Synthesis of aldehydes from acid chlorides was carried out using four types of supported Pd/SiO2 catalysts, which were prepared by a complexing agent-assisted sol-gel method and two types of impregnations with organic solvents or water, and a commercial Pd/BaSO4 catalyst. The performance of the catalysts was much affected by the catalyst preparation and activation conditions. The sol-gel catalysts activated under milder conditions exhibited the highest performance for the formation of aldehydes. The high performance of the sol-gel catalysts was due to the organic residues derived from acetylacetone and ethylene glycol used in the sol-gel catalyst preparation process. The organic residues play a role similar to that of a poison added into the reaction solution for the traditional Rosenmund reduction, while being kept in the silica gel matrices.