Rugged Forest Morphology of Magnetoplasmonic Nanorods that Collect Maximum Light for Photoelectrochemical Water Splitting

Abstract A feasible nanoscale framework of heterogeneous plasmonic materials and proper surface engineering can enhance photoelectrochemical (PEC) water‐splitting performance owing to increased light absorbance, efficient bulk carrier transport, and interfacial charge transfer. This article introduces a new magnetoplasmonic (MagPlas) Ni‐doped Au@Fe_xO_y nanorods (NRs) based material as a novel photoanode for PEC water‐splitting. A two stage procedure produces core–shell Ni/Au@Fe_xO_y MagPlas NRs. The first‐step is a one‐pot solvothermal synthesis of Au@Fe_xO_y. The hollow Fe_xO_y nanotubes (NTs) are a hybrid of Fe₂O₃ and Fe₃O₄, and the second‐step is a sequential hydrothermal treatment for Ni doping. Then, a transverse magnetic field‐induced assembly is adopted to decorate Ni/Au@Fe_xO_y on FTO glass to be an artificially roughened morphologic surface called a rugged forest, allowing more light absorption and active electrochemical sites. Then, to characterize its optical and surface properties, COMSOL Multiphysics simulations are carried out. The core–shell Ni/Au@Fe_xO_y MagPlas NRs increase photoanode interface charge transfer to 2.73 mAcm⁻² at 1.23 V RHE. This improvement is made possible by the rugged morphology of the NRs, which provide more active sites and oxygen vacancies as the hole transfer medium. The recent finding may provide light on plasmonic photocatalytic hybrids and surface morphology for effective PEC photoanodes.