Adsorption microcalorimetric studies of the interaction between oxygen and an industrial ammonia synthesis catalyst

Ammonia Synthesis

“…It is noted that the same trends and problems occur with the thermodynamics of the chemisorption of the catalyst poison oxygen. At l ow coverages the initial enthalpy of chemisorption of oxygen is up to 420 kJ/mole [32] dropping to less than 10% for full coverage. The reaction is fully irreversible and cannot be investigated with temperature programmed methods as dissolution and bulk oxide formation sets in.…”

“…At low coverages, the initial enthalpy of chemisorption is up to 420 kJ mol −1 [71], dropping to less than 10% for full coverage. At low coverages, the initial enthalpy of chemisorption is up to 420 kJ mol −1 [71], dropping to less than 10% for full coverage.…”

Structure and Surface Chemistry of Industrial Ammonia Synthesis Catalysts

“…The enthalpy of chemisorption for an industrial catalyst is 420 kJjmole up to 0.25 monolayer of O2, then the enthalpy drops to 34 kJjmole [573]. The strength of adsorption and the adsorption capacity for O2 on the catalyst increases with temperature [574].…”

Oxygen Poisoning in Laboratory Testing of Iron‐Based Ammonia Synthesis Catalysts and its Potential Sources

“…While oxygen chemisorbs strongly on the iron surface leading to its oxidation/poisoning (Eq. , ), the iron surface is reduced/regenerated by converting the adsorbed oxygen in a reversible reaction with hydrogen to water (Eq. , ).…”