Rapid Synthesis of Mesoporous, Nano‐Sized MgCr2O4 and Its Catalytic Properties

Abstract

Monophasic MgCr2O4 has been synthesized by calcining the gel formed by the addition of epoxide to an ethanolic solution containing MgCl2·6H2O and CrCl3·6H2O. The sample has been characterized by a variety of analytical techniques including powder X‐ray diffraction (PXRD), FT‐IR, Raman, UV–Visible spectroscopy, transmission electron microscopy, and magnetic measurements at room temperature. Calcining the xerogel at 500°C and 700°C for 2 h yielded MgCr2O4 (yield of almost 61% by weight). BET surface area of 33.95 m2/g with an average pore diameter of 28.45 nm was obtained for the sample after calcination at 700°C. Square facets of the cubic spinel structure were observed in TEM images with an average crystallite diameter of 18 nm. HR‐TEM experiments and SAED measurements confirmed the spinel structure and negated the presence of other phases. The presence of MO4 tetrahedral and MO6 octahedral units in MgCr2O4 has also been evidenced from FTIR and Raman spectra. The sample showed paramagnetic behavior at room temperature with μeff of 3.54 B.M suggesting the presence of Cr in III oxidation state. Its use as an efficient catalyst for the oxidative degradation of Xylenol Orange (XO) and the photo degradation of Rhodamine‐6G (Rh‐6G) dyes have been demonstrated as these dye molecules are environmental pollutants.