Fig. 3.

Structural evolution of 0.17%Pt@MCM-22-300H₂ under CO + O₂ conditions. During the in situ TEM experiments, the sample was treated in mixture of CO (0.2 torr) and O₂ (0.1 torr) for 15 min at different reaction temperature, respectively. In order to avoid the carbon deposition of CO by the electron beam, the TEM chamber was evacuated to remove CO gas after exposure of the sample to CO + O₂ gases. a Room temperature, b 100 °C, c 150 °C, d 200 °C, e 300 °C, f 400 °C. Scale bar in all the images in this figure: 10 nm