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 H x K1−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 H x K1−xNbO3 semiconductor (the pods) with strong VIS and NIR light harvesting abilities. Moreover, the characteristic 3D metal-semiconductor junction of the Au@Nb@H x K1−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@H x K1−xNbO3 NPPs highly promising for widespread photoactive devices.