Palladium-alumina catalysts are widely used in chemical industry. They are often used in hydrogenation, dehydrogenation and cross-coupling of organic synthesis reactions, which can effectively accelerate the reaction speed. Such catalysts can be classified according to the support form and concentration of palladium, and there are various forms on the market such as granular, thin film and nano-form. At the same time, the content of palladium will directly affect the catalytic efficiency and stability of the catalyst.