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Electronic regulation of two-dimensional (2D) transition metal dichalcogenides (TMDCs) is a crucial step towards next-generation optoelectronics and electronics. Here, we demonstrate controllable and selective-area defect engineering in 2D molybdenum disulfide (MoS2) using a focused ion beam with a low-energy gallium ion (Ga+) source. We find that the surface defects of MoS2 can be tuned by the precise control of ion energy and dose. Furthermore, the field-effect transistors based on the monolayer MoS2 show a significant threshold voltage modulation over 70 V after Ga+ irradiation. First-principles calculations reveal that the Ga impurities in the monolayer MoS2 introduce a defect state near the Fermi level, leading to a shallow acceptor level of 0.25 eV above the valence band maximum. This defect engineering strategy enables direct writing of complex pattern at the atomic length scale in a controlled and facile manner, tailoring the electronic properties of 2D TMDCs for novel devices.

Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode is considered to be among the most promising candidates for high-energy-density lithium-ion batteries (LIBs). However, both capacity fading and structural degradation occur during long-term cycling, which extremely limit the commercial applications of NCM811, especially at a high cutoff voltage (>4.3 V). Here, we design a double-shell hybrid nanostructure consisting of a Li2SiO3 coating layer and a cation-mixed layer (Fm3m phase) to improve its electrochemical performance. Consequently, the Si-modified NCM811 electrode shows outstanding cycling stability with a 95.2% capacity retention at 4.3 V after 100 cycles and 87.3% at a 4.5 V high cutoff voltage after 100 cycles. This designed double-shell hybrid nanostructure alleviates side reactions, structural degradation, and internal cracking, effectively enhancing the surface structural stability. This efficient strategy provides a valuable step toward further commercial applications of the LiNi0.8Co0.1Mn0.1O2 cathode and enriches the fundamental understanding of layered cathode materials.

The most abundant rare earth metals in the Earth's crust have received considerable recent attention as efficient electrocatalysts for full water splitting, but it is highly desired to explore a new strategy to improve their catalytic activity. In this communication, we report the development of nanoporous CeO2 nanowire array on Ti mesh (np-CeO2/TM) derived from MnO2–CeO2/TM via an acid etching strategy, and MnO2 acts as a pore-forming agent through selective etching with oxalic acid. As a rare earth metal catalyst, np-CeO2/TM needs an overpotential of 91 mV for the hydrogen evolution reaction (HER) and 279 mV for the oxygen evolution reaction (OER) to drive a current density of 10 mV cm−2 in 1.0 M KOH, 93 mV and 101 mV less than that needed by MnO2–CeO2/TM, respectively. We also demonstrate the use of np-CeO2/TM to make a two-electrode electrolyzer capable of driving 10 mV cm−2 at a cell voltage of 1.57 V.

Currently, there is an urgent demand for Ni-rich cathode materials with excellent electrochemical properties under harsh conditions; however, obtaining such materials is very challenging. Here, we propose an innovative modification strategy that combines gradient phosphate polyanion doping and dual-conductive layer (Li3PO4-PANI) coating. The phosphate polyanion gradient doping can be described as acting in a “support role” to optimize the crystal structure. Moreover, the dual-conductive (Li3PO4-PANI) layers can be described as acting in a “palisade role” to inhibit side reactions and enhance the ionic/electronic conductivity of the NCM cathode. For the NCM cathode, this strategy synergistically achieves three main objectives: enhancement of structure stability, improvement of the ionic/electronic conductivity of the interface, and reduction of residual lithium salts. The modified NCM cathode delivers superior cycling stability, with 81.4% capacity retention after 100 cycles (4.5 V/55 °C), whereas the orig...

Achieving a highly stabilized surface structure is the key to successfully enhancing the cycling stability of LiNi0.8Co0.1Mn0.1O2 (NCM) cathode material for Li-ion batteries at high cut-off voltage (4.5 V). In this work, we report a highly surface-stabilized NCM material via a high-valent titanium ion (Ti4+)-induced nanostructured hybrid surface with a core-shell structure. Consequently, the Ti-modified LiNi0.8Co0.1Mn0.1O2 cathode provides an excellent cycling stability with 92.3% capacity retention (100 cycles, 0.5C, 2.7–4.5 V). This proposed hybrid core-shell nanostructure prominently mitigates the surface structural degradations, continuous microcracking and parasitic reactions, effectively improving the surface structural stability. This efficient strategy provides a step towards further commercial application of the LiNi0.8Co0.1Mn0.1O2 material and can be extended to other layered cathode materials.

