Synergistic effect of Yttrium and pyridine-functionalized carbon nanotube on platinum nanoparticles toward the oxygen reduction reaction in acid medium

Platinum, and platinum containing Yttrium (Y) species nanoparticles (NPs) supported by carbon black, Vulcan XC-72, oxidized multi-walled carbon nanotube, ox.MWCNT, pyridine functionalized multi-walled carbon nanotube, (ox.MWCNT)-Py, were prepared via carbonyl chemical route, followed by heat-treatment. X-ray diffraction (XRD) analyses showed, beside Pt fcc-phase, the presence of Pt_xY alloy in Pt-Y nanoobjects supported onto functionalized MWCNTs. X-ray photoelectron spectroscopy (XPS) revealed, essentially, that Pt surface was decorated by Y₂O₃; therefore, such nanoobjects were labeled Pt-Y. By analyzing the surface atomic ratio of Pt/N and Pt/Y in Pt-Y/(ox.MWCNT)-Py, it is suggested that Pt atoms interact with Y₂O₃, pyridine group, and Y nano-alloying Pt. The transmission electron microscopy (TEM) shows similar mean particle size values, in Pt-Y/Vulcan, Pt-Y/ox.MWCNT and Pt-Y/(ox.MWCNT)-Py, in opposition to Pt NPs supported onto Vulcan, ox.MWCNT and (ox.MWCNT). The surface electrochemistry demonstrated a unique behavior of Pt on Pt-Y/(ox.MWCNT)-Py with respect to other samples. The ORR kinetics of this catalyst was the highest among all the samples, revealing a synergistic effect of Y₂O₃, pyridine functionalization, and nano-alloyed Y alloyed on Pt toward ORR.