The striped flea beetle (SFB, Phyllotreta striolata) can cause serious harm to cruciferous crops in both the larval and adult stages. Presently, there are no other sustainable alternatives to the use ...of chemical pesticides for controlling SFB infestation. In this study, the use of a seed-pelletized coating of spinetoram effectively reduced the numbers of SFB and its feedings on the flowering cabbage seedlings, whereas, in combination with the insect-proof net, it controlled the SFB infestation throughout the cabbage growth period. The analysis of the pesticide residues in soil and different cabbage parts indicated the degradation dynamics of spinetoram. The concentration of spinetoram in cabbage parts decreased over time, while increased first and subsequently decreased in soil. Furthermore, estimation of the half-life of spinetoram revealed that via seed-palletized application spinetoram half-life was found to be 2.82 days in soil, 4.21 days in the root, 5.77 days in the stem, and 3.57 days in the leaf, respectively. Both the lower pesticide residues and the half-life of spinetoram in soil and cabbage parts suggested it to be a promising environment and food-safe pesticide in controlling SFB. Moreover, the seed-pelletized coating ensured a sustainable release of spinetoram that can reduce the pesticide application frequency and be cost-effective and pocket-friendly for the farmers.
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Highlights
The growth of high-quality single-crystalline Te nanobelts is reported by introducing atomically flat hexagonal boron nitride (h-BN) nanoflakes into the chemical vapor deposition system as ...the growth substrate.
The field-effect transistor based on Te grown on h-BN exhibits an ultrahigh hole mobility up to 1370 cm
2
V
−1
s
−1
at room temperature.
The lack of stable
p
-type van der Waals (vdW) semiconductors with high hole mobility severely impedes the step of low-dimensional materials entering the industrial circle. Although
p
-type black phosphorus (bP) and tellurium (Te) have shown promising hole mobilities, the instability under ambient conditions of bP and relatively low hole mobility of Te remain as daunting issues. Here we report the growth of high-quality Te nanobelts on atomically flat hexagonal boron nitride (h-BN) for high-performance
p
-type field-effect transistors (FETs). Importantly, the Te-based FET exhibits an ultrahigh hole mobility up to 1370 cm
2
V
−1
s
−1
at room temperature, that may lay the foundation for the future high-performance
p
-type 2D FET and metal–oxide–semiconductor (p-MOS) inverter. The vdW h-BN dielectric substrate not only provides an ultra-flat surface without dangling bonds for growth of high-quality Te nanobelts, but also reduces the scattering centers at the interface between the channel material and the dielectric layer, thus resulting in the ultrahigh hole mobility
.
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Subtle structural changes during electrochemical processes often relate to the degradation of electrode materials. Characterizing the minute-variations in complementary aspects such as crystal ...structure, chemical bonds, and electron/ion conductivity will give an in-depth understanding on the reaction mechanism of electrode materials, as well as revealing pathways for optimization. Here, vanadium pentoxide (V
2
O
5
), a typical cathode material suffering from severe capacity decay during cycling, is characterized by
in-situ
X-ray diffraction (XRD) and
in-situ
Raman spectroscopy combined with electrochemical tests. The phase transitions of V
2
O
5
within the 0–1 Li/V ratio are characterized in detail. The V–O and V–V distances became more extended and shrank compared to the original ones after charge/discharge process, respectively. Combined with electrochemical tests, these variations are vital to the crystal structure cracking, which is linked with capacity fading. This work demonstrates that chemical bond changes between the transition metal and oxygen upon cycling serve as the origin of the capacity fading.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Irreversible phase transition caused capacity fading has been considered as an obstacle for rechargeable batteries. An in-depth investigation of the irreversible phase transition is critical for ...understanding the reaction mechanism and developing advanced batteries. In this work, taking vanadium oxide and its alkali ion-stabilized intercalation compounds (A-V-O, A = Li, Na, K) as prototypes, utilizing operando characterizations, we discovered coupled discontinuous (interlayer)-continuous (intralayer) transitions in the stabilized multielectron intercalation cathodes. The highly ordered crystal of vanadium pentoxide irreversibly transfers to a disordered/amorphous structure after the first cycle, whereas A-V-O enables reversible discontinuous lattice transitions at the interlayer pathway for facilitating lithium diffusion. Among the A-V-O family, K-V-O, with the highest capacity retention, shows a coupled discontinuous-continuous transition, which exhibits a continuous transition and the minimum volume change at the V-O intralayer during lithium intercalation/deintercalation. These coupled discontinuous-continuous lattice transitions were captured for the first time in cathode materials. It implies that the suitable ion intercalation induced continuous intralayer transition inhibits the irreversible ion intercalation and phase transition.
The development of manganese dioxide as the cathode for aqueous Zn‐ion battery (ZIB) is limited by the rapid capacity fading and material dissolution. Here, a highly reversible aqueous ZIB using ...graphene scroll‐coated α‐MnO2 as the cathode is proposed. The graphene scroll is uniformly coated on the MnO2 nanowire with an average width of 5 nm, which increases the electrical conductivity of the MnO2 nanowire and relieves the dissolution of the cathode material during cycling. An energy density of 406.6 Wh kg−1 (382.2 mA h g−1) at 0.3 A g−1 can be reached, which is the highest specific energy value among all the cathode materials for aqueous Zn‐ion battery so far, and good long‐term cycling stability with 94% capacity retention after 3000 cycles at 3 A g−1 are achieved. Meanwhile, a two‐step intercalation mechanism that Zn ions first insert into the layers and then the tunnels of MnO2 framework is proved by in situ X‐ray diffraction, galvanostatic intermittent titration technique, and X‐ray photoelectron spectroscopy characterizations. The graphene scroll‐coated metallic oxide strategy can also bring intensive interests for other energy storage systems.
