Effect of hybridization of Pt supported mesoporous-CMK-3 into Pt-CB as cathode catalyst on cell performance and durability in proton exchange membrane fuel cell

• Mesoporous carbon molecular sieve, CMK-3 was synthesized using SBA-10.
• Pt nanoparticles were deposited onto CMK-3 and hybridized by different Pt-CB contents.
• An appropriate ratio of Pt-CMK-3/Pt-CB could enhance the cell performance.
• Durability of Pt-CMK-3/Pt-CB hybrid catalyst or Pt-CMK-3 is much better than that of Pt-CB.

Mesoporous carbon molecular sieve, CMK-3 is successfully prepared through the carbonization of hexagonally arrayed mesoporous SBA-15 as a template and Pt nanoparticles are then deposited onto CMK-3. Mesoporous Pt-CB(1 − x)/Pt-CMK-3x hybrid catalysts (x = 0.0, 0.4, 0.5, 0.7 and 1.0) are adopted as a cathode catalyst in polymer electrolyte membrane fuel cell for the purpose of enhancing mass transfer and durability. Transmission electron micrograph and X-ray diffraction micrograph analyses show the uniform dispersion of Pt nanoparticles without any distinct agglomeration through the mesopores of CMK-3 with particle size of ∼2.3 nm. X-ray photoelectron spectroscopy analysis confirms the oxidation state of Pt species deposited onto CMK-3. The electrochemical active surface areas (ECSA) obtained by cyclic voltammetry analysis for various Pt-CB(1 − x)/Pt-CMK-3x are estimated to be 27.4 m2 g−1, 38.9 m2 g−1, 44.7 m2 g−1, 36.9 m2 g−1 and 30.8 m2 g−1 for x = 0.0, 0.4, 0.5, 0.7 and 1.0, respectively. The single cell test shows that the cell performance is highly consistent with ECSA: that is, the cell performance of Pt-CB(0.5)/Pt-CMK-3(0.5) is drastically enhanced by 62% and 322% compared with those of Pt-CMK-3 and Pt-CB alone, respectively. The drastic enhancement in cell performance is attributed to synergistic effect of enhanced mass transfer and fairly good Pt utilization. Accelerated durability test shows a drastic enhancement in durability of Pt-CMK-3 and various Pt-CB/Pt-CMK-3 hybrid catalysts compared to that of Pt-CB. The start-up/shut-down cycling test shows that mesoporous CMK-3 could be an excellent candidate for alternative supporting materials to commercial Pt-CB.

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