Co3O4 Nanoparticle Water-Oxidation Catalysts Made by Pulsed-Laser Ablation in Liquids

Surfactant-free, size- and composition-controlled, unsupported, <5-nm, quantum-confined cobalt oxide nanoparticles with high electrocatalytic oxygen-evolution activity were synthesized by pulsed laser ablation in liquids. These crystalline Co3O4 nanoparticles have a turnover frequency per cobalt surface site among the highest ever reported for Co3O4 nanoparticle oxygen evolution catalysts in base and overpotentials competitive with the best electrodeposited cobalt oxides, with the advantage that they are suitable for mechanical deposition on photoanode materials and incorporation in integrated solar water-splitting devices.