Enhanced electrocatalytic performances of alpha-Fe2O3 pseudo-nanocubes for oxygen reduction reaction in alkaline solution with conductive coating

摘要

Exploring of high-efficient, low-cost and eco-friendly catalysts for oxygen reduction reaction (ORR) is one of the vital issues for fuel cells and metal-air batteries. Herein, alpha-Fe2O3 pseudo-nanocubes have been synthesized with a facile solvothermal method, and then alpha-Fe2O3@N-C composite catalysts were prepared through chemical polymerization of pyrrole on alpha-Fe2O3, following with pyrolyzed in nitrogen atmosphere. The synthesized composite catalysts display enhanced ORR catalytic performances, including the positive shifting of the onset potential, improving of the limited current density with long-term stability compared to those of the pristine alpha-Fe2O3. The enhanced electrocatalytic performances could be ascribed to the low intrinsic and charge transfer resistances, the high content of pyridinic-N and/or Fe-N, the emergence of graphitic-N and abundant oxygen vacancy on the composite surface. This study here implies that the catalytic activity and stability of metal oxides with poor conductivity could be controlled and improved by simply coating with a nanoscale conductive layer, which shows promising potential applications as precious-metal free catalysts for various metal-air batteries and fuel cells. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.