Effect of Addition of Ru and/or Fe in the Stability of PtMo/C Electrocatalysts in Proton Exchange Membrane Fuel Cells

In this work, the activity, stability, and CO tolerance of ternary and quaternary electrocatalysts formed by PtMo/C-PtFe/C, PtMo/C-PtRu/C, and PtMo/C-PtRuC-PtFe/C were studied in the anodes of proton exchange membrane fuel cells (PEMFCs). Cyclic voltammetry (CV) was used to study the surface characteristics and stability of the electrocatalysts and polarization curves were used to investigate the performance of PEMFC anodes supplied with pure hydrogen and hydrogen containing 100 ppm CO. Online mass spectrometry (OLMS) and CO stripping experiments were conducted to investigate the CO tolerance mechanism. The PtMo/C-PtRu/C-PtFe/C, PtMo/C-PtFe/C, and PtMo/C-PtRu/C electrocatalysts showed better performance for the oxidation of hydrogen in the presence of hydrogen containing 100 ppm CO as compared to the PtMo/C electrocatalyst. It was found that the partial dissolution of Mo, Ru, and Fe, and their migration/diffusion from the anode to the cathode occur during a CV cycling from 0.1 to 0.7 V vs. RHE at a scan rate of 50 mVs-1 up to total of 5,000 cycles. The results also showed that the stability of PtMo/C-PtRu/C-PtFe/C, PtMo/C-PtFe/C, and PtMo/C-PtRu/C are better than that of PtMo/C.