In this research, pistachio shells were used as raw materials to prepare biochar at 500 degrees 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 NaBH4 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 (alpha) 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).
