Mechanistic Insight into the Facet-Dependent Adsorption of Methanol on a Pt3Ni Nanocatalyst

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• 作者：Pan Du ; Ping Wu ; Chenxin Cai
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 13, 2015
• 年：2015
• 卷：119
• 期：32
• 页码：18352-18363
• 全文大小：678K
• ISSN：1932-7455

文摘

There is great interest in the design of catalysts for use in direct methanol fuel cells (DMFCs). However, our atomistic understanding of the adsorption and oxidation mechanism of CH₃OH at the different crystal planes of metal catalysts is far from satisfactory. This study endeavors to gain mechanistic insight into the intrinsic facet-dependent adsorption properties of CH₃OH on the surface of a Pt₃Ni catalyst. We analyzed the adsorption characteristics of CH₃OH by optimizing the structures and calculating the adsorption energies at each site on the (111), (100), and (110) surfaces of a Pt₃Ni catalyst using density functional theory (DFT) calculations with van der Waals (vdW) corrections to the total energy. Our results indicate that the adsorption strength of CH₃OH at the surface of the Pt₃Ni catalyst is facet-dependent, following the order (110) > (111) > (100). The mechanism of the facet-dependent adsorption of CH₃OH on the catalyst is rationalized in terms of shifts of the d-band center of the Ni component relative to the Fermi level, density of states, changes to the work function of each surface of the Pt₃Ni catalyst, and polarization effects of the adsorbed CH₃OH. We believe that the present results will provide useful information to help guide the rational design and construction of nanoarchitectured catalyst surfaces for optimal heterogeneous catalysis.