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Gas‐phase investigations on acetone, under the influence of electric pulsed discharge has provided distinct insight related to its decomposition. Time‐of‐flight mass spectrometry has been utilized to identify different products generated upon dissociation/ionization of acetone, under the influence of electric discharge. In addition to molecular (C3H6O+) and protonated acetone (C3H7O+) ions, predominant ions signal corresponding to C3H4O+, C3O+ and CH3CO+ were observed in the mass spectrum. Under discharge condition, acetone undergoes soft dissociation/ionization producing C3H4O+ and C3O+ ions, which are distinctive from usual fragment ions reported upon decomposition of acetone, in the gas‐phase. Though metastable in nature, significant ion yield has been obtained for C3O+ ions. Computational studies have been carried out to understand the mechanism of acetone decomposition in gas‐phase. Based on experimental and computational findings, generation of these ions (C3O+ and C3H4O+) has been ascribed to step‐wise H2 elimination reaction originating from acetone molecule, followed by ionization of resultant fragments under the influence of electric pulsed discharge. Present studies are of relevance for plasma pyrolysis of volatile organic compounds and laboratory astrochemical investigations. [ABSTRACT FROM AUTHOR]

Adsorption and diffusion of small sized PdGa bimetallic clusters on the MgO(100) surface are studied by density functional theory, and the growth mechanism of these bimetallic clusters is studied by graph-theoretical kinetic Monte Carlo simulations. All the pure clusters except Ga tetramers are found to be mobile on the surface, and the slow kinetics of Ga tetramers is attributed to its planar shape. At 300 K, all these clusters are kinetically stable and the vacancy sites act as the trapping centers. Upon increasing the temperature, Ga 2 , Ga 3 , and Pd 1 Ga 2 clusters tend to escape from the vacancy sites rather than decomposing, whereas all other clusters tend to decompose. The growth of the pure Pd and Ga clusters is heterogeneous, though the elementary reactions involved in the growth process for these two clusters are very different. For the bimetallic PdGa clusters, our simulations show that the thermodynamically more stable Pd adatoms trapped at the vacancy site act as nucleation centers for the cluster growth, and the freely mobile Ga adatoms significantly influence the kinetics of cluster formation. When bimetallic clusters are grown by depositing Pd and Ga adatoms with an equal deposition rate, the bimetallic clusters are formed in the large proportion, especially the clusters with 1:1 atomic ratio are found in the highest fraction. Further, the clusters with the desired stoichiometric ratios can be obtained in a large fraction by varying the deposition rates of the Pd and Ga adatoms on the surface. [ABSTRACT FROM AUTHOR]

[Display omitted] • The stability of metal atoms on the boron vacancy (BV) is higher than nitrogen vacancy (NV). • The interaction energy of M@NV with O 2 is higher than that of M@BV systems. • While NV acts as electron donor, BV acts as electron acceptor. • The highest O O bond stretching is found for Cu@NV. • Spontaneous CO oxidation has been demonstrated by the Cu@NV system. The stability of isolated metal atom on a support plays very crucial role to avoid ensemble effects of agglomeration and clustering. Defects in support matrix provide additional binding to enhance the stability of single atom catalyst. Here, using plane wave based pseudo-potential approach, we report the activation of oxygen molecule by Co, Ni and Cu embedded h-BN sheet with both B and N vacancy. We have used O O bond stretching as probe for the activation. The results show that the stability of these metal atoms is higher at the vacancy site than on pristine h-BN. The atomic charge distribution of the metal embedded h-BN sheet suggests that while for boron vacancy defects metal atoms donate electronic charge, for nitrogen vacancy defects metal atoms accept electronic charge from the sheet. The chemical reactivity of the M doped h-BN sheet has been analyzed through electronic density of states spectrum. The interaction of O 2 molecule with metal supported h-BN sheet suggests that the interaction energy as well as the O O bond stretching is higher on metal atom at the nitrogen defected site. A case study of CO oxidation on the Cu embedded NV sheet has been demonstrated by co-adsorption of CO and O 2 molecules. [ABSTRACT FROM AUTHOR]