One-step green synthesis of Au@Pd concave nanocubes in deep eutectic solvents and their highly catalytic activities for selective hydrogenation

Concave nanomaterials possess superior properties, but their synthesis usually requires complicated steps, specific conditions and additional reagents (surfactants, capping agents, seeds, etc.). Herein, the well-defined Au@Pd concave nanocubes (CNCs) is facile one-step fabricated in a deep eutectic solvent (DES, named reline) composed of choline chloride (ChCl) and urea. It is found that the reline is crucial to the formation of Au@Pd CNCs. Owing to the concave core-shell structures, and electronic effects between Au core and Pd shell, Au@Pd CNCs exhibited excellent catalytic performance, and recovery convenience in the selective hydrogenation of 4nitrostyrene. Specifically, under normal temperature and pressure conditions (25 degrees C, 0.1 MPa), 4-nitrostyrene can be completely hydrogenated to 4-nitroethylbenzene within 7.0 min. After five cycles, Au@Pd CNCs still maintain the highly catalytic activity and 100 % selectivity toward 4-nitroethylbenzene. It is expected that wellconstructed Au@Pd CNCs also display advanced potentials in other applications.