化学
催化作用
质子交换膜燃料电池
纳米材料基催化剂
纳米颗粒
铂金
合金
扩展X射线吸收精细结构
浸出(土壤学)
化学工程
无机化学
吸收光谱法
有机化学
物理
工程类
土壤科学
土壤水分
量子力学
环境科学
作者
Amado Velázquez-Palenzuela,Federico Masini,Anne Juul Pedersen,Marı́a Escudero-Escribano,Davide Deiana,Paolo Malacrida,Thomas Willum Hansen,Daniel Friebel,Anders Nilsson,Ifan E. L. Stephens,Ib Chorkendorff
标识
DOI:10.1016/j.jcat.2014.12.012
摘要
Mass-selected platinum–gadolinium alloy nanoparticles (PtxGd NPs) are synthesized for the first time as oxygen reduction reaction (ORR) electrocatalysts using the gas aggregation technique, under ultrahigh vacuum (UHV) conditions. The morphology of the PtxGd catalysts is characterized, and their catalytic performance toward the ORR is assessed in acidic media using a half-cell configuration. The PtxGd 8-nm catalyst shows a high activity (3.6 A (mg Pt)−1), surpassing the highest activity reached so far with PtxY NP catalysts. In addition, the optimum PtxGd catalyst also presents high stability, as suggested by the accelerated stability tests under ORR potential cycling. Extended X-ray absorption fine structure (EXAFS) spectroscopy measurements confirm that as-prepared PtxGd NPs are compressively strained, relative to pure Pt, and that a PtxGd core/Pt-rich shell structure is adopted after partial Gd leaching. The activity correlates strongly with the compressive strain. On that basis, we propose that the ORR enhancement is due to the compressive strain within the Pt shell induced by the alloy core. The results herein confirm the suitability of PtxGd NPs as cathode nanocatalysts for proton exchange membrane fuel cells (PEMFCs).
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