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Electro-Design of Bimetallic PdTe Electrocatalyst for Ethanol Oxidation: Combined Experimental Approach and Ab Initio Density Functional Theory (DFT)—Based Study
oleh: Andile Mkhohlakali, Xolile Fuku, Min Ho Seo, Mmalewane Modibedi, Lindiwe Khotseng, Mkhulu Mathe
Format: | Article |
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Diterbitkan: | MDPI AG 2022-10-01 |
Deskripsi
An alternative electrosynthesis of PdTe, using the electrochemical atomic layer deposition (E-ALD) method, is reported. The cyclic voltammetry technique was used to analyze Au substrate in copper (Cu<sup>2+</sup>), and a tellurous (Te<sup>4+</sup>) solution was used to identify UPDs and set the E-ALD cycle program. Results obtained using atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques reveal the nanometer-sized flat morphology of the systems, indicating the epitaxial characteristics of Pd and PdTe nanofilms. The effect of the Pd:Te ratio on the crystalline structure, electronic properties, and magnetic properties was investigated using a combination of density functional theory (DFT) and X-ray diffraction techniques. Te-containing electrocatalysts showed improved peak current response and negative onset potential toward ethanol oxidation (5 mA; −0.49 V) than Pd (2.0 mA; −0.3 V). Moreover, DFT ab initio calculation results obtained when the effect of Te content on oxygen adsorption was studied revealed that the d-band center shifted relative to the Fermi level: −1.83 eV, −1.98 eV, and −2.14 eV for Pd, Pd<sub>3</sub>Te, and Pd<sub>3</sub>Te<sub>2</sub>, respectively. The results signify the weakening of the CO-like species and the improvement in the PdTe catalytic activity. Thus, the electronic and geometric effects are the descriptors of Pd<sub>3</sub>Te<sub>2</sub> activity. The results suggest that Pd<sub>2</sub>Te<sub>2</sub> is a potential candidate electrocatalyst that can be used for the fabrication of ethanol fuel cells.