Ga–Doped Pt–Ni Octahedral Nanoparticles as a Highly Active and Durable Electrocatalyst for Oxygen Reduction Reaction

Abstract

Bimetallic PtNi nanoparticles have been considered as a promising electrocatalyst for oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) owing to their high catalytic activity. However, under typical fuel cell operating conditions, Ni atoms easily dissolve into the electrolyte, resulting in degradation of the catalyst and the membrane-electrode assembly (MEA). Here, we report gallium-doped PtNi octahedral nanoparticles on a carbon support (Ga-PtNi/C). The Ga-PtNi/C shows high ORR activity, marking an 11.7-fold improvement in the mass activity (1.24 A mg) and a 17.3-fold improvement in the specific activity (2.53 mA cm) compared to the commercial Pt/C (0.106 A mg and 0.146 mA cm). Density functional theory calculations demonstrate that addition of Ga to octahedral PtNi can cause an increase in the oxygen intermediate binding energy, leading to the enhanced catalytic activity toward ORR. In a voltage-cycling test, the Ga-PtNi/C exhibits superior stability to PtNi/C and the commercial Pt/C, maintaining the initial Ni concentration and octahedral shape of the nanoparticles. Single cell using the Ga-PtNi/C exhibits higher initial performance and durability than those using the PtNi/C and the commercial Pt/C. The majority of the Ga-PtNi nanoparticles well maintain the octahedral shape without agglomeration after the single cell durability test (30,000 cycles). This work demonstrates that the octahedral Ga-PtNi/C can be utilized as a highly active and durable ORR catalyst in practical fuel cell applications.

Carbon‐Free Nanocoral‐Structured Platinum Electrocatalyst for Enhanced Methanol Oxidation Reaction Activity with Superior Poison Tolerance

“…Those (111), (200), and (220) peaks are face centered cubic and consistent with the other reported works . The ncs‐Pt showed high‐index facets (200), (210), (211), and (300) compared to other reported works . This consequently leads to higher catalytic activity due to the presence of high‐density atomic steps, ledges, and kinks .…”

“…[31] The ncs-Pt showed high-index facets (200), (210), (211), and (300) compared to other reported works. [10,16,[32][33][34][35] This consequently leads to higher catalytic activity due to the presence of high-density atomic steps, Articles ledges, and kinks. [36] Moreover, at 2θ values of 38.35°and 44.46°t wo diffraction patterns appeared which can be assigned to Au (111) and Au (200), respectively; which probably occurred due to the Au coated substrate.…”

Surface and Interface Control in Nanoparticle Catalysis

“…100 A recent study by Cho and co-workers compared the morphological and compositional evolutions of Pt−Ni octahedra with and without Ga modification ( Figure 7b). 107 It revealed that the majority of Pt−Ni particles incorporated with <2 at. % of Ga maintained their octahedral shape after 30k cycles, while the Pt−Ni counterparts became spherical after only 4k cycles.…”

“…2020, 120, 1184−1249 maintaining the octahedral shape in a long-term electrochemical measurement. 100,107,112 The addition of Mo has been demonstrated to suppress the dissolution of Ni in acidic media. 113 In Mo-doped Pt 3 Ni octahedra, DFT calculations suggested that there is a strong tendency for Mo to segregate onto vertex sites of octahedra, stabilizing both Ni and Pt atoms through the formation of relatively strong Mo−Pt and Mo−Ni bonds.…”

Synthesis of Au@Pt Core—Shell Nanoparticles as Efficient Electrocatalyst for Methanol Electro-Oxidation

“…In addition, the Pt-based catalysts are easily poisoned by the generation of intermediates of carbon monoxide (CO) during the electrooxidation reaction of methanol, which propitiates complete cuts down the electrocatalytic activity and stability of the catalysts [6]. Substantial investigation has been directed toward development of new catalysts via alloying of Pt with other less expensive metals such as Pd, Ag, Au, Cu, etc., either as bimetallic alloys or core–shell architecture in order to reduce the Pt-utlization and, at the same time, to enhance significantly the electrocatalytic activity [7,8,9]. One promising strategy is to design a catalyst comprising of Pt-monolayer onto a less expensive metallic substrates (Pd, Ag, Au, Ir, Co, etc.)…”