With the rapid development of twodimensional MXene materials,numerous preparation strategies have been proposed to enhance synthesis efficiency,mitigate environmental impact,and enable scalability for large-scale prod...With the rapid development of twodimensional MXene materials,numerous preparation strategies have been proposed to enhance synthesis efficiency,mitigate environmental impact,and enable scalability for large-scale production.The compound etching approach,which relies on cationic oxidation of the A element of MAX phase precursors while anions typically adsorb onto MXene surfaces as functional groups,remains the main prevalent strategy.By contrast,synthesis methodologies utilizing elemental etching agents have been rarely reported.Here,we report a new elemental tellurium(Te)-based etching strategy for the preparation of MXene materials with tunable surface chemistry.By selectively removing the A-site element in MAX phases using Te,our approach avoids the use of toxic fluoride reagents and achieves tellurium-terminated surface groups that significantly enhance sodium storage performance.Experimental results show that Te-etched MXene delivers substantially higher capacities(exceeding 50%improvement over conventionally etched MXene)with superior rate capability,retaining high capacity at large current densities and demonstrating over 90%capacity retention after 1000 cycles.This innovative synthetic strategy provides new insight into controllable MXene preparation and performance optimization,while the as-obtained materials hold promises for high-performance sodium-ion batteries and other energy storage systems.展开更多
Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450...Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450℃induces significant temperature gradients,resulting in a proliferation of defects.The scarcity of comprehensive research on this crystal’s defects hinders the enhancement of crystal quality.In this study,we employed the chemical etching method to examine the etching effects on Lu_(2)O_(3)crystals under various conditions and to identify the optimal conditions for investi⁃gating the dislocation defects of Lu_(2)O_(3)crystals(mass fraction 70%H3PO4,160℃,15-18 min).The morphologies of dislocation etch pits on the(111)-and(110)-oriented Lu_(2)O_(3)wafers were characterized using microscopy,scanning electron microscopy and atomic force microscopy.This research addresses the gap in understanding Lu_(2)O_(3)line defects and offers guidance for optimizing the crystal growth process and improving crystal quality.展开更多
Systematic CR-39 bulk etching experiments were conducted over a wide range of concentrations(2–30 N)of NaOH-based etchant.Critical analysis and a deep discussion of the results are presented.A comprehensive nuclear t...Systematic CR-39 bulk etching experiments were conducted over a wide range of concentrations(2–30 N)of NaOH-based etchant.Critical analysis and a deep discussion of the results are presented.A comprehensive nuclear track chemical etching data bank was developed.Three regimes of CR-39 bulk etching were identified.Regime I spans etchant concentrations from 2 to 12 N.Regime II spans concentrations from 12 to 25 N.We call this the dynamic bulk etching regime.Regime III is for concentrations greater than 25 N.In this regime,the bulk etch rate is saturated with respect to the etchant concentration.This classification is discussed and explained.The role of ethanol in NaOH-based etchants is explored and discussed.A parameter called the“reduced bulk etch rate”is defined here,which helps in analyzing the dependence of bulk etching on the amount of ethanol in the etchant.The bulk etch rate shows a natural logarithmic dependence on the density of ethanol in the etchant.展开更多
The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method na...The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method named plasma-based atom-selective etching(PASE)is proposed to achieve the highly efficient,atomic-scale,and damage-free polishing of β-Ga_(2)O_(3).The plasma is excited through the inductive coupling principle and carbon tetrafluoride is utilized as the main reaction gas to etch β-Ga_(2)O_(3).The core of PASE polishing of β-Ga_(2)O_(3)is the remarkable lateral etching effect,which is ensured by both the intrinsic property of the surface and the extrinsic temperature condition.As revealed by density functional theory-based calculations,the intrinsic difference in the etching energy barrier of atoms at the step edge(2.36 eV)and in the terrace plane(4.37 eV)determines their difference in the etching rate,and their etching rate difference can be greatly enlarged by increasing the extrinsic temperature.The polishing of β-Ga_(2)O_(3)based on the lateral etching effect is further verified in the etching experiments.The Sa roughness of β-Ga_(2)O_(3)(001)substrate is reduced from 14.8 nm to 0.057 nm within 120 s,and the corresponding material removal rate reaches up to 20.96μm·min^(−1).The polished β-Ga_(2)O_(3)displays significantly improved crystalline quality and photoluminescence intensity,and the polishing effect of PASE is independent of the crystal face of β-Ga_(2)O_(3).In addition,the competition between chemical etching and physical reconstruction,which is determined by temperature and greatly affects the surface state of β-Ga_(2)O_(3),is deeply studied for the first time.These findings not only demonstrate the high-efficiency and high-quality polishing of β-Ga_(2)O_(3)via atmospheric plasma etching but also hold significant implications for guiding future plasma-based surface manufacturing of β-Ga_(2)O_(3).展开更多
A new type of 785 nm semiconductor laser device has been proposed.The thin cladding and mode expansion layer structure incorporated into the epitaxy on the p-side significantly impacts the regulation of grating etchin...A new type of 785 nm semiconductor laser device has been proposed.The thin cladding and mode expansion layer structure incorporated into the epitaxy on the p-side significantly impacts the regulation of grating etching depth.Thinning of the p-side waveguide layer makes the light field bias to the n-side cladding layer.By coordinating the confinement effect of the cladding layer,the light confinement factor on the p-side is regulated.On the other hand,the introduction of a mode expansion layer facilitates the expansion of the mode profile on the p side cladding layer.Both these factors contribute positively to reducing the grating etching depth.Compared to the reported epitaxial structures of symmetric waveguides,the new structure significantly reduces the etching depth of the grating while ensuring adequate reflection intensity and maintaining resonance.Moreover,to improve the output performance of the device,the new epitaxial structure has been optimized.Based on the traditional epitaxial structure,an energy release layer and an electron blocking layer are added to improve the electronic recombination efficiency.This improved structure has an output performance comparable to that of a symmetric waveguide,despite being able to have a smaller gain area.展开更多
