High performance of the novel Pd CeO2-NR/C (cerium oxide nanorods) nanocatalyst for the oxidation of C1, C2 and C3 organic molecules for fuel cells applications

Abstract

Cerium oxide nanorods treated at 200 (CeO2-NR2) and 400 °C (CeO2-NR4) were used to synthesize of PdCeO2-NR2/C and PdCeO2-NR4/C nanocatalysts to promote the Methanol, Ethanol, Ethylene Glycol and Glycerol Oxidation Reactions (MOR, EOR, EGOR and GOR, respectively). The crystalline nanocatalysts had morphology of agglomerated Pd nanoparticles dispersed on Vulcan and on the nanorods as well. The polarization curves in 0.5 M KOH showed that the catalytic activity decreases in all reactions in the order PdCeO2-NR4/C > PdCeO2-NR2/C > Pd/C, which confirmed the synergetic effect of the nanorods on the catalytic behavior of Pd, particularly after heat treatment at 400 °C. The highest mass current density has been obtained from the EGOR (jf = 6661 mA mgPd−1) with the PdCeO2-NR4/C nanocatalyst, which catalyzed the reaction with an onset potential (Eonset) of −0.26 V/SHE. Meanwhile, the EOR was promoted with the most negative Eonset (−0.40 V/SHE), delivering 5719 mA mgPd−1, also using PdCeO2-NR4/C. Therefore, considering electrocatalysis parameters for fuel cells applications, the oxidation of C2H6O2 and C2H5OH showed advantages using PdCeO2-NR4/C.