Polymorphic LiZnSbO4 with orthorhombic and monoclinic phases for efficient photocatalytic degradation of wastewater

Abstract

In this work, polymorphic LiZnSbO4 powders have been synthesized via solid-state reaction route, and their photocatalytic performance were invested under ultraviolet (UV) light illumination. XRD analysis discloses that a phase transition from orthorhombic (α-LiZnSbO4) to monoclinic (β-LiZnSbO4) crystal system occurs above 1100 oC sintering. Under UV light illumination for 90 min, α-LiZnSbO4 exhibits higher degradation ratio (92%) for RhB (5 mg L-1) compared to β-LiZnSbO4 (27%), which is due to its relative high crystal symmetry and surface area and thus effectively increasing the carrier mobility. The α-LiZnSbO4 catalyst also displays remarkable recyclability even after four successive cycles. On basis of the scavenging and electron paramagnetic resonance (EPR) trapping measurement results, the confirmed active radicals are •OH and •O2- in the photocatalytic reaction. The degradation routes of RhB have been elucidated according to the intermediates detected. Besides RhB, the tetracycline (TC) can also be efficiently degraded by α-LiZnSbO4.