The low porosity and low permeability of shale remain the primary challenges in shale gas exploitation.Traditional single permeability enhancement techniques have shown limited efficacy,failing to effectively address ...The low porosity and low permeability of shale remain the primary challenges in shale gas exploitation.Traditional single permeability enhancement techniques have shown limited efficacy,failing to effectively address these technical bottlenecks.This study investigates the synergistic effects of perforationinduced permeability enhancement and acidizing operations on the mechanical properties and micropore structure of shale.The improved Split Hopkinson Pressure Bar(SHPB)technique was employed to simulate dynamic impact damage under triaxial stress conditions.Damaged and undamaged rock specimens were immersed in a 15%hydrochloric acid solution to fabricate combined-damage specimens and acid-etched specimens with varying damage states.Uniaxial compression tests,X-ray diffraction(XRD)analysis,and scanning electron microscopy(SEM)were conducted on these specimens.SEM images were binarized,and combined with low-temperature nitrogen adsorption tests,the effects of different damage states on the mechanical behavior,energy dissipation,micro-morphology,and pore characteristics of shale were systematically evaluated.Results demonstrate that the peak stress and elastic modulus of shale exhibit a negative correlation with acid-etching duration.The mechanical properties of combined-damage specimens are inferior to those of pure acid-etched specimens,with the minimum peak stress reaching 147.10 MPa—a 43.53%reduction compared to untreated specimens.The energy dissipation ratio significantly increases,with a maximum value of 34.74%.XRD analysis reveals that prolonged acid immersion effectively reduces the carbonate content in specimens,while composite treatment accelerates the reaction between rock matrix and acid solution.Microstructural characterization indicates that acid etching enhances the porosity of shale,particularly the area of mesopores and macropores,with more pronounced pore development and a fragmented interface structure.These findings deepen the understanding of physical mechanisms during shale gas extraction and provide critical theoretical support for optimizing integrated permeability enhancement technologies.展开更多
Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and...Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and life.This study incorporates the investigation of micrometeorites(MMs),abundant cosmic materials on Earth,to understand their influence on the chemical composition and biogeochemistry of the ocean.Comprehensive etching and flux analyses reveal that∼95%of cosmic spherules(CSs)entering seawater are etched or wholly dissolved,supplying nutrients to phytoplankton.Barred spherules show the highest degree of etching(∼19%),followed by porphyritic(∼17%),glass(∼15%),cryptocrystalline(∼12%),scoriaceous(∼10%),G-type(∼9%),and I-type(∼6%).Annually,∼3080 tonnes(t)of olivine from MMs dissolve into seawater,contributing∼495 t of Mg^(2+),∼1110 t of Fe^(2+),and∼1928 t of silicic acid.This signifies that over the Indian Ocean’s∼40 Myr history,∼23 Gt of olivine from CSs has dissolved,providing nutrients to seawater and sequestering∼7 Gt of CO_(2).The world ocean during this time has sequestered∼35 Gt of CO_(2),with fluctuations influenced by extraterrestrial activity.For instance,the Veritas event,lasting∼1.5 Myr,sequestered∼6 Gt of CO_(2)from the atmosphere.A robust flux calculation based on∼2 t of deep-sea sediments from 3610 MMs provides a more accurate estimate of the time-averaged flux of∼229 t yr^(−1).These comprehensive analyses reveal MM’s original characteristics,post-deposition processes,geological record and their overall impact on Earth’s marine environments,thereby contributing to our knowledge of the interconnection between terrestrial and extraterrestrial processes.展开更多
Horizontally aligned semiconducting single-wall carbon nanotube(s-SWCNT)arrays are ideal candidates for next-generation integrated circuits.However,the mainstream synthesis methods for obtaining s-SWCNTs mainly utiliz...Horizontally aligned semiconducting single-wall carbon nanotube(s-SWCNT)arrays are ideal candidates for next-generation integrated circuits.However,the mainstream synthesis methods for obtaining s-SWCNTs mainly utilize the differences in structure and chemical reactivity between them and their metallic counterparts.These differences are too small to greatly improve their purity and reproducibility.Here we report an energy engineering strategy to expand the etching energy barrier difference of SWCNTs with different conductivities.In addition to density functional theory calculations on the energy barrier change,hydrogenation of single-wall carbon nanotubes(SWCNTs)by hydrogen plasma treatment and reversible dehydrogenation by annealing were realized experimentally.The structure-dependent hydrogenation and following selective oxidative etching of SWCNTs were demonstrated.As a result,horizontally aligned s-SWCNT arrays with high purity were obtained.展开更多
FeCl_(3) solution is commonly used in the etching process of stainless steel.The typical etching waste liquid contains a significant amount of Fe^(3+),Fe^(2+),Cr^(3+),and Ni^(2+),making it difficult to reuse and posin...FeCl_(3) solution is commonly used in the etching process of stainless steel.The typical etching waste liquid contains a significant amount of Fe^(3+),Fe^(2+),Cr^(3+),and Ni^(2+),making it difficult to reuse and posing pollution issues.The FeCl_(3) etching waste liquid was the present subject,which aimed to extract Cr^(3+)and Ni^(2+)by selectively adjusting process parameters.Additionally,it investigates the migration behavior and phase transition mechanisms of the iron,chromium,and nickel in different solution systems during treatment,systematically elucidating the regeneration mechanisms of FeCl_(3) etching waste liquid.The results indicate that Cr and Ni can be recycled by controlling parameters such as pH value,temperature,and the valence states of the ions.Following a selective reduction of Fe^(3+)to Fe^(2+)using Fe powder,98.3%of Cr^(3+)was recovered by adjusting the solution’s pH.Subsequently,93.3%of Ni^(2+)was extracted from the Cr-depleted solution through further adjustments to the process parameters.The recovered Cr and Ni can be used to prepare Fe–Cr and Fe–Ni alloy powders.Furthermore,the FeCl_(3) etching solution was regenerated by oxidizing Fe^(2+)and recovering impurities.The theoretical support for the development of new processes for treating FeCl_(3) etching waste liquid is provided.展开更多
