ZIF-67 with Argon annealing treatment for visible light responsive degradation of organic dyes in a wide pH range

Zeolite imidazolate frameworks (ZIFs) are a novel kind of zeolite materials with regular porous network structures, belonging to mental-organic frameworks (MOFs). Thanks to their high porosity and large specific surface area, ZIFs could have potential applications in the field of photocatalysis. In this paper, visible light responsive photocatalyst of ZIF-67 was synthesized by a one-step hydrothermal method under a mild condition. We explored three organic dyes in aqueous solutions were degraded under visible light irradiation. And corresponding photocatalytic performances of ZIF-67 with controllable synthetic conditions were evaluated systematically. It was found that ZIF-67(9 h) had the highest degradation efficiency. Besides, the ZIF-67(9 h) were heated in Ar can maintain their crystal structure and microporous form, but exposed more sites to improve photocatalytic activity with partial bond breakage. More than 75% methyl orange (MO), 85% methyl blue (MB) and 54% Rhodamine B (RhB) can be degraded with a 0.5 g L-1 ZIF-67(9 h)(Ar) under visible light irradiation. Moreover, the ZIF-67(9 h)(Ar) demonstrates a strong pH changing tolerance in both acid and alkaline aqueous solutions, the degradations can be well performed in a wide pH range from 3.0 to 11.0.