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 Cu 2 O nanospheres template under air conditions, which is responsible for the generation of the Pd–Cu alloy and the convenient removal of the Cu 2 O nanospheres template at room temperature. Compared to the commercial Pd black, the Pd–Cu HPANSs show remarkably improved catalytic activity for the reduction of K 2 Cr 2 O 7 by HCOOH at room temperature, attributing to the enhanced catalytic activity of the Pd–Cu HPANSs for the dehydrogenation decomposition of HCOOH.