Bulky nanodiamond-confined synthesis of sub-5 nanometer ordered intermetallic Pd_(3)Pb catalysts

Modulation of geometric and electronic structures of supported Pd-based catalysts by forming atomically ordered intermetallic phases enables an effective way to optimize catalytic performance.However,the synthesis of small-sized Pd-based intermetallic nanoparticle catalysts with improved mass-based activity remains formidable challenges,since high-temperature annealing generally required for atom ordering inevitably leads to severe metal sintering and thus large crystallites.Here,we present a bulky nanodiamond-confined method to prepare sub-5 nm Pd_(3)Pb intermetallic nanocatalysts by mitigating metal sintering at high temperatures,which is induced by the electronic interactions between metal and defect-rich graphene shells reinforced by diamond cores in the bulky nanodiamond support.The prepared small-sized Pd_(3)Pb intermetallic catalyst displays a high activity with a turnover frequency of 932 h−1 for the semihydrogenation of phenylacetylene under mild conditions(room temperature,3 bar H_(2)),along with a high selectivity of>96%to styrene near the complete conversion of phenylacetylene.