Synergistic effect of copper and nickel oxides from MOF-74 precursors for enhanced catalytic reduction of p-nitrophenol

Abstract

Catalytic reduction stands out as a promising approach for wastewater treatment due to its inherent simplicity, mild reaction conditions, and high efficiency. In this work, Cu/Ni-MOF-74 precursors with different Cu2+/Ni2+ ratios were prepared by hydrothermal method and calcined them at 400 °C for 2 h to obtain the corresponding CuO/NiO composite catalysts. The experimental results showed that the catalytic reduction of 4-Nitrophenol (4-NP) by CuO/NiO was significantly stronger than that of CuO and NiO separately. Remarkably, the best CuO/NiO-1 catalytic reduction of 4-NP exhibits the pseudo-first-order kinetic constant k of 0.28 min−1 and the mass normalization constant km of 56 min−1 mg−1. Compared with CuO and NiO, the prepared CuO/NiO-1 composite catalyst with a large specific surface area can provide more active sites for the adsorption and diffusion of 4-NP. Notably, this catalytic reaction mechanism aligned with the Langmuir-Hinshelwood model. Theoretical investigations further elucidated that the synergistic interplay between CuO and NiO bolstered the adsorption of H species and 4-NP, while also aiding in product desorption. This study not only presents a novel approach for designing and synthesizing highly active catalysts for 4-NP but also lays the groundwork for future advancements in this field.