The development of high-performance nanocatalysts relies essentially on the generation of stable and active surface sites at the atomic scale through synthetic control of the size, shape, and chemical composition of nanoscale metals and metal oxides. One promising route is to induce the exposure of catalytically active high-index facets of nanostructures through shape-controlled syntheses. We have designed and prepared two types of Pd nanoshells that are enclosed by high-index {730} and {221} facets through heteroepitaxial growth on high-index-faceted Au nanocrystals. The turnover numbers per surface atom of the high-index-faceted Pd nanoshells have been found to be 3-7 times those of Pd and Au-Pd core-shell nanocubes that possess only {100} facets in catalyzing the Suzuki coupling reaction. These results open up a potential for the development of inexpensive and highly active metal nanocatalysts.

Bimetallic Pt–Pd nanoicosahedrons (NIs) with multiple {111} twins were obtained through a facile one-pot hydrothermal synthesis in a high shape selectivity of 82%. The {111}-enclosed NIs exhibited superior electrocatalytic activities to {111}-enclosed Pt–Pd nanotetrahedrons as well as commercial Pt catalysts (Pt black and Pt/C) for methanol oxidation.

An effective synthetic strategy is demonstrated for preparing highly ordered crystallized mesoporous TiO(2) by introducing rare earth in the synthesis process; the obtained product exhibits near-infrared photocatalytic activity.

20 tree plots, 60 shrub plots, 100 grass plots and 100 litter plots were established in Central Tianshan Mountain to study the biomass and carbon storage of P. schrenkiana var. tianshanica — A. millefolium community, P. schrenkiana var. tianshanica — S. pohuashanensis community and P. schrenkiana var. tianshanica — S. pseudosabina community. Results showed that: (1) Biomass of above ground and below ground of P. schrenkiana var. tianshanica made up about 85.27 % and 14.73 % of the totals, respectively. Biomass of stems, branches and leaves made up 52.99 %, 29.16 % and 13.55 % of the totals, respectively. (2) Total biomass of P. schrenkiana var. tianshanica — A. millefolium, P. schrenkiana var. tianshanica — S. pohuashanensis and P. schrenkiana var. tianshanica — S. pseudosabina community was 259.94 thm2, 210.97 thm2 and 91.39 thm2, respectively. Biomass of tree layers of three communities above mentioned was 248.1 thm2, 194.3 thm2 and 72.1 thm2, respectively. Biomass of shrub layers of three communities above mentioned was 0.2 thm2, 9.9 thm2 and 17.1 thm2, respectively. Biomass of herbage layers was 0.18 thm2, 0.29 thm2 and 0.28 thm2, respectively. Biomass of litter layers was 11.48 thm2, 6.54 thm2 and 1.92 thm2, respectively. (3) Carbon storage of three communities above mentioned was 130.87 thm2, 106.00 thm2 and 45.83 thm2, respectively. Carbon storage of tree layers of three communities above mentioned was 124.03 thm2, 97.14 thm2 and 36.03 thm2, respectively. Carbon storage of shrub layers was 0.11 thm2, 4.94 thm2 and 8.56 thm2. Carbon storage of herbage layers was 0.08 thm2, 0.13 thm2 and 0.13 thm2, respectively. Carbon storage of litter layers was 6.66 thm2, 3.79 thm2 and 1.11thm2, respectively.

Pt/CeO(2) hetero-nanocomposites were prepared from Pt/CeO(2)@SiO(2) obtained by a microemulsion-mediated method. Facilitated by the earlier calcination under the protection of a silica shell, the as-formed Pt/CeO(2) hetero-nanocomposites exhibit a good thermal stability, which can preserve their pristine properties after subsequent calcination at even 450 degrees C. The thermally stable Pt/CeO(2) hetero-nanocomposites possess the characteristics of small particle size, low aggregation, and maximized Pt/CeO(2) interfaces and thus exhibit high catalytic activity in CO oxidation.