Zinc-Copper-Nickel Mixed Metal Oxide as Heterogeneous Catalytic Material for the Reductive Degradation of Nitroarene and Azo Dye

Abstract

Transition metal-based mixed metal oxides (MMOs) are nexus nanomaterials that garner significant interest from scientists because of their unique magnetic, electronic, optical and catalytic properties that can easily be tailored by varying their composition and structure. Although MMOs hold significant potential in multifunctional applications, but they are plagued by certain challenges such as identifying the appropriate method for synthesis, complications in controlling the surface area and the oxidation states of the constituent transition metals, while also ensuring the homogenous distribution of the constituent metal ions. Therefore, the present work aims to study the formation of homogenous and porous zinc-copper-nickel mixed metal oxide (ZnCuNi-MMO) by performing calcination of ZnCuNi-LDH at 350 °C. The obtained ZnCuNi-MMO was characterized using PXRD, SEM–EDX and BET techniques. Thereafter, ZnCuNi-MMO was applied as a heterogeneous catalyst for the hydrogenation of p-nitroaniline (p-NA) and catalytic reduction of methyl orange (MO) dye. The pollutant degradation characteristics were assessed using time-dependent UV–Visible absorption spectroscopy showing advanced efficient behavior of ZnCuNi-MMO towards the hydrogenation of p-NA (96.98%) and reduction of MO (95.58%). The catalyst exhibited fast reaction rates (0.402 min⁻¹ for hydrogenation of p-NA and 0.471 min⁻¹ for catalytic reduction of MO) and kinetics analysis of the experimental data was found to be coherent with the pseudo-first order model, thereby implying that the catalysis proceeded through the Langmuir–Hinshelwood mechanism. Thus the obtained experimental results highlight the utility and viability of synthesized MMO as an efficacious and sustainable catalytic material.

Graphical Abstract