ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Atomic molar ratio optimization of carbon nanotube supported PdAuCo catalysts for ethylene glycol and methanol electrooxidation in alkaline media

Berdan Ulas, Aykut Caglar, Arif Kivrak, and Hilal Kivrak

Van Yuzuncu Yil University, Van, Turkey

E-mail: hilalkivrak@yyu.edu.tr

Abstract: In this study, carbon nanotube supported Pd, PdAu, and PdAuCo electrocatalysts (Pd/CNT, PdAu/CNT, and PdAuCo/CNT) were synthesized via NaBH₄ reduction method at varying molar atomic ratios to investigate their performance for methanol and ethylene glycol electrooxidation in alkaline media. The characterization of the as-prepared catalysts was performed using X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, N₂ adsorption–desorption, and small-angle X-ray-scattering analysis. From the physical characterization results, it was seen that PdAuCo/CNT catalysts were successfully prepared. X-ray photoelectron spectroscopy results showed that Pd and Au atoms employed in the preparation of the catalysts exist mainly in their elemental state. X-ray diffraction results indicated the formation of a new phase. Furthermore, the mean particle size of Pd₅₀Au₃₀Co₂₀/CNT was determined as 7.9 and 8.7 nm using small-angle X-ray scattering and transmission electron microscopy analyses. Pd₅₀Au₃₀Co₂₀/CNT demonstrated the type V adsorption isotherms with H1-type hysteresis, which indicates the mesoporous structure of the catalyst. Electrocatalytic activity of the catalysts for ethylene glycol and methanol electrooxidation was investigated with cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalytic activity of Pd₅₀Au₃₀Co₂₀/CNT was determined as 262 and 694 mA/mg Pd for methanol and ethylene glycol electrooxidation. In accordance with cyclic voltammetry and electrochemical impedance spectroscopy results, Pd₅₀Au₃₀Co₂₀/CNT possesses the highest electrocatalytic activity for both electrooxidation.

Keywords: PdAu ; PdAuCo ; Alloy ; Ethylene glycol ; Methanol ; Electrooxidation 

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-018-0601-9

Chemical Papers 73 (2) 425–434 (2019)