Nanostructured Fe-N-C Electrocatalysts with CeO2 Additives for PEM Fuel Cells

Abstract

The development of cost-effective electrocatalysts for polymer electrolyte membrane fuel cells (PEM fuel cells) is essential for the widespread use of this technology. The high cost and limited availability of Pt-group metals (PGMs) used as catalyst materials are the main barriers to the widespread commercialization and development of PEM fuel cells. [1] Therefore, the use of high surface area and effective catalysts without Pt have gained great importance in PEM fuel cells. This study introduces high surface area electrocatalysts that are free of platinum group metals (non-PGM) consisting of iron-nitrogen-carbon (Fe-N-C). Here, the uniform distribution of Fe was achieved using graphene oxide (GO) nanoparticles to enhance the catalyst's performance for oxygen reduction reaction (ORR). [2] Furthermore, the addition of a small amount of cerium oxide (CeO2) nanoparticles to the catalyst layer helps to prevent the degradation of the catalyst and ionomer by preventing H2O2 formation as well as increasing the ORR activity due to high oxygen storage capacity. [3] Initially, GO is synthesized by improved Hummer’s method. The GO nanoparticles are obtained through a process involving ball-milling and acid treatment. These nanoparticles are then thermally reduced and nitrogen-doped to form nitrogen-doped reduced graphene oxide nanoparticles. Fe-N-C complexes are synthesized by reacting these nanoparticles with FeCl2 precursor, which are then hydrothermally treated to introduce CeO2 additives. The resulting catalysts are analyzed using various techniques (FT-IR, XPS, SEM, TEM, EDX) and display excellent electrochemical performance. The ORR activity of the Fe-N-C catalysts was investigated and compared with the electrocatalysts prepared with larger graphene oxide particles. A similar comparison is also made with and without CeO2 additives. The authors gratefully acknowledge the financial support of The Scientific and Technological Research Council of Turkey (TÜBİTAK) (Grant Number: 122M429) References [1] He, C., Desai, S., Brown, G., & Bolleplli, S. (2005). PEM fuel cell catalysts: Cost, performance, and durability. The electrochemical society Interface, 14(3), 41.[2] Weiss, J., Zhang, H., & Zelenay, P. (2020). Recent progress in the durability of Fe-NC oxygen reduction electrocatalysts for polymer electrolyte fuel cells. Journal of Electroanalytical Chemistry, 875, 114696.[3] Taşdemir, A., Iskandarani, B., Yürüm, A., Gürsel, S. A., & Kaplan, B. Y. (2021). CeO2 nanorod decorated NrGO additives for boosting PEMFC performance. International Journal of Hydrogen Energy, 46(63), 32250-32260.