Facile Synthesis of CuMo Nanoparticles as Highly Active and Cost-Effective Catalysts for the Hydrolysis of Ammonia Borane

Noble-metal-free CuMo nanoparticles (NPs) without surfactant or support have been facilely prepared using NaBH4 as a reducing agent. The as-prepared CuMo nanocatalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) surface area measurements, and used as catalysts for the hydrolysis of ammonia borane (AB, NH3BH3) at room temperature. The as-synthesized Cu0.9Mo0.1 NPs exhibited a high activity towards the hydrolysis of AB with a turnover frequency (TOF) of 14.9 min-1, a higher value than that reported for Cu catalysts. Our synthesis is not limited to CuMo NPs alone, but can easily be extended to CuW (3.6 min-1), CuCr (2 min-1), NiMo (55.6 min-1), and CoMo (21.7 min-1) NPs, providing a general approach to Cu-M (M = Mo, W, Cr) and TM-Mo (TM = Cu, Ni, Co) NPs as a series of novel catalysts for the hydrolysis of AB. The enhanced activity of bimetallic NPs may be attributed to the synergistic effects of the Cu-M NPs induced by the strain and ligand effects.