Germanium(Ge)-air battery,a new type of semiconductor-air battery,has garnered increasing attention owing to its environmental friendliness,safety,and excellent dynamic performance.However,the flat Ge anode is prone t...Germanium(Ge)-air battery,a new type of semiconductor-air battery,has garnered increasing attention owing to its environmental friendliness,safety,and excellent dynamic performance.However,the flat Ge anode is prone to passivation,owing to GeO_(2) accumulation on its surface,resulting in premature discharge termination.In this study,various nano-Ge pyramid structures(GePS)were prepared using chemical etching(CE)and metal-assisted chemical etching(MACE)methods to enhance the specific surface area of the Ge anode,thereby facilitating the dissolution of the passivation layer.This study revealed that the MACE method significantly accelerated the etching rate of the Ge surface,producing exceptional GePS.Furthermore,Ge-air batteries employing Ge anodes prepared using MACE demonstrated an exceptional discharge life of up to 9240 h(385 days).The peak power density reached 3.03mW/cm^(2),representing improvements of more than 2 times and 1.8 times,respectively,compared with batteries using flat Ge anodes.This study presents a straightforward approach to enhance Ge anode performance,thereby expanding the potential applications of Ge-air batteries.展开更多
Metal-organic frameworks(MOFs)have emerged as promising materials owing to their high surface areas,tunable pore sizes,and diverse functionalities.However,their practical deployment is frequently hindered by intrinsic...Metal-organic frameworks(MOFs)have emerged as promising materials owing to their high surface areas,tunable pore sizes,and diverse functionalities.However,their practical deployment is frequently hindered by intrinsic microporosity and structural fragility.In this review,we systematically analyze recent advancements in MOF etching techniques,which strategically modify framework architectures to enhance mass transport,expose active sites,and improve stability.The discussion encompasses a range of methods―including acid,base,ion,solvent,steam,selective,in-situ,pyrolysis,and physical etching―with emphasis on the underlying mechanisms that govern the formation of hierarchical pore structures,defect engineering,and heterojunction formation.Notably,etching approaches facilitate precise control over crystal morphology and surface chemistry,thereby optimizing MOF performance in catalysis,electrocatalysis,photocatalysis,adsorption,energy storage,sensing,and biomedical applications.We also outline challenges such as etchant toxicity,over-etching risks,and scalability,while highlighting emerging strategies and computational simulations to refine the etching process.Ultimately,this review underscores the transformative impact of etching on MOF properties,paving the way for the design of next-generation multifunctional materials that address critical issues in environmental remediation,energy conversion,and beyond.展开更多
Bimetallic oxides are promising electrocatalysts due to their rich composition,facile synthesis,and favorable stability under oxidizing conditions.This paper innovatively proposes a strategy aimed at constructing a on...Bimetallic oxides are promising electrocatalysts due to their rich composition,facile synthesis,and favorable stability under oxidizing conditions.This paper innovatively proposes a strategy aimed at constructing a one-dimensional heterostructure(Fe–NiO/NiMoO_(4) nanoparticles/nanofibers).The strategy commences with the meticulous treatment of NiMoO_(4) nanofibers,utilizing in situ etching techniques to induce the formation of Prussian Blue Analog compounds.In this process,[Fe(CN)_(6)]^(3-)anions react with the NiMoO_(4) host layer to form a steady NiFe PBA.Subsequently,the surface/interface reconstituted NiMoO_(4) nanofibers undergo direct oxidation,leading to a reconfiguration of the surface structure and the formation of a unique Fe–NiO/NiMoO_(4) one-dimensional heterostructure.The catalyst showed markedly enhanced electrocatalytic performance for the oxygen evolution reaction.Density functional theory results reveal that the incorporation of Fe as a dopant dramatically reduces the Gibbs free energy associated with the rate-determining step in the oxygen evolution reaction pathway.This pivotal transformation directly lowers the activation energy barrier,thereby significantly enhancing electron transfer efficiency.展开更多
Perovskite oxides have been widely applied as an effective catalyst in heterogeneous catalysis.However,the rational design of active catalysts has been restricted by the lack of understanding of the electronic structu...Perovskite oxides have been widely applied as an effective catalyst in heterogeneous catalysis.However,the rational design of active catalysts has been restricted by the lack of understanding of the electronic structure.The correlations between surface properties and bulk electronic structure have been ignored.Herein,a simple handler of LaFeO_(3)with diluted HNO3 was employed to tune the electronic structure and catalytic properties.Experimental analysis and theoretical calculations elucidate that acid etching could raise the Fe valence and enhance Fe-O covalency in the octahedral structure,thereby lessening charge transfer energy.Enhanced Fe-O covalency could lower oxygen vacancy formation energy and enhance oxygen mobility.In-situ DRIFTS results indicated the inherent adsorption capability of Toluene and CO molecules has been greatly improved owing to higher Fe-O covalency.As compared,the catalysts after acid etching exhibited higher catalytic activity,and the T_(90)had a great reduction of 45 and 58℃ for toluene and CO oxidation,respectively.A deeper understanding of electronic structure in perovskite oxides may inspire the design of high-performance catalysts.展开更多
