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Platinum Nanoparticle During Electrochemical Hydrogen Evolution: Adsorbate Distribution, Active Reaction Species, And Size Effect, Teck L. Tan, Lin-Lin Wang, Jia Zhang, Duane D. Johnson, Kewu Bai
Platinum Nanoparticle During Electrochemical Hydrogen Evolution: Adsorbate Distribution, Active Reaction Species, And Size Effect, Teck L. Tan, Lin-Lin Wang, Jia Zhang, Duane D. Johnson, Kewu Bai
Ames Laboratory Publications
For small Pt nanoparticles (NPs), catalytic activity is, as observed, adversely affected by size in the 1–3 nm range. We elucidate, via first-principles-based thermodynamics, the operation H* distribution and cyclic voltammetry (CV) during the hydrogen evolution reaction (HER) across the electrochemical potential, including the underpotential region (U ≤ 0) that is difficult to assess in experiment. We consider multiple adsorption sites on a 1 nm Pt NP model and show that the characteristic CV peaks from different H* species correspond well to experiment. We next quantify the activity contribution from each H* species to explain the adverse effect of size ...
Configurational Thermodynamics Of Alloyed Nanoparticles With Adsorbates, Lin-Lin Wang, Teck L. Tan, Duane D. Johnson
Configurational Thermodynamics Of Alloyed Nanoparticles With Adsorbates, Lin-Lin Wang, Teck L. Tan, Duane D. Johnson
Ames Laboratory Publications
Changes in the chemical configuration of alloyed nanoparticle (NP) catalysts induced by adsorbates under working conditions, such as reversal in core–shell preference, are crucial to understand and design NP functionality. We extend the cluster expansion method to predict the configurational thermodynamics of alloyed NPs with adsorbates based on density functional theory data. Exemplified with PdRh NPs having O-coverage up to a monolayer, we fully detail the core–shell behavior across the entire range of NP composition and O-coverage with quantitative agreement to in situ experimental data. Optimally fitted cluster interactions in the heterogeneous system are the key to enable ...