Effect of Bubble Behavior on the Morphology of Foamed Porous Copper Prepared via Electrodeposition

Abstract

Hydrogen evolution reaction (HER) was intensified to produce bubbles as dynamic templates for the preparation of foamed porous copper (FPCu) in acidic cupric electrolyte. The macroscopic morphologies of FPCu, including pore size distribution and pore density, were determined by the bubble diameter. Bubble assemble behavior was the most important in overall process of gas evolution. Growth of hydrogen bubbles caused coalescence of bubbles and resulted in size increment of the templates. Furthermore, bubble behavior was in tight relation with residence time and current density. Results showed that the morphologies were dependent on deposition time and current density. Small pores in FPCu were attributed to the un-coalesced bubbles and large pores were ascribed to the coalesced bubbles. The embedding and nesting of small holes by the large ones contributed to the formation of hierarchical porous framework. A “stack up layers” model was proposed to illuminate the morphological transformation of FPCu from two-dimensional structure to 3-dimensional framework. Understanding of this model facilitated the preparation of macroporous copper with favorable morphologies.