Alkaline hydrothermal synthesis of homogeneous titania microspheres with urchin-like nanoarchitectures for dye effluent treatments

► Alkali-hydrothermal treatments of a remnant of Ti-H2O2 reaction achieve titania microspheres. ► Inhibited heterogeneous nucleation and low supersaturation contribute to the uniform size. ► Radially aligned anatase nanowires construct the microspheres. ► The microspheres possess a BET surface area of 45.4 m2/g. ► The microspheres exhibit a high activity to assist photodegradation of rhodamine B in water.