Synergistic Catalysis of PdFe Bimetallic Nanoparticles Supported on SiO₂ for Hydrogenative Cleavage of C–N Bonds

SiO2-supported Pd nanocatalysts were doped with Fe for hydrogenative cleavage of C–N bonds over the substrates hexabenzylhexaazaisowurtzitane (HBIW) and tetraacetyldibenzylhexaazaisowurtzitane (TADBIW). The volcanic type trend of the catalytic performance can be exhibited with an increasing Fe amount. Low Fe content showed high yields by synergistic catalysis with Pd, while high Fe loading decreased surface proportion of active metallic Pd and then lowered the catalytic performances. Interestingly, the nanoalloy structures have been identified to be the origin of synergistic catalysis on the bimetallic nanocatalysts obtained by a simultaneous codeposition-precipitation (CO–DP) method. Moreover, in the CO–DP process, the competitive deposition-precipitation of Fe promoted a more uniform distribution of Pd nanoparticles and a higher activation efficiency of H2 via modifying adsorption–desorption, therefore boosting the catalytic performances.