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Atomically deviated Pd-Te nanoplates boost methanol-tolerant fuel cells

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Science Advances  29 Jul 2020:
Vol. 6, no. 31, eaba9731
DOI: 10.1126/sciadv.aba9731
  • Fig. 1 Morphology characterization of Pd-Te HPs.

    (A and B) HAADF-STEM images and (C) elemental mappings of Pd-Te HPs. (D) Line scan of single Pd-Te HP. (E) AFM image and (F and G) thickness distributions of Pd-Te HPs.

  • Fig. 2 Structure analysis of Pd-Te HPs.

    (A) SAED pattern of a single HP along the [0001] direction with TEM image. (B) Projection of reconstructed 3D-EDT data along a random direction. (C) Low-magnification HAADF-STEM image. (D and E) Solved crystal structure model viewed along the [0001] and [21¯1¯0] directions. (F to H) High-resolution HAADF-STEM images taken from areas of “F,” “G,” and “H” in (C). Insets in (F) are simulated image with crystal thickness of 190 Å and Fourier diffractogram. (I) p6 symmetry averaged image overlaid with the structure model.

  • Fig. 3 Electrocatalytic performance of Pd-Te HPs/C, commercial Pt/C, and commercial Pd/C for ORR.

    (A) CV curve of Pd-Te HPs/C in 0.1 M KOH solution with a scan rate of 20 mV s−1. (B) ORR polarization curves in O2-saturated 0.1 M KOH with a scan rate of 10 mV s−1 and rotation speed of 1600 rpm, (C) histogram comparison of half-wave potential and mass activity, and (D) ORR polarization curves before and after 20,000 potential cycles of Pd-Te HPs/C, commercial Pt/C, and commercial Pd/C. (E) Chronopotentiometric responses of Pd-Te HPs/C, commercial Pt/C, and commercial Pd/C at 0.90 V versus RHE in O2-saturated 0.1 M KOH. The inset in (E) is elemental mapping of Pd-Te HPs/C after chronopotentiometry for 50,000 s.

  • Fig. 4 Electrocatalytic performance of Pd-Te HPs/C and commercial Pt/C for methanol-tolerant ORR and DMFC.

    The response of (A) Pd-Te HPs/C and (B) commercial Pt/C at different CH3OH concentrations in O2-saturated 0.1 M KOH. (C) Chronoamperometric responses of Pd-Te HPs/C and commercial Pt/C by adding 0.3 M CH3OH (at ~200 s) at 0.75 V versus RHE in O2-saturated 0.1 M KOH. Polarization and power density curves of alkaline DMFC with (D) Pd-Te HPs/C and (E) commercial Pt/C as cathode. (F) Curves of OCV (up) and peak power density (down) varying with CH3OH concentration with Pd-Te HPs/C and commercial Pt/C as cathode.

  • Fig. 5 Spin-polarized DFT computations of Pd-Te HPs/C.

    (A) Geometric structure in main view and side view for Pd20Te7 (0001) facet. Pd is shown in blue, and Te is shown in yellow. (B) Calculated free energy profiles at 0 and 0.87 V for ORR on Pd20Te7 (0001) facet, respectively. (C) Free energies for the possible intermediates on Pd20Te7 HPs during MOR. The most stable intermediates for each step are shown in red. In black are energy levels for free gas molecules. Other intermediates with high energy levels are shown in blue. The optimized structures of the key intermediates are shown above the ORR and MOR free energy diagrams, correspondingly.

Supplementary Materials

  • Supplementary Materials

    Atomically deviated Pd-Te nanoplates boost methanol-tolerant fuel cells

    Ying Zhang, Bolong Huang, Gan Luo, Tu Sun, Yonggang Feng, Yucheng Wang, Yanhang Ma, Qi Shao, Yafei Li, Zhiyou Zhou, Xiaoqing Huang

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