Abstract
Scalable and sustainable solar hydrogen production through photocatalytic water splitting requires highly active and stable earth-abundant co-catalysts to replace expensive and rare ...platinum. Here we employ density functional theory calculations to direct atomic-level exploration, design and fabrication of a MXene material, Ti
3
C
2
nanoparticles, as a highly efficient co-catalyst. Ti
3
C
2
nanoparticles are rationally integrated with cadmium sulfide via a hydrothermal strategy to induce a super high visible-light photocatalytic hydrogen production activity of 14,342 μmol h
−1
g
−1
and an apparent quantum efficiency of 40.1% at 420 nm. This high performance arises from the favourable Fermi level position, electrical conductivity and hydrogen evolution capacity of Ti
3
C
2
nanoparticles. Furthermore, Ti
3
C
2
nanoparticles also serve as an efficient co-catalyst on ZnS or Zn
x
Cd
1−
x
S. This work demonstrates the potential of earth-abundant MXene family materials to construct numerous high performance and low-cost photocatalysts/photoelectrodes.
Water waves are one of the most common phenomena in nature, the study of which helps in designing the related industries. In this paper, a generalized (
3
+
1
)-dimensional B-type ...Kadomtsev–Petviashvili equation for the water waves is investigated. Gramian solutions are constructed via the Kadomtsev–Petviashvili hierarchy reduction. Based on the Gramian solutions, we construct the breathers. We graphically analyze the breather solutions and find that the breathers can be reduced to the homoclinic orbits. For the higher-order breather solutions, we obtain the mixed solutions consisting of the breathers and homoclinic orbits. According to the long-wave limit method, rational solutions are constructed. We look at two types of the rational solutions, i.e., the lump and line rogue wave solutions, and give the condition for the lumps being reduced to the line rogue waves. Taking another set of the parameters for the Gramian solutions, we also derive the kinky breather solutions which can be reduced to the kink solitons. For the higher-order kinky breather solutions, we obtain the mixed solutions consisting of the breathers and kink solitons. Combining the breather and rational solutions, we construct two kinds of the hybrid solutions composed of the breathers, lumps, line rogue waves and kink solitons. Characteristics of those hybrid solutions are graphically analyzed and the conditions for the generation of those hybrid solutions are given.
Development of easy‐to‐make, highly active, and stable bifunctional electrocatalysts for water splitting is important for future renewable energy systems. Three‐dimension (3D) porous Ni/Ni8P3 and ...Ni/Ni9S8 electrodes are prepared by sequential treatment of commercial Ni‐foam with acid activation, followed by phosphorization or sulfurization. The resultant materials can act as self‐supported bifunctional electrocatalytic electrodes for direct water splitting with excellent activity toward oxygen evolution reaction and hydrogen evolution reaction in alkaline media. Stable performance can be maintained for at least 24 h, illustrating their versatile and practical nature for clean energy generation. Furthermore, an advanced water electrolyzer through exploiting Ni/Ni8P3 as both anode and cathode is fabricated, which requires a cell voltage of 1.61 V to deliver a 10 mA cm−2 water splitting current density in 1.0 m KOH solution. This performance is significantly better than that of the noble metal benchmark—integrated Ni/IrO2 and Ni/Pt–C electrodes. Therefore, these bifunctional electrodes have significant potential for realistic large‐scale production of hydrogen as a replacement clean fuel to polluting and limited fossil‐fuels.
Three‐dimension nickel‐based electrocatalytic electrodes (Ni/Ni8P3 and Ni/Ni9S8) are developed for application in water splitting. The as‐obtained Ni/Ni8P3 catalytic electrode, particularly exhibiting excellent electrocatalytic activity and stability due to its advanced structure effects, can serve as a highly efficient and stable bifunctional catalyst for overall water splitting.
Scope: The proliferation and differentiation of intestinal stem cells (ISCs) are the basis of intestinal renewal and regeneration, and gut microbiota plays an important role in it. Dietary nutrition ...has the effect of regulating the activity of ISCs; however, the regulation effect of α‐linolenic acid (ALA) has seldom been reported.
Methods and Results: After intervening mice with different doses of ALA for 30 days, it is found that ALA (0.5 g kg−1) promotes small intestinal and villus growth by activating the Wnt/β‐catenin signaling pathway to stimulate the proliferation of ISCs. Furthermore, ALA administration increases the abundance of the Ruminococcaceae and Prevotellaceae, and promotes the production of short‐chain fatty acids (SCFAs). Subsequent fecal transplantation and antibiotic experiments demonstrate that ALA on the proliferation of ISCs are gut microbiota dependent, among them, the functional microorganism may be derived from Ruminococcaceae. Administration of isobutyrate shows a similar effect to ALA in terms of promoting ISCs proliferation. Furthermore, ALA mitigates 5‐fluorouracil‐induced intestinal mucosal damage by promoting ISCs proliferation.
Conclusion: These results indicate that SCFAs produced by Ruminococcaceae mediate ALA promote ISCs proliferation by activating the Wnt/β‐catenin signaling pathway, and suggest the possibility of ALA as a prebiotic agent for the prevention and treatment of intestinal mucositis.
In this work, it is shown that short‐chain fatty acids (SCFAs) produced by Ruminococcaceae mediate α‐linolenic acid (ALA) promote intestinal stem cells (ISCs) proliferation by activating the Wnt/β‐catenin signaling pathway, and suggest the possibility of ALA as a prebiotic agent for the prevention and treatment of intestinal mucositis.
