One-Pot Fabrication of Hollow and Porous Pd-Cu Alloy Nanospheres and Their Remarkably Improved Catalytic Performance for Hexavalent Chromium Reduction

Noble metal nanostructures (NMNSs) play a crucial role in many heterogeneous catalytic reactions. Hollow and porous NMNSs possess generally prominent advantages over their solid counterparts due to their unordinary structural features. In this work, we describe a facial one-pot synthesis of hollow and porous Pd-Cu alloy nanospheres (Pd-Cu HPANSs) through a polyethylenimine (PEI)-assisted oxidation-dissolution mechanism. The strong coordination interaction between Cu^II and PEI facilitates the oxidation-dissolution of the Cu₂O nanospheres template under air conditions, which is responsible for the generation of the Pd-Cu alloy and the convenient removal of the Cu₂O nanospheres template at room temperature. Compared to the commercial Pd black, the Pd-Cu HPANSs show remarkably improved catalytic activity for the reduction of K₂Cr₂O₇ by HCOOH at room temperature, attributing to the enhanced catalytic activity of the Pd-Cu HPANSs for the dehydrogenation decomposition of HCOOH.