Plasmonic Gold Nanoprism-Cobalt Molecular Complex Dyad Mimics Photosystem-II for Visible-NIR Illuminated Neutral Water Oxidation

Constructing an artificial assembly for efficient photocatalytic water splitting is key in the pursuit for a solar-driven renewable energy economy. Here, we have fabricated a covalently linked gold nanoprism-cobalt molecular catalyst construct that stimulated efficient photoelectrocatalytic water oxidation reaction. This assembly generated significant photocurrent (∼50 μA/cm²) in neutral aqueous conditions with a minimal onset overpotential (∼250 mV). This dyad imitates the light-harvesting properties of natural photosystem-II by producing 0.66 μmoles of O<inf>2</inf> and 1.32 μmoles of H<inf>2</inf> simultaneously per hour (0.8% photon to chemical fuel conversion efficiency) following complete water splitting under light with ∼0.075-0.01% incident photon to photocurrent conversion efficiency (IPCE). The presence of the plasmonic gold nanomaterial in this assembly instigates broad-band absorbance spanning from the visible to NIR region (400-1200 nm) covering the majority of the natural solar spectrum. This dyad construct also exhibited appreciable durability under photoelectrocatalytic conditions to demonstrate its prospective applications in alternative energy fields.