Synthesis of Chemically Ordered Pt₃Fe/C Intermetallic Electrocatalysts for Oxygen Reduction Reaction with Enhanced Activity and Durability via a Removable Carbon Coating

Abstract

Recently, PtM (M = Fe, Ni, Co, Cu, etc.) intermetallic compounds have been highlighted as promising candidates for oxygen reduction reaction (ORR) catalysts. In general, to form those intermetallic compounds, alloy phase nanoparticles are synthesized and then heat-treated at a high temperature. However, nanoparticles easily agglomerate during the heat treatment, resulting in a decrease in electrochemical surface area (ECSA). In this study, we synthesized Pt-Fe alloy nanoparticles and employed carbon coating to protect the nanoparticles from agglomeration during heat treatment. As a result, PtFe L1 structure was obtained without agglomeration of the nanoparticles; the ECSA of Pt-Fe alloy and intermetallic PtFe/C was 37.6 and 33.3 m g, respectively. PtFe/C exhibited excellent mass activity (0.454 A mg) and stability with superior resistances to nanoparticle agglomeration and iron leaching. Density functional theory (DFT) calculation revealed that, owing to the higher dissolution potential of Fe atoms on the PtFe surface than those on the Pt-Fe alloy, PtFe/C had better stability than Pt-Fe/C. A single cell fabricated with PtFe/C showed higher initial performance and superior durability, compared to that with commercial Pt/C. We suggest that PtM chemically ordered electrocatalysts are excellent candidates that may become the most active and durable ORR catalysts available.

Platinum Alloy Catalysts for Oxygen Reduction Reaction: Advances, Challenges and Perspectives

“…Compared to disordered Pt 3 Co, intermetallic Pt 3 Co was reported to have 2-fold enhancement in mass activity and 3-fold enhancement in area-specific activity in ORR. To address the agglomeration and sintering issue during high temperature annealing that was required in intermetallic alloy preparation, Jung et al demonstrated the utilization of a carbon layer coating for protection, [45] wherein 1,2-hexadecanediol and Fe (acac) 3 were used as carbon sources. During the thermal treatment, PtÀ Fe alloy was converted into intermetallic alloy and the carbon coating was removed simultaneously.…”

Fe-doped Co3O4@C nanoparticles derived from layered double hydroxide used as efficient electrocatalyst for oxygen evolution reaction

“…Based on the above consideration, it should be a promising pathway to enhance the OER performance by fabrication of uniformly dispersed Co 3 O 4 nanoparticles with doping foreign metals. However, it is hard to fabricate the doping Co 3 O 4 nanoparticles in a facile way because the nanomaterials tend to aggregate owing to its higher surface energy, which usually results in decreased electrochemical surface area (ECSA) and worse electrochemical performance [28][29][30] .…”

Hofmann-like metal–organic-framework-derived PtxFe/C/N-GC composites as efficient electrocatalysts for methanol oxidation

“…It should be noted that these values are 10.3 and 24.2 times higher than those of commercial Pt/C (20%) catalysts because a greater number of active sites in the main phase (Pt 3 Fe) are exposed on the surface of Pt x Fe/C/N-GC-700. 30,31 Results and discussion Powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) were employed to characterize the crystallite morphology and structure of the Pt/Fe-MOFs. The PXRD pattern of the Pt/Fe-MOFs ( Fig.…”