Anodic polarization behavior of gold, silver, copper, nickel and iron in potentiostatic condition has been examined in an alkaline aqueous thiourea solution, where gold is hardly dissoluble normally. The addition of N...Anodic polarization behavior of gold, silver, copper, nickel and iron in potentiostatic condition has been examined in an alkaline aqueous thiourea solution, where gold is hardly dissoluble normally. The addition of Na2SO3 into the solution can accelerate anodic dissolution of gold. The factors affecting selective dissolution of gold in the alkaline thiourea solution by electrolysis have been studied, and the optimum condition was obtained. In 0.1 mol/L thiourea solution of pH 12. 5 containing 0. 5 mol/L Na2SO3 and 2. 5% acetone, at the potential of 0. 34 V vs NHE, at the temperature of 323 K, the dissolved mass of gold anode with the exposed area of 1. 0 cm2 reached more than 300 mg·dm-3 within 30 min, and other metals such as silver, copper, nickel and iron could hardly dissolve.展开更多
Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic s...Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.展开更多
Color filters are produced using semiconductor production techniques although problems with low yield remain to be addressed. This study presents a new means of selective removal using excimer irradiation, chemical et...Color filters are produced using semiconductor production techniques although problems with low yield remain to be addressed. This study presents a new means of selective removal using excimer irradiation, chemical etching, or electrochemical machining on the fifth generation TFT LCDs. The selective removal of microstructure layers from the color filter surface of an optoelectronic flat panel display, as well as complete removal of the ITO thin-films, RGB layer, or resin black matrix (BM) layer from the substrate is possible. Individual defective film layers can be removed, or all films down to the Cr layer or bare glass can be completely eliminated. Experimental results demonstrate that defective ITO thin-films, RGB layers, or the resin BM layer can now be recycled with a great precision. When the ITO or RGB layer proves difficult to remove, excimer light can be used to help with removal. During this recycling process, the use of 225 nm excimer irradiation before chemical etching, or electrochemical machining, makes removal of stubborn film residues easy, effectively improving the quality of recycled color filters and reducing fabrication cost.展开更多
We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the c...We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated.展开更多
Reservoirs in the Xing＇anling Group in the Suderte Oil Field,Hailar Basin exhibit ultra-low to low permeability and high tuffaceous material content.This study comprehensively analyzed diagenesis and quality evolutio...Reservoirs in the Xing＇anling Group in the Suderte Oil Field,Hailar Basin exhibit ultra-low to low permeability and high tuffaceous material content.This study comprehensively analyzed diagenesis and quality evolution of these low-permeability reservoirs using thin sections,SEM samples,rock physical properties,pore water data,as well as geochemical numerical simulations.Calcite and analcite are the two main types of cements precipitated in the eodiagenetic stage at shallow burial depths in the reservoirs.These two cements occupied significant primary intergranular pores and effectively retarded deep burial compaction.Petrography textures suggest selective dissolution of massive analcite and little dissolution of calcite in the mesodiagenetic stage.Chemical calculations utilizing the Geochemist＇s Workbench 9.0indicated that the equilibrium constant of the calcite leaching reaction is significantly smaller than that of the analcite leaching reaction,resulting in extensive dissolution of analcite rather than calcite in the geochemical system with both minerals present.Numerical simulations with constraints of kinetics and pore water chemistry demonstrated that the pore water in the Xing＇anling group is saturated with respect to calcite,but undersaturated with analcite,leading to dissolution of large amounts of analcite and no dissolution of calcite.Significant secondary intergranular pores have formed in analcite-cemented reservoirs from selective dissolution of analcite in the mesodiagenetic stage;the analcite dissolution formed preferential flow paths in the reservoirs,which promoted feldspar dissolution;and dissolution of such minerals led to the present reservoirs with medium porosity and low permeability.Calcite-cemented tight reservoirs have not experienced extensive dissolution of cements,so they exhibit ultra-low porosity and permeability.展开更多
Gold dissolves easily in an alkaline thiourea solution with Na2SO3 and Na2S2O8, where the accompanied elements of Au, such as Ag, Cu, Ni and Fe can hardly dissolve. It was considered that electrochemical reduction and...Gold dissolves easily in an alkaline thiourea solution with Na2SO3 and Na2S2O8, where the accompanied elements of Au, such as Ag, Cu, Ni and Fe can hardly dissolve. It was considered that electrochemical reduction and catalytic action of SO32- prevent thiourea from decomposing irreversibly and accelerates dissolution of gold.The S2O82- as an oxidant can control the potential so that formamidine disulfide may form efficiently. The dissolution of gold is mainly through oxidation of Au by formamidine disulfide and complexation of thiourea with An+,and not direct oxidation of S2O82-. Thus,sufficient formamidine disulfide is necessary to accelerate the dissolution of gold. The reason for Ag, Cu hardly being dissoluble is that the black layers of Ag2S and Cu1.92S form on the surface of Ag and Cu. The metal Ni and Fe do not dissolve in the alkaline media due to their sulfide films passivation samely.展开更多
