Stability and electronic properties of IrnV (n = 2–10) nanoclusters and their reactivity toward N2H4 molecule

• Published in: Structural chemistry 2020-02, Vol.31 (1), p.203-214
• Main Authors: Karaman, Abdelhak, Boudjahem, Abdel-Ghani, Boulbazine, Mouhssin, Gueid, Abdelhak
• Format: Article
• Language: English
• Subjects: Adsorption; Chemisorption; Chemistry; Chemistry and Materials Science; Clusters; Computer Applications in Chemistry; Dipole moments; Energy gap; Enthalpy; Hydrazines; Iridium; Mathematical analysis; Nanoclusters; Organic chemistry; Original Research; Physical Chemistry; Properties (attributes); Stability; Theoretical and Computational Chemistry
• ISSN: 1040-0400; 1572-9001
• DOI: 10.1007/s11224-019-01391-0

DFT calculations have been carried out over the Ir n V ( n = 2–10) clusters in order to predict their stability, electronic, and catalytic properties. Based on the fragmentation energy (Δ E f ) and the second-order difference energy (Δ 2 E ), the results show that the V-doped iridium clusters with sizes of n = 5 and 7 were found more stable than their neighboring clusters. Our results also exhibit that the calculated energy gaps ( E g ) for these clusters are in the range 0.074–0.603 eV, suggesting that the metallic character can manifest in these binary clusters. Therefore, the Ir n V clusters can be utilized as catalysts in several catalytic reactions. MEP analysis exhibits that the highest positive charge resides on the V atom, thus the V atom in the binary clusters can be considered as the most active site for the nucleophilic attack. So, it represents a favorable electrophilic adsorption site that can strongly interact with the electron-rich molecules. The influence of the N 2 H 4 adsorption over the electronic properties of Ir n V clusters was also investigated. The results show that the adsorption energies ( E ads ) vary between − 21.3 and − 46.6 kcal mol −1 , suggesting a chemisorption process. The change in enthalpy (Δ H ads ) is in the range of − 24.6 to − 51.0 kcal mol −1 , indicating that the interaction between the Ir n V clusters and the N 2 H 4 molecule is very strong, and the formed complexes by chemisorption between the clusters and the N 2 H 4 molecule are thermodynamically stable at standard conditions. The energy gaps of clusters are sharply changed upon adsorption of hydrazine onto the surface of the clusters, implying a great sensitivity of these clusters toward N 2 H 4 molecule. The calculated dipole moments were also largely increased after chemisorption of the N 2 H 4 molecule over the clusters.