Recent advancements in electrocatalysis have highlighted the exceptional application value of amorphous electrocatalysts. Withtheir unique atomic configurations, these electrocatalysts exhibit superior catalytic perfo...Recent advancements in electrocatalysis have highlighted the exceptional application value of amorphous electrocatalysts. Withtheir unique atomic configurations, these electrocatalysts exhibit superior catalytic performance compared to that of their crystalline coun-terparts. Transition metal(TM) amorphous ribbon-shaped electrocatalysts have recently emerged as a new frontier in the catalysis field.Dealloying is widely considered a fascinating method for enhancing the electrocatalyst performance. In this review, we comprehensivelyexamine the principles of water electrolysis, discuss the prevalent methods for fabricating ribbon-configured electrocatalysts, and providean overview of amorphous alloys. Furthermore, we discuss binary, ternary, and high-entropy amorphous TM-based electrocatalysts,which satisfy the requirements necessary for effective water electrolysis. We also propose strategies to enhance the activity of amorphousTM-based ribbons, including morphology control, defect engineering, composition optimization, and heterostructure creation in differentelectrolytes. Our focus extends to the latest developments in the design of heterogeneous micro/nanostructures, management of prepara-tion techniques, and synthesis of different compositions. Finally, we address the ongoing challenges and provide a perspective on the fu-ture development of broadly applicable, self-supporting TM ribbon-shaped electrocatalysts.展开更多
To study the influence of Fe addition on the Al-based amorphous alloys,the structure and properties of Al84Ni10La6 and Al84Ni9Fe1La6 alloys were investigated through various techniques.The results show that 1% Fe（mol...To study the influence of Fe addition on the Al-based amorphous alloys,the structure and properties of Al84Ni10La6 and Al84Ni9Fe1La6 alloys were investigated through various techniques.The results show that 1% Fe（molar fraction） addition increases the area of the pre-peak in the structure factor and decreases the thermal expansion coefficient difference between the crystalline and amorphous states.1% Fe addition also improves the glass forming ability（GFA）,micro-hardness,fracture toughness,electric resistivity,absolute diamagnetism and corrosion resistance of Al-Ni-La alloys,which is related to the changes of medium-range order and quench-in free volume caused by 1% Fe addition.展开更多
Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) amorphous coatings were prepared using cold gas kinetic spray technology.The results show that Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) amorphous coatings are achieved with the porosit...Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) amorphous coatings were prepared using cold gas kinetic spray technology.The results show that Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) amorphous coatings are achieved with the porosity about 3.2%,thickness about 893 μm,the amount of amorphous phase about 82.5%,the hardness about 300 HV0.2.The corrosion potential and anti-corrosion life of 7075 T6 alloy aluminum are about-0.78 V and 72 h,respectively.The electrochemical analysis and neutral salt spray are about-0.69 V corrosion potential and 274 h anti-corrosion life for amorphous Al-based coatings,respectively.Therefore,the life of the Albased amorphous coatings is about 3.8 times that of 7075 T6 aluminum alloy.Besides,the failure mechanism was analyzed using TEM in this investigation.In a word,Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) coatings keep dense structure,high amorphous content,favorable amorphous phase stabilizing ability and longer anticorrosion life.That is,Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) coatings have better comprehensive properties.Therefore,these findings indicate that the present Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) amorphous coatings prepared using cold gas kinetic spray technique can protect aluminum alloy very well and they can be considered to be used in aviation field.展开更多
Transmission electron microscopy （TEM） is usually used to identify the amorphicity. However, some artifacts may be introduced due to improper TEM foil preparation. In this paper, three Al-rich metallic glasses with ...Transmission electron microscopy （TEM） is usually used to identify the amorphicity. However, some artifacts may be introduced due to improper TEM foil preparation. In this paper, three Al-rich metallic glasses with and without a glass transition were selected for characterizing the effect of the electropolishing condition on the as-quenched structure during TEM specimen preparation. It is shown that the occurrence of the modulated bright-dark structure under TEM observation is closely sensitive to the electropolishing condition, which suggests us being careful about the possible artifacts induced by specimen preparation when examining amorphous alloys under TEM.展开更多
The Al-based amorphous and nanocrystalline composite coatings with the composition of Al-Ni-Y-Co and Al-Ni-Mm-Fe were prepared on AZ91 Mg-based alloys by high velocity arc spraying technique(HVAS).The structure charac...The Al-based amorphous and nanocrystalline composite coatings with the composition of Al-Ni-Y-Co and Al-Ni-Mm-Fe were prepared on AZ91 Mg-based alloys by high velocity arc spraying technique(HVAS).The structure character of the coatings indicates that coatings contain the mixture of amorphous phases and crystalline and there are both less than 2%porosity.The electrochemical tests of the coatings and the substrate were studied.The coatings show the passivation ability during polarization,but AZ91 Mg-based alloys show little passivation.The corrosion current density of the coatings is lower than that of AZ91 Mg-based alloys.The results show that the coatings have an excellent corrosion resistance for AZ91 Mg-based alloys in 5 wt%NaCl solution.展开更多