It is possible to achieve selective electrochemical etching between different materials,such as p-and n-type silicon.However,achieving selective electrochemical etching on two different regions of the same p-type sili...It is possible to achieve selective electrochemical etching between different materials,such as p-and n-type silicon.However,achieving selective electrochemical etching on two different regions of the same p-type silicon material is a problem that has rarely been considered.Herein,a novel selective electrochemical etching technique for cantilever-type silicon-on-insulator(SOI)wafer-based microswitches is proposed.In this study,a p-type handle layer was selectively etched,and a p-type device layer was passivated.This was achieved using a circuit with two voltage sources:voltages of−1.2 and 0 V were applied to the handle and device layers,respectively.It was found that the proposed etching process can effectively prevent the in-use sticking of a cantilever-type switch.This is accomplished by increasing the gap between the device layer and its underlying handle layer and increasing the roughness of these layers.The technique is applicable to the fabrication of various cantilever-type SOI microelectromechanical systems,irrespective of the resistivity of the SOI wafer.展开更多
Controllable syntheses of different-sized gold nanoclusters are of great significance for their fundamental science and practical applications. In this work, we achieve the controllable and selective syntheses of Au7 ...Controllable syntheses of different-sized gold nanoclusters are of great significance for their fundamental science and practical applications. In this work, we achieve the controllable and selective syntheses of Au7 and Au13 clusters through adding HCl to the traditional Aull synthetic route at different reaction time. Time-dependent mass spectra and UV- Vis spectra were ernployed to monitor these two HCl-directed processes, and revealed the distinct roles of HCl as an etchant or a growth prornotor, respectively. Furthermore, parallel experiments on independent synthetic routes involving only non-chlorine H＋ （acetic acid） or Cl （tetraethy larnrnoniurn chloride） instead of HCl were perforrned, which illustrated the main role of H^＋-etching and Cl^ -assisted growth in HCl-directed cluster synthetic routes. We propose the HCl-etching is mainly achieved via the H＋ action to break the Au（I）-PPh3 part of clusters, while the HCl-prornoted growth is realized via the attachment of Au-Cl species to the pre-forrned clusters.展开更多
An inductively coupled plasma (ICP) discharge and its etching behaviors for aluminum alloys were investigated in this report. A radio frequency power supply was used for plasma generation. The unique hardware configur...An inductively coupled plasma (ICP) discharge and its etching behaviors for aluminum alloys were investigated in this report. A radio frequency power supply was used for plasma generation. The unique hardware configuration enabled one to control ion energy separately from plasma density. Plasma properties were measured with a Langmuir probe. Electron temperature, plasma potential and plasma density were found to be comparable with those reported from Electron Cyclotron Resonance (ECR) and other types of reactors[1].A mixture of HBr and chlorine gases were used for this aluminum etch study. Experimental matrices were designed with Response Surface Methodology (RSM) to analyze the process trends versus etch parameters, such as source power, bias power and gas composition. An etch rate of 8500A to 9000A per minute was obtained at 5 to 15 mTorr pressure ranges. Anisotropic profiles with high photoresist selectivity (5 to 1) and silicon dioxide selectivity greater than 10 were achieved with HBr addition into chlorine plasma.Bromine-containing chemistry for an aluminum etch in a low pressure ICP discharge showed great potential for use in ULSI fabrication. In addition, the hardware used was very simple and the chamber size was much smaller than other high density plasma sources.展开更多
High entropy compounds were proven to exhibit excellent catalytic activity.Here,a series of amorphous CrMnFeCoNi Oxy-carbide films were successfully synthesized by one-step electrodeposition.As demonstrated,the film p...High entropy compounds were proven to exhibit excellent catalytic activity.Here,a series of amorphous CrMnFeCoNi Oxy-carbide films were successfully synthesized by one-step electrodeposition.As demonstrated,the film presented superior electrocatalytic activity for oxygen evolution reaction(OER)with an overpotential of 295 mV at a current density of 10 mA/cm^(2).Uniquely,selective dissolution of Chromium(Cr)was observed,which increased the catalytic activity and showed high stability under a large current density of up to 400 mA/cm^(2).Cr dissolution not only increased the surface area but also improved the conductivity due to newly formed metal-metal bonding,promoting electron transfer and improving OER performance.As revealed by density functional theory(DFT)calculations,Cr-dissolution mediates the bonding of OER intermediates over surface active sites and ultimately reduces OER overpotential.The one-step electrodeposition method and the micro-dissolution mechanism provided a potential way to design and prepare high entropy compound electrodes,aiming to achieve efficient water electrolysis.展开更多
