Efficient visible-light-induced photocatalytic reduction of 4-nitroaniline to p-phenylenediamine over nanocrystalline PbBi2Nb2O9

► Nanocrystalline PbBi2Nb2O9 photocatalyst was prepared by a sol-gel method. ► It showed visible light photocatalytic activity for the reduction of 4-nitroaniline. ► The crystallinity and surface area determined its photocatalytic activity. ► Hole scavengers and deaerated condition were indispensable for the reduction of 4-NA. ► Mechanism for the photoreduction of 4-nitroaniline to p-phenylenediamine was studied.