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 O₂ and 1.32 μmoles of H₂ 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.