Development of non-noble Co-N-C electrocatalyst for high-temperature proton exchange membrane fuel cells

Abstract

The development of a non-noble Co-N/MWCNT (MWCNT = multi-walled carbon nano tubes) electrocatalyst is achieved through the high-temperature pyrolysis method and successfully characterized by five-step physico-chemical analysis. By utilizing high resolution analytical surface characterization methods, the chemical states of elements are determined, and the presence of Co-N-x sites is confirmed. ORR activity of a Co-N/MWCNT is found to be auspicious. The maximum number of transferred-electron (n) and the diffusion-limiting current density (j(d)) are calculated as 3.95 and 4.53 mA.cm(-2), respectively. The catalyst is further evaluated under a single-cell test station. The test results show that the current and power density values of Co-N/MWCNT are found superior to those of the commercial Pt/C at the 150 degrees C and 160 degrees C (e.g., 57 vs. 69 mW.cm(-2) at 150 degrees C). Due to some stability issues, it is observed that the performance of the Co-N/MWCNT catalyst is slightly decreased while switching the temperature towards 180 degrees C. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.