Transformation of hollow ZnFe-ZIF-8 nanocrystals into hollow ZnFe–N/C electrocatalysts for the oxygen reduction reaction

A uniform bimetallic hollow ZnFe–N/C (80–180 nm) electrocatalyst is synthesized using a precursor ZnFe-ZIF-8 (100–200 nm) subjected to pyrolysis in an argon atmosphere at 800 °C for 2 hours. The ZnFe–N/C catalyst was deposited on a glassy carbon electrode (GCE), and exhibited a superior electrocatalytic activity with a high onset potential (0.97 V vs. RHE) and half-wave potential (0.85 V vs. RHE), high stability in an alkaline electrolyte, and remarkable resistance to methanol. The high performance of the ZnFe–N/C-3 electrocatalyst is attributed to the hollow structure containing metallic Fe/Fe3C and N doping.