Au@Nb@HxK1-xNbO3 nanopeapods with near-infrared active plasmonic hot-electron injection for water splitting

Full-spectrum utilization of diffusive solar energy by a photocatalyst for environmental remediation and fuel generation has long been pursued. In contrast to tremendous efforts in the UV-to-VIS light regime of the solar spectrum, the NIR and IR areas have been barely addressed although they represent about 50% of the solar flux. Here we put forward a biomimetic photocatalyst blueprint that emulates the growth pattern of a natural plant-a peapod-to address this issue. This design is exemplified via unidirectionally seeding core-shell Au@Nb nanoparticles in the cavity of semiconducting HxK1-xNbO3 nanoscrolls. The biomimicry of this nanopeapod (NPP) configuration promotes near-field plasmon-plasmon coupling between bimetallic Au@Nb nanoantennas (the peas), endowing the UV-active HxK1-xNbO3 semiconductor (the pods) with strong VIS and NIR light harvesting abilities. Moreover, the characteristic 3D metal-semiconductor junction of the Au@Nb@HxK1-xNbO3 NPPs favors the transfer of plasmonic hot carriers to trigger dye photodegradation and water photoelectrolysis as proofs-of-concept. Such broadband solar spectral response renders the Au@Nb@HxK1-xNbO3 NPPs highly promising for widespread photoactive devices.