engleski

A 3D oxalate-bridged [CuIIFeII] coordination polymer as molecular precursor for CuFe2O4 spinel – photocatalytic features

A 3D heterometallic oxalate-bridged coordination polymer [CuIIFeII2(H2O)(terpy)(C2O4)3]n (terpy = 2, 2′:6′, 2″-terpyridine) (1) was investigated both as photocatalyst for the organic dye removal and as a single-source precursor for the preparation of the copper ferrite (CuFe2O4) nanocrystals by thermal processing. The dual functionality of 1 was supported by the degradation of aqueous solutions of rhodamine B (RhB) and methylene blue (MB) solutions under visible (Vis) and ultraviolet (UV) light irradiation, powder X-ray diffraction data collection at room temperature, and the optical and scanning electron microscopy analyses. A close inspection of the X-ray diffraction patterns unveiled qualitative and quantitative information on the phase composition obtained after the single-source molecular precursor route to spinel oxide. By optimizing the temperature levels and setting the controlled heating rate at 6 h of holding time, the phase composition of thermal processing of 1 was evaluated—thermal treatment of 1 at 950◦C for 6 h and a heating/cooling rate of 10◦C min−1 resulted in the formation of solely tetragonal spinel phase of CuFe2O4, whereas the formation of both tetragonal and cubic CuFe2O4 phases was observed at 950◦C by the heating rate of 30◦C min−1. To obtain the high-temperature cubic CuFe2O4 oxide, compound 1 was heated and then quenched at 925◦C, which led to the formation of the cubic spinel ferrite as the main crystalline oxide phase. Moreover, the photocatalytic properties of the t-CuFe2O4 spinel were investigated under the same conditions as for 1. The optical bandgap energies were estimated from UV–Vis absorption spectra for both metal oxide and precursor powder.

bandgap ; photocatalysis ; precursors ; spinels ; thermal decomposition

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