2 research outputs found

    CO<sub>2</sub> Electroreduction Performance of Phthalocyanine Sheet with Mn Dimer: A Theoretical Study

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    Due to the high surface ratio and dispersed metal sites, organometallic sheets provide a very special platform for catalysis. Here we investigate the CO<sub>2</sub> electroreduction performance of expanded phthalocyanine sheets with different transition metal dimers using density functional theory. We have determined Mn dimer to be the best active center, and the reaction path CO<sub>2</sub> → COOH* → CO* → CHO* → CH<sub>2</sub>O* → CH<sub>3</sub>O* → CH<sub>3</sub>OH is identified as the preferable one with the overpotential of 0.84 eV. Electronic structures analyses show that σ-bonding−π-backbonding mode exists when COOH* adsorbed on Mn<sub>2</sub>-Pc, which is different from the bonding mode on Mn-Pc counterpart. Our study indicates that the introduction of metal dimer in porous covalent organic frameworks provides a new strategy for the design of catalytic materials for CO<sub>2</sub> electroreduction

    Identifying the Ground State Geometry of a MoN<sub>2</sub> Sheet through a Global Structure Search and Its Tunable p‑Electron Half-Metallicity

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    MoN<sub>2</sub> and MoS<sub>2</sub> sheets are representatives of two-dimensional transition metal dinitrides and dichalcogenides, respectively. Their similarity in atomic ratios misled people to make an incorrect assumption in previous studies that the former adopts the geometry of the latter. However, compared with S, N is smaller and has fewer valence electrons, and N is more effective in mediating magnetic couplings; therefore, a different geometry and different properties can be expected for the MoN<sub>2</sub> sheet. Here using a global structure search, for the first time we have identified the ground state geometry of this sheet named Tetra-MoN<sub>2</sub> that is much more stable than the H phase proposed previously. Different from the metallic nature of H-MoN<sub>2</sub>, Tetra-MoN<sub>2</sub> is a semiconductor having an indirect band gap of 1.41 eV with a flexible strain tunability. In particular, Tetra-MoN<sub>2</sub> can exhibit rich half-metallic behaviors mediated by the polarized p electron of N and induced by low-concentration hole doping and small strains that are readily achievable experimentally
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