Influence of Ice Templating on Oxygen Reduction Catalytic Activity of Metal‐Free Heteroatom‐Doped Mesoporous Carbon Derived from Polypyrrole for Zinc–Air Batteries
Maria Kurian, Meena Ghosh, Vidyanand Vijayakumar, Priyanka Pandinhare Puthiyaveetil, Arun Torris, Sreekumar Kurungot
Abstract
The development of highly active, cost‐effective, and durable, noble metal‐free oxygen reduction electrocatalysts is inevitable for the full‐fledged implementation of fuel cells and zinc–air batteries. This work reports the synthesis of heteroatom (N, P, S)‐doped metal‐free mesoporous carbon‐based electrocatalyst derived from polypyrrole by combining the ice templating, freeze‐drying, and carbonization processes. The correlation between the structure and electrochemical activity of the polypyrrole‐derived carbon‐based electrocatalyst in the presence and absence of ice templating is investigated. The optimized electrocatalyst, aided by the ice‐templating and freeze‐drying step, shows an onset and half‐wave potential ( E 1/2 ) of 0.94 and 0.78 V vs reversible hydrogen electrode, respectively, in an alkaline electrolyte (0.1 m KOH). Later, the application of the optimized electrocatalyst is demonstrated in a primary zinc–air battery (ZAB) cell. The results prove that the ZAB device performance based on the homemade catalyst is on par with that of the state‐of‐the‐art Pt/C cathode. The catalyst performance is correlated with the heteroatom doping and the enhanced porosity of the sample benefitted from ice templating. Ultimately, this work depicts a facile and rational synthesis of a truly metal‐free electrocatalyst for the primary ZABs that can be a potential replacement for state‐of‐the‐art systems.