Pd–M/C (M = Pd, Cu, Pt) Electrocatalysts for Oxygen Reduction Reaction in Alkaline Medium: Correlating the Electronic Structure with Activity

Abstract

The increasing global needs for clean and renewable energy have fostered the design of new and highly efficient materials for fuel cells applications. In this work, Pd-M (M = Pd, Cu, Pt) and Pt nanoparticles were prepared by a green synthesis method. The carbon-supported nanoparticles were evaluated as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline medium. A comprehensive electronic and structural characterization of these materials was achieved using X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Their electrochemical properties were investigated by cyclic voltammetry, while their activities for the ORR were characterized using steady-state polarization experiments. The results revealed that the bimetallic nanoparticles consist of highly crystalline nanoalloys with size around 5 nm, in which the charge transfer involving Pd and M atoms affects the activity of the electrocatalysts. Additionally, the samples with higher ORR activity are those whose d-band center is closer to the Fermi level.

Titanium–tantalum oxide as a support for Pd nanoparticles for the oxygen reduction reaction in alkaline electrolytes

“…The K-L plots show a linear behavior of the inverse of the current density with the reciprocal of the square root of the rotation speed. By applying the Levich equation [61] to the linear fitting of the experimental data, from the slope (B) we calculate the transferred electron number (n). The diffusion coefficient of oxygen in the electrolyte (D), the cinematic viscosity of the electrolyte (ν), and the bulk concentration of oxygen in the electrolyte (C*) are taken from Ref.…”

Bifunctional Pd‐CeO2 Nanorods/C Nanocatalyst with High Electrochemical Stability and Catalytic Activity for the ORR and EOR in Alkaline Media

“…Nevertheless, it can be observed that over a large potential interval in Figure 7 a), the mass activity of Pd-CeO 2-NR /C is higher than that of Pd/C. Even more, Figure 7 b) shows that despite the presence of the oxide, which may have induced a screening effect on Pd nanoparticles, [49] the specific activity of Pd-CeO 2-NR /C is also higher over the potential range studied. From the results evaluated so far, by comparing the behavior of Pd-CeO 2-NR /C and Pd/C before ADT, the former has the same value of E 1/2 as that of the monometallic.…”

High‐Performance Ordered PdCuFe/C Intermetallic Catalyst for Electrochemical Oxygen Reduction in Proton Exchange Membrane Fuel Cells

“…Studying and developing Pd‐based catalysts is useful in theory and application. Many innovative approaches have been reported for the rational design and synthesis of Pd‐based alloys nanoparticles (NPs) with controlled shape, size, composition, and atomic arrangement . Among these strategies, forming alloys of Pd and transition metal (Fe, Co, Ni, and Cu) is a common approach to improve catalytic performance and stability.…”