Fabrication of biochar@Cu-Ni nanocatalyst for reduction of aryl aldehyde and nitroarene compounds

In this research, pistachio shells were used as raw materials to prepare biochar at 500 °C. A novel biochar@Cu-Ni bimetallic heterojunction nanocatalyst was successfully prepared using a hydrothermal method. The catalytic performance of the synthesized nanocatalyst was investigated for the hydrogenation of 4‐nitrophenol (4-NP), 4-nitroaniline (4-NA), 2-nitroaniline (2-NA), and aldehyde derivatives. The results indicated that in the presence of NaBH 4 as the source of hydride anion, this nanocatalyst had good catalytic activity for the selective reduction of various aldehydes and the hydrogenation of nitroaromatic compounds in a short time. The catalyst was recovered using an external magnet and reused several times without considerable loss of catalytic activity. The conversion percentage (α) of 4-NP, 4-NA, and 2-NA to 4-aminophenol, 4-phenylenediamine, and 2-phenylenediamine were individually calculated. The kinetic data acquired for the hydrogenation of nitroaromatic compounds were matched to first-order rate equations. Moreover, the apparent rate constants ( K app ) for the hydrogenation of 4-NP, 4-NA, and 2-NA were calculated to be 0.4086 min −1 , 0.6369 min −1 , and 0.4251 min −1 , respectively. The structure and morphology of the prepared nanocatalyst were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Graphical abstract