Z. Kowalczyk et al., EFFECT OF POTASSIUM ON THE KINETICS OF AMMONIA-SYNTHESIS AND DECOMPOSITION OVER FUSED IRON CATALYST AT ATMOSPHERIC-PRESSURE, Journal of catalysis, 169(2), 1997, pp. 407-414
Ammonia synthesis and decomposition have been performed over a doubly
promoted (Al2O3, CaO) and a triply promoted (Al2O3, CaO, K2O) fused ir
on catalyst at atmospheric pressure, Additionally, the temperature-pro
grammed surface reaction (TPSR) of N-ads with H-2 has been studied ove
r both catalysts. No effect of potassium on the turnover frequency of
NH3 synthesis was found, On the contrary, a significant fivefold incre
ase in the rate of NH3 decomposition in the presence of potassium was
observed. The effect was found to be strongly dependent on the concent
ration of NH3 in the gas phase, The promoting mechanism of potassium i
s discussed in relation to the surface structure of the catalyst under
varying operating conditions. (C) 1997 Academic Press.