Synthesis of Au/Al₂O₃ Nanocatalyst and its Application in the Reduction of <i>p</i>‐Nitrophenol

Abstract

Abstract Gold (Au) nanoparticles supported on alumina (Al 2 O 3 ) were prepared at several pH levels via the deposition‐precipitation (DP) method. The effects of pH at below and above the isoelectric point (IEP) of Al 2 O 3 as well as the pH adjustment before and after the addition of the support into the gold chloride solution were investigated. The results revealed the formation of cationic, clusters and metallic Au on alumina. The catalytic activity of these species was tested in the reduction of p ‐nitrophenol ( p ‐NP) using hydrazine as a reductant. The catalytic reaction was monitored spectrophotometerically and the highest rate constant ( k ‐) achieved based on pseudo first order kinetic model was 12.7 × 10 ‐3 s ‐1 . Structural and elemental characterizations of the supported gold nanoparticles were carried out using X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy‐dispersive X‐rays (EDX), atomic absorption spectrometry (AAS), and ultraviolet‐visible spectroscopy (UV‐Vis).