Highly Active Mixed-Metal Nanosheet Water Oxidation Catalysts Made by Pulsed-Laser Ablation in Liquids

Surfactant-free mixed-metal hydroxide water oxidation nanocatalysts were synthesized by pulsed-laser ablation in liquids. In a series of [Ni-Fe]-layered double hydroxides with intercalated nitrate and water, [Ni_1–<i>x</i>Fe_<i>x</i>(OH)₂]­(NO₃)_<i>y</i>(OH)_{<i>x</i>−<i>y</i>}·<i>n</i>H₂O, higher activity was observed as the amount of Fe decreased to 22%. Addition of Ti⁴⁺ and La³⁺ ions further enhanced electrocatalysis, with a lowest overpotential of 260 mV at 10 mA cm^–2. Electrocatalytic water oxidation activity increased with the relative proportion of a 405.1 eV N 1s (XPS binding energy) species in the nanosheets