Controlled synthesis of dendritic ruthenium nanostructures under microwave irradiation and their catalytic properties for p-chloronitrobenzene hydrogenation

In this study, the shape-controlled synthesis of ruthenium (Ru) nanostructures was examined using microwave irradiation. Dendritic Ru nanostructures, with an average diameter of about 34.7 nm, were successfully synthesized when ruthenium chloride (RuCl3) was reduced using a reducing agent of benzyl alcohol, in the presence of polyvinylpyrrolidone (PVP) under microwave irradiation for 360 s. By examining selected parameters affecting the shape-controlled synthesis of dendritic Ru nanostructures, i.e., the concentration of the RuCl3 precursor, different reducing agents, molecular weight of PVP and the molar ratio of RuCl3/PVP, were identified as key factors affecting the successful synthesis of dendritic Ru nanostructures. The catalytic performance of obtained dendritic Ru nanostructures was evaluated for hydrogenation of p-chloronitrobenzene (p-CNB). High selectivity to p-chloroaniline (p-CAN) of about 99.58% was obtained using dendritic Ru nanostructure catalysts at 80 °C under 1 MPa hydrogen pressure, having a 72.81% conversion rate of p-CNB. The selectivity to p-CAN with a dendritic Ru nanostructure catalyst is notably higher than that of conventional 5% ruthenium/carbon catalysts (62.12%). Here in we demonstrate that synthesized dendritic Ru nanostructures present a promising catalytic performance in the hydrogenation of p-CNB, having potential applicability to a wide range of catalytic reactions.