What are the important characterization methods for solid catalysts?

Key methods include: BET surface area (N2 adsorption measures total surface area), pore size distribution (BJH method from adsorption isotherm), chemisorption (metal dispersion and active sites), XRD (crystal structure and phase identification), TEM/SEM (particle size and morphology), TPR/TPO (reducibility and oxidation behavior), XPS (surface composition and oxidation states), and FTIR (adsorbed species identification). Combination of methods provides complete catalyst understanding for development and troubleshooting.