Application of the shallow water waves in environmental engineering and hydraulic engineering is seen. In this paper, a (3+1)-dimensional generalized nonlinear evolution equation (gNLEE) for the ...shallow water waves is investigated. The
N
th-order Wronskian, Gramian and Pfaffian solutions are proved, where
N
is a positive integer. Soliton solutions are constructed from the
N
th-order Wronskian, Gramian and Pfaffian solutions. Moreover, we analyze the second-order solitons with the influence of the coefficients in the equation and illustrate them with graphs. Through the Hirota-Riemann method, one-periodic-wave solutions are derived. Relationship between the one-periodic-wave solutions and one-soliton solutions is investigated, which shows that the one-periodic-wave solutions can approach to the one-soliton solutions under certain conditions. We reduce the (3+1)-dimensional gNLEE to a two-dimensional planar dynamic system. Based on the qualitative analysis, we give the phase portraits of the dynamic system.
Studies on the water waves contribute to the design of the related industries, such as the marine and offshore engineering, while the media with the negative refractive index can be applied as the ...carrier media in fiber optics. In consideration of the inhomogeneities of the media and nonuniformities of the boundaries in the real physical backgrounds, a quintic time-dependent-coefficient derivative nonlinear Schrödinger equation for certain hydrodynamic wave packets or medium with the negative refractive index is investigated in this paper. Bilinear forms and the
N
-soliton solutions with respect to the nonzero background, which are different from those in the existing studies, are derived under the certain constraints. Conditions for the dark/anti-dark/gray solitons are deduced due to the properties of the solitons derived via the asymptotic analysis. Effects of the dispersion coefficient
λ
(
t
)
, self-steepening coefficient
α
(
t
)
, cubic nonlinearity
μ
(
t
)
and quintic nonlinearity
ν
(
t
)
on the interactions between the anti-dark and gray solitons under the certain condition are investigated. Interactions among the dark, anti-dark and gray solitons are discussed under two cases: when
α
(
t
)
/
λ
(
t
)
and
μ
(
t
)
/
λ
(
t
)
are the constants, whether the interaction is elastic or not depends on whether
λ
(
t
)
,
α
(
t
)
and
μ
(
t
)
are the constants or the functions of
t
; when
α
(
t
)
/
λ
(
t
)
and
μ
(
t
)
/
λ
(
t
)
are related to
t
, if the velocity of the soliton is a periodic function of
t
, the propagation of the corresponding soliton is periodic and the corresponding interaction is inelastic. Interactions among the three/four solitons are described to be elastic or inelastic based on the changes in the velocities and waveforms of the three/four solitons after the interactions.
Plasmas are believed to be possibly “the most abundant form of ordinary matter in the Universe”. In this paper, a coupled nonautonomous nonlinear Schrödinger system is investigated, which describes ...the propagation of two envelope solitons in a weakly inhomogeneous plasma with the t-dependent linear and parabolic density profiles and nonconstant collisional damping. Lax pair with the nonisospectral parameter and infinitely-many conservation laws are derived. Based on the Lax pair, the Nth-step Darboux transformation is constructed. Utilizing the Nth-step Darboux transformation, we obtain the breather and rogue wave solutions, and find that the amplitude of the nonzero background is nonconstant and dependent on the inhomogeneous coefficients in the system under investigation. Characteristics of the breathers and rogue waves are discussed, and effects of the inhomogeneous coefficients on the breathers and rogue waves are analyzed. Breathers and rogue waves with the dark or bright soliton together are also constructed and their characteristics are discussed. We find that the dark and bright solitons can coexist and generate the breather-like waves.
Fluids, as a phase of matter including liquids, gases and plasmas, are seen to be common in nature, the study of which helps the design in the related industries. In this paper, we optimize the ...Pfaffian technique and investigated the Boiti–Leon–Manna–Pempinelli equation for an irrotational incompressible fluid. Higher-order hybrid solutions consisting of the
L
lumps,
M
breathers and
N
solitons are constructed with
L
,
M
and
N
being positive integers. Relative extrema of the breather and lump are presented, respectively. Breather is found to be localized along the curve
a
1
x
+
b
1
φ
(
y
)
+
ω
1
t
+
ξ
1
=
0
and periodic along the curve
α
1
x
+
β
1
φ
(
y
)
+
γ
1
t
+
θ
1
=
0
. Under the lump existence condition, higher-order rogue wave solutions do not exist. Hybrid solutions composed of breathers, lumps and solitons are illustrated graphically. It can be found that when certain parameters are chosen, the breather, lump and soliton included in the hybrid solutions possess the same properties as those of the breather and lump solutions.
Fluid mechanics has the applications in a wide range of disciplines, such as oceanography, astrophysics, meteorology, and biomedical engineering. Under investigation in this paper is the (
2
+
1
...)-dimensional generalized Caudrey–Dodd–Gibbon–Kotera–Sawada equation in fluid mechanics. Via the Pfaffian technique and certain constraint on the real constant
α
, the
N
th-order Pfaffian solutions are derived. One- and two-soliton solutions are obtained via the
N
th-order Pfaffian solutions. Based on the Hirota–Riemann method, one- and two-periodic wave solutions are constructed. With the help of the analytic and graphic analysis, we notice that: (1) of the one soliton, amplitude is irrelevant to
γ
, a real constant coefficient in the equation, velocity along the
x
direction is independent of
γ
, while velocity along the
y
direction is proportional to
γ
; (2) one soliton keeps its amplitude and velocity invariant during the propagation and total amplitude of the two solitons in the interaction region is lower than that of any soliton; (3) one-periodic wave can be viewed as a superposition of the overlapping solitary waves, placed one period apart; (4) periodic behaviors for the two-periodic wave exist along the
x
and
y
directions, respectively; (5) under certain limiting conditions, one-periodic wave solutions approach to the one-soliton solutions and two-periodic wave solutions approach to the two-soliton solutions.
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