Metal-dependent photocatalytic activity and magnetic behaviour of a series of 3D Co–Ni metal organic frameworks

Abstract

Crystalline MOF materials with adjustable properties are of great interest for multiple potential applications. In this study, a series of 3D isostructural mixed metal MOFs {[M3(L)2(4,4'-bpy)2(H2O)2]·14H2O}n (M = Co (1), Co0.7Ni0.3 (2), Ni0.5Co0.5 (3), Co0.3Ni0.7 (4), Co0.1Ni0.9 (5), and Ni (6); H3L = 1-aminobenzene-3,4,5-tricarboxylic acid) have been synthesized. The crystal color changed regularly with the increase in the Ni ion content from red to green, and a new ultraviolet absorption spectrophotometry method has been developed for the accurate determination of the metal content of Co in MOF materials. In the detection of magnetic behaviour, 1 shows antiferromagnetism. As the Ni ion component gradually increases in 2-6, the magnetic behaviour of the complexes appears to transition from antiferromagnetic to ferromagnetic. Moreover, complex 1 exhibits preeminent photocatalysis activity in the degradation of organic dyes under visible light irradiation. As the ratio of Ni ions increases gradually in the complexes, the photocatalytic activities of 1-6 decrease. This work offers controllable regulation of the photocatalytic properties and magnetic behaviour of MOFs by changing the metal ions.