摘要
CONSPECTUS:Catalyzing the oxygen evolution reaction(OER)is important for key energy-storage technologies,particularly water electrolysis and photoelectrolysis for hydrogen fuel production.Under neutral-to-alkaline conditions,first-row transitionmetal oxides/(oxy)hydroxides are the fastest-known OER catalysts and have been the subject of intense study for the past decade.Critical to their high performance is the intentional or accidental addition of Fe to Ni/Co oxides that convert to layered(oxy)hydroxide structures during the OER.Unraveling the role that Fe plays in the catalysis and the molecular identity of the true“active site”has proved challenging,however,due to the dynamics of the host structure and absorbed Fe sites as well as the diversity of local structures in these disordered active phases.In this Account,we highlight our work to understand the role of Fe in Ni/Co(oxy)hydroxide OER catalysts.We first discuss how we characterize the intrinsic activity of the first-row transition-metal(oxy)hydroxide catalysts as thin films by accounting for the contributions of the catalyst-layer thickness(mass loading)and electrical conductivity as well as the underlying substrate’s chemical interactions with the catalyst and the presence of Fe species in the electrolyte.We show how Fe-doped Ni/Co(oxy)hydroxides restructure during catalysis,absorb/desorb Fe,and in some cases degrade or regenerate their activity during electrochemical testing.We highlight the relevant techniques and procedures that allowed us to better understand the role of Fe in activating other first-row transition metals for OER.We find several modes of Fe incorporation in Ni/Co(oxy)hydroxides and show how those modes correlate with activity and durability.We also discuss how this understanding informs the incorporation of earthabundant transition-metal OER catalysts in anion-exchange-membrane water electrolyzers(AEMWE)that provide a locally basic anode environment but run on pure water and have advantages over the more-developed proton-excha
基金
funded by National Science Foundation grant 1955106
DOE EERE grant DE-EE0008841.