The efficient recovery of silver(Ag)from retired photovoltaic(PV)panels is crucial for resource sustainability and envi-ronmental protection.This study developed an environmentally friendly leaching method using ammon...The efficient recovery of silver(Ag)from retired photovoltaic(PV)panels is crucial for resource sustainability and envi-ronmental protection.This study developed an environmentally friendly leaching method using ammonia(NH_(3)·H_(2)O)and hydrogen peroxide(H_(2)O_(2)),achieving the selective dissolution of Ag from retired crystalline silicon solar panels.Meanwhile,nonprecious metals such as aluminum(Al)and lead(Pb),which are commonly found in PV cells,were barely dissolved,dem-onstrating the excellent selectivity of this method for Ag.Light irradiation significantly improved the dissolution efficiency of Ag and reduced the amount of the reagent used.Ag dissolution occurred owing to a dual-pathway synergistic effect,which stemmed from the direct oxidation of Ag by H_(2)O_(2).The strongly oxidizing hydroxyl radicals generated by photocatalysis accelerated the oxidation and dissolution of Ag.In addition,NH 3·H_(2)O effectively promoted the dissolution and stabilization of oxidation products by forming soluble Ag–NH3·H2O complexes([Ag(NH3)2]+).This article reports an efficient,selective,and environmentally friendly strategy of Ag recovery and elucidates the radical-mediated dissolution mechanism under light-driven conditions,offering a feasible way for sustainably recovering valuable metals from retired PV panels.展开更多
The effects of acid surface dissolution on the flotation kinetics of ilmenite(IL)and its common accompanied gangue minerals including olivine-pyroxene(Ol-Px),tremolite-clinochlore(Tr-Cch)and quartz were investigated.T...The effects of acid surface dissolution on the flotation kinetics of ilmenite(IL)and its common accompanied gangue minerals including olivine-pyroxene(Ol-Px),tremolite-clinochlore(Tr-Cch)and quartz were investigated.The results show that through the surface dissolution the adsorption rate constant for ilmenite increases from 5.272 to 8.441 mol/(g·min)while it decreases for Ol-Px,Tr-Cch and quartz from 6.332,7.309 and 7.774 mol/(g·min)to 5.034,6.223 and 7.371 mol/(g·min),respectively.Also,the flotation experiments on a binary mixture of minerals indicate that after surface dissolution the values of modified rate constant for ilmenite flotation from Ol-Px,Tr-Cch and quartz are enhanced from 36.15,36.52 and 47.86 min-1 to 41.72,45.78 and 56.24 min-1,respectively.This results in the improvement of kinetic selectivity index(SI)in the separation of treated ilmenite from gangue minerals.As evidenced by ICP-MS analysis,the decrease of kinetic parameters for gangue minerals can be due to the removal of Fe^2+,Ca^2+and Mg^2+ions from their surfaces,which results in the lack of enough active sites to interact with collector species.As confirmed by contact angle measurements,this prevents the formation of a stable hydrophobic layer on the minerals surfaces for creating stable attachments between minerals and bubbles.Generally,the improvement of ilmenite flotation kinetics has a negative correlation with the iron content in its accompanied gangue minerals.展开更多
Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution...Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution which could allow separation of tin from the copper alloy dross. The tin as H2SnO3(metastannic acid) phase was precipitated in the solution with centrifuging process and transformed to tin dioxide(SnO2) after drying process. The dried sample was heat-treated at low temperature and its phase characteristics, surface morphology and chemical composition were investigated.展开更多
Although an increasing interest has been attracted to further develop heterostructured catalysts from metallic glasses(MGs) by heat treatment, overcoming surface oxidation effect is still a critical problem for such e...Although an increasing interest has been attracted to further develop heterostructured catalysts from metallic glasses(MGs) by heat treatment, overcoming surface oxidation effect is still a critical problem for such environmental catalysts. Herein, a short-time electrochemical etching of partially crystallized Febased ribbons in 0.3 M H3 PO4 electrolyte enables the formation of honeycomb-like nanoporous structure as effective catalytic active sites in Fenton-like process. Studies of structure and surface morphologies reveal that the formation of nanoporous structure by potentiostatic etching originates from electrochemical potential difference of nanocrystals(a-Fe(Si) and Fe2 B) and residual amorphous phase in partially crystallized ribbons, where Fe2 B having a lower open circuit potential tends to be selectively dissolved.Simultaneously, thin oxide layer after electrochemical etching exposes more active sites for H2 O2 activation and provides an effective protection of nanocrystals from massive loss during etching. Investigation of optimal processing conditions suggests that the selection of electrolyte plays an important role;dye degradation rates of etched ribbons in HNO3 and Na2 SO4 electrolytes can also achieve at least 2 times higher than that of as-annealed ribbons. This work holds the promise to develop novel environmental catalysts by effective electrochemical etching of partially crystallized ribbons.展开更多
