A palladium catalyst is a substance that speeds up chemical reactions without being consumed in the process. It is made from palladium, a precious metal known for its ability to facilitate various reactions, particularly in organic chemistry. Palladium catalysts are commonly used in processes like hydrogenation, where hydrogen is added to unsaturated compounds. These catalysts are essential in industries such as pharmaceuticals and petrochemicals, helping to produce important chemicals more efficiently. Their effectiveness often comes from their ability to form complexes with reactants, lowering the energy needed for reactions to occur.