Self-Terminated Electrodeposition of Monolayer Electrocatalysts

Wednesday, 27 May 2015: 09:10
Conference Room 4B (Hilton Chicago)
S. H. Ahn, Y. Liu (NIST), R. Wang, U. Bertocci, and T. Moffat (National Institute of Standards and Technology)
In a recent publication Pt deposition at negative potentials revealed an unanticipated self-terminating characteristic that enables controlled deposition of Pt monolayer films from a K2PtCl4-NaCl electrolyte. Herein we explore the generality of such reactions by examining a variety of other transition metal systems. In the case of Pt, the deposition reaction is quenched at potentials just negative of proton reduction by alteration of the double layer structure and adsorption properties induced by a saturated surface coverage of underpotential deposited hydrogen, (Hupd). The surface may be reactivated for Pt deposition by stepping the potential to more positive values where Hupd is oxidized and fresh sites for adsorption of PtCl42- become available. Periodic pulsing of the potential enables sequential deposition of additional Pt layers to fabricate films of desired thickness relevant to a range of advanced technologies in manner that is tantamount to wet atomic layer deposition (ALD).  This talk will present an update on the exploration and use of self-terminating electrodeposition reactions to form electrocatalysts for use in water electrolysis and related reactions.