Synthesis and characterization of inorganic mixed metal oxide nanoparticles derived from Zn–Al layered double hydroxide and their antibacterial activity

Abstract Inorganic metal oxides represent a class of materials that have been used for health applications. In this research, a series of novel environmental-friendly mixed metal oxide nanoparticles with general formula ZnO/MAl 2 O 4 (M= Cu, Ni, Co and Mg) were synthesized by mixing Zn–Al layered double hydroxide as precursor with various metal nitrate salts. For this purpose, in the first step, the Zn–Al layered double hydroxide (Zn–Al LDH) as precursor was synthesized by a simple and rapid chemical co-precipitation method. In the second step, by simple mixing of Zn–Al LDH compound as precursor with related metal nitrate salts M (NO 3 ) 2 . x H 2 O (M= Cu, Ni, Mg and Co), the mixed metal oxide nanoparticles of ZnO/CuAl 2 O 4 , ZnO/NiAl 2 O 4 , ZnO/CoAl 2 O 4 , and ZnO/MgAl 2 O 4 were synthesized and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV–vis diffusive reflectance spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Furthermore, the antibacterial activity of the synthesized mixed metal oxides was evaluated against the gram-negative bacterial species Escherichia coli and the gram-positive bacterial species Staphylococcus aureus . The crystallite size and play a critical role. Thus, the antibacterial activity of the mixed metal oxides was demonstrated to be in the following order: ZnO/NiAl 2 O 4 > ZnO/CuAl 2 O 4 > ZnO/MgAl 2 O 4 > ZnO/CoAl 2 O 4 .