Direct low-temperature hydrothermal synthesis of uniform Pd nanoparticles encapsulated mesoporous TS-1 and its excellent catalytic capability

A simple and direct low-temperature hydrothermal synthesis approach (100 °C) has been developed to encapsulate Pd nanoparticles (ca. 2.3 nm) within nano-sized mesoporous TS-1 zeolite by utilizing dichloro(ethylenediamine)palladium (DEAP) and cetyltrimethylammonium bromide (CTAB) as palladium source and mesoporogen, respectively. It's demonstrated that the aging process of the mother liquid and low-temperature hydrothermal treatment can effectively inhibit the premature precipitation of metal precursor and thus the successful encapsulation of Pd nanoparticles into mesoporous TS-1 nanocrystals, so that the frequently occurring of Pd nanoparticle aggregation at high temperature was expectedly avoided. Consequently, the as-synthesized catalysts with highly thermal stability and mesoporous channels exhibit excellent catalytic activity and recyclability in the oxidation of CO with relatively low Pd content (0.53 wt% Pd) and catalytic wet air oxidation of phenol (66.2% of phenol conversion, 100 °C).