Efficient catalytic hydrogen storage of N-ethylcarbazole over RuNi alloy nanoparticles loaded on SBA-15 prepared by electrostatic adsorption

Abstract

SBA-15 loaded RuNi alloy nanocatalysts (RuxNi1-x/SBA15) with high activity were synthesized by an electrostatic adsorption method. The as-prepared RuxNi1-x/SBA15 catalysts were characterized by XRD, XPS, H2-TPR, TEM, nitrogen adsorption–desorption, FT-IR and other analytical methods. It was found that Ru and Ni formed alloy species improved the catalytic activity. The complexation between RuNi alloy NPs and surface hydroxyl groups enhanced the catalytic stability. Ru0.7Ni0.3/SBA15 showed excellent activity in N-ethylcarbazole (NEC) hydrogenation. Under the condition of 90 ℃ and 5 MPa H2 pressure, the percentage of hydrogen storage over Ru0.7Ni0.3/SBA15 reached 99.63 %, which is higher than 97.45 % over Ru1.0/SBA15. The conversion of NEC over Ru0.7Ni0.3/SBA15 at 60 ℃ still reached 91.98 %, much more than that over commercial Ru/Al2O3. The Ea of Ru0.7Ni0.3/SBA15 catalyzed NEC hydrogenation was 38.54 kJ/mol, which was lower than that reported in related literature. This was attributed to the hydrogen spillover effect from the active site of RuNi alloy, and the activated hydrogen species promoted the hydrogen storage reaction process. The electrostatic adsorption between metal ions and surface hydroxyl groups of SBA-15 promoted the RuNi alloy nanoparticles (NPs) highly dispersed. The synergy of small particle size of NPs and the interaction between Ru and Ni enhanced the catalytic activity.