Radiogenic uranium isotope disequilibrium(^(234)U/^(238)U)has been used to trace a variety of Earth surface processes,and is usually attributed to direct recoil of^(234)Th and preferential dissolution of radioactively...Radiogenic uranium isotope disequilibrium(^(234)U/^(238)U)has been used to trace a variety of Earth surface processes,and is usually attributed to direct recoil of^(234)Th and preferential dissolution of radioactively damaged lattices at the mineral surface.However,the relative contribution of these two mechanisms in the natural environment remains unresolved,making it hard to use the extent of disequilibrium to quantify processes such as weathering.This study tests the contribution of preferential dissolution using well-characterized weathered moraines and river sediments from the southeastern Tibetan Plateau.The observations show that weathering of recent moraines where the contribution from direct recoil is negligible and is not associated with depletion of^(234)U at the mineral surface.It suggests a limited role for preferential dissolution in this setting.We attribute this lack of preferential dissolution to a near-to-equilibrium dissolution at the weathering interfaces,with little development of etch pits associated with radioactively damaged energetic sites.展开更多
Gold dissolves electrochemically in alkaline solutions containing ligands to form complex ions with gold ion. Therefore, selective leaching of noble metals is expected without dissolution of base metals such as steels...Gold dissolves electrochemically in alkaline solutions containing ligands to form complex ions with gold ion. Therefore, selective leaching of noble metals is expected without dissolution of base metals such as steels, aluminum alloys in scrap treatment. Gold electrodes were investigated using linear sweep voltammetry, EQCM method and potentiostatic electrolysis in alkaline solutions containing thiourea, Na 2SO 3 and Na 2S 2O 3. The solution composition, electrode potential affect gold dissolution rate and current efficiency. The gold dissolved from anode electrode forms complex ions, suspension particles as compound precipitates and deposits on cathode electrode as a metal. Anodic efficiency for gold dissolution is between 10% and 22%. This is caused by the oxidation decomposition of sulfite ions and thiourea. The stability of the alkaline solution containing these elements was also estimated by capillary electrophoresis technique.展开更多
This research aims to extract Cu from Cu-Co alloy with high efficiency and selectivity by employing binary Mg-Pb melt. The optimal conditions for the extraction of Cu were determined. The results showed under optimal ...This research aims to extract Cu from Cu-Co alloy with high efficiency and selectivity by employing binary Mg-Pb melt. The optimal conditions for the extraction of Cu were determined. The results showed under optimal conditions, 96.5% of Cu in the Cu-Co alloy could be selectively extracted after treatment at 800 ℃ for 1 h, with the extraction rates of only 0.2% Fe, 0.6% Co, and 1.4% Si. The dissolution mechanism involved the counter diffusion of Mg/Pb and Cu across the diffusion zone of the Cu-Co alloy, and Mg in the binary Mg-Pb melt played a major role in the selective dissolution of Cu, especially at the dissolution forefront. The rate-controlling step of the extraction was dominated by the interfacial reaction.展开更多
Selective catalytic NH_(3)-to-N_(2) oxidation(NH_(3)-SCO)is highly promising for abating NH_(3) emissions slipped from stationary flue gas after-treatment devices.Its practical application,however,is limited by the no...Selective catalytic NH_(3)-to-N_(2) oxidation(NH_(3)-SCO)is highly promising for abating NH_(3) emissions slipped from stationary flue gas after-treatment devices.Its practical application,however,is limited by the non-availability of low-cost catalysts with high activity and N_(2) selectivity.Here,using defect-rich nitrogen-doped carbon nanotubes(NCNT-AW)as the support,we developed a highly active and durable copper-based NH_(3)-SCO catalyst with a high abundance of cuprous(Cu^(+))sites.The obtained Cu/NCNT-AW catalyst demonstrated outstanding activity with a T_(50)(i.e.the temperature to reach 50% NH_(3) conversion)of 174℃ in the NH_(3)-SCO reaction,which outperformed not only the Cu catalyst supported on N-free O-functionalized CNTs(OCNTs)or NCNT with less surface defects,but also those most active Cu catalysts in open literature.Reaction kinetics measurements and temperature-programmed surface reactions using NH_(3)as a probe molecule revealed that the NH_(3)-SCO reaction on Cu/NCNT-AW follows an internal selective catalytic reaction(i-SCR)route involving nitric oxide(NO)as a key intermediate.According to mechanistic investigations by X-ray photoelectron spectroscopy,Raman spectroscopy,and X-ray absorption spectroscopy,the superior NH_(3)-SCO performance of Cu/NCNT-AW originated from a synergy of surface defects and N-dopants.Specifically,surface defects promoted the anchoring of Cu O nanoparticles on N-containing sites and,thereby,enabled efficient electron transfer from N to Cu O,increasing significantly the fraction of SCR-active Cu^(+)sites in the catalyst.This study puts forward a new idea for manipulating and utilizing the interplay of defects and N-dopants on carbon surfaces to fabricate Cu^(+)-rich Cu catalysts for efficient abatement of slip NH_(3)emissions via selective oxidation.展开更多
Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(...Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.展开更多
文摘Anodic polarization behavior of gold, silver, copper, nickel and iron in potentiostatic condition has been examined in an alkaline aqueous thiourea solution, where gold is hardly dissoluble normally. The addition of Na2SO3 into the solution can accelerate anodic dissolution of gold. The factors affecting selective dissolution of gold in the alkaline thiourea solution by electrolysis have been studied, and the optimum condition was obtained. In 0.1 mol/L thiourea solution of pH 12. 5 containing 0. 5 mol/L Na2SO3 and 2. 5% acetone, at the potential of 0. 34 V vs NHE, at the temperature of 323 K, the dissolved mass of gold anode with the exposed area of 1. 0 cm2 reached more than 300 mg·dm-3 within 30 min, and other metals such as silver, copper, nickel and iron could hardly dissolve.
