Catalyst for decarbonylation and carbonylation coupling reaction as well as preparation method and application of catalyst

The invention discloses a catalyst for decarbonylation and carbonylation coupling reaction as well as a preparation method and application of the catalyst. The catalyst comprises a carrier, palladium and phosphate. The preparation method of the catalyst comprises the following steps: (1) loading a palladium precursor on a carrier by an impregnation method, and drying and reducing to obtain a catalyst intermediate; and (2) impregnating the catalyst intermediate obtained in the step (1) into an impregnation liquid containing phosphate, and drying and roasting in an inert atmosphere to obtain the catalyst. The catalyst is a novel bifunctional catalyst, can effectively promote decarbonylation and carbonylation coupling reaction, realizes self-production and self-use of CO, improves the atom utilization rate, can improve bifunctional catalytic activity when being used for coupling a reaction for preparing dimethyl carbonate from dimethyl oxalate and a reaction for preparing methyl 3-pentenoate from 1, 3 butadiene,