Density functional calculations demonstrate that ordinary Lewis sites containing three- and five-coordinated Al are unlikely to decompose N2O, since the formation of a weak Al-O bond does not compensate the N-O bond rupture. The ground state of the calculated cluster-oxygen adsorption complexes is triplet. The considered hypothetical site Al(OH)(4)AlO can be reactive towards the N2O decomposition with the heat -17.8 kcal/mol and activation barrier 19.7 kcal/mol.