Spontaneous Orientation Polarization of Anisotropic Equivalent Dipoles Harnessed by Entropy Engineering for Ultra‑Thin Electromagnetic Wave Absorber

The synthesis of carbon supporter/nanoscale high-entropy alloys(HEAs)electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engineering of conductive/dielectric genes.Electron migration modes within HEAs as manipulated by the electronegativity,valence electron configurations and molar proportions of constituent elements determine the steady state and efficiency of equivalent dipoles.Herein,enlightened by skin-like effect,a reformative carbothermal shock method using carbonized cellulose paper(CCP)as carbon supporter is used to preserve the oxygencontaining functional groups(O·)of carbonized cellulose fibers(CCF).Nucleation of HEAs and construction of emblematic shell-core CCF/HEAs heterointerfaces are inextricably linked to carbon metabolism induced by O·.Meanwhile,the electron migration mode of switchable electronrich sites promotes the orientation polarization of anisotropic equivalent dipoles.By virtue of the reinforcement strategy,CCP/HEAs composite prepared by 35%molar ratio of Mn element(CCP/HEAs-Mn_(2.15))achieves efficient electromagnetic wave(EMW)absorption of−51.35 dB at an ultra-thin thickness of 1.03 mm.The mechanisms of the resulting dielectric properties of HEAs-based EMW absorbing materials are elucidated by combining theoretical calculations with experimental characterizations,which provide theoretical bases and feasible strategies for the simulation and practical application of electromagnetic functional devices(e.g.,ultra-wideband bandpass filter).

Tracking charge transfer pathways in SrTiO_(3)/CoP/Mo_(2)C nanofibers for enhanced photocatalytic solar fuel production

Photocatalytic solar fuel generation is currently a hot topic because of its potential for solving the energy crisis owing to its low cost and zero-carbon emissions.However,the rapid bulk recombination of photoexcited carrier pairs is a fundamental disadvantage.To resolve this problem,we synthesized a dual cocatalysts system of cobalt phosphide(Co P)and molybdenum carbide(Mo_(2)C)embedded on strontium titanate(Sr TiO_(3))nanofibers.Compared with those of pristine SrTiO_(3) and binary samples,the dual cocatalysts system(denoted SCM)showed a significant improvement in the hydrogen evolution and CO_(2) reduction performance.Further,the structure of SCM effectively promoted spatial charge separation and enhanced the photocatalytic performance.In addition,the Schottky junction formed between the SrTiO_(3) and cocatalysts enabled the rapid transfer of photoexcited electrons from SrTiO_(3) to the cocatalysts,resulting in effective separation and prolonged photoexcited electron lifetimes.The electron migration route between SrTiO_(3) and the cocatalysts was determined by in situ irradiation X-ray spectroscopy,and band structures of Sr TiO_(3) and the cocatalysts are proposed based on results obtained from UV-vis diffraction reflection spectroscopy and ultraviolet photoelectron spectroscopy measurements.On the basis of our results,the dual cocatalysts unambiguously boosts charge separation and enhances photocatalytic performance.In summary,we have investigated the flux of photoexcited electrons in a dual cocatalysts system and provided a theoretical basis and ideas for subsequent research.

Rational distribution of Ru nanodots on 2D Ti_(3−x)C_(2)T_(y)/g-C_(3)N_(4)heterostructures for boosted photocatalytic H_(2)evolution

Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the space distribution of metal NDs for optimizing charge transport pathways remains a significant challenge,particularly in two-dimensional(2D)face-to-face heterostructures.Herein,we develop a simple targeted self-reduction strategy for selectively loading Ru NDs onto the Ti_(3−x)C_(2)T_(y)(TC)surface of 2D TC/g-C_(3)N_(4)(CN)heterojunction based on the reductive Ti vacancy defects creatively increased during the preparation of TC/CN by reducing calcination.Notably,the optimized Ru/TC/CN photocatalyst exhibits an outstanding H_(2)evolution rate of 3.21 mmol·g^(−1)·h^(−1)and a high apparent quantum efficiency of 30.9%at 380 nm,which is contributed by the unidirectional transfer of the photogenerated electrons from CN to Ru active sites(CN→TC→Ru)and the suppressed backflow of electrons from Ru sites to CN,as revealed by comprehensive characterizations and density functional theory(DFT)calculations.This work provides a novel strategy for synthesizing the highly efficient photocatalysts with a controllable charge transfer paths,which will boost the development of photocatalysis.

Tetracycline removal by a magnetic heterojunction Cu_(2)O/CoFe_(2)O_(4) activating peroxymonosulfate

The electron transfer mechanism in the process of peroxymonosulfate(PMS)activation using heterojunction catalyst was controversial.In this work,magnetic heterojunction Cu_(2)O/CoFe_(2)O_(4)(CC)was first synthesized to activate PMS.An innovative reaction mechanism based on built-in electric field-driven electron migration from Cu2O to CoFe2O4 and effective magnetic moment of CC for enhancing PMS activation was proposed.Meanwhile,the CC/PMS system was used for efficient removal of antibiotic tetracycline(TC).Under optimal conditions,98.0%TC could be removed using CC/PMS catalytic system after only 30 min.The catalytic activity was higher than that of Cu_(2)O/PMS and CoFe_(2)O_(4)/PMS.Meanwhile,the impact of solution pH on TC removal was insignificant,suggesting the pH-insensitive PMS activation ability of CC.Besides,the coexisting inorganic ions in the environment,such as HCO_(3)-,H_(2)PO4-,NO_(3)-,Cl-and humic acid(HA)as representative of natural organic matter,did not inhibit TC removal in CC/PMS system.Furthermore,CC/PMS system exhibited excellent reusability with more than94.0%TC removal after the 5th reuse.Electron paramagnetic resonance(EPR)tests and quenching experiments showed that O_(2)·-and 1O_(2) played vital roles in TC removal.The intermediate products and corresponding toxicity assessment revealed that this catalytic system could reduce TC toxicity.This work provided new insights into the PMS activation mechanism using heterogeneous magnetic catalysts,including transition metal oxide.