Spin-glass behavior and redox catalytic properties of room temperature produced ZnCrMnO4.

Recognizing the multifunctional capability of spinels, synthesis, and properties of oxide spinel with an equal concentration of Jahn Teller active Mn3+ and geometrically frustrated Cr3+ with non-magnetic Zn2+ have been explored. ZnCrMnO 4 , resulting from the room temperature oxidation reaction, has an average crystallite size of 16 nm. Nearly 25% of Zn occupies the octahedral sites along with Cr and Mn, as revealed by the successful structural refinement in the Fd-3m space group. Electron microscopic results confirm cubic spinel formation. Raman spectrum shows the disordered nature of the spinel. X-ray photoelectron spectral (XPS) analysis establishes mixed valences of manganese ((III), (IV)) and chromium ((III) and (VI)). ZnCrMnO 4 displays electronic transitions typical of Mn3+ and Cr3+ in its UV–Visible diffuse reflectance spectrum. Spin-glass frustration at 26 K, followed by an antiferromagnetic ordering at 10 K, is noticed for the sample from the magnetic measurements. The sample exhibits a surface area of 138 m2/g (BET measurements) and catalyzes the oxidation of aromatic alcohols (phenol, benzyl alcohol) and reduction of nitroaromatics efficiently. [ABSTRACT FROM AUTHOR]