Aligning Fe₂O₃ photo-sheets on TiO₂ nanofibers with hydrophilic and aerophobic surface for boosting photoelectrochemical performance

Photoelectrochemical (PEC) nanomaterials are critical to producing clean oxygenation or value-added chemical production by utilizing sustainable solar energy, but are always limited by simultaneous integration of architectural engineering and electronic regulation in one structure. Directed by density functional theory (DFT) calculations and finite element analysis (FEA), the bio-inspired ivy-like Fe₂O₃ heterostructures with enriched oxygen defects on TiO₂ nanofibers are designed for boosting PEC performances. Ivy-like Fe₂O₃ photo-sheets remarkably enhanced the light harvesting by multiple light–mater interactions. The oxygen vacancies on Fe₂O₃ photo-sheets could aid the photons catching and promote the reactivity at active sites. More importantly, demonstrated by a well-designed dynamic observation, the abundant tip-edges within ivy-like Fe₂O₃ photo-sheets enabled the surface of heterostructure with hydrophilic and aerophobic properties. The functionalized surface allowed the rapid desorption of produced bubbles and thus ensured a high density of unoccupied active sites for electrolyte accessing. Featured by these attributes, the Fe₂O₃@TiO₂ nanofibers delivered an excellent photocurrent of 40.8 mA/mg, high donor density (1.2 × 10¹⁸ cm⁻³), and rapid oxygen production rate (1 mmol/(L∙h)). This work demonstrates a new strategy on nano-structural design for enhancing light-harvesting and making a hydrophilic/aerophobic surface on low-dimensional oxide nanomaterial, holding great potential on designing high-performance PEC devices for producing survival source gas, carbon-neutral fuel, and valued-chemicals.