Ethanol, O, and CO adsorption on Pt nanoparticles: effects of nanoparticle size and graphene support.
Ethanol, O, and CO adsorption on Pt nanoparticles: effects of nanoparticle size and graphene support.
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DOI：
10.1039/c8cp04798g
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发表时间：
2018-10
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影响因子：
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通讯作者：
L. G. Verga;A. Russell;Chris-Kriton Skylaris
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文献类型：
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作者：
L. G. Verga;A. Russell;Chris-Kriton Skylaris
分散在碳质载体上的Pt纳米颗粒被广泛用作不同应用的催化剂，使得对尺寸和载体效应之间的相互作用的研究对于合理的催化剂设计是不可或缺的。在这里，我们使用DFT计算来模拟O，CO和乙醇之间的相互作用与自由铂立方八面体纳米粒子与多达147个原子和相同的Pt纳米粒子支持在单层石墨烯与多达720个碳原子。我们计算吸附能量为每个吸附在不同的吸附位点的支持和不支持的Pt纳米粒子。我们发现，随着Pt纳米颗粒的生长，吸附能降低，并且尺寸效应对于O和CO吸附比对于乙醇更重要。我们观察到，每个吸附位点的广义配位数控制的相互作用强度为O和CO在更大的程度上比乙醇。电子电荷的重新分布和密度的状态投影在d带的相互作用的Pt刻面，以获得更好的理解之间的差异，为每个吸附物的电子相互作用。对于负载在石墨烯上的Pt纳米颗粒，支撑效应减弱了所有吸附物的吸附能，但这种效应随着纳米颗粒的增大而迅速减小，并且仅对我们最小的纳米颗粒Pt 13有意义。通过证明，纳米颗粒的尺寸和支持的影响是不同的乙醇相比，O和CO，我们得出结论，它应该是可以修改不同的参数，在催化剂的设计，以调整Pt纳米粒子与特定的吸附物相互作用。
Pt nanoparticles dispersed over carbonaceous supports are widely used as catalysts for different applications, making studies on the interplay between size and support effects indispensable for rational catalyst design. Here, we use DFT calculations to simulate the interaction between O, CO, and ethanol with free platinum cuboctahedral nanoparticles with up to 147 atoms and with the same Pt nanoparticles supported on a single layer of graphene with up to 720 carbon atoms. We compute adsorption energies for each adsorbate on different adsorption sites for supported and unsupported Pt nanoparticles. We show that as the Pt nanoparticle grows the adsorption energy decreases, and that the size effect is more important for O and CO adsorption than for ethanol. We observe that the generalized coordination number of each adsorption site controls the interaction strength for O and CO to a much larger extent than for ethanol. Electronic charge redistributions and density of states projected on the d band of the interacting Pt facets are used to obtain a better understanding of the differences between the electronic interactions for each adsorbate. For Pt nanoparticles supported on graphene, the support effects weaken the adsorption energies for all the adsorbates, but this effect rapidly decreases with larger nanoparticles, and it is only significant for our smallest nanoparticle Pt13. By demonstrating that the effects of nanoparticle size and support are different for ethanol as compared with O and CO, we conclude that it should be possible to modify different parameters in the catalyst design in order to tune the Pt nanoparticle to interact with specific adsorbates.