文摘Potassium chloride, Na-pyrophosphate, CuCl2, NH4-oxalate, dithionite-citrate-bicarbonate (DCB) and Na-citrate solutions were employed to extract aluminum (Al) and iron (Fe) sequentially and separately from 15 acidic soils located at the Mangshan Mountains, Hunan Province, China. Many evidences showed that separate pyrophosphate extracted mainly KCI-extractable Al, organo-Al complexes and some inorganic Al compounds, whereas separate CuCl2 extracted KCl-extractable Al and some organo-Al complexes. CuCl2 extracted much less amounts of Al than pyrophosphate did from the soils. Separate oxalate did not extract all KCl-Pyrophosphate- CuCl2 -oxalate sequentially extractable Al and Fe. Also, separate DCB did not extract all KCl- pyrophosphate- CuCl2 -oxalate- DCB sequentially extractable Al. The forms of Al extracted by oxalate and DCB from the soils were majorly noncrystalline. The interlayered materials of 1.4-nm intergrade minerals of the soils were attributed mainly to hydroxy Al polymers.
基金supported by the BEN TEN CO., and National Science Council contracts 98-2221-E-152-001 and 99-2221-E-152-001
文摘Color filters are produced using semiconductor production techniques although problems with low yield remain to be addressed. This study presents a new means of selective removal using excimer irradiation, chemical etching, or electrochemical machining on the fifth generation TFT LCDs. The selective removal of microstructure layers from the color filter surface of an optoelectronic flat panel display, as well as complete removal of the ITO thin-films, RGB layer, or resin black matrix (BM) layer from the substrate is possible. Individual defective film layers can be removed, or all films down to the Cr layer or bare glass can be completely eliminated. Experimental results demonstrate that defective ITO thin-films, RGB layers, or the resin BM layer can now be recycled with a great precision. When the ITO or RGB layer proves difficult to remove, excimer light can be used to help with removal. During this recycling process, the use of 225 nm excimer irradiation before chemical etching, or electrochemical machining, makes removal of stubborn film residues easy, effectively improving the quality of recycled color filters and reducing fabrication cost.
基金Supported by the National Basic Research Program of China under Grant No 2012CB921804the National Natural Science Foundation of China under Grant Nos 11204236 and 61308006the Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated.
基金financially supported by the National Science and Technology Special Grant (No. 2011ZX05009003)China Postdoctoral Science Fund (2015M580617)+1 种基金Shandong Postdoctoral Innovation Fund (201502028)2014 Innovation Project of China University of Petroleum (YCX2014002)
文摘Reservoirs in the Xing＇anling Group in the Suderte Oil Field,Hailar Basin exhibit ultra-low to low permeability and high tuffaceous material content.This study comprehensively analyzed diagenesis and quality evolution of these low-permeability reservoirs using thin sections,SEM samples,rock physical properties,pore water data,as well as geochemical numerical simulations.Calcite and analcite are the two main types of cements precipitated in the eodiagenetic stage at shallow burial depths in the reservoirs.These two cements occupied significant primary intergranular pores and effectively retarded deep burial compaction.Petrography textures suggest selective dissolution of massive analcite and little dissolution of calcite in the mesodiagenetic stage.Chemical calculations utilizing the Geochemist＇s Workbench 9.0indicated that the equilibrium constant of the calcite leaching reaction is significantly smaller than that of the analcite leaching reaction,resulting in extensive dissolution of analcite rather than calcite in the geochemical system with both minerals present.Numerical simulations with constraints of kinetics and pore water chemistry demonstrated that the pore water in the Xing＇anling group is saturated with respect to calcite,but undersaturated with analcite,leading to dissolution of large amounts of analcite and no dissolution of calcite.Significant secondary intergranular pores have formed in analcite-cemented reservoirs from selective dissolution of analcite in the mesodiagenetic stage;the analcite dissolution formed preferential flow paths in the reservoirs,which promoted feldspar dissolution;and dissolution of such minerals led to the present reservoirs with medium porosity and low permeability.Calcite-cemented tight reservoirs have not experienced extensive dissolution of cements,so they exhibit ultra-low porosity and permeability.
文摘Gold dissolves easily in an alkaline thiourea solution with Na2SO3 and Na2S2O8, where the accompanied elements of Au, such as Ag, Cu, Ni and Fe can hardly dissolve. It was considered that electrochemical reduction and catalytic action of SO32- prevent thiourea from decomposing irreversibly and accelerates dissolution of gold.The S2O82- as an oxidant can control the potential so that formamidine disulfide may form efficiently. The dissolution of gold is mainly through oxidation of Au by formamidine disulfide and complexation of thiourea with An+,and not direct oxidation of S2O82-. Thus,sufficient formamidine disulfide is necessary to accelerate the dissolution of gold. The reason for Ag, Cu hardly being dissoluble is that the black layers of Ag2S and Cu1.92S form on the surface of Ag and Cu. The metal Ni and Fe do not dissolve in the alkaline media due to their sulfide films passivation samely.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51575248 and 32071900).
