Blog
About

45
views
0
recommends
+1 Recommend
0
shares
  • Review: found
Is Open Access

Review of 'Active and Stable Platinum/Ionic Liquid/Carbon Nanotube Electrocatalysts for Oxidation of Methanol'

Bookmark
4
Average rating:
    Rated 4 of 5.
Level of importance:
    Rated 4 of 5.
Level of validity:
    Rated 4 of 5.
Level of completeness:
    Rated 4 of 5.
Level of comprehensibility:
    Rated 4 of 5.
Competing interests:
None

Reviewed article

  • Record: found
  • Abstract: found
  • Article: found
Is Open Access

Active and Stable Platinum/Ionic Liquid/Carbon Nanotube Electrocatalysts for Oxidation of Methanol

(2014)
Platinum (Pt) nanoparticles (NPs) on carbon nanotubes (CNTs) from PtCl62– ions through a facile ionic liquid (IL)-assisted method has been developed and used for methanol oxidation. 1-Butyl-3-methylimidazolium (BMIM) with four different counter ions (PF6–, Cl–, Br–, and I–) have been tested for the preparation of Pt/IL/CNT nanohybrids, showing the counter ions of ILs play an important role in the formation of small sizes of Pt NPs. Only [BMIM][PF6] and [BMIM][Cl] allow reproducible preparation of Pt/IL/CNT nanohybrids. The electroactive surface areas of Pt/[BMIM][PF6]/CNT, Pt/[BMIM][Cl]/CNT, Pt/CNT, and commercial Pt/C electrodes are 62.8, 101.5, 78.3, and 87.4 m2 g-1, respectively. The Pt/[BMIM][Cl]/CNT nanohybrid-modified electrodes provide higher catalytic activity (251.0 A g–1) at a negative onset potential of -0.60 V than commercial Pt/C-modified ones do (133.5 A g–1) at -0.46 V. The Pt/[BMIM][Cl]/CNT electrode provides the highest ratio (4.52) of forward/reverse oxidation current peak, revealing a little accumulation of carbonaceous residues.
    Bookmark

    Review information

    10.14293/S2199-1006.1.SOR-CHEM.AYZQJS.v1.RQBAES

    This work has been published open access under Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com.

    Review text

    The authors write (p2, c1, l 4) that ‘The BMIM-based ILs were adsorbed onto the surfaces of CNTs …’ How did they ensure that the CNT’s are appropriately covered with IL? Can the surface coverage be quantified?
    The authors have provided detailed characterization of the electrodes and claim reactivity in MOR. Have they also performed and measured the performance of their electordes in MOR?

    Minor remarks:
    P1, c2, l5: Please explain what is meant by CO and COH as these abbreviations can be misunderstood. Should COH be CHO (aldehyde) and CO should be C=O (carbonyl)?

    P1, bottom: rewrite:
    Having excellent properties of good chemical and thermal sta- bility, almost negligible vapor pressure, good electrical con- ductivity, and a wide electrochemical window [18, 19], ionic liquids (ILs) have been found useful for the modification of CNTs [1, 20].

    Ionic liquids (ILs) have been found useful for the modification of CNTs [1, 20] as they have excellent properties of good chemical and thermal stability, negligible vapor pressure, good electrical conductivity, and a wide electrochemical window [18, 19].

    Comments

    We would like to thank the referee’s for their valuable comments on our manuscript entitled “Active and stable platinum/ionic liquid/carbon nanotube electrocatalysts for oxidation of methanol (DOI: 10.14293/S2199-1006.1.SORCHEM.AYZQJS.v1). We have revised the manuscript according to the referee’s comments. 

    Response to the reviewers:

    Reviewer 1 (Dr. Thomas Wirth)

    1) The authors write (p2, c1, l 4) that ‘The BMIM-based ILs were adsorbed onto the surfaces of CNTs …’ How did they ensure that the CNT’s are appropriately covered with IL? Can the surface coverage be quantified?

    Response: We noted that capacitive current of the CNT electrodes decreased greatly after treatment with ILs, showing that CNTs are covered with ILs. However, it is difficult to estimate the amount of IL covered on the surfaces of CNTs and its surface coverage because only CNT/IL electrodes do not undergo any Faradaic or charge transfer process. Relative to a commercial Pt/C electrode, PT/CNT/IL nanohybrid electrodes exhibited all the characteristic peaks. We have calculated the electrochemical surface area (EASA) value of the platinum nanoparticles adsorbed on the surfaces of CNT/ILs with different counter ions using the Pt loading (mg cm-2) in the electrode and by integrating the charges associated with the hydrogen adsorption–desorption peaks (Q, mC cm-2) and assuming 210 μC cm-2 needed for a monolayer of H as-atoms in Figure 3A [42] (see P. 5). The EASAs of as-prepared Pt/[BMIM][PF6]/CNT, Pt/[BMIM][Cl]/CNT and Pt/CNT nanohybrids and commercial Pt/C NPs are 62.8, 101.5, 78.3, and 87.4 m2 g-1, respectively. The results reveal that the counterions of ILs affected the adsorbed amounts of Pt NPs, mainly because the species of anions, cations, and the length of the lateral alkyl groups on the heterocyclic rings affects the physicochemical properties of ILs [27].

    2) The authors have provided detailed characterization of the electrodes and claim reactivity in MOR. Have they also performed and measured the performance of their electrodes in MOR?

    Response: We haven’t performed and measured the single cell polarization curves of the electrodes for MOR in a complete DMFC set up. We have tested the MOR activity of Pt/[BMIM][PF6]/CNT, Pt/[BMIM][Cl]/CNT, and Pt/CNT nanohybrids relative to a commercial Pt/C NPs modified electrode in a three electrode electrochemical cell using 0.5 M KOH containing 0.5 M methanol as electrolyte. We have also tested the durability of all these electrodes for 20,000s. Our results reveal that the nanohybrid electrodes have great potential to be used in DMFCs.

    3) P1, bottom: rewrite:

    Having excellent properties of good chemical and thermal stability, almost negligible vapor pressure, good electrical conductivity, and a wide electrochemical window [18, 19], ionic liquids (ILs) have been found useful for the modification of CNTs [1, 20].

    Ionic liquids (ILs) have been found useful for the modification of CNTs [1, 20] as they have excellent properties of good chemical and thermal stability, negligible vapor pressure, good electrical conductivity, and a wide electrochemical window [18, 19].

    Response: The above sentence has been rewritten as suggested.

    Submitted on behalf of Professor Huan-Tsung Chang,

     

    2015-09-15 08:08 UTC
    +1

    Comment on this review