Controlling Pt Crystal Defects on the Surface of Ni–Pt Core–Shell Nanoparticles for Active and Stable Electrocatalysts for Oxygen Reduction

Abstract

A strategy of direct growth of Pt on Ni was used to create and control Pt crystal defects on the surface of Ni–Pt core–shell nanoparticles. The control over the types of defects was easily achieved by changing the surfactant system. In this work, two types of crystal defects have been introduced into Ni–Pt core–shell nanoparticles: polycrystalline shells with multiple grain boundaries and step-edge shells with undercoordinated atoms at corners and steps. We show that the step-edge shell has a higher specific activity for the oxygen reduction reaction (ORR), while the thinner polycrystalline shell results in a higher activity per mass and stability. Our results suggest that Ni–Pt core–shell nanoparticles with a thin Pt shell that have high density of crystal defect should be targeted for high performance ORR catalysts.

Faceted Branched Nickel Nanoparticles with Tunable Branch Length for High‐Activity Electrocatalytic Oxidation of Biomass

“…To synthesize uniform branched Ni nanoparticles, it is important to decompose the Ni precursor at a pressure of > 3 bar H 2 gas to ensure that Ni preferentially grows in the metastable hcp crystal phase. [20][21][22][23] A solution of Ni(acac) 2 , hexadecylamine, trioctylphosphine, and mesitylene was added to monodisperse fcc Au seeds of 8.7 AE 0.9 nm (Supporting Information (SI), Figure S1) and reacted at 140 8C for 24 h under 5 bar H 2 in an autoclave . The transmission electron microscopy (TEM) image in Figure 1 a shows the successful synthesis of Au-core Ni-branched nanoparticles.…”

Fluorocyclization of N‐Propargyl Carboxamides by λ3‐Iodane Catalysts with Coordinating Substituents

“…To synthesize uniform branched Ni nanoparticles, it is important to decompose the Ni precursor at a pressure of >3 bar H2 gas to ensure that Ni preferentially grows in the metastable hcp crystal phase. [20][21][22][23] A solution of Ni(acac)2, hexadecylamine, trioctylphophine and mesitylene was added to monodisperse fcc Au seeds of 8.7 ± 0.9 nm (SI, Figure S1) and reacted at 140 o C for 24 h under 5 bar H2 in an autoclave. The transmission electron microscopy (TEM) image in Figure 1a shows the successful synthesis of Au-core Ni-branched nanoparticles.…”

Environmental Technologies to Treat Rare Earth Element Pollution: Principles and Engineering

“…Unfortunately, rapid degradation and slow reaction kinetics substantially reduce the rate of commercialization of low-temperature FCs (Guterman et al, 2009(Guterman et al, , 2014. To mitigate these drawbacks, the following approaches have been tried: forming platinum alloys with d-metals (Gudko et al, 2009;McKeown & Rhen, 2018), control over the NPs size and shape (Chen et al, 2014(Chen et al, , 2020, formation of the core-shell (Alinezhad et al, 2020), Pt-skin or skeleton (Stamenkovic et al, 2006) and yolk (Ao et al, 2018) structures, preparation of PGM-free catalysts like Fe/N/C (Wan et al, 2019), Co/N/C (Haile et al, 2021;Li et al, 2019), Fe/Co/N/C (Lastovina et al, 2018b;Pimonova et al, 2019aPimonova et al, , 2019b, metal-free carbons, transition metal carbides (Guil-López et al, 2010) and nitrides (Abdelkareem et al, 2020) and ternary catalysts (Antolini, 2007).…”