Investigating the durability of a direct methanol fuel cell equipped with commercial Platinum Group Metal-free cathodic electro-catalysts

For the first time a long-term (500 h) durability study in direct methanol fuel cells (DMFCs) is carried out on a Platinum Group Metal-free (PGM-free) cathodic electro-catalyst commercially available on market. The electro-catalyst is tested for 500 h at a fixed cell voltage (0.3 V), recording the polarization curves during the operation. A drastic decrease in performance is observed after the first 100 h (from 220 to 75 mA cm(-2)); afterwards, the decrease is flatter, passing from 75 to 25 mA cm(-2) (at 500 h). The causes of this performance degradation are investigated by postmortem physicochemical analyzes, such as X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with X-ray energy dispersive analysis (EDX). Possible reasons of degradation are indicated to be PGM-free catalyst aggregation, carbon and nitrogen species decrease, Ruthenium dissolution and migration from the anode to the cathode, poisoning both membrane and cathode catalyst. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this study, a long-term durability investigation was conducted on a Platinum Group Metal-free cathodic electro-catalyst for direct methanol fuel cells. Results showed a significant performance decrease after 100 hours of operation, with potential causes including catalyst aggregation, reduction of carbon and nitrogen species, and Ruthenium migration leading to poisoning of the membrane and cathode catalyst.