文摘It is possible to achieve selective electrochemical etching between different materials,such as p-and n-type silicon.However,achieving selective electrochemical etching on two different regions of the same p-type silicon material is a problem that has rarely been considered.Herein,a novel selective electrochemical etching technique for cantilever-type silicon-on-insulator(SOI)wafer-based microswitches is proposed.In this study,a p-type handle layer was selectively etched,and a p-type device layer was passivated.This was achieved using a circuit with two voltage sources:voltages of−1.2 and 0 V were applied to the handle and device layers,respectively.It was found that the proposed etching process can effectively prevent the in-use sticking of a cantilever-type switch.This is accomplished by increasing the gap between the device layer and its underlying handle layer and increasing the roughness of these layers.The technique is applicable to the fabrication of various cantilever-type SOI microelectromechanical systems,irrespective of the resistivity of the SOI wafer.
基金supported by the National Natural Science Foundation of China (No.11475176, No.U1632263, and No.21533007)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No.11621063)
文摘Controllable syntheses of different-sized gold nanoclusters are of great significance for their fundamental science and practical applications. In this work, we achieve the controllable and selective syntheses of Au7 and Au13 clusters through adding HCl to the traditional Aull synthetic route at different reaction time. Time-dependent mass spectra and UV- Vis spectra were ernployed to monitor these two HCl-directed processes, and revealed the distinct roles of HCl as an etchant or a growth prornotor, respectively. Furthermore, parallel experiments on independent synthetic routes involving only non-chlorine H＋ （acetic acid） or Cl （tetraethy larnrnoniurn chloride） instead of HCl were perforrned, which illustrated the main role of H^＋-etching and Cl^ -assisted growth in HCl-directed cluster synthetic routes. We propose the HCl-etching is mainly achieved via the H＋ action to break the Au（I）-PPh3 part of clusters, while the HCl-prornoted growth is realized via the attachment of Au-Cl species to the pre-forrned clusters.
文摘An inductively coupled plasma (ICP) discharge and its etching behaviors for aluminum alloys were investigated in this report. A radio frequency power supply was used for plasma generation. The unique hardware configuration enabled one to control ion energy separately from plasma density. Plasma properties were measured with a Langmuir probe. Electron temperature, plasma potential and plasma density were found to be comparable with those reported from Electron Cyclotron Resonance (ECR) and other types of reactors[1].A mixture of HBr and chlorine gases were used for this aluminum etch study. Experimental matrices were designed with Response Surface Methodology (RSM) to analyze the process trends versus etch parameters, such as source power, bias power and gas composition. An etch rate of 8500A to 9000A per minute was obtained at 5 to 15 mTorr pressure ranges. Anisotropic profiles with high photoresist selectivity (5 to 1) and silicon dioxide selectivity greater than 10 were achieved with HBr addition into chlorine plasma.Bromine-containing chemistry for an aluminum etch in a low pressure ICP discharge showed great potential for use in ULSI fabrication. In addition, the hardware used was very simple and the chamber size was much smaller than other high density plasma sources.
基金supported by the JSPS KAKENHI(Grant No.JP21K04724)the Iketani Science and Technology Foundation(No.0331126-A).
文摘High entropy compounds were proven to exhibit excellent catalytic activity.Here,a series of amorphous CrMnFeCoNi Oxy-carbide films were successfully synthesized by one-step electrodeposition.As demonstrated,the film presented superior electrocatalytic activity for oxygen evolution reaction(OER)with an overpotential of 295 mV at a current density of 10 mA/cm^(2).Uniquely,selective dissolution of Chromium(Cr)was observed,which increased the catalytic activity and showed high stability under a large current density of up to 400 mA/cm^(2).Cr dissolution not only increased the surface area but also improved the conductivity due to newly formed metal-metal bonding,promoting electron transfer and improving OER performance.As revealed by density functional theory(DFT)calculations,Cr-dissolution mediates the bonding of OER intermediates over surface active sites and ultimately reduces OER overpotential.The one-step electrodeposition method and the micro-dissolution mechanism provided a potential way to design and prepare high entropy compound electrodes,aiming to achieve efficient water electrolysis.
基金supported by the National Science Foundation of China(Nos.22525606,22176128,22236005,22406131,22506126)the Innovation Program of Shanghai Municipal Education Commission(No.2023ZKZD50)+13 种基金Shanghai Leading Talent Program of Eastern Talent Plan(No.LJ2023002)Shanghai Government(Nos.22dz1205400,23520711100)Chinese Education Ministry Key Laboratory and International Joint Laboratory on Resource ChemistryShanghai Eastern Scholar ProgramThe authors also thank Fellowship of China National Postdoctoral Program for Innovative Talents(No.BX20240229)the China Postdoctoral Science(No.2024M762100)the Foundation the Shanghai Science and Technology Commission Project(No.24ZR1455700)Shanghai Post-doctoral Excellence Pro-gram(No.2024787)the Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Com-mission(No.24CGA49)the“111 Innovation and Talent Recruitment Base on Photochemical and Energy Materials”(No.D18020)Yunnan University Collaborative Innovation Center(Qujing Green Photovoltaic Industry Collaborative Innovation Center)Technology Talent and Platform Plan Project of Yunnan Provincial Department of Science and Technology(No.202305AF150088)Shanghai Engineering Research Center of Green Energy Chemical Engineering(No.18DZ2254200)Shanghai Frontiers Science Center of Biomimetic Catalysis.