Two-dimensional(2D)nitride MXenes are predicted to exhibit exceptional metallic properties and high polarity;however,their synthesis remains challenging.Research has relied on traditional molten salt etching,highlight...Two-dimensional(2D)nitride MXenes are predicted to exhibit exceptional metallic properties and high polarity;however,their synthesis remains challenging.Research has relied on traditional molten salt etching,highlighting the need for a scalable,high-purity approach.Here,we present the first solution-based synthesis of Ti_(4)N_(3)T_(x)MXene via a novel saturated salt solution(S^(3))etching technique employing alkali metal salts.By optimizing the sintering process for high-purity Ti_(4)AlN_(3)MAX and refining the S^(3)etching route,we significantly reduced the etch pit density to 1.2×10^(6)cm^(-2)and lowered the etch pit formation rate to 4%,yielding high-quality,phasepure Ti_(4)N_(3)T_(x)MXene.Our study highlights the critical role of alkali metal ions in selective A-layer removal and demonstrates the impressive electrical conductivity and electromagnetic interference shielding performance of 2D nitride MXene,setting a new benchmark for this underexplored material.These findings pave the way for advancing 2D nitride MXenes and their diverse applications.展开更多
Currently, a conventional two-step method has been used to generate black silicon （BS） surfaces on silicon substrates for solar cell manufacturing. However, the performances of the solar cell made with such surface ...Currently, a conventional two-step method has been used to generate black silicon （BS） surfaces on silicon substrates for solar cell manufacturing. However, the performances of the solar cell made with such surface generation method are poor, because of the high surface recombination caused by deep etching in the conventional surface generation method for BS. In this work, a modified wet chemical etching solution with additives was developed. A homogeneous BS layer with random porous structure was obtained from the modified solution in only one step at room temperature. The BS layer had low reflectivity and shallow etching depth. The additive in the etch solution performs the function of pH-modulation. After 16-min etching, the etching depth in the samples was approximately 200 nm, and the spectrum-weighted-reflectivity in the range from 300 nm to 1200 nm was below 5%. BS solar cells were fabricated in the production line. The decreased etching depth can improve the electrical performance of solar cells because of the decrease in surface recombination. An efficiency of 15.63% for the modified etching BS solar cells was achieved on a large area, p- type single crystalline silicon substrate with a 624.32-mV open circuit voltage and a 77.88% fill factor.展开更多
The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 el...The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 electrolyte at 80 ℃. The pitting potential and self corrosion potential of A1 foil were measured with polarization curves （PC）. The potentiostatic current--time curve was recorded and the surface and cross section images of etched A1 foil were observed with SEM. The electrochemical impedance spectroscopy （EIS） of etched A1 foil and potential transient curves （PTC） during initial etching stage were measured. The results show the chemical pretreatments can activate A1 foil surface, facilitate the absorption, diffusion and migration of C1- onto the A1 foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched A1 foil.展开更多
The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such ...The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such Zn-deposited Al foil was quickly transferred into HCl-H 2 SO 4 solution for DC-etching. The effects of Zn impurity on the surface and cross-section etching morphologies and electrochemical behavior of Al foil were investigated by SEM, polarization curve （PC） and electrochemical impedance spectroscopy （EIS）. The special capacitance of 100 V formation voltage of etched foil was measured. The results show that the chemical plating Zn on Al substrate in alkali solution can reduce the pitting corrosion resistance, enhance the pitting current density and improve the density and uniform distribution of pits and tunnels due to formation of the micro Zn-Al galvanic local cells. The special capacitance of etched foil grows with the increase of Zn2＋concentration.展开更多
In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching proc...In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.展开更多
A combination of atomic force microscopy （AFM） and scanning electron microscopy （SEM） is used to characterize dislocation etch pits in Si-doped GaN epilayer etched by molten KOH. Three types of etch pits with diff...A combination of atomic force microscopy （AFM） and scanning electron microscopy （SEM） is used to characterize dislocation etch pits in Si-doped GaN epilayer etched by molten KOH. Three types of etch pits with different shapes and specific positions in the surface have been observed,and a model of the etching mechanism is proposed to explain their origins. The pure screw dislocation is easily etched along the steps that the dislocation terminates. Consequently a small Ga-polar plane is formed to prevent further vertical etching,resulting in an etch pit shaped like an inverted truncated hexagonal pyramid at the terminal chiasma of two surface steps. However, the pure edge dislocation is easily etched along the dislocation line,inducing an etch pit of inverted hexagonal pyramid aligned with the surface step. The polarity is found to play an important role in the etching process of GaN.展开更多
基金supported by the National Natural Science Foundation of China(52472228,22309202)Natural Science Foundation of Sichuan Province(2023NSFSC1942)the Gusu Leading Talents Program(ZXL2023190)。
文摘With the rapid development of twodimensional MXene materials,numerous preparation strategies have been proposed to enhance synthesis efficiency,mitigate environmental impact,and enable scalability for large-scale production.The compound etching approach,which relies on cationic oxidation of the A element of MAX phase precursors while anions typically adsorb onto MXene surfaces as functional groups,remains the main prevalent strategy.By contrast,synthesis methodologies utilizing elemental etching agents have been rarely reported.Here,we report a new elemental tellurium(Te)-based etching strategy for the preparation of MXene materials with tunable surface chemistry.By selectively removing the A-site element in MAX phases using Te,our approach avoids the use of toxic fluoride reagents and achieves tellurium-terminated surface groups that significantly enhance sodium storage performance.Experimental results show that Te-etched MXene delivers substantially higher capacities(exceeding 50%improvement over conventionally etched MXene)with superior rate capability,retaining high capacity at large current densities and demonstrating over 90%capacity retention after 1000 cycles.This innovative synthetic strategy provides new insight into controllable MXene preparation and performance optimization,while the as-obtained materials hold promises for high-performance sodium-ion batteries and other energy storage systems.
