Nickel/Cobalt-Containing polypyrrole hydrogel-derived approach for efficient ORR electrocatalyst

With the advancement of society, the energy and environmental crisis is particularly prominent. Therefore, the development of efficient, stable and inexpensive catalysts for oxygen reduction reactions (ORR) is critical for many technologies such as fuel cells and metal-air batteries. Herein, we report a hydrogel polymerization strategy to synthesize a nickel-containing polypyrrole hydrogel (NiPcTs/PPy hydrogel). The nickel/cobaltcontaining PPy hydrogel (NiPcTs/Co/PPy hydrogel) can be getting after immersing the NiPcTs/PPy hydrogel in Co3+ aqueous solution. Furthermore, the pyrolyzed product of NiPcTs/Co/PPy hydrogel is a kind of efficiently active ORR catalysts. Although the NiPcTs/Co/PPy catalyst exhibits a similar catalytic activity compared to commercial Pt/C (20%) on the basis of the initial voltage, it shows a similar diffusion-limiting current density compare to Pt/C within the applied potential range. It is worth to mention that the cost of the NiPcTs/Co/PPy catalyst is much lower. This work provides a new strategy for the development of highly active and non-precious metal based electrocatalysts for electrochemical energy devices.