Behavior of gold-enhanced electrocatalytic performance of NiPtAu hollow nanocrystals for alkaline methanol oxidation
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Published online 25 August 2020 | https://doi.org/10.1007/s40843-020-1460-y
Behavior of gold-enhanced electrocatalytic performance of NiPtAu hollow nanocrystals for alkaline methanol oxidation 1
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Chang Liu , Zelin Chen , Dewei Rao , Jinfeng Zhang , Yunwei Liu , Yanan Chen , Yida Deng and 1,3 Wenbin Hu ABSTRACT The Pt-based catalyst tends to be poisoned by carbon monoxide (CO)-like intermediates produced in fuel cell reactions, which seriously deteriorates its catalytic performance. Herein, noble metal Au with the capacity of resistance to CO-like intermediates poisoning was employed to construct multi-element Pt-based catalysts. Two trimetallic NiPtAu hollow nanocrystals (HNCs) with different surface Au contents were synthesized to explore the role of Au in electrocatalysis for alkaline methanol oxidation reaction (MOR). The trimetallic NiPtAu-SRAu HNCs catalyst with the relative rich Au content (15.17 at%) on surface exhibits a much lower CO oxidation peak potential than the other HNCs counterpart and 20 wt% Pt/C, which indicates the more exceptional COresisting performance. Besides, the MOR specific activity of −2 NiPtAu-SRAu HNCs (31.52 mA cm ) is 7 times higher than −2 that of 20 wt% Pt/C (4.50 mA cm ). This enhancement in catalytic activity as well as anti-CO poisoning capability for NiPtAu-SRAu HNCs can be mainly ascribed to the weakened CO adsorption due to the exposure of Au atoms on NiPt surface evidenced by the experimental data and density functional theory calculations. This study not only investigates the role of Au in MOR catalysis but also could be helpful for designing and optimizing the electrocatalysts for high-active and robust fuel cell applications. Keywords: trimetallic NiPtAu, hollow nanocrystals, methanol oxidation, carbon monoxide poisoning
INTRODUCTION The direct methanol fuel cells (DMFCs) are expected to be one of the most significant new resource fuel cells for
their higher utilization efficiency, higher power density, and intrinsically lower environmental pollution than that of traditional energy sources to meet the energy and environmental challenges [1–3]. It is vital to get an appropriate catalyst to improve the efficiency of the methanol oxidation reaction (MOR) of DMFCs. It is believed that platinum (Pt) is the most effective element employed in the design and synthesis of the catalyst for MOR [4–6]. Up to now, a series of Pt-based catalysts with various structures have been synthesized, including alloy nanoparticles [7–9], core-shell nanostructures [10,11], and hollow nanostructures [12–14]. Among these, hollow nanostructures have many advantages in improving the electrocatalytic performance with a large specific surface area and abundant active sites [15]. There are several strategies for synthesizing the hollow nanostructures [16,17], including the Kirkendall effect [18], seed-mediated growth followed by etching [19], and galvanic replacement [20]. The last approach has been proposed that the metal with a relatively low redox potential can be facilely use
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