Abstract

Ammonia synthesis on three metal surfaces (Zr, Ru, and Pd) is investigated using density functional theory calculations. In addition to N(2) dissociation, all the transition states of the hydrogenation reactions from N to NH(3) are located and the reaction energy profiles at both low and high surface coverages are compared and analyzed. The following are found: (i) Surface coverage effect on dissociation reactions is more significant than that on association reactions. (ii) The difference between N and H chemisorption energies, the so-called chemisorption energy gap which is a measure of adsorption competition, is vital to the reactivity of the catalysts. (iii) The hydrogenation barriers can considerably affect the overall rate of ammonia synthesis. A simple model to describe the relationship between dissociation and association reactions is proposed.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call