文摘The efficient recovery of silver(Ag)from retired photovoltaic(PV)panels is crucial for resource sustainability and envi-ronmental protection.This study developed an environmentally friendly leaching method using ammonia(NH_(3)·H_(2)O)and hydrogen peroxide(H_(2)O_(2)),achieving the selective dissolution of Ag from retired crystalline silicon solar panels.Meanwhile,nonprecious metals such as aluminum(Al)and lead(Pb),which are commonly found in PV cells,were barely dissolved,dem-onstrating the excellent selectivity of this method for Ag.Light irradiation significantly improved the dissolution efficiency of Ag and reduced the amount of the reagent used.Ag dissolution occurred owing to a dual-pathway synergistic effect,which stemmed from the direct oxidation of Ag by H_(2)O_(2).The strongly oxidizing hydroxyl radicals generated by photocatalysis accelerated the oxidation and dissolution of Ag.In addition,NH 3·H_(2)O effectively promoted the dissolution and stabilization of oxidation products by forming soluble Ag–NH3·H2O complexes([Ag(NH3)2]+).This article reports an efficient,selective,and environmentally friendly strategy of Ag recovery and elucidates the radical-mediated dissolution mechanism under light-driven conditions,offering a feasible way for sustainably recovering valuable metals from retired PV panels.
文摘The effects of acid surface dissolution on the flotation kinetics of ilmenite(IL)and its common accompanied gangue minerals including olivine-pyroxene(Ol-Px),tremolite-clinochlore(Tr-Cch)and quartz were investigated.The results show that through the surface dissolution the adsorption rate constant for ilmenite increases from 5.272 to 8.441 mol/(g·min)while it decreases for Ol-Px,Tr-Cch and quartz from 6.332,7.309 and 7.774 mol/(g·min)to 5.034,6.223 and 7.371 mol/(g·min),respectively.Also,the flotation experiments on a binary mixture of minerals indicate that after surface dissolution the values of modified rate constant for ilmenite flotation from Ol-Px,Tr-Cch and quartz are enhanced from 36.15,36.52 and 47.86 min-1 to 41.72,45.78 and 56.24 min-1,respectively.This results in the improvement of kinetic selectivity index(SI)in the separation of treated ilmenite from gangue minerals.As evidenced by ICP-MS analysis,the decrease of kinetic parameters for gangue minerals can be due to the removal of Fe^2+,Ca^2+and Mg^2+ions from their surfaces,which results in the lack of enough active sites to interact with collector species.As confirmed by contact angle measurements,this prevents the formation of a stable hydrophobic layer on the minerals surfaces for creating stable attachments between minerals and bubbles.Generally,the improvement of ilmenite flotation kinetics has a negative correlation with the iron content in its accompanied gangue minerals.
基金supported by the "Energy Efficiency & Resources" of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 20125010100030-11-2-400)
文摘Preliminary study on concentration and separation of tin(Sn) from copper alloy dross by selective dissolution method was conducted. The tin in the copper alloy dross did not dissolve in an aqueous nitric acid solution which could allow separation of tin from the copper alloy dross. The tin as H2SnO3(metastannic acid) phase was precipitated in the solution with centrifuging process and transformed to tin dioxide(SnO2) after drying process. The dried sample was heat-treated at low temperature and its phase characteristics, surface morphology and chemical composition were investigated.
基金Financial supports from Australian Research Council through Discovery Project(DP130103592)National Natural Science Foundation of China(Grant No.51771103)。
文摘Although an increasing interest has been attracted to further develop heterostructured catalysts from metallic glasses(MGs) by heat treatment, overcoming surface oxidation effect is still a critical problem for such environmental catalysts. Herein, a short-time electrochemical etching of partially crystallized Febased ribbons in 0.3 M H3 PO4 electrolyte enables the formation of honeycomb-like nanoporous structure as effective catalytic active sites in Fenton-like process. Studies of structure and surface morphologies reveal that the formation of nanoporous structure by potentiostatic etching originates from electrochemical potential difference of nanocrystals(a-Fe(Si) and Fe2 B) and residual amorphous phase in partially crystallized ribbons, where Fe2 B having a lower open circuit potential tends to be selectively dissolved.Simultaneously, thin oxide layer after electrochemical etching exposes more active sites for H2 O2 activation and provides an effective protection of nanocrystals from massive loss during etching. Investigation of optimal processing conditions suggests that the selection of electrolyte plays an important role;dye degradation rates of etched ribbons in HNO3 and Na2 SO4 electrolytes can also achieve at least 2 times higher than that of as-annealed ribbons. This work holds the promise to develop novel environmental catalysts by effective electrochemical etching of partially crystallized ribbons.
基金supported by the Royal Society-Newton Advanced Fellowship(No.NA201244)the Natural Science Foundation of China(Nos.42061130212,41991321,41877351,41761144058,and 41730101)+2 种基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(No.2019QZKK0707)the Fundamental Research Funds for the Central Universities(No.0206-14380124)support from the China Scholarship Council Fellowship。
文摘Radiogenic uranium isotope disequilibrium(^(234)U/^(238)U)has been used to trace a variety of Earth surface processes,and is usually attributed to direct recoil of^(234)Th and preferential dissolution of radioactively damaged lattices at the mineral surface.However,the relative contribution of these two mechanisms in the natural environment remains unresolved,making it hard to use the extent of disequilibrium to quantify processes such as weathering.This study tests the contribution of preferential dissolution using well-characterized weathered moraines and river sediments from the southeastern Tibetan Plateau.The observations show that weathering of recent moraines where the contribution from direct recoil is negligible and is not associated with depletion of^(234)U at the mineral surface.It suggests a limited role for preferential dissolution in this setting.We attribute this lack of preferential dissolution to a near-to-equilibrium dissolution at the weathering interfaces,with little development of etch pits associated with radioactively damaged energetic sites.
