RESUMEN
The photocatalytic activity of g-C3N4 can be enhanced by improving photoinduced carrier separation and exposing sufficient reactive sites. In this study, we synthesized B-doped porous tubular g-C3N4 (BCNT) using a H3BO3-assisted supramolecular self-template method, wherein H3BO3 helped in B-doping, building a porous structure, and maintaining one-dimensional nanotubes. The tubular structure had an ultrathin tube wall and large aspect ratio, which are conducive to the directional transmission and separation of photogenerated carriers; moreover, the abundant pore structure of the tube wall could fully expose the reactive sites. The introduction of B and the cyano group modulated the bandgap of g-C3N4 and elevated the position of the conduction band, thus enhancing the photoreduction ability and effectively improving the hydrogen evolution performance. Consequently, the hydrogen evolution of BCNT-2 (220.8, 53.2 µmol·h-1) was 1.82 and 1.54 times that of ultrathin g-C3N4 nanosheets (CNN, 121.3, 34.6 µmol·h-1) under simulated sunlight and LED lamp irradiation, respectively. Thus, this work provides in-depth insights into the rational design of one-dimensional g-C3N4 nanotubes with high hydrogen evolution activity under visible irradiation.
RESUMEN
[Purpose] The main objective of this study was to assess the reliability of the method for testing the attention distribution ability of the elderly using mental arithmetic response time. [Participants and Methods] The participants included in the study were 30 healthy elderly people (over 65â years old), 11 males and 19 females, eight of whom had experienced falls in the past year.In the quiet standing position and the free walking state, we recorded the mental calculation response time of the participants by calculating the two-digit plus or minus one-digit values within 100. The test of the two states were tested in 24 hour intervals. [Results] In the quiet standing and free walking state, the correlation coefficient of the mental arithmetic response time group of the elderly was excellent. The intra-group correlation coefficient of mental arithmetic response time of more than three tests under free walking was greater than 0.9. [Conclusion] We found that the mental arithmetic response time can be used to objectively evaluate the ability of attention distribution in the elderly.
RESUMEN
High-capacity germanium-based anode materials are alternative materials for outstanding electrochemical performance lithium-ion batteries (LIBs), but severe volume variation and pulverization problems during charging-discharging processes can seriously affect their electrochemical performance. In addressing this challenge, a simple strategy was used to prepare the self-assembled GeOX/Ti3C2TX composite in which the GeOX nanoparticles can grow directly on Ti3C2TX layers. Nanoscale GeOX uniformly renucleates on the surface and interlayers of Ti3C2TX, forming the stable multiphase structure, which guarantees its excellent electrochemical performance. Electrochemical evaluation has shown that the rate capability and reversibility of GeOX/Ti3C2TX are both greatly improved, which delivers a reversible discharge specific capacity of above 1400 mAh g-1 (at 100 mA g-1) and a reversible specific capacity of 900 mAh g-1 after 50 cycles while it still maintains a stable specific capacity of 725 mAh g-1 at 5000 mA g-1. Furthermore, the composite exhibits an exceptionally superior rate capability, making it a good electrochemical performance anode for LIBs.
RESUMEN
MoSe2 is a prospective anode material for Na-ion batteries because of its layered structure and high theoretical capacity, while the unsatisfied electrochemical performance limits its further development. Herein, we report MoSe2 nanosheets anchored on dual-heteroatoms functionalized graphene by a solvothermal method. The heteroatoms and carbon matrix coexist in the form of graphitic-N/pyridinic-N/pyrrolic-N and P-C/PâO bonds, which result in excellent electronic conductivity of the materials and provide abundant active sites for electrochemical process. Results indicated that organic intercalation increased the layer spacing of the materials to facilitate sodium-ion diffusion, and the in situ formed carbon networks improved the conductivity among the layers of the materials and alleviated volume expansion during the continued charge and discharge process. As an anode of Na-ion batteries, the nanosheets materials exhibited ultrahigh rate performance and deliver capacities of approximately 200 mAh g-1 at the current density of 10 A g-1. The ultrahigh-rate performance can be attributed to its unique nanosheets structure, the dual-heteroatoms functionalized graphene, and the considerable pseudocapacitive quality of the material.
RESUMEN
A multiple linkage modification (MLM) method was investigated to comprehensively improve the properties of lithium-rich layered oxides. MLM Li1.2Mn0.54Ni0.13Co0.13O2 was successfully synthesized via continuous and appropriate heat treatment. The synthesized Li1.2Mn0.54Ni0.13Co0.13O2 particles were coated with a Li2ZrO3 layer and doped with Zr4+ by using a Zr compound as the MLM reagent. The Li2ZrO3 coating layer could protect materials from the corrosion of hydrogen fluoride, and the structure of the base materials was stabilized due to Zr4+ doping. In addition, the formation of Li2ZrO3 captured inactive residual lithium on the surface and absorbed lithium of host materials, thereby leading to the reduction in the Li/M ratio of materials and promoting the first-cycle Coulombic efficiency. The MLM material delivered the highest initial cycle Coulombic efficiency (â¼85%), the best cycle and rate performance among bare and ZrO2-coated particles. These results indicate that MLM is an important technique for improving the performance of electrode materials.