New theoretical and computational approaches to study catalytic mechanisms of low dimensional materials (nanoparticles, nanowires, nanoporous metals) are increasingly relying on ab initio modeling of electronic, structural and thermal properties in more complex and less idealized systems. One powerful example of such direct link between dynamic structure and reactivity is the relationship between the d-band center, which is a good descriptor of catalytic activity of Pt catalysts, and mechanical strain in the catalyst structure.  In situ measurements of thermodynamic properties in nanostructured materials by core-level spectroscopy (x-ray absorption fine structure and resonant inelastic x-ray scattering) is particularly valuable for validating, fine tuning, and challenging such theories. In this talk I will review recent results obtained in nanoporous Au and in Pt nanoparticles. In the former system, the lowering of Debye temperature relative to bulk Au is interpreted in terms of the reduced bond vibration frequency near the pore surface, and in the latter system the values of d-band center shift, strain energy, and heat of adsorption are interpreted in the framework of a single model that incorporates all dominant factors of the three-phase (particle-support-adsorbate) system. 

Thermodynamics of nanostructured metals: Synchrotron X-ray studies

244th National Meeting (2012)

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