基金Supported by National Key Research and Development Program of China(2021YFB3601403)National Natural Science Foundation of China(62105181)Taishan Scholar of Shandong Province(tsqn202306014)。
文摘Lutetium oxide(Lu_(2)O_(3))is recognized as a potential laser crystal material,and it is noted for its high ther⁃mal conductivity,low phonon energy,and strong crystal field.Nevertheless,its high melting point of 2450℃induces significant temperature gradients,resulting in a proliferation of defects.The scarcity of comprehensive research on this crystal’s defects hinders the enhancement of crystal quality.In this study,we employed the chemical etching method to examine the etching effects on Lu_(2)O_(3)crystals under various conditions and to identify the optimal conditions for investi⁃gating the dislocation defects of Lu_(2)O_(3)crystals(mass fraction 70%H3PO4,160℃,15-18 min).The morphologies of dislocation etch pits on the(111)-and(110)-oriented Lu_(2)O_(3)wafers were characterized using microscopy,scanning electron microscopy and atomic force microscopy.This research addresses the gap in understanding Lu_(2)O_(3)line defects and offers guidance for optimizing the crystal growth process and improving crystal quality.
文摘Systematic CR-39 bulk etching experiments were conducted over a wide range of concentrations(2–30 N)of NaOH-based etchant.Critical analysis and a deep discussion of the results are presented.A comprehensive nuclear track chemical etching data bank was developed.Three regimes of CR-39 bulk etching were identified.Regime I spans etchant concentrations from 2 to 12 N.Regime II spans concentrations from 12 to 25 N.We call this the dynamic bulk etching regime.Regime III is for concentrations greater than 25 N.In this regime,the bulk etch rate is saturated with respect to the etchant concentration.This classification is discussed and explained.The role of ethanol in NaOH-based etchants is explored and discussed.A parameter called the“reduced bulk etch rate”is defined here,which helps in analyzing the dependence of bulk etching on the amount of ethanol in the etchant.The bulk etch rate shows a natural logarithmic dependence on the density of ethanol in the etchant.
基金supported by the National Natural Science Foundation of China(52375437,52035009)the Natural Science Foundation of Guangdong Province(2024B1515020027)+2 种基金the Shenzhen Science and Technology Program(Grant No.KQTD20170810110250357)for the financial supportthe assistance of SUSTech Core Research Facilitiessupported by Shenzhen Engineering Research Center for Semiconductorspecific Equipment。
文摘The highly efficient manufacturing of atomic-scale smooth β-Ga_(2)O_(3)surface is fairly challenging because β-Ga_(2)O_(3)is a typical difficult-to-machine material.In this study,a novel plasma dry etching method named plasma-based atom-selective etching(PASE)is proposed to achieve the highly efficient,atomic-scale,and damage-free polishing of β-Ga_(2)O_(3).The plasma is excited through the inductive coupling principle and carbon tetrafluoride is utilized as the main reaction gas to etch β-Ga_(2)O_(3).The core of PASE polishing of β-Ga_(2)O_(3)is the remarkable lateral etching effect,which is ensured by both the intrinsic property of the surface and the extrinsic temperature condition.As revealed by density functional theory-based calculations,the intrinsic difference in the etching energy barrier of atoms at the step edge(2.36 eV)and in the terrace plane(4.37 eV)determines their difference in the etching rate,and their etching rate difference can be greatly enlarged by increasing the extrinsic temperature.The polishing of β-Ga_(2)O_(3)based on the lateral etching effect is further verified in the etching experiments.The Sa roughness of β-Ga_(2)O_(3)(001)substrate is reduced from 14.8 nm to 0.057 nm within 120 s,and the corresponding material removal rate reaches up to 20.96μm·min^(−1).The polished β-Ga_(2)O_(3)displays significantly improved crystalline quality and photoluminescence intensity,and the polishing effect of PASE is independent of the crystal face of β-Ga_(2)O_(3).In addition,the competition between chemical etching and physical reconstruction,which is determined by temperature and greatly affects the surface state of β-Ga_(2)O_(3),is deeply studied for the first time.These findings not only demonstrate the high-efficiency and high-quality polishing of β-Ga_(2)O_(3)via atmospheric plasma etching but also hold significant implications for guiding future plasma-based surface manufacturing of β-Ga_(2)O_(3).
文摘A new type of 785 nm semiconductor laser device has been proposed.The thin cladding and mode expansion layer structure incorporated into the epitaxy on the p-side significantly impacts the regulation of grating etching depth.Thinning of the p-side waveguide layer makes the light field bias to the n-side cladding layer.By coordinating the confinement effect of the cladding layer,the light confinement factor on the p-side is regulated.On the other hand,the introduction of a mode expansion layer facilitates the expansion of the mode profile on the p side cladding layer.Both these factors contribute positively to reducing the grating etching depth.Compared to the reported epitaxial structures of symmetric waveguides,the new structure significantly reduces the etching depth of the grating while ensuring adequate reflection intensity and maintaining resonance.Moreover,to improve the output performance of the device,the new epitaxial structure has been optimized.Based on the traditional epitaxial structure,an energy release layer and an electron blocking layer are added to improve the electronic recombination efficiency.This improved structure has an output performance comparable to that of a symmetric waveguide,despite being able to have a smaller gain area.
