Self-assembled copper/cobalt-containing polypyrrole hydrogels for highly efficient ORR electrocatalysts

Abstract

The exploitation of high-efficiency, inexpensive, as well as durable electrocatalysts for the oxygen reduction reaction (ORR) is of vital importance for a number of emerging technologies, such as fuel cells to counter energy and environment crises. Herein, we describe a novel approach for the synthesis of conducting electrocatalysts derived from copper/cobalt-containing polypyrrole (PPy) hydrogel. This strategy relies on a pervasive supramolecular way toward controlled in situ synthesis of one-dimensional nanostructured conductive hydrogels using a reasonable dopant counter ion, which is a disc-shaped liquid crystal molecule copper phthalocyanine- 3,4′,4″,4‴-tetrasulfonic acid tetrasodium salt (CuPcTs). The formation of supramolecular crosslinked PPy hydrogel allows for efficient and homogeneous incorporation of highly active Co ion. Moreover, Co nanoparticles are also formed and doped into the carbon layer after pyrolysis, which further enhance the electrochemical activities. The prepared catalysts show outstanding electrocatalytic activity for the ORR reaction and the reaction process obviously conformed to a four-electron reduction mechanism in the alkaline electrolyte. Given the uniform nanostructures in present hydrogels, it is accredited that such strategy can offer new approach in high active nonprecious-metal-based electrocatalysts.