A Long-Term Stability Study of Co-Pc-Modified Nanosilver for Anion Exchange Membrane Fuel Cells

This study investigated the modification of nanosilver (Ag) by Co-Pc (phthal–cyanine) and the synergistic effect of Ag-Co/CNT (carbon nanotube) for the long-term stability of AEMFCs (anion exchange membrane fuel cells). This study also aimed to use non-precious metal catalysts on both the cathode and anode to reduce the catalyst costs. Through a simple and efficient chemical synthesis method, a composite catalyst consisting of Co-Pc-modified Ag/CNT was successfully prepared and characterized for its structure and composition. Co-Pc and Ag were chosen for their high durability and catalytic activity in fuel cells, combined with a multi-wall carbon nanotube (MWCNT) as a carrier for the cathode catalyst, and the anode catalyst used Pd-CeO2/C. The performance of the cell module was tested based on a commercial anion exchange membrane (X37-50RT). The experiment focused on different synthesis times and ratios of catalyst and ionomer, observing the enhancement in Co on the active sites of Ag/CNT. Finally, the cell performance was tested for the optimal loading amount. It was observed that when the loading of the nanosilver–cobalt/carbon nanotube (Ag-Co/CNT) is 1 mg/cm2, the highest power density is 434.1 mW/cm2. Through 100 cycles of testing, only an 18% decrease was observed, while the decrease in open circuit voltage was approximately 4.6%. Compared to nanosilver (Ag/CNT), the Co-Pc-modified nano-Ag with the degradation rate has significantly slowed down, and its catalytic activity has also improved significantly. The enhanced stability of this synergistic effect is mainly attributed to the introduction of cobalt metal, which prevents excessive fusion of nano-Ag particles and surface oxidation, effectively maintaining durability in catalytic activity.