Data that support the structural, chemical and morphological characterization and its influence on the electrochemical performance of stabilized PdxPt1-x alloys as electrode materials for methanol oxidation in alkaline medium

Structural, compositional, morphological and electrochemical characterization are important to determinate the influence of platinum in the methanol oxidation in alkaline media. These data and analysis support the research article catalytic performance of alloyed PtxPd1-x nanostructures supported on Vulcan XC-72R for the methanol oxidation in alkaline medium [1]. The data here presented included changes in the chemical composition, structure and microstructure. Also, complement data of cyclic voltammograms during activation in alkaline media as well as in presence of 1 M CH3OH to observe CO tolerance and Electrochemical Impedance Spectroscopy measurements at two different overpotentials (0.2 and 0.3 mV) on the onset potential for methanol electro-oxidation are published in this paper. The data can be used as a reference to determinate the effect of added different amounts of Pd to Pt/C catalysts, using an organometallic compounds method and octylamine as stabilizer. The data provided in this article have not been previously published and are available to enable critical or extended analyses.

Alkaline media Pt base catalysts Organometallic method voltammograms during activation in alkaline media as well as in presence of 1 M CH 3 OH to observe CO tolerance and Electrochemical Impedance Spectroscopy measurements at two different overpotentials (0.2 and 0.3 mV) on the onset potential for methanol electro-oxidation are published in this paper. The data can be used as a reference to determinate the effect of added different amounts of Pd to Pt/C catalysts, using an organometallic compounds method and octylamine as stabilizer. The data provided in this article have not been previously published and are available to enable critical or extended analyses. © 2020 The Author(s

Data format
Raw, filtered, fitted curves and analyzed data.

Experimental factors
The chemical and microstructural data were acquired on synthesized samples containing different amounts of Pd (30, 50 and 70 wt %) in Pt catalysts. The electrochemical data were obtained using 50th potential cycles for stabilization, and 50th cycles in presence of methanol at scan rate of 10 mV s À1 . The EIS measurements were acquired at two different over potentials (0.2 and 0.3 mV) on the onset potential for methanol electro-oxidation.

Experimental features
The relationship between chemical, structural morphological and electrochemical performance of Pt x Pd 1-x electrode materials The data were acquired in the as-prepared samples without special treatment. Data source location XPS spectra were taken at Centro de Nanociencias y Nanotecnología, Carr. Tijuana-Ensenada km 107, Playitas, 22,860, Ensenada B.C. TEM images were taken at the Centro de Nanociencias micro y Nanotecnologías del Instituto Polit ecnico Nacional C.P. 07300 M exico, DF, M exico. CV, EIS techniques and XRD patterns were collected at Centro de investigaci on en Ciencia Aplicada y Tecnología Avanzada del Instituto Polit ecnico Nacional, C.P. 89600 Altamira, Tamaulipas, M exico.

Data accessibility
All data are available with this article In press.

Value of the Data
The data are valuable because show changes in the crystallite size with different amounts of Pd to Pt/C catalysts when an organometallic approach is used in presence of octylamine as stabilizer.
The data also show differences in the nominal composition due to the formation of surface oxide compounds. The data can be used to correlate microstructure with the electrochemical performance. The data could be used to obtain new electrode materials for Methanol oxidation reaction in alkaline media.

Data
The data set of the deconvolution XRD to separate the signal of carbon from Pt x Pd 1-x bimetallic materials and used to determinate the crystallite size is shown in Fig. 1aec. Small changes in the intensities and widening with the amount of Pd were observed, which provokes a reduction in the crystallite size. Fig. 2 displays XPS survey spectra recorded for the surface of as-obtain mono-and bi-metallic materials. From these spectra, the range of binding energy for each metal composition in the high resolution was determinate and observed changes in the electronic properties during alloy formation [2]. Fig. 3 shows the semispherical morphology of the Pt x Pd 1-x nanostructures and the average particle size, using at least 10 particles [3]. Fig. 4 shows the CV diagrams realized for the stabilization of the electrode materials in N 2 purge KOH (1 M) electrolyte during 50th potential cycles. The synergistic effect by the Pd addition is only observed with a nominal composition of Pt 30 Pd 70, which it is also most stable than the other electrodes [4].
In Fig. 5, it is seen the electrocatalytic behavior of the mono-and bi-metallic materials on MOR and its evolution after 50th potential cycles [5].

Preparation of electrode materials
The catalysts were prepared by ligands displacement of organometallic compounds [6]. The metallic catalysts were prepared in-situ on Vulcan Carbon (XC 72R) which was adjusted to obtain a 10 wt% of metallic load and 90 wt% of support. The bimetallic precursors Pt 2 (dba) 3 and Pd(dba) 2 were synthesized from K 2 PtCl 4 and Pd(dba) 2 . The precursors were mixed with THF anhydrous in a Fisher-Porter reactor, for starting the reaction, the reactor was filled with H 2 at 3 bar, for 20 hours. Then, the solution was concentrated to separate the metallic powders, purified with anhydrous pentane and dried under reduced pressure. All the reagents were acquired from Sigma-Aldrich, Inc. and specific details of the experimental procedure were presented in reference [1].

Microstructure and chemical characterization
Powders were characterized by XRD (Bruker Advanced D8) with a Lynxeye detector and Cu Ka radiation (l ¼ 0.15406 nm) at a range of 20 e100 (2q) at 40 kV and 40 kA and a scan rate of 0.021 Fig. 3. HRTEM morphologies of the mono and bimetallic nanocatalysts obtained from ligand displacement method and its corresponding average particle size. min À1 . The microstructure of the as-synthesized Pt x Pd 1-x powders was investigated by means of a JEM-ARM200CF, JEOL electron microscope, operating at 200 kV.
The chemical composition of the films was characterized by XPS using a commercial VG Microtech Multilab ESCA 2000 with a CLAM MCD detector, Al Ka radiation (1486.6 eV), operating at 1 Â 10 À8 Torr. Survey scans were obtained in the range of 0e1400 eV, with an energy step of 1.0 eV, and pass energy of 100 eV. Collected data were analyzed with a Shirley background subtraction, performed with a Gaussian-Lorentzian profile.

Electrochemical characterization
Electrochemical experiments were carried out in a standard three-electrode cell at room temperature. After preparation, the electrodes were rinsed, and their surface protected by a drop of water before being transferred through the air to the electrochemical cell. A platinum mesh was used as counter electrode and Hg/HgSO 4 as reference electrode. All the working electrodes had a nominal mass of 0.1 mg cm À2 .
The activation of electrodes was realized by cyclic voltammetry using an AUTOLAB (Metrohm, 50,404) pontentiostat/galvanostat in the potential range from À1.200 V to 700 V vs Hg/HgSO 4 in 1.0 M KOH deareated solution in absence and presence of methanol (1.0 M) at scan rate of 10 mV s À1 . To adequate comparison with the literature, all the potentials were converted to the scale of normal hydrogen electrode (NHE).