文摘The low porosity and low permeability of shale remain the primary challenges in shale gas exploitation.Traditional single permeability enhancement techniques have shown limited efficacy,failing to effectively address these technical bottlenecks.This study investigates the synergistic effects of perforationinduced permeability enhancement and acidizing operations on the mechanical properties and micropore structure of shale.The improved Split Hopkinson Pressure Bar(SHPB)technique was employed to simulate dynamic impact damage under triaxial stress conditions.Damaged and undamaged rock specimens were immersed in a 15%hydrochloric acid solution to fabricate combined-damage specimens and acid-etched specimens with varying damage states.Uniaxial compression tests,X-ray diffraction(XRD)analysis,and scanning electron microscopy(SEM)were conducted on these specimens.SEM images were binarized,and combined with low-temperature nitrogen adsorption tests,the effects of different damage states on the mechanical behavior,energy dissipation,micro-morphology,and pore characteristics of shale were systematically evaluated.Results demonstrate that the peak stress and elastic modulus of shale exhibit a negative correlation with acid-etching duration.The mechanical properties of combined-damage specimens are inferior to those of pure acid-etched specimens,with the minimum peak stress reaching 147.10 MPa—a 43.53%reduction compared to untreated specimens.The energy dissipation ratio significantly increases,with a maximum value of 34.74%.XRD analysis reveals that prolonged acid immersion effectively reduces the carbonate content in specimens,while composite treatment accelerates the reaction between rock matrix and acid solution.Microstructural characterization indicates that acid etching enhances the porosity of shale,particularly the area of mesopores and macropores,with more pronounced pore development and a fragmented interface structure.These findings deepen the understanding of physical mechanisms during shale gas extraction and provide critical theoretical support for optimizing integrated permeability enhancement technologies.
基金ISRO-RESPOND GAP3332 and PMN-MOES GAP2175 Project support this work.NIO-PMN and MOES-NCPOR supported the deep-sea and Antarctica micrometeorite collections,respectively.
文摘Extraterrestrial phenomena have influenced Earth’s processes throughout geological history.Evaluating the impact of extraterrestrial material on the environment is crucial for understanding the evolution of Earth and life.This study incorporates the investigation of micrometeorites(MMs),abundant cosmic materials on Earth,to understand their influence on the chemical composition and biogeochemistry of the ocean.Comprehensive etching and flux analyses reveal that∼95%of cosmic spherules(CSs)entering seawater are etched or wholly dissolved,supplying nutrients to phytoplankton.Barred spherules show the highest degree of etching(∼19%),followed by porphyritic(∼17%),glass(∼15%),cryptocrystalline(∼12%),scoriaceous(∼10%),G-type(∼9%),and I-type(∼6%).Annually,∼3080 tonnes(t)of olivine from MMs dissolve into seawater,contributing∼495 t of Mg^(2+),∼1110 t of Fe^(2+),and∼1928 t of silicic acid.This signifies that over the Indian Ocean’s∼40 Myr history,∼23 Gt of olivine from CSs has dissolved,providing nutrients to seawater and sequestering∼7 Gt of CO_(2).The world ocean during this time has sequestered∼35 Gt of CO_(2),with fluctuations influenced by extraterrestrial activity.For instance,the Veritas event,lasting∼1.5 Myr,sequestered∼6 Gt of CO_(2)from the atmosphere.A robust flux calculation based on∼2 t of deep-sea sediments from 3610 MMs provides a more accurate estimate of the time-averaged flux of∼229 t yr^(−1).These comprehensive analyses reveal MM’s original characteristics,post-deposition processes,geological record and their overall impact on Earth’s marine environments,thereby contributing to our knowledge of the interconnection between terrestrial and extraterrestrial processes.
基金supported by the National Natural Science Foundation of China(Nos.52130209,51927803,52188101,52372054,and 22003074)the National Key R&D Program of China(No.2022YFA1203302)+2 种基金Guangdong Provincial Key Laboratory Program of the Guangdong Science and Technology Department(No.2021B1212040001)the Youth Innovation Promotion Association CAS(No.2022366)Shenzhen Science and Technology Program(No.JCYJ20240813154813018).
文摘Horizontally aligned semiconducting single-wall carbon nanotube(s-SWCNT)arrays are ideal candidates for next-generation integrated circuits.However,the mainstream synthesis methods for obtaining s-SWCNTs mainly utilize the differences in structure and chemical reactivity between them and their metallic counterparts.These differences are too small to greatly improve their purity and reproducibility.Here we report an energy engineering strategy to expand the etching energy barrier difference of SWCNTs with different conductivities.In addition to density functional theory calculations on the energy barrier change,hydrogenation of single-wall carbon nanotubes(SWCNTs)by hydrogen plasma treatment and reversible dehydrogenation by annealing were realized experimentally.The structure-dependent hydrogenation and following selective oxidative etching of SWCNTs were demonstrated.As a result,horizontally aligned s-SWCNT arrays with high purity were obtained.
基金financially supported by the National Natural Science Foundation of China(Nos.52074078 and 52374327)the Applied Fundamental Research Program of Liaoning Province(No.2023JH2/101600002)+5 种基金the Liaoning Provincial Natural Science Foundation of China(No.2022-YQ-09)the Shenyang Young Middle-Aged Scientific and Technological Innovation Talent Support Program,China(No.RC220491)the Liaoning Province Steel Industry-University-Research Innovation Alliance Cooperation Project of Bensteel Group,China(No.KJBLM202202)the Fundamental Research Funds for the Central Universities,China(Nos.N2201023 and N2325009)the Key Scientific Research Project of Liaoning Provincial Department of Education(2024JYTZD-03)the 111 Project(B16009).
