Characterization and Thermal Stability Properties of Bulk Hierarchical Porous Pd Prepared by Kirkendall Effect and Dealloying Method

We present a facile strategy to synthesize bulk hierarchical porous Pd materials (BHPPd) with pores ranging from a few nanometers to tens of micrometers through chemical dealloying of porous PdAl intermetallics. Owing to the small surface diffusivities of Pd atoms, the pore/ligament size of BHPPd did not coarsen remarkably as the concentration of HCl aqueous solution increases. Thermal stability properties of BHPPd materials at different temperature ranging from 673 to 1073 K were evaluated. BHPPd materials show superior thermal stability, whose bicontinuous interpenetrating ligament-channel structure can be maintained even after being annealed at 1073 K for 30 min. Such properties can be attributed to less defects and less-noble metal residues. Moreover, compression properties of BHPPd materials were also investigated.