Dendrite-Embedded Platinum–Nickel Multiframes as Highly Active and Durable Electrocatalyst toward the Oxygen Reduction Reaction

Abstract

Pt-based nanoframe catalysts have been explored extensively due to their superior activity toward the oxygen reduction reaction (ORR). Herein, we report the synthesis of Pt-Ni multiframes, which exhibit the unique structure of tightly fused multiple nanoframes and reinforced by an embedded dendrite. Rapid reduction and deposition of Ni atoms on Pt-Ni nanodendrites induce the alloying/dealloying of Pt and Ni in the overall nanostructures. After chemical etching of Ni, the newly formed dendrite-embedded Pt-Ni multiframes show an electrochemically active surface area (ECSA) of 73.4 m g and a mass ORR activity of 1.51 A mg at 0.93 V, which is 30-fold higher than that of the state-of-the-art Pt/C catalyst. We suggest that high ECSA and ORR performances of dendrite-embedded Pt-Ni multiframes/C can be attributed to the porous nanostructure and numerous active sites exposed on surface grain boundaries and high-indexed facets.

Fine‐Tuning Intrinsic Strain in Penta‐Twinned Pt–Cu–Mn Nanoframes Boosts Oxygen Reduction Catalysis

“…Fabricating Pt‐based nanoframes (NFs) with highly open structure is an effective strategy to tackle this problem due to the large surface area‐to‐volume ratio, high utilization efficiency of surface active sites, and lower consumption of Pt. To date, numerous state‐of‐the‐art Pt‐based NFs have exhibited remarkably enhanced performance in fuel cells toward the cathodic ORR . Particularly, the Pt‐based NFs with abundant surface defects usually show superior catalytic activity .…”

Shape Control of Monodispersed Sub‐5 nm Pd Tetrahedrons and Laciniate Pd Nanourchins by Maneuvering the Dispersed State of Additives for Boosting ORR Performance

“…Specifically, (1) the ultrasmall size of sub-5 nm Pd tetrahedrons is the most simple yet important feature to guarantee high atom utilization efficiency. [44,45] 2) The 3D self-supported structure is less susceptible to dissolution, Ostwald ripening, and agglomeration, thus guaranteeing the structural stability. [15,43] Meanwhile, the Pd LUs also exhibited enhanced ORR/FAOR activity and stability than commercial Pd black, which possibly due to the following reasons: 1) The highly branched structure not only provides abundant active sites on the steps, ledges and kink sites, but also facilitates mass diffusion and transport during the catalytic reaction, which in turn promotes the reaction kinetics.…”

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

“…[38] Characterizations showed 1 nm thickness and more than 100 nm length of the nanowires by average ( Figure 5), with individual nanowire being composed of roughly six atomic layers. These Pt 3 Ni nanowires had a mass activity of 0.546 A/ mg Pt at 0.9 V. Kwon et al synthesized a dendrite-embedded multi-frame highly porous PtÀ Ni catalyst by precisely controlling nucleation of dendrite and chemical etching, [41] which exposed (211) and (311) high indexed facets ( Figure 6). This PtÀ Ni multi-frame alloy nanostructure catalyst was reported with a high ECSA of 73.4 m 2 /g Pt and an exceptionally high mass ORR activity of 5.03 A/mg Pt at 0.9 V. Wang et al prepared three dimensional porous PtAg hollow nanochain networks with a scalable one-pot synthesis.…”

“…(c) HAADF-STEM image and elemental mapping of PtÀ Ni nanoframes. Reproduced with permission [41]. Copyright 2018, American Chemical Society.…”