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 CuII 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.