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