Pt3M (M: Co, Ni and Fe) Bimetallic Alloy Nanoclusters as Support-Free Electrocatalysts with Improved Activity and Durability for Dioxygen Reduction in PEM Fuel Cells

Abstract

Pt 3 M (M: Co, Ni and Fe) bimetallic alloy nanoclusters were synthesized by a novel and simple chemical reduction approach, and employed as the promising electrocatalyst to accelerate the kinetics of oxygen reduction reaction (ORR) for polymer electrolyte membrane fuel cells. From XRD, the positive shift of diffraction angle confirms the alloy formation between Pt and M and the elemental composition was confirmed by energy dispersive X-ray spectroscopy analysis. The nanocluster morphology and particle size was determined using scanning and transmission electron microscopy analysis. The ORR kinetic parameters for Pt-M electrocatalysts were calculated and compared with reported Pt/C catalysts. Among the Pt-M electrocatalysts, Pt-Co was found to be the most efficient catalyst having the higher mass and specific activity (at 0.9 V vs. RHE) of 0.44 mA/μg and 0.69 mA/cm 2 , respectively. The accelerated durability test reveals that the Pt-M bimetallic alloy nanoclusters retain appreciable surface area and mass activity after 8000 potential cycles confirms good long-term durability, and also competing with the reported benchmark ORR catalysts.

PtM (M = Fe, Co, Ni) Bimetallic Nanoclusters as Active, Methanol-Tolerant, and Stable Catalysts toward the Oxygen Reduction Reaction

“…Hence, the utilization of NCs can both enhance the ORR performance and reduce the materials cost. 16,17 More importantly, the introduction of M (M = Fe, Co, Ni) atoms can hinder the adsorption of methanol, and thus leads to an enhanced methanol tolerance. 18,19 As mentioned above, even if PtM (M = Fe, Co, Ni) bimetallic NCs possess various merits, how to synthesize bimetallic NCs with relatively controllable size via facile methods and how to anchor and disperse PtM (M = Fe, Co, Ni) bimetallic NCs onto a suitable matrix are key issues to ensure durable catalytic performance and stability of bimetallic NCs without any protective agents because NCs possess high surface energy, and it is easy for them to aggregate.…”

“…Among various recently proposed strategies, developing Pt-based bimetallic transition 3d metal M (M = Fe, Co, Ni) nanoclusters (NCs) without any protective agents with diameters of 2–5 nm manifests great potentials in practical applications in that it can dramatically lower the Pt consumption and offer a feasible strategy to design versatile nanostructures with relatively controllable properties. − Furthermore, PtM (M = Fe, Co, Ni) bimetallic NCs demonstrate more satisfactory performance compared with their single counterparts in specific physiochemical properties including electronic, optical sensing, plasmatic, and catalytic properties because of the synergistic effects between the two metals. − In particular, tailoring PtM (M = Fe, Co, Ni) bimetallic electrocatalysts into NCs endows them with a high fraction of low-coordinated surface atoms, and O 2 molecules can be adsorbed and activated more easily on the surface Pt atoms. Hence, the utilization of NCs can both enhance the ORR performance and reduce the materials cost. , More importantly, the introduction of M (M = Fe, Co, Ni) atoms can hinder the adsorption of methanol, and thus leads to an enhanced methanol tolerance. , …”

Ordered Porous TiO2@C Layer as an Electrocatalyst Support for Improved Stability in PEMFCs

“…Moreover, the unique core-shell structure composed of a hollow macroporous core connected with the porous shell in the TiO 2 @C affords fast mass transport and enhanced cycling stability. Such important impacts have been frequently reported in literature for diverse catalysis and electrochemical energy-related applications [34][35][36][37][38][39][40][41][42][43][44][45].…”

Modulating Catalytic Activity and Durability of PtFe Alloy Catalysts for Oxygen Reduction Reaction Through Controlled Carbon Shell Formation

“…Among them, alloying of Pt with transition metals to form a bimetallic structure, Pt−M, has advantages of showing greatly improved activity for the ORR due to the modified electronic structure and physico-chemical properties [3]. On the other hand, these alloy catalysts show much less durability compared to Pt since their 3 d transition metals are prone to dissolution in acidic electrolytes when they are exposed to high potential during long-term operation [19,20,21]. To circumvent this problem, there are several studies devoted to improving the durability of Pt−M alloy catalysts [22,23].…”