17 research outputs found
Composition-Dependent Catalytic Activity of Bimetallic Nanocrystals: AgPd-Catalyzed Hydrodechlorination of 4‑Chlorophenol
Ag–Pd bimetallic nanocrystals
(NCs) with tunable compositions and narrow size distributions were
produced by a one-pot synthesis. The NC growth process was investigated
by time-dependent TEM, XRD, and UV–vis studies. In the hydrodechlorination
of 4-chlorophenol, the AgPd<sub><i>x</i></sub> (<i>x</i> = 2, 4, 6, 9, 19) showed pronounced composition-dependent
catalytic activities, leading to the AgPd<sub>9</sub> catalyst with
excellent activity
Flexible and Free-Standing Organic/Carbon Nanotubes Hybrid Films as Cathode for Rechargeable Lithium-Ion Batteries
Organic
carbonyl compounds are promising electrode materials for
high-performance lithium-ion batteries (LIBs), but generally suffer
from poor cycling stability, low utilization, inferior rate performance,
and relatively low reduction potential. In order to solve these problems,
we report a dissolution-recrystallization method to prepare flexible,
binder-free, and free-standing hybrid films of sodium 1,4-dioxonaphthalene-2-sulfonate
and multiwalled carbon nanotubes (NQS/MWNTs) as high-performance cathode
for rechargeable LIBs. The hybrid films demonstrate high utilization
of NQS, stable cycling, and high-rate capability. The superior electrochemical
performance is attributed to decreased size and high polarity of NQS,
three-dimensional intertwined conductive network formed by MWNTs.
Moreover, NQS/MWNTs show high initial reduction potential at 2.97
V, which is well explained via density functional theory (DFT) calculations.
Meanwhile, the reversible redox mechanism of NQS/MWNTs during discharge/charge
process is revealed by in situ infrared spectroscopy (IR) test and
the stability of fully discharged product is further confirmed by
DFT calculations. This study illustrates a facile method to build
high-performance flexible rechargeable batteries with sustainable
organic materials
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Effects of Catalyst Processing on the Activity and Stability of Pt–Ni Nanoframe Electrocatalysts
Pt-based
alloys have shown great promise as cathodic catalysts
for cost-effective proton-exchange membrane fuel cells. Post-synthesis
treatment has been recognized as a critical step to improve the catalytic
performance of Pt-based alloys. Here, we present the effects of catalyst
processing on the catalytic behavior of Pt–Ni nanoframe electrocatalysts
in oxygen reduction reaction. The Pt–Ni nanoframes were made
by corroding the Ni-rich phase from solid rhombic dodecahedral particles.
A total of three different corrosion procedures were compared. Among
them, electrochemical corrosion led to the highest initial specific
activity (1.35 mA cm<sup>–2</sup> at 0.95 V <i>versus</i> reversible hydrogen electrode) by retaining more Ni in the nanoframes.
However, the high activity gradually went down in a subsequent stability
test due to continuous Ni loss and concomitant surface reconstruction.
On the other hand, the best stability was achieved by a more-aggressive
corrosion using oxidative nitric acid. Although the initial activity
was compromised, this procedure imparted a less-defective surface,
and thus, the specific activity dropped by only 7% over 30 000
potential cycles. These results indicate a delicate trade-off between
the activity and stability of Pt–Ni nanoframe electrocatalysts.
The obtained understanding of how to balance the activity–stability
trade-off <i>via</i> catalyst processing can be generalized
to other Pt-based alloys
Towards the digitalisation of porous energy materials: evolution of digital approaches for microstructural design
Porous energy materials are essential components of many energy devices and systems, the development of which have been long plagued by two main challenges. The first is the ‘curse of dimensionality’,
i.e. the complex structure–property relationships of energy materials are largely determined by a highdimensional parameter space. The second challenge is the low efficiency of optimisation/discovery
techniques for new energy materials. Digitalisation of porous energy materials is currently being
considered as one of the most promising solutions to tackle these issues by transforming all material
information into the digital space using reconstruction and imaging data and fusing this with various
computational methods. With the help of material digitalisation, the rapid characterisation, the prediction
of properties, and the autonomous optimisation of new energy materials can be achieved by using
advanced mathematical algorithms. In this paper, we review the evolution of these computational and
digital approaches and their typical applications in studying various porous energy materials and devices.
Particularly, we address the recent progress of artificial intelligence (AI) in porous energy materials and
highlight the successful application of several deep learning methods in microstructural reconstruction
and generation, property prediction, and the performance optimisation of energy materials in service.
We also provide a perspective on the potential of deep learning methods in achieving autonomous
optimisation and discovery of new porous energy materials based on advanced computational
modelling and AI techniques.</p
Age-specific mean central corneal thickness among the three ethnic groups.
<p>Age-specific mean central corneal thickness among the three ethnic groups.</p
Distribution of central corneal thickness among the three ethnic groups.
<p>Distribution of central corneal thickness among the three ethnic groups.</p
Principle component analysis one the association between ethnicity and other significant associated factors.
<p>Principle component analysis one the association between ethnicity and other significant associated factors.</p
Demographic, systemic and ocular parameters among the three ethnic groups.
<p>Demographic, systemic and ocular parameters among the three ethnic groups.</p
Associations of central corneal thickness with systemic and ocular factors.
<p>CI = confidence interval</p><p>Associations of central corneal thickness with systemic and ocular factors.</p
A Consecutive Spray Printing Strategy to Construct and Integrate Diverse Supercapacitors on Various Substrates
The rapid development
of printable electronic devices with flexible and wearable characteristics
requires supercapacitor devices to be printable, light, thin, integrated
macro- and micro-devices with flexibility. Herein, we developed a
consecutive spray printing strategy to controllably construct and
integrate diverse supercapacitors on various substrates. In such a
strategy, all supercapacitor components are fully printable, and their
thicknesses and shapes are well controlled. As a result, supercapacitors
obtained by this strategy achieve diverse structures and shapes. In
addition, different nanocarbon and pseudocapacitive materials are
applicable for the fabrication of these diverse supercapacitors. Furthermore,
the diverse supercapacitors can be readily constructed on various
objects with planar, curved, or even rough surfaces (e.g., plastic
film, glass, cloth, and paper). More importantly, the consecutive
spray printing process can integrate several supercapacitors together
in the perpendicular and parallel directions of one substrate by designing
the structure of electrodes and separators. This enlightens the construction
and integration of fully printable supercapacitors with diverse configurations
to be compatible with fully printable electronics on various substrates