Spectroscopy: Techniques like Infrared (IR) and Nuclear Magnetic Resonance (NMR) spectroscopy help in understanding the chemical environment of active sites. Microscopy: High-resolution imaging techniques such as Scanning Tunneling Microscopy (STM) and Transmission Electron Microscopy (TEM) are used to visualize active sites. X-ray Diffraction (XRD): Helps in determining the crystalline structure of the catalyst and locating active sites. Computational Methods: Techniques like Density Functional Theory (DFT) simulations provide insights into the electronic structure and active sites of catalysts.