Highly dispersed Pd based catalysts for selective hydrogenation reactions

Abstract A new method of preparation of Pd supported catalysts is presented allowing to prevent the electron deficient character of highly dispersed metallic particles. Starting with a stabilised aqueous soluble Pd complex and under well-chosen activation procedure, ultradispersed Pd alumina supported particles obtained exhibit similar diene hydrogenation activity expressed by surface exposed atoms than bigger particles obtained by classical dried impregnation methods. Characterisation techniques (EXAFS, XPS, TPR, TEM) clearly evidence the non electro deficient character of these small particles. Catalytic performances (orthoxylene and butadiene hydrogenation) are discussed in relation with characterisation results.