Novel ultralong and photoactive Bi₂Ti₄O₁₁/TiO₂ heterojunction nanofibers toward efficient textile wastewater treatment

Abstract

The elimination of dyes from textile wastewater with a lower carbon footprint is highly contingent on the design of green catalysts. Here, we innovatively developed ultralong one-dimensional Bi2Ti4O11/TiO2 heterojunction nanofibers via electrospinning so as to photocatalytically degrade dyes efficiently and sustainably through the utilisation of renewable solar irradiation. The heterostructured Bi2Ti4O11/TiO2 nanofibers exhibited desirable activity in the visible light region through the slight shift of the absorption edge to a longer wavelength. The Bi2Ti4O11/TiO2 nanofibers calcined at 550 °C had a lower optical band gap (3.08 eV) than that of the pure TiO2 (3.32 eV), as evidenced by their higher photocatalytic degradation kinetics of a model dye (Acid Orange 7) (2.5 times greater than those of pure TiO2). The enhanced visible light photocatalytic performance arose from the formation of both the Bi2Ti4O11/TiO2 heterojunction and the effective separation of photogenerated holes and electrons. The employment of ultralong Bi2Ti4O11/TiO2 heterojunction nanofibers for dye removal/decolourisation under visible light is an efficient, cost effective and sustainable solution, which will provide significant insights for practical textile wastewater treatment in view of practical engineering applications.