Bismuth titanate microspheres: Directed synthesis and their visible light photocatalytic activity

► BIT microspheres were synthesized through hydrothermal method. ► BIT samples were characterized by various characterization technologies. ► BIT samples presented outstanding visible-light-induced photocatalytic performance. ► The photoactivity of BIT microspheres is highly affected by its crystal size. ► BIT microspheres prepared at OH− concentration of 3 M showed the highest photocatalytic activity.