文摘Gold dissolves electrochemically in alkaline solutions containing ligands to form complex ions with gold ion. Therefore, selective leaching of noble metals is expected without dissolution of base metals such as steels, aluminum alloys in scrap treatment. Gold electrodes were investigated using linear sweep voltammetry, EQCM method and potentiostatic electrolysis in alkaline solutions containing thiourea, Na 2SO 3 and Na 2S 2O 3. The solution composition, electrode potential affect gold dissolution rate and current efficiency. The gold dissolved from anode electrode forms complex ions, suspension particles as compound precipitates and deposits on cathode electrode as a metal. Anodic efficiency for gold dissolution is between 10% and 22%. This is caused by the oxidation decomposition of sulfite ions and thiourea. The stability of the alkaline solution containing these elements was also estimated by capillary electrophoresis technique.
基金funded by the National Natural Science Foundation of China(Nos.51904350,51874371)the Hunan Natural Science Foundation,China(No.2021JJ30854).
文摘This research aims to extract Cu from Cu-Co alloy with high efficiency and selectivity by employing binary Mg-Pb melt. The optimal conditions for the extraction of Cu were determined. The results showed under optimal conditions, 96.5% of Cu in the Cu-Co alloy could be selectively extracted after treatment at 800 ℃ for 1 h, with the extraction rates of only 0.2% Fe, 0.6% Co, and 1.4% Si. The dissolution mechanism involved the counter diffusion of Mg/Pb and Cu across the diffusion zone of the Cu-Co alloy, and Mg in the binary Mg-Pb melt played a major role in the selective dissolution of Cu, especially at the dissolution forefront. The rate-controlling step of the extraction was dominated by the interfacial reaction.
基金supported by the National Natural Science Foundation of China(Nos.21806039,21976058)the Natural Science Foundation of Guangdong Province(No.2023A1515011682)+2 种基金the Fundamental Research Funds for the Central Universities(No.2022ZYGXZR018)the Science and Technology Program of Guangzhou(No.202102080490).P.C.appreciates the funding from the Pearl River Talent Recruitment Program of Guangdong Province(No.2019QN01L170)the Innovation&Entrepreneurship Talent Program of Shaoguan City。
文摘Selective catalytic NH_(3)-to-N_(2) oxidation(NH_(3)-SCO)is highly promising for abating NH_(3) emissions slipped from stationary flue gas after-treatment devices.Its practical application,however,is limited by the non-availability of low-cost catalysts with high activity and N_(2) selectivity.Here,using defect-rich nitrogen-doped carbon nanotubes(NCNT-AW)as the support,we developed a highly active and durable copper-based NH_(3)-SCO catalyst with a high abundance of cuprous(Cu^(+))sites.The obtained Cu/NCNT-AW catalyst demonstrated outstanding activity with a T_(50)(i.e.the temperature to reach 50% NH_(3) conversion)of 174℃ in the NH_(3)-SCO reaction,which outperformed not only the Cu catalyst supported on N-free O-functionalized CNTs(OCNTs)or NCNT with less surface defects,but also those most active Cu catalysts in open literature.Reaction kinetics measurements and temperature-programmed surface reactions using NH_(3)as a probe molecule revealed that the NH_(3)-SCO reaction on Cu/NCNT-AW follows an internal selective catalytic reaction(i-SCR)route involving nitric oxide(NO)as a key intermediate.According to mechanistic investigations by X-ray photoelectron spectroscopy,Raman spectroscopy,and X-ray absorption spectroscopy,the superior NH_(3)-SCO performance of Cu/NCNT-AW originated from a synergy of surface defects and N-dopants.Specifically,surface defects promoted the anchoring of Cu O nanoparticles on N-containing sites and,thereby,enabled efficient electron transfer from N to Cu O,increasing significantly the fraction of SCR-active Cu^(+)sites in the catalyst.This study puts forward a new idea for manipulating and utilizing the interplay of defects and N-dopants on carbon surfaces to fabricate Cu^(+)-rich Cu catalysts for efficient abatement of slip NH_(3)emissions via selective oxidation.
基金financially supported by National Natural Science Foundation of China(22466010)Guizhou Provincial Basic Research Program(Natural Science)ZK[2023]47 and key program ZD[2025]075+6 种基金Innovation and Entrepreneurship Project for overseas Talents in Guizhou Province[2022]02Specific Natural Science Foundation of Guizhou University(X202207)the national undergraduate innovation and entrepreneurship training program(gzugc2023006gzusc2024012)SRT project of Guizhou university(2023SRT0292023SRT024)supported by Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University。
文摘Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.
