One-pot hydrothermal synthesis of type-II MnIn2S4/In(OH)3 heterojunctures with efficient MB degradation and Cr(VI) reduction under visible light irradiation

The speedy recombination of photoelectrons and holes is a frustrating issue in photocatalysis. Delicate design and simple synthesis of heteroarchitectures by tightly integrating two or more nanosemiconductors with well-matched electronic and geometrical structure is an effective strategy to improve the light-absorption and charge-separation. A novel MnIn2S4/In(OH)3 type-II heterojuncture with compact contact is fabricated firstly by in-situ growth of MnIn2S4 nanosheets onto In(OH)3 surface via an one-pot hydrothermal synthesis. Benefiting from the increased specific surface area, visible-light absorption and charge-separation due to the formation of nano-heterojunctions among the ingredients, MnIn2S4/In(OH)3 heterostructures demonstrate extraordinarily improved photocatalytic performance for MB degradation and Cr(VI) reduction relative to its single counterparts. The optimal MnIn2S4/In(OH)3 (R = 6) manifests a removal percentage of MB (93.9%) and Cr(VI) (97.2%) under visible light illumination. Based on the band-structure analyses, PL, TPC, EIS measurements as well as the predominating active species trapping/detecting experiments, the charge-transfer pathways for MB degradation and Cr(VI) reduction over MnIn2S4/In(OH)3 heterostructures are proposed. This work offers an eco-friendly, viable pathway for in-situ growth of heterostructured photocatalysts with good performance for removing recalcitrant substances in environmental rectification.