Evaluating the size of Fe nanoparticles for ammonia adsorption and dehydrogenation

G. S. OTERO; B. PASCUCCI; M. M. BRANDA; P. G. BELELLI

COMPUTATIONAL MATERIALS SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 124 p. 220 - 227

0927-0256

The interaction of NH3 with different Fe clusters and nanoparticles was evaluated using a periodic densityfunctional theory method. The preferred adsorption sites, adsorption energies of NH3, the transitionstates and the corresponding activation energies of the first NH3 dehydrogenation reaction on differentsmall Fe nanoparticles were compared with those obtained for bare Fe(1 1 1) and Fe(1 1 1) with an adatom.On seven clusters investigated (Fe16, Fe22, Fe32, Fe59, Fe80, Fe113 and Fe190), NH3 was found to adsorbon top sites, while the NH2 and H products adsorb on bridge and hollow sites, respectively. Higher NH3adsorption energies were obtained and the dehydrogenation reaction was found to be more exothermicwhen the size of clusters increases. Although similar activation barriers were found for different nanoparticlesand bare surfaces, the NH3 first dehydrogenation is favored when the size of nanoclusters increases.