Investigation of NH3NH3 and H2H2 adsorption on PtnPtn(n = 2-15, 18, 22, 24) clusters by using density functional theory

• Published in: Journal of alloys and compounds 2014-04, Vol.591, p.188-200
• Main Authors: Kadioglu, Y, Demirkiran, A, Yaraneri, H, Aktuerk, O
• Format: Article
• Language: English
• Subjects: Adsorption; Approximation; Clusters; Density functional theory; Fermi surfaces; Mathematical analysis; Molecular orbitals; Platinum
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2013.12.074

The adsorption of NH3NH3 and H2H2 molecules on PtnPtn clusters is investigated by density functional theory calculations within generaliz ed gradient approximation. The size dependence of adsorption energy, highest occupied molecular orbital, lowest unoccupied molecular orbital, magnetization, and bond length values are investigated. A strong interaction is found between Pt and N atoms. It is surprisingly observed that NH3NH3 dissociation occurs at Pt14Pt14 cluster. We found that H2H2 molecule dissociates at different adsorption sites for all clusters except Pt3Pt3 cluster. Each of H atom seems to prefer to bound different Pt atoms. We see that d orbital of Pt is dominant near the Fermi level in NH3NH3 and H2H2 adsorbed PtnPtn clusters. Metallic and conductivity properties of PtnPtn clusters change with adsorption of NH3NH3 and H2H2 molecules. NH3NH3 adsorbed Pt2Pt2 cluster can show half metallic properties. HOMO-LUMO gap (HLG) values for NH3NH3 and H2H2 adsorbed PtnPtn clusters are evaluated. The results also imply charge transfer from Pt to H atoms in H2H2 adsorbed PtnPtn clusters and a polarization between Pt and N atoms in NH3NH3 adsorbed clusters. These results also comply with Lowdin analysis.