I sequentially synthesize Pd nanoparticles less than 10 nm on carbon paper and then Pt thin film or layers on Pd particles by electrodeposition. How to related mass activity or specific activity of Pd-Pt core shell with pure Pt performance in methanol oxidation or just take into account the potential peak shift in cyclic Voltammetry, which involve the d band shift of Pt with Pd?
Unfortunately it is not possible to qualify the the activity of any electrode material on cyclic voltammetry data. The improvement of a electrode material toward a given electrochemical reaction, mainly bimetallic materials, may be caused by geometric, electronic, bifunctional or even a combination of these factors. That is a really deeper study than it is supposed. For instance, I would suggest, as a first approach, to perform X-Ray absorption experiments to observe the variation of the d-orbital vacancy as a consequence of the Pt-Pd combination. This will provide you with information on the electronic configuration of the adsorption site in comparison to pure Pt.
Thanks for your valuable suggestion. X-ray photoelectron spectroscopy is a tool for investigating the d band shift of Pd-Pt catalyst. We do use this method in our study and examine a distinct synergistic effect for Pd-Pt catalyst in cyclic Voltammetry. Electronic configuration of catalyst would change the adsorption energy of Pt by bimetallic materials as you mentioned. I concord with that it is a good means to study the adsorption energy respect to d-band center chemical shift. Do you think that the other way is the strain of lattice constant between two different catalytic elements by XRD? Thank you again.
Yes, XPS is also an important tool for obtaining electronic information from the shift of binding energy of some electrons. However I meant X-Ray Absorption Specstroscopy (XAS) in the EXAFS and XANES regions. With this technique you will check out the vacancy of d-orbitals in Pt, Pd and Au surface sites. I am not sure that XRD could provide valuable information for you in this specific field.
Should compare the effeciencies of the two metal s from kinetic analyses of the. Re action products. Y ou will get some. Idea if there is. a ny char. N
I think that you could do it by CV in a very slow sweep, but the most correct would be through the chronoamperometry. After you could use metal loading or CO stripping to normalize your results (I prefer CO stripping). However, to prove somethings about d band, you need to make a physical characterization of this materials (XRD, XAS,...).
Thanks, Bruno Previdello. It is supposed that chronoamperometry (CA) is typically suitable for decay study of these catalysts in electrochemical reaction to see if the catalyst is durable or not. I believe that a long term decay measurement is necessary, at last.
A serious point of core shell catalyst still remains a problem that how long it could be sustained. Personally, that depends on thickness of shell on the core of catalyst and what overpotential we applied in electrochemical reactions . Normalized current density by loading Pt mass is a popular criterion to compare essential electrochemical characters of catalyst in different research situation. There is another point of electrochemical surface area (ECSA) for Pd and Pt. How to separate the ECSA between Pd and Pt? As you mention by CO stripping in CV?
I don't think so. The peak potential changes for Pd and Pt during the CO stripping, but in alloy case the peak should be shift between this ones (d band effect) depending of the shell thickness.
Just curious about this experiment. You first synthesized Pd 10nm nanoparticles on carbon paper, which I thought that is very rough made from woven carbon fibers, then you electrodeposited Pt on this Pd NPs decorated Carbon paper. Is this possible to produce Pd-Pt core-shell NPs on carbon paper by this method? I mean, Pd NPs already attached onto carbon fiber, and when you electrodeposite Pt, maybe the resulted is Pt islands on this sample, not homogenously, also not as thin film. Did you check by SEM and TEM?
Second point, breaking C-H bond in methanol oxidation means that you need maybe in situ FTIR simultenously with your CV to confirm that the product is up to CO2 and how much.
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