Understanding the Improved Kinetics of the Hydrogen Evolution/Oxidation Reactions of the Platinum-Oxophilic Metal Systems in Alkaline Media

Abstract

Realization of the hydrogen economy relies on effective hydrogen production, storage, and utilization. The slow kinetics of hydrogen evolution and oxidation reaction (HER/HOR) in alkaline media limits many practical applications involving hydrogen generation and utilization, and how to overcome this fundamental limitation remains debatable. Herein, we report that a wide broad of PtM (M represents oxophilic metals such as Ni, Nb, Ru, etc.) systems exhibit superior HER/HOR activity to Pt in alkaline media. Combined electrochemical and in situ spectroscopic data show that the improved HER/HOR kinetics is not attributable to the M-induced weakening of the Pt-H hydrogen binding energy, or the negative shift of the underpotential deposited hydrogen HUPD stripping peak, but rather related to the surface hydroxide species at the HER/HOR potential region accommodated by the surface M that is in the form of oxides. The possible beneficial role of the surface hydroxide, either reorienting the water molecules in the interface, and/or facilitating the removal of hydrogen adsorbates on Pt sites via the bifunctional mechanism will be discussed in the context of new electrochemical and spectroscopic data. Acknowledgements Current financial support from ARPA-E ((DE-AR0000688)) lead by Pajarito Powders is deeply appreciated. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Use of Beamline 2-2 at SSRL and ISS 8-ID of the NSLS II was supported by the National Synchrotron Light Source (NSLS) II, Brookhaven National Laboratory, under U.S. DOE Contract No. DE-SC0012704. Figure 1