Facile low temperature reflux synthesis of Bi self-doped Bi2MoO6 and construction of CaFe2O4/Bi2MoO6 0D QD-2D p-n heterojunction photocatalyst for efficient bisphenol A degradation and Cr(VI) reduction

• Bi- self doped Bi 2 MoO 6 with nanoplate morphology prepared by reflux route. • Bi self-doping induces part reduction of Mo 6+ to Mo 5+ and creation of Mo vacancy. • CaFe 2 O 4 /Bi 2 MoO 6 0D-2D p-n heterojunction fabricated by integrating CaFe 2 O 4 QDs. • Improved activity for bisphenol A (k app = 0.0132 min -1 ) degradation and Cr(VI) (k app =0.15 min -1 ) reduction. • Reaction rates for p-n heterojunction 5-9 times higher than pure semiconductors. In this study, a mild reflux route was developed for facile synthesis of Bi-self doped Bi 2 MoO 6 (BMOR) with nanoplate morphology. Microstructural study revealed substitution of Bi 5+ ions in the molybdate layer which resulted in partial reduction of Mo 6+ to Mo 5+ ions and creation of Mo vacancy. The defect engineered BMOR material exhibited improved optical and photoelectrochemical properties compared to its undoped analogue. The BMOR material was subsequently employed as host lattice for construction of CaFe 2 O 4 /Bi 2 MoO 6 0D-2D p-n heterojunctions by using an in situ preparative strategy. Well dispersed CaFe 2 O 4 quantum dots over BMOR nanoplates provide a strong interfacial contact conducive for fast charge mobilization. Comprehensive characterization of the composites revealed extended UV-Vis response, improved charge carrier separation, prolonged excited state life time and robust radical generation efficiency compared to pure components. The CaFe 2 O 4 /Bi 2 MoO 6 composites displayed improved photocatalytic performance for bisphenol A (BPA) degradation (k app = 0.0132 min -1 ) and Cr(VI) reduction (k app =0.15 min -1 ) with reaction rates 5-9 times higher than pure components. The involvement of • OH and • O 2 − radicals in the photodegradation of BPA was confirmed from radical trapping study. The formation of an interfacial p-n heterojunction and a double charge migration mechanism accounted for the improved photocatalytic efficacy of the composite.