo Wang, Kai Sun, Rongming Wang et al., Chem. Commun., 2014, 50, 1804. Showcasing research from Rongming Wang’s Laboratory/ Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191, P. R. China In situ tracing of atom migration in Pt/NiPt hollow spheres during catalysis of CO oxidation In situ HR-STEM imaging and 3D reconstruction were performed to evidence the migration of Pt atoms in Pt/NiPt hollow nanospheres during catalysis of CO oxidation by quantitative analysis on the experimental images. Atom immigration on the surface of the nanospheres during catalytic process was obtained, providing a practical insight into the structural stability of bimetallic catalysts. www.rsc.org/chemcomm