Advancing Nb2O5 photoanodes via coupling Fe2O3 interface and FeNiOx Cocatalyst in water oxidation

Niobium pentoxide (Nb 2 O 5 ) has been explored as photoactive material for photoelectrochemical water splitting, yet it suffers from limited visible light absorption and poor charge carrier separation. In present study, we fabricated Nb 2 O 5 thin films on fluorine-doped tin oxide substrates via hydrothermal synthesis, followed by coupling with Fe 2 O 3 overlayer and further decoration with FeNiO x cocatalyst. Structural characterizations, including such as X-ray diffraction (XRD), scanning electron microscopy, confirmed the formation of phase-pure Nb 2 O 5 with sea urchin-like nanospheres and successful decoration of Fe 2 O 3 overlayer and FeNiO x cocatalyst. The Fe 2 O 3 modification induced a red shift in absorption onset to the visible region, enhancing light utilization. The optimized FTO/Nb 2 O 5 /Fe 2 O 3 photoanode exhibited over 20-fold photocurrent enhancement at 0.3 V vs. Ag/AgCl compared to bare Nb 2 O 5 , attributed to improved charge separation via heterojunction formation. Further integration of FeNiO x cocatalyst boosted the photocurrent by 55 times, owing to accelerated surface water oxidation kinetics and reduced charge transfer resistance. These findings demonstrate the synergistic role of Fe 2 O 3 heterojunction and FeNiO x cocatalyst in advancing Nb 2 O 5 -based photoanodes for PEC water splitting. Graphical abstract The alternative text for this image may have been generated using AI.