Plasmon-enhanced nitrogen-doped Nb2O3 nanoplates for efficient solar hydrogen generation

Efficient solar-to-hydrogen conversion remains challenging due to the limited visible-light activity and rapid charge recombination in conventional photocatalysts. Here, we report a plasmon-enhanced nitrogen-doped niobium pentoxide (N–Nb₂O₅) photocatalyst decorated with gold nanoparticles (Au@N–Nb₂O₅) for high-performance solar-driven photocatalytic hydrogen generation. N–Nb₂O₅ was synthesized via a simple wet-chemical route and calcined at 500 °C, forming crystalline orthorhombic nanoplates with XRD-derived crystallite sizes of 50–55 nm and lateral dimensions of ~ 150 nm (FE-SEM). Gold nanoparticles were subsequently deposited via photodeposition, extending visible-light absorption and narrowing the band gap to 2.3–2.5 eV (UV–DRS). XPS analysis confirmed successful nitrogen incorporation and surface metallization. Photoluminescence studies revealed efficient charge separation and concentration-dependent suppression of radiative recombination. The optimised Au@N–Nb₂O₅ (2 wt% Au) achieved a hydrogen evolution rate of 2168 µmol h⁻1 g⁻1 under natural sunlight, nearly fourfold higher than pristine Nb₂O₅ and N–Nb₂O₅. The ordered nanoplate morphology facilitates charge transport, complementing the interfacial effects of Au, providing a scalable strategy for designing high-performance Nb₂O₅-based photocatalysts for sustainable solar water splitting.