Facile interface engineering of hierarchical flower spherical-like Bi-metal-organic framework microsphere/Bi2MoO6 heterostructure for high-performance visible-light photocatalytic tetracycline hydrochloride degradation

Abstract

The self-assembled Bi-based metal-organic framework microspheres (Bi-MOF-M) by nanorods were successfully constructed by the glycol-assisted solvothermal method. Using Bi-MOF-M as a homologous template, a petal-like Bi₂MoO₆ (BMO) layer was grown in situ on its surface to facilely construct a chemically bonded heterojunction interface, realizing a micro/nano hierarchical flower spherical-like Bi-MOF-M/BMO heterojunction composite photocatalyst. The as-prepared series of Bi-MOF-M/BMO-x catalysts show higher visible light catalytic performance for tetracycline hydrochloride (TC) degradation. Among them, Bi-MOF-M/BMO-0.3 has the optimal catalytic activity, and the degradation efficiency can reach 93.6% within 60 min of light irradiation with superior mineralization ability and structural stability, and the degradation kinetic constant is 6.12 times that of Bi-MOF-M and 5.69 times that of BMO, respectively. The homologously grown Bi-MOF-M/BMO chemically bonded heterojunction not only effectively broadens the spectral absorption range and enhances the absorption intensity but also promotes the efficient separation of photogenerated carriers through forming a favorable interfacial electric field and well-matched energy band alignment. A reasonable mechanism for the visible light degradation of TC by the Bi-MOF-M/BMO composite catalyst with h⁺ and ¹O₂ as the main reactive species is proposed. The micro/nano hierarchical structure of the Bi-MOF/BMO catalyst allows it to exhibit the easy recovery advantage of micron-scale materials while maintaining the high catalytic activity of the primary nano-components.

Keywords: In situ growth; Interface engineering; Metal-organic framework; Photocatalytic degradation; Recyclable.