Facile Synthesis and in situ TEM Observation of Nanoporous Pd for Enhanced Catalytic Applications

A facile, efficient and green photochemical synthetic approach has been used to prepare sponge-like porous Pd nanoparticles. Obtained by ultraviolet irradiation using a K2PdCl4 precursor solution, the final products exhibited three dimensionally interconnected porous structures made up of ~3.6 nm sized Pd nanoparticles. In situ liquid cell TEM results indicated such porous structures are in a dynamic stable state when the particles are distributed in aqueous solution. The porous Pd nanoparticles exhibited electrochemical active surface area (ECSA) of up to 43 m^2·g^–1 and mass activity of 1144 mA·mg^–1 in menthol oxidation, kapp of 0.22 min^–1 and normalized kapp/m (kn) of 8.3×10^4 min^–1·g^-1 in 4-nitrophenol (4-NP) reduction reactions. Comparing with the literature, it is demonstrated that our porous Pd nanoparticles with clean surfaces exhibited very high catalytic performances. This work may shed a light on facile and green synthesis of noble-metal particles with better catalytic performances.