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Abstract Fe-containing transition-metal (oxy)hydroxides are highly active oxygen-evolution reaction (OER) electrocatalysts in alkaline media and ubiquitously form across many materials systems. The complexity and dynamics of the Fe sites within the (oxy)hydroxide have slowed understanding of how and where the Fe-based active sites form—information critical for designing catalysts and electrolytes with higher activity and stability. We show that where/how Fe species in the electrolyte incorporate into host Ni or Co (oxy)hydroxides depends on the electrochemical history and structural properties of the host material. Substantially less Fe is incorporated from Fe-spiked electrolyte into Ni (oxy)hydroxide at anodic potentials, past the nominally Ni^2+/3+redox wave, compared to during potential cycling. The Fe adsorbed under constant anodic potentials leads to impressively high per-Fe OER turn-over frequency (TOF_Fe) of ~40 s⁻¹at 350 mV overpotential which we attribute to under-coordinated “surface” Fe. By systematically controlling the concentration of surface Fe, we find TOF_Feincreases linearly with the Fe concentration. This suggests a changing OER mechanism with increased Fe concentration, consistent with a mechanism involving cooperative Fe sites in FeO_xclusters. 

Abstract Oxaliplatin, a platinum compound in broad clinical use, can induce cell death through a nucleolar stress pathway rather than the canonical DNA damage response studied for other Pt(II) compounds. Previous work has found that the oxaliplatin 1,2‐diaminocyclohexane (DACH) ring but not the oxalate leaving group is important to the ability to induce nucleolar stress. Here we study the influence of DACH ring substituents at the 4‐position on the ability of DACH−Pt(II) compounds to cause nucleolar stress. We determine that DACH−Pt(II) compounds with 4‐position methyl, ethyl, or propyl substituents induce nucleolar stress, but DACH−Pt(II) compounds with 4‐isopropyl substituents do not induce nucleolar stress. This effect is independent of whether the substituent is in the axial or equatorial position relative to thetransdiamines of the ligand. These results suggest that spatially sensitive interactions could be involved in the ability of platinum compounds to cause nucleolar stress. 

Host-mediated liquid–liquid extraction is a convenient method for the separation of inorganic salts.