Characterizing metal oxide thin films is essential to understand their properties and catalytic performance. Common characterization techniques include: 1. X-ray Diffraction (XRD): To determine crystallographic structure. 2. Scanning Electron Microscopy (SEM): To observe surface morphology. 3. Transmission Electron Microscopy (TEM): For high-resolution imaging of thin films. 4. X-ray Photoelectron Spectroscopy (XPS): To analyze surface composition and chemical states. 5. Atomic Force Microscopy (AFM): To measure surface roughness and topography.