Effect of Pore Confinement of NaNH 2 andKNH 2 on Hydrogen Generation from Ammonia

The development of efficient catalysts for hydrogen generation via ammonia decomposition is crucial for the use of ammonia as an energy carrier. Here, we report the effect of pore confinement of NaNH2 and KNH2 on ammonia decomposition catalysis. For the first time, Ni- or Ru-doped NaNH2 and KNH2 were confined in carbon nanopores using a combination method of solution impregnation and melt infiltration. Structure characterization indicates the nanoscale intimacy between transition metals and alkali metal amides inside the pores of the carbon support. As a result, 8 wt % Ni-doped NaNH2 and KNH2 nanocomposites give NH3 conversions of 79 and 60%, respectively at 425 °C, close to the performance of a 5 wt % Ru/C reference catalyst. 0.8 wt % Ru-doped nanocomposites exhibit even better catalytic performance, with about 95% NH3 conversion at a moderate temperature of 375 °C. The hydrogen production rates of these Ni- and Ru-doped nanocomposites in a pure NH3 flow are about 3–4 times higher than for the recently r...