文摘FeCl_(3) solution is commonly used in the etching process of stainless steel.The typical etching waste liquid contains a significant amount of Fe^(3+),Fe^(2+),Cr^(3+),and Ni^(2+),making it difficult to reuse and posing pollution issues.The FeCl_(3) etching waste liquid was the present subject,which aimed to extract Cr^(3+)and Ni^(2+)by selectively adjusting process parameters.Additionally,it investigates the migration behavior and phase transition mechanisms of the iron,chromium,and nickel in different solution systems during treatment,systematically elucidating the regeneration mechanisms of FeCl_(3) etching waste liquid.The results indicate that Cr and Ni can be recycled by controlling parameters such as pH value,temperature,and the valence states of the ions.Following a selective reduction of Fe^(3+)to Fe^(2+)using Fe powder,98.3%of Cr^(3+)was recovered by adjusting the solution’s pH.Subsequently,93.3%of Ni^(2+)was extracted from the Cr-depleted solution through further adjustments to the process parameters.The recovered Cr and Ni can be used to prepare Fe–Cr and Fe–Ni alloy powders.Furthermore,the FeCl_(3) etching solution was regenerated by oxidizing Fe^(2+)and recovering impurities.The theoretical support for the development of new processes for treating FeCl_(3) etching waste liquid is provided.
基金financially supported by the National Natural Science Foundation of China(No.61904073)Spring City Plan-Special Program for Young Talents(No.K202005007)+2 种基金Yunnan Talents Support Plan for Yong Talents(No.XDYC-QNRC-2022-0482)Yunnan Local Colleges Applied Basic Research Projects(No.202101BA070001-138)Frontier Research Team of Kunming University 2023.
文摘Germanium(Ge)-air battery,a new type of semiconductor-air battery,has garnered increasing attention owing to its environmental friendliness,safety,and excellent dynamic performance.However,the flat Ge anode is prone to passivation,owing to GeO_(2) accumulation on its surface,resulting in premature discharge termination.In this study,various nano-Ge pyramid structures(GePS)were prepared using chemical etching(CE)and metal-assisted chemical etching(MACE)methods to enhance the specific surface area of the Ge anode,thereby facilitating the dissolution of the passivation layer.This study revealed that the MACE method significantly accelerated the etching rate of the Ge surface,producing exceptional GePS.Furthermore,Ge-air batteries employing Ge anodes prepared using MACE demonstrated an exceptional discharge life of up to 9240 h(385 days).The peak power density reached 3.03mW/cm^(2),representing improvements of more than 2 times and 1.8 times,respectively,compared with batteries using flat Ge anodes.This study presents a straightforward approach to enhance Ge anode performance,thereby expanding the potential applications of Ge-air batteries.
基金the financial support of the National Natural Science Foundation of China(Nos.22308296)。
文摘Metal-organic frameworks(MOFs)have emerged as promising materials owing to their high surface areas,tunable pore sizes,and diverse functionalities.However,their practical deployment is frequently hindered by intrinsic microporosity and structural fragility.In this review,we systematically analyze recent advancements in MOF etching techniques,which strategically modify framework architectures to enhance mass transport,expose active sites,and improve stability.The discussion encompasses a range of methods―including acid,base,ion,solvent,steam,selective,in-situ,pyrolysis,and physical etching―with emphasis on the underlying mechanisms that govern the formation of hierarchical pore structures,defect engineering,and heterojunction formation.Notably,etching approaches facilitate precise control over crystal morphology and surface chemistry,thereby optimizing MOF performance in catalysis,electrocatalysis,photocatalysis,adsorption,energy storage,sensing,and biomedical applications.We also outline challenges such as etchant toxicity,over-etching risks,and scalability,while highlighting emerging strategies and computational simulations to refine the etching process.Ultimately,this review underscores the transformative impact of etching on MOF properties,paving the way for the design of next-generation multifunctional materials that address critical issues in environmental remediation,energy conversion,and beyond.
基金supported by the National Natural Science Foundation of China(52203257)Natural Science Foundation of Heilongjiang Province(YQ2022B008).
文摘Bimetallic oxides are promising electrocatalysts due to their rich composition,facile synthesis,and favorable stability under oxidizing conditions.This paper innovatively proposes a strategy aimed at constructing a one-dimensional heterostructure(Fe–NiO/NiMoO_(4) nanoparticles/nanofibers).The strategy commences with the meticulous treatment of NiMoO_(4) nanofibers,utilizing in situ etching techniques to induce the formation of Prussian Blue Analog compounds.In this process,[Fe(CN)_(6)]^(3-)anions react with the NiMoO_(4) host layer to form a steady NiFe PBA.Subsequently,the surface/interface reconstituted NiMoO_(4) nanofibers undergo direct oxidation,leading to a reconfiguration of the surface structure and the formation of a unique Fe–NiO/NiMoO_(4) one-dimensional heterostructure.The catalyst showed markedly enhanced electrocatalytic performance for the oxygen evolution reaction.Density functional theory results reveal that the incorporation of Fe as a dopant dramatically reduces the Gibbs free energy associated with the rate-determining step in the oxygen evolution reaction pathway.This pivotal transformation directly lowers the activation energy barrier,thereby significantly enhancing electron transfer efficiency.
基金the National Natural Science Foundation of China(Nos.22376178,22322606,22276105)the National Key Research and Development Program of China(No.2022YFC3704300)the Beijing Natural Science Foundation(No.8222054).
文摘Perovskite oxides have been widely applied as an effective catalyst in heterogeneous catalysis.However,the rational design of active catalysts has been restricted by the lack of understanding of the electronic structure.The correlations between surface properties and bulk electronic structure have been ignored.Herein,a simple handler of LaFeO_(3)with diluted HNO3 was employed to tune the electronic structure and catalytic properties.Experimental analysis and theoretical calculations elucidate that acid etching could raise the Fe valence and enhance Fe-O covalency in the octahedral structure,thereby lessening charge transfer energy.Enhanced Fe-O covalency could lower oxygen vacancy formation energy and enhance oxygen mobility.In-situ DRIFTS results indicated the inherent adsorption capability of Toluene and CO molecules has been greatly improved owing to higher Fe-O covalency.As compared,the catalysts after acid etching exhibited higher catalytic activity,and the T_(90)had a great reduction of 45 and 58℃ for toluene and CO oxidation,respectively.A deeper understanding of electronic structure in perovskite oxides may inspire the design of high-performance catalysts.
