(Invited) Nickel Based Electrocatalysts for Water Electrolysis Under Large Current

Abstract

Water electrolysis is a promising approach to produce pure hydrogen and oxygen without releasing greenhouse gases. For practical applications, electrolyzers working at large current density (on the order of A cm-2) are desired. Consequently, highly efficient, stable, and low cost electrocatalysts to expedite anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER) are necessary. In this presentation, I will introduce our recent progress on nickel based electrocatalysts, including Ni2(1-x)Mo2xP, NiFe layered double hydroxide, and Fe-Ni-P for water electrolysis at a current density of 1 A cm-2. The electrocatalysts were prepared by high temperature reaction of precursors with nickel foams, which ensure high electrical and robust mechanical connections. After IR correction in 1 M KOH, our typical overpotential at 1 A cm-2 for HER is ~300 mV, and that for OER is also less than 300 mV. Interestingly, NiFe layered double hydroxide and Fe-Ni-P can effectively catalyze both HER and OER, which may benefit fabrications of electrolyzers. I will also present theoretical understandings on catalyzing HER by density functional theory (DFT) calculations.