First-​row transition metal oxide nanoparticle water oxidation catalysts made by pulsed laser ablation in liquids

Abstract

Conversion of solar energy into storable fuels, such as hydrogen from light-driven water splitting, will be the most viable future source of energy. To meet the world's energy demand, materials must be robust, based on earth-abundant elements, and efficient. We synthesized novel first-row transition metal oxide nanomaterials, using pulsed laser ablation in liqs. (PLAL). This method offers size and compn. control through many tunable exptl. parameters. Unlike electrodeposited catalysts, nanoparticles made by PLAL are suitable for mech. deposition on photoanodes in integrated solar water splitting devices. Mixed-metal materials were synthesized by adding metal ions into the aq. ablation liq. With PLAL, many different nanocatalysts can readily be prepd. and screened for water oxidn. activity. Our iron-nickel-oxygen nanocatalysts exhibited varying nickel content and cryst. phases, depending on ablation target, ion concn., and laser pulse energy. Characterization with XPS, powder x-ray diffraction, and electrochem. revealed that high amts. of jamborite nickel hydroxide in the partially cryst. nanomaterials led to highest water oxidn. activity in alk. conditions, with overpotentials of <300 mV at 10 mA cm^(-2).