Self-supported Pt-doped ceria nanofilms directly investigated by transmission electron microscopy

In this study, we report a direct deposition of three-dimensional freestanding nanostructures of platinum-doped ceria films on holey carbon coated copper transmission electron microscopy (TEM) grid by direct liquid injection chemical vapor deposition (DLI-CVD). TEM was then directly performed on the pristine thin films, without any kind of mechanical or ion thinning. High-resolution TEM reveals that highly porous and crystallized layers were deposited over the whole membrane. The existence of platinum in the ceria grains was confirmed by Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS). Moreover, the substitution of carbon membrane by Pt-CeO2 layer was highlighted by Electron Energy Loss Spectroscopy (EELS), showing that the Pt-CeO2 nanofilms are freestanding. These results are very promising and represent an important step for performing specific nanoscale TEM analyses necessary for the study of the growth mechanism of nanofilms on substrates.