In-situ preparation of NH2-MIL-125(Ti)/BiOCl composite with accelerating charge carriers for boosting visible light photocatalytic activity

Metal-organic frameworks (MOFs), a new class of porous and crystalline materials, which have drawn increasing attention in diverse areas. The development of highly active MOFs-based photocatalysts have become a research hotspot owing to the tunable semiconducting properties and highly porous nanostructure. The unique roles of photocatalysis by MOFs can be conventionally optimized towards addressing the environment and energy issues. In this paper, NH2-MIL-125(Ti)/BiOCl composite was studied as a novel visible-light responsive photocatalyst for the removal of organic contaminants. The composite displays significantly enhanced photocatalytic activity for contaminant degradation as compared with BiOCl and NH2-MIL-125(Ti), and the optimal NH2-MIL-125(Ti) content is 10 wt%. The remarkable enhancement of the photocatalytic performance can be ascribed to the absorption of visible-light as well as the efficient charge separation and transfer on the interface contact between BiOCl and NH2-MIL-125(Ti). Superoxide radicals and holes were determined to be the main active species in the photocatalytic process via the reactive species trapping experiments and electron spin resonance, and the plausible photocatalytic mechanism is presented. This work aims to provide guidelines for developing more organic-inorganic hybrid materials for environmental remediation.