The urgent need for large-scale, low-cost energy storage has driven a new wave of research focusing on innovative batteries. Due to the high capacity and the low-cost of elemental Al, aluminum-ion batteries (AIBs) are expected as promising candidates for future energy storage. However, further development of AIBs is restricted by the performance of existing carbonbased cathodes and metal chalcogenide cathode materials. In this work, we deposited polythiophene (Pth) on a graphene oxide (Pth@GO) composite and used it as an AIB cathode material. This Pth@GO composite possesses high exposure of Pth active sites, high conductivity, and high structure stability while providing a very high discharge capacity (up to 130 mAh g −1 ) and outstanding cyclic stability (maintaining above 100 mAh g −1 after 4000 cycles). First principles calculations and experimental results show that the charge is stored on Pth@GO through an electrostatic attraction between AlCl 4 − and β-hydrogen (C β −H) sites in polythiophene.
Adsorption and dehydrogenation of C2-C6 n-alkanes are investigated on Pt substrate using density functional theory (DFT) calculations, and size effects of alkane molecule and Pt substrate are discussed in detail....
Understanding the active sites of metal/oxide catalysts
is of great
significance in heterogeneous catalysis. In this work, we performed
periodic density functional theory calculations to study the C–S
bond activation of CH3SH on Pt/α-Al2O3 catalysts. Five different types of sites were investigated,
which are single Pt-atom site in Pt1/α-Al2O3, Pt(111) site in Pt slab/α-Al2O3, and top-edge, interface, and atop-Al sites in Pt nanorod/α-Al2O3, respectively. In contrast to the common thought
that lower-coordinated atoms at the surface of small metal nanoparticles
(NPs) would lead to the higher reaction activity, the present work
clearly demonstrates that the coordination-unsaturated sites over
Pt NPs have subtle influence on the C–S bond scission. On the
basis of energetic analysis, we propose that the interfacial Pt (type
I) site, summarized as the “Pt–Al” dual perimeter
site, could be the active site for the C–S bond activation.
The presence of alumina support adversely impacts catalytic performance
of Pt nanoparticle itself but exerts positive influence along the
Pt/alumina interfacial boundary. The origin of this positive effect
on the C–S bond activation over the “Pt–Al”
dual perimeter site can be understood from the electronic perspective,
in which the active interfacial Pt atoms act as electron acceptors
(Ptδ−) while alumina support acts as electron
donors. The electron-rich property of Ptδ− and the energy-level downshifting of the C–S antibonding
orbitals of CH3SH both facilitate the electron transfer
from Pt to the C–S antibonding orbitals, leading to subsequent
C–S bond cleavage. The electron transferred from the support
to Pt is the determining factor to activate the C–S bond of
CH3SH and is dependent on the termination type of alumina.
The present work provides geometric and electronic insights into the
nature of active sites and sheds light on the design of more active
metal/oxide catalysts toward catalytic desulfurization.
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