Palladium-Coated Platinum Powders with Tunable, Nanostructured Surfaces for Applications in Catalysis,ACS Applied Nano Materials

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Palladium-Coated Platinum Powders with Tunable, Nanostructured Surfaces for Applications in Catalysis
ACS Applied Nano Materials ( IF 5.3 ) Pub Date : 2020-01-10 , DOI: 10.1021/acsanm.9b02090
Sita Gurung ₁ , David B. Robinson ₂ , Patrick J. Cappillino ₁

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Simultaneous control of nanoscale surface morphology and composition remains a challenge in preparing bimetallic catalysts, particularly at the large scale required for industrial application and with high-surface-area substrates. Atomic layer electroless deposition (ALED) is a scalable approach to prepare surface-modified metal powders in which elements more noble than the surface hydrides of the substrate metal are deposited layer-by-layer in a surface-limited fashion. Herein we demonstrate that high-surface-area Pt powder is a viable substrate for controlled deposition of Pd adlayers using this technique, with the potential for large-scale preparation, for use in electrocatalytic and catalytic applications such as fuel cells and functionalization of petrochemical feedstocks. Two different growth mechanisms have been proposed based on bulk and surface Pd atomic fractions obtained from atomic absorption spectroscopy and X-ray photoelectron spectroscopy, respectively. Further, spectral simulations were performed to strengthen the proposed growth mechanisms, favoring conformal growth in initial deposition followed by island formation in subsequent cycles. Observation of multiple pathways suggests a means of controlling adlayer surface morphology of ALED materials, in which an initial cycle of deposition sets the fractional coverage and subsequent cycles tune adlayer thickness.

中文翻译：

具有可调谐，纳米结构表面的钯涂层铂粉，用于催化

在制备双金属催化剂中，同时控制纳米级表面形态和组成仍然是一个挑战，特别是在工业应用所需的大规模和高表面积基材的情况下。原子层化学沉积（ALED）是一种可扩展的方法，用于制备表面改性的金属粉末，其中，比基底金属的表面氢化物更贵重的元素以表面受限的方式逐层沉积。本文中，我们证明高表面积的Pt粉末是使用此技术控制Pd沉积物沉积的可行基质，具有大规模制备的潜力，可用于电催化和催化应用，例如燃料电池和石化原料的功能化。基于分别从原子吸收光谱法和X射线光电子光谱法获得的本体和表面Pd原子分数，已经提出了两种不同的生长机理。此外，进行光谱模拟以增强建议的生长机制，有利于初始沉积中的保形生长，随后在随后的循环中形成岛。多种途径的观察提示了一种控制ALED材料的Adlayer表面形态的方法，其中沉积的初始循环设置分数覆盖率，随后的循环调整Adlayer的厚度。有利于初始沉积中的保形生长，随后在随后的循环中形成岛。多种途径的观察提示了一种控制ALED材料的Adlayer表面形态的方法，其中沉积的初始循环设置分数覆盖率，随后的循环调整Adlayer的厚度。有利于初始沉积中的保形生长，随后在随后的循环中形成岛。多种途径的观察提示了一种控制ALED材料的Adlayer表面形态的方法，其中沉积的初始循环设置分数覆盖率，随后的循环调整Adlayer的厚度。

更新日期：2020-01-10

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