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CaO-Promoted Graphene-Supported Palladium Nanocrystals as a Universal Electrocatalyst for Direct Liquid Fuel Cells

Shamraiz, Umair, Ahmad, Zeeshan, Raza, Bareera, Badshah, Amin, Ullah, Sajid, Nadeem, Muhammad Arif
ACS applied materials & interfaces 2020 v.12 no.4 pp. 4396-4404
Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, atomic absorption spectrometry, calcium oxide, carbon monoxide, catalysts, catalytic activity, electrochemistry, energy-dispersive X-ray analysis, ethanol, formic acid, fuel cells, graphene, graphene oxide, liquids, methanol, nanocrystals, oxidation, palladium, scanning electron microscopy, sodium borohydride, transmission electron microscopy
Here, we present the fabrication of a reduced graphene oxide-supported PdCa (PdCa/rGO) alloyed catalyst via a NaBH₄ reduction method for direct alcohol fuel cells in basic medium and direct formic acid fuel cells in acidic medium. Powder X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller, inductively coupled plasma mass spectrometry, and Raman spectroscopy are used to characterize the PdCa/rGO catalyst. We proved that the calcium oxide significantly enhances the electrocatalytic methanol, ethanol, and formic acid oxidation over the Pd/rGO surface. The obtained mass activities for PdCa/rGO are 4838.06, 4674.70, and 3906.49 mA mg–¹ for formic acid, methanol, and ethanol, respectively. Long-term stability, high activity, and high level of tolerance to CO poisoning of the PdCa/rGO electrocatalyst are attributed to the presence of calcium oxide. These results prove that the PdCa/rGO catalyst has improved electrocatalytic performance for the oxidation of formic acid, methanol, and ethanol with reference to the Pd/rGO.