Simple Route for the Synthesis of Highly Active Bimetallic Nanoparticle Catalysts with Immiscible Ru and Ni Combination by utilizing a TiO2 Support

TiO2 support was proven to be acted as an efficient platform for the synthesis of RuNi bimetallic alloy, which are essentially immiscible at most of equilibrium composition, by simple impregnation followed by H-2 reduction at 300 degrees C. Characterization by means of HAADF-STEM and EDX analysis confirmed the formation of RuNi bimetallic nanoparticles (NPs) with a mean diameter of 2.3 nm. H-2-TPR and insitu XAFS measurements suggested the intraparticle hydrogen spillover mechanism on the surface of TiO2, which originated from the improved reducibility of the Ni species and retarded reducibility of the Ru species in comparison with those for the monometallic samples. RuNi/TiO2 catalyst exhibits remarkably high catalytic activity for the dehydrogenation from ammonia borane (AB, NH3BH3) (TOF=914 min(-1)) compared with those prepared with other conventional supports. DFT calculation study also suggested the synergistic alloying effect due to the random distribution of Ru-Ni NPs plays a crucial role in the improvement of the adsorption energy of AB, which ultimately resulted in the exceptional catalytic performance.