Graphene scroll‐coated α‐MnO2 nanowires are studied as the cathode material for an aqueous Zn‐ion battery. The graphene layer increases the electrical conductivity of MnO2 nanowire and relieves the dissolution of the cathode material. An energy density of 406.6 Wh kg−1 can be reached, which is the highest specific energy value among all the cathode materials for aqueous Zn‐ion batteries so far.
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The aqueous zinc ion batteries (ZIBs) composed of inexpensive zinc anode and nontoxic aqueous electrolyte are attractive candidates for large-scale energy storage applications. However, their ...development is limited by cathode materials, which often deliver inferior rate capability and restricted cycle life. Herein, the VO2 nanorods show significant electrochemical performance when used as an intercalation cathode for aqueous ZIBs. Specifically, the VO2 nanorods display high initial capacity of 325.6 mAh g–1 at 0.05 A g–1, good rate capability, and excellent cycling stability of 5000 cycles at 3.0 A g–1. Furthermore, the VO2 unit cell expands in a, b, and c directions sequentially during the discharge process and contracts back reversibly during the charge process, and the zinc storage mechanism is revealed to be a highly reversible single-phase reaction by operando techniques and corresponding qualitative analyses. Our work not only opens a new door to the practical application of VO2 in ZIB systems but also broadens the horizon in understanding the electrochemical behavior of rechargeable ZIBs.
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Layered 2D materials, such as graphene, transition metal dichalcogenides, transition metal oxides, black phosphorus, graphitic carbon nitride, hexagonal boron nitride, and MXenes, have attracted ...intensive attention over the past decades owing to their unique properties and wide applications in electronics, catalysis, energy storage, biomedicine, etc. Further reducing the lateral size of layered 2D materials down to less than 10 nm allows for preparing a new class of nanostructures, namely, nanodots derived from layered materials. Nanodots derived from layered materials not only can exhibit the intriguing properties of nanodots due to the size confinement originating from the ultrasmall size, but also can inherit some unique properties of ultrathin layered 2D materials, making them promising candidates in a wide range of applications, especially in biomedicine and catalysis. Here, a comprehensive summary on the materials categories, advantages, synthesis methods, and potential applications of these nanodots derived from layered materials is provided. Finally, personal insights about the challenges and future directions in this promising research field are also given.
Nanodots derived from layered materials not only exhibit the intriguing properties of traditional nanodots due to the size confinement effect, but also inherit some unique properties of layered materials, making them promising candidates in various applications. The state‐of‐the‐art progress on the preparation and applications of nanodots derived from layered materials is reviewed.
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Compared with most cathodes for lithium-ion batteries (LIBs), α-MoO3 exhibits high specific capacity and therefore receives widespread attention. However, due to its irreversible structural ...transformation, the capacity of α-MoO3 declines rapidly upon discharge-charge process. Herein, via H2 plasma etching, oxygen-deficient α-MoO3-x with improved electrochemical performance is prepared on the basis of pristine α-MoO3 (MoO3 (I)). The obtained MoO3 (II) (10 min etching) and MoO3 (III) (20 min etching) have reduced bandgap and expanded van der Waals gap (vdW gap). Electrochemical test results demonstrate MoO3(II) obtains the largest Li+ diffusion coefficient, the lowest charge transfer resistance and the slightest polarization. In situ X-ray diffraction characterization further reveals that during cycling, vdW gap of MoO3 (II) changes periodically within a small range, indicating a stabilized crystal structure. This work shows that moderate oxygen vacancies can enhance the capacity and stabilize the structure of molybdenum trioxide cathode for LIBs, which has great potential in other cathode materials.
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•Oxygen-deficient α-MoO3-x is successfully prepared via H2 plasma etching.•The as-prepared α-MoO3-x has largely expanded van der Waals gap and reduced bandgap.•The α-MoO3-x with moderate O vacancies shows much enhanced structural stability and specific capacity.•The increased conductivity can explain the improved electrochemical performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Phase engineering of nanomaterials (PEN) is critically important for the preparation of nanomaterials with new phases, which are key for the investigation of phase‐dependent physicochemical ...properties and applications. This essay presents the state‐of‐the‐art development of PEN for the unique properties of nanomaterials with unconventional phases and their applications in energy storage and conversion and catalytic reactions. Finally, personal perspectives on the challenges and future opportunities of PEN in various applications are also provided.
Phase engineering of nanomaterials (PEN) is an important strategy for the preparation of nanomaterials with unconventional phases, which is critical for the investigation of phase‐dependent physicochemical properties and applications. This essay presents the state‐of‐the‐art development of PEN and its applications in a variety of energy storage and conversion and catalytic reactions.
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As a novel and potential transition metal dichalcogenide (TMDC), NbSe2 has low ion diffusion barrier when applied in energy-storage systems, such as traditional lithium-ion batteries and novel ...magnesium-ion batteries (MIBs). In this work, we have developed a novel hexagonal NbSe2 material with a nanosized surface via a facile microwave–hydrothermal method. The Li+-storage mechanism of NbSe2 with surface conversion and internal intercalation is thoroughly revealed by in situ X-ray diffraction (XRD), ex situ high-resolution transmission electron microscopy, and ex situ scanning electron microscopy. Besides, Mg2+ intercalation mechanism is confirmed via ex situ XRD and ex situ X-ray photoelectron spectroscopy for the first time. In addition, as the cathode for MIBs, NbSe2 with a nanosized surface exhibits a high rate capacity of 101 mA h g–1 at 200 mA g–1 with a high discharge plateau at 1.30 V. Our work builds a deep understanding of ion-storage mechanisms in TMDCs and provides guidance for designing new electrode materials with high electrochemical performances.
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