基金supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(Grant No.RS-2024-00408180)by Institute for Basic Science(No.IBS-R019-G1).
文摘Two-dimensional(2D)nitride MXenes are predicted to exhibit exceptional metallic properties and high polarity;however,their synthesis remains challenging.Research has relied on traditional molten salt etching,highlighting the need for a scalable,high-purity approach.Here,we present the first solution-based synthesis of Ti_(4)N_(3)T_(x)MXene via a novel saturated salt solution(S^(3))etching technique employing alkali metal salts.By optimizing the sintering process for high-purity Ti_(4)AlN_(3)MAX and refining the S^(3)etching route,we significantly reduced the etch pit density to 1.2×10^(6)cm^(-2)and lowered the etch pit formation rate to 4%,yielding high-quality,phasepure Ti_(4)N_(3)T_(x)MXene.Our study highlights the critical role of alkali metal ions in selective A-layer removal and demonstrates the impressive electrical conductivity and electromagnetic interference shielding performance of 2D nitride MXene,setting a new benchmark for this underexplored material.These findings pave the way for advancing 2D nitride MXenes and their diverse applications.
文摘Currently, a conventional two-step method has been used to generate black silicon （BS） surfaces on silicon substrates for solar cell manufacturing. However, the performances of the solar cell made with such surface generation method are poor, because of the high surface recombination caused by deep etching in the conventional surface generation method for BS. In this work, a modified wet chemical etching solution with additives was developed. A homogeneous BS layer with random porous structure was obtained from the modified solution in only one step at room temperature. The BS layer had low reflectivity and shallow etching depth. The additive in the etch solution performs the function of pH-modulation. After 16-min etching, the etching depth in the samples was approximately 200 nm, and the spectrum-weighted-reflectivity in the range from 300 nm to 1200 nm was below 5%. BS solar cells were fabricated in the production line. The decreased etching depth can improve the electrical performance of solar cells because of the decrease in surface recombination. An efficiency of 15.63% for the modified etching BS solar cells was achieved on a large area, p- type single crystalline silicon substrate with a 624.32-mV open circuit voltage and a 77.88% fill factor.
基金Project supported by University New Materials Disciplines Constructions Program of Beijing Region,ChinaProject(51172102/E020801) supported by the National Natural Science Foundation of China
文摘The aluminum foil for high voltage aluminum electrolytic capacitor was immersed in 0.5 mol/L H3PO4 or 0.125 mol/L NaOH solution at 40 ℃ for different time and then DC electro-etched in 1 mol/L HC1＋2.5 mol/L H2SO4 electrolyte at 80 ℃. The pitting potential and self corrosion potential of A1 foil were measured with polarization curves （PC）. The potentiostatic current--time curve was recorded and the surface and cross section images of etched A1 foil were observed with SEM. The electrochemical impedance spectroscopy （EIS） of etched A1 foil and potential transient curves （PTC） during initial etching stage were measured. The results show the chemical pretreatments can activate A1 foil surface, facilitate the absorption, diffusion and migration of C1- onto the A1 foil during etching, and improve the initiation rate of meta-stable pits and density of stable pits and tunnels, leading to much increase in the real surface area and special capacitance of etched A1 foil.
基金Project (51172102) supported by the National Natural Science Foundation of ChinaProject (BS2011CL011) supported by Promotive Research Fund for Young and Middle-aged Scientists of Shandong Province(doctor fund),China
文摘The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2＋and Zn was chemically plated on its surface through an immersion-reduction reaction. Such Zn-deposited Al foil was quickly transferred into HCl-H 2 SO 4 solution for DC-etching. The effects of Zn impurity on the surface and cross-section etching morphologies and electrochemical behavior of Al foil were investigated by SEM, polarization curve （PC） and electrochemical impedance spectroscopy （EIS）. The special capacitance of 100 V formation voltage of etched foil was measured. The results show that the chemical plating Zn on Al substrate in alkali solution can reduce the pitting corrosion resistance, enhance the pitting current density and improve the density and uniform distribution of pits and tunnels due to formation of the micro Zn-Al galvanic local cells. The special capacitance of etched foil grows with the increase of Zn2＋concentration.
基金Project (2011A090200123) supported by Industry-Universities-Research Cooperation Project of Guangdong Province and Ministry of Education of ChinaProject (111gpy06) supported by Fundamental Research Funds for the Central Universities,ChinaProject (101055807) supported by the Innovative Experiment Plan Project for College Students of Sun Yat-sen University,China
文摘In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.
文摘A combination of atomic force microscopy （AFM） and scanning electron microscopy （SEM） is used to characterize dislocation etch pits in Si-doped GaN epilayer etched by molten KOH. Three types of etch pits with different shapes and specific positions in the surface have been observed,and a model of the etching mechanism is proposed to explain their origins. The pure screw dislocation is easily etched along the steps that the dislocation terminates. Consequently a small Ga-polar plane is formed to prevent further vertical etching,resulting in an etch pit shaped like an inverted truncated hexagonal pyramid at the terminal chiasma of two surface steps. However, the pure edge dislocation is easily etched along the dislocation line,inducing an etch pit of inverted hexagonal pyramid aligned with the surface step. The polarity is found to play an important role in the etching process of GaN.
