Silver nanoparticle embedded copper oxide as an efficient core–shell for the catalytic reduction of 4-nitrophenol and antibacterial activity improvement

Abstract

A facile and eco-friendly method was developed to prepare a microporous CuO@Ag⁰ core–shell with high catalytic and antibacterial activities. Scanning and transmission electron microscopy revealed a preponderance of nearly spherical 50 nm particles with slight structure compaction. Comparison of the hysteresis loops confirmed the structure compaction after AgNP incorporation, and a significant decrease of the specific surface area from 55.31 m² g⁻¹ for CuO to 8.03 m² g⁻¹ for CuO@Ag⁰ was noticed. A kinetic study of 4-nitrophenol (4-NP) reduction into 4-aminophenol (4-AP) with sodium borohydride revealed a first order reaction that produces total conversion in less than 18 minutes. CuO@Ag⁰ also exhibited appreciable antibacterial activity against Staphylococcus aureus. The antibacterial effects were found to strongly depend on the size, contact surface, morphology and chemical composition of the catalyst particles. The addition of Ag⁰-NPs produced more reactive oxygen species in the bacteria medium. These results open promising prospects for its potential applications as a low cost catalyst in wastewater treatment and antibacterial agent in cosmetics.