Reactivity of neutral and charged B13 clusters with O2: A theoretical study

Strong chemisorption of CO2 on B10-B13 planar-type clusters

An ab initio density functional study was performed investigating the adsorption of CO₂ on neutral boron B _n (n  =  10-13) clusters that are characterized by planar and quasiplanar ground-state atomic structures. For all four clusters, we found large chemisorption binding energies, reaching 1.6 eV between CO₂ and B₁₂, with the adsorbed molecule oriented in the plane of the cluster and adsorbed along the cluster edge. A configuration with chemisorbed dissociated CO₂ molecule also exists for B₁₁ and B₁₃ clusters. The strong adsorption is due to the bending of the CO₂ molecule, which provides energetically accessible fully in-plane frontier molecular orbitals matching the edge states of the clusters. At the same time, the intrinsic dipole moment of a bent CO₂ molecule facilitates the transfer of excess electronic charge from the cluster edges to the molecule.

Phosphorene oxide: stability and electronic properties of a novel two-dimensional material

Phosphorene, the monolayer form of (black) phosphorus, was recently exfoliated from its bulk counterpart. Phosphorene oxide, by analogy to graphene oxide, is expected to have novel chemical and electronic properties, and may provide an alternative route to the synthesis of phosphorene. In this research, the physical and chemical properties of phosphorene oxide including its formation by oxygen adsorption on the bare phosphorene was investigated. Analysis of the phonon dispersion curves finds stoichiometric and non-stoichiometric oxide configurations to be stable at ambient conditions, thus suggesting that the oxygen adsorption may not degrade the phosphorene. The nature of the band gap of the oxides depends on the degree of functionalization of phosphorene; an indirect gap is predicted for the non-stoichiometric configurations, whereas a direct gap is predicted for the stoichiometric oxide. Application of mechanical strain or an external electric field leads to tunability of the band gap of the phosphorene oxide. In contrast to the case of the bare phosphorene, dependence of the diode-like asymmetric current-voltage response on the degree of stoichiometry is predicted for the phosphorene oxide.