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

Abstract

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-PtRuCPtFe/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.

CO Tolerance and Stability of Proton Exchange Membrane Fuel Cells with Nafion® and Aquivion® Membranes and Mo‑Based Anode Electrocatalysts

“…PtMo supported (20 wt.%) on Vulcan XC-72R (Cabot, previously heat-treated as described above) was prepared following a previously described preparation procedure. [10][11][12] The method is essentially the same as that used for incorporation of Pt on MoO 2 …”

“…The materials and method for the preparation of MEA and its components are described in details elsewhere. [8][9][10][11][12][22][23][24] The gas diffusion layer comprised a mixture of carbon powder (Vulcan XC-72, Cabot) with 15 wt.% of polytetrafluoroethylene (PTFE, TE 3893, DuPont) placed on both sides of the carbon cloth substrate (Panex 30, Zoltek), each with a carbon + PTFE load of 3 mg cm -2 . The catalyst layer was deposited on one of the faces of the diffusion layers using a homogeneous suspension formed by appropriated amounts of Nafion ® (Aldrich, 5 wt.%) or Aquivion ® (D9825BS, Aldrich, diluted to 5 wt.% in water), the electrocatalysts (PtMo/C, Pt/MoO 2 -C, and Pt/C) and isopropanol.…”

“…These experiments were performed using a potentiostat-galvanostat (Solartron 1285) coupled to the standard fuel cell hardware, with the anode fed with argon functioning as the working electrode, while the cathode was constantly fed with hydrogen and used as both, counter electrode and the reversible hydrogen reference electrode (RHE). [9][10][11][12] Accelerate aging test of these catalysts constituted of the anode potential cycling between 0.1 and 0.7 V, at a scan rate of the 50 mV s -1 . The cycling was performed at room temperature up to 5000 cycles.…”

“…5, 2018 Several previous works have been focused on developing CO tolerant catalysts. [8][9][10][11][12] For carbon supported bimetallic PtMo (60:40, Pt:Mo atomic proportion) materials, it has been found that a heat treatment at 600 °C under hydrogen atmosphere was very much beneficial to improve the stability and the activity for the hydrogen oxidation, either in the absence and in the presence of CO. Among a series of tungsten-based catalysts, tungsten carbide supported Pt catalyst showed reasonable performance and reliable stability in comparison to simple carbon supported PtW catalyst, although an uneven level of catalytic activity towards H 2 oxidation in the presence of CO is observed for the former as compared to Mo containing catalyst.…”

Activity and Stability of Dispersed Multi Metallic Pt-based Catalysts for CO Tolerance in Proton Exchange Membrane Fuel Cell Anodes

“…Nowadays, it is generally accepted that the association between Pt and a second metal improves the electrocatalytic activity, because it allows the catalyst to perform the oxidative removal of adsorbed CO. Also, these bimetallic catalysts have further been modified either with a third or fourth element for the purpose of improvements in the activity and stability. More recently, it has been found that the addition of Ru and/or Fe to the PtMo/C catalyst leads to an improvement in the activity towards H 2 oxidation in the presence of CO as well as in the stability of the resultant catalysts (Hassan et al 2014c). In subsequent work it has been shown that the addition of Au nanopartilces to the lattice of PtRu catalyst causes a decrease in the onset potential for methanol oxidation in addition to the gain in stability up to 10,000 voltammetric cycles.…”