(286f) Structural Analysis of Chalcogenide-Functionalized Precious Metal Nanoparticles from First Principles

Authors: 
Lowe, J. S., Purdue University
Yadav, V., Purdue University
Shumski, A. J., Purdue University
Li, C. W., Purdue University
Greeley, J., Purdue University
Although there is increased demand to develop renewable fuels such as hydrogen, it is challenging to efficiently produce hydrogen via the hydrogen evolution reaction (HER). Functionalized nanoparticles have received growing attention for use as electrocatalysts for the HER. In particular, metal chalcogenide ligands can be used to bridge between platinum group metals and a precious metal nanoparticle. In our recent experimental work, tetrathiomolybdate (MoS42-) ligands were used to deposit small clusters of platinum atoms on silver nanoparticles. This functionalization allowed us to tune the electronic structure of the platinum clusters. However, broad electrochemical behaviors were observed for these catalysts. To investigate this behavior, in this work, we analyze the structure of these catalysts with density functional theory (DFT) calculations. We show how the electronic structures of the MoS42- ligand and the platinum clusters are modified by the silver surface. Results of the computational analyses are then used to explain the catalytic behaviors observed in the experimental system. Further, electronic descriptors are identified for the effect of the silver surface modification and correlated with measured/calculated changes in the catalytic properties, thus paving the way for more systematic design efforts for these and related systems.