Self-terminating electrodeposition of ultrathin Pt films on Ni: An active, low-cost electrode for H2 production
Yihua Y. Liu, Carlos M. Hangarter, Thomas P. Moffat
Self-terminating electrodeposition was developed for depositing ultrathin Pt overlayers on segmented electrodeposited Ni films supported on Au. The partitioned substrates provided an internal reference, namely, Pt on Au versus Pt on Ni, for every growth experiment. Deposition at large overpotentials yielded a Pt overlayer approximately 1 monolayer thick on Au or 2-3 monolayers thick on Ni as determined by X-ray photoelectron spectroscopy (XPS). Ion scattering spectroscopy (ISS) indicated that Pt covered 60% of the Ni surface forming a Pt50Ni50 surface alloy stabilized by excess Pt-Ni bond enthalpy supplemented by O- and H-induced Ni segregation. The Pt deposition rate on Ni was constrained by Ni oxide reduction while self-termination was mediated by formation of a layer of adsorbed hydrogen (Hupd) on the Pt-Ni surface. Multi-cycle Pt deposition on Ni involved emersion and rapid water rinsing in air to oxidize the Hupd followed by re-immersion for additional Pt deposition. Four deposition cycles resulted in a Pt terminated surface. The electrocatalytic activity for hydrogen production in alkaline media was significantly enhanced on the Pt-Ni monolayer film relative to Pt. The Pt-Ni electrode deactivated with time although intermittent oxidation at, or above, 1 VRHE restructured the electrode to form an active Pt-Ni(OH)2 composite surface.
, Hangarter, C.
and Moffat, T.
Self-terminating electrodeposition of ultrathin Pt films on Ni: An active, low-cost electrode for H2 production, Journal of the American Chemical Society
(Accessed December 9, 2023)