The corrosion-induced crystallization of Al94 exNixGd6（x=6 and 10, in at.%） metallic glasses as well as phase separation, oxidation and cracking in good conductivity solution has been investigated by various techniq...The corrosion-induced crystallization of Al94 exNixGd6（x=6 and 10, in at.%） metallic glasses as well as phase separation, oxidation and cracking in good conductivity solution has been investigated by various techniques.The transmission electronic microscopy（TEM） result reveals that crystalline intermetallics and oxides present on the electrochemically thinned hole edge, and the phase separation occurs in the matrix of the as-spun ribbons with the circumferential speed Rcof 29.3 m/s. In addition, the bending and cracking of the samples occur after corrosion. The influence of Ni content on the phase separation, bending and cracking can be explained by the fact that the percolation of the backbone clusters in the amorphous alloy melts and glasses is enhanced by increasing the composition of Ni.展开更多
The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spac...The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results.In this study,we compared two fluorinated salts:4-(trifluoromethyl)benzamidine hydrochloride(4TF-BA·HCl)and 4-fluorobenzamidine hydrochloride(4F-BA·HCl)to engineer the 3D/2D perovskite films.Surprisingly,4F-BA formed a high-performance 3D/2D heterojunction,while4TF-BA produced an amorphous layer on the perovskite films.Our findings indicate that the balanced intramolecular charge polarization,which leads to effective hydrogen bonding,is more favorable in 4F-BA than in 4TF-BA,promoting the formation of a crystalline 2D perovskite.Nevertheless,4TF-BA managed to improve efficiency to 24%,surpassing the control device,primarily due to the natural passivation capabilities of benzamidine.Interestingly,the devices based on 4F-BA demonstrated an efficiency exceeding 25%with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.展开更多
Exploring high-performance and cost-effective electrocatalysts that are applicable in oxygen evolution reaction(OER)is crucial for water splitting and energy storage.In this work,a facile and scalable chemical reducti...Exploring high-performance and cost-effective electrocatalysts that are applicable in oxygen evolution reaction(OER)is crucial for water splitting and energy storage.In this work,a facile and scalable chemical reduction strategy is developed to synthesize FeCoNiPB non-noble metal-based amorphous high-entropy oxides for the OER in alkaline media.The FeCoNiPB oxides exhibit overpotentials of 235 and 306 mV at current densities of 10 and 100 mA/cm^(2),respectively,as well as a small Tafel slope of 53 mV/dec in 1.0 M KOH solution,outperforming the performance of FeCoPB,FeNiPB,and CoNiPB oxides and the commercial RuO_(2),while maintaining excellent stability with negligible overpotential amplification over 40 h.The superior OER electrocatalytic efficiency and stability of the FeCoNiPB catalyst is primarily attributed to its unique amorphous high-entropy nanostructure,synergistic effect of the multiple components,and in situ-formed amorphous sheets with a thin(FeCoNi)OOH crystalline layer on the edge during long-term OER.This work provides new insights to design and prepare low-cost,highly efficient,and durable OER electrocatalysts.展开更多
Amorphous metal-based catalysts(AMCs)have sparked intense research interests in the field of electrocatalysis elicited by their hallmark features such as unlimited volume and morphology,manipulated electronic structur...Amorphous metal-based catalysts(AMCs)have sparked intense research interests in the field of electrocatalysis elicited by their hallmark features such as unlimited volume and morphology,manipulated electronic structures,enriched defects,and unsaturated surface atom coordination.Nevertheless,the manipulation of the amorphous phase in metal-based catalysts is so far impractical,and thus their electrocatalytic mechanism yet remains ambiguous.In this review,the latest advances in AMCs are systematically reviewed,covering amorphous-phase engineering strategy,structure manipulation,and amorphization of various material categories for electrocatalysis.Specifically,a series of applications of AMCs in electrocatalysis for the oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),and oxygen evolution reaction(OER)are summarized based on the classification criteria of substances.Finally,we put forward current challenges that have not yet been clarified in the field of AMCs,and propose possible solutions,particularly from the perspective of the evolution of electron microscopy.It is expected to promote the understanding of the amorphization-catalysis relationship and provide a guideline for designing high-performance electrocatalysts.展开更多
The Al-Ni-La-Ce-Pr-Nd amorphous ribbon with a super-thickness of 140 mm has been produced by the melt spinning technique. The thickness is as twice as that achieved by the melt spinning technique in the corresponding ...The Al-Ni-La-Ce-Pr-Nd amorphous ribbon with a super-thickness of 140 mm has been produced by the melt spinning technique. The thickness is as twice as that achieved by the melt spinning technique in the corresponding period (the largest thickness of 65 mm). The crystallization was characterized by using a differential scanning calorimetry. The activation energies are calculated based on the Kissinger equation and the effects of the La, Ce, Pr and Nd on the glass forming ability of Al-based alloy are discussed in the paper.展开更多
Zr_~65 Al_~10 Ni_~10 Cu_~15 , Zr_~52.5 Al_~10 Ni_~10 Cu_~15 Be_~12.5 and Zr_~52.5 Al_~10 Ni_~14.6 Cu_~17.9 Ti_5 bulk amorphous alloys were prepared by copper mould casting. The crystallization kinetics was measured by...Zr_~65 Al_~10 Ni_~10 Cu_~15 , Zr_~52.5 Al_~10 Ni_~10 Cu_~15 Be_~12.5 and Zr_~52.5 Al_~10 Ni_~14.6 Cu_~17.9 Ti_5 bulk amorphous alloys were prepared by copper mould casting. The crystallization kinetics was measured by differential scanning calorimeter(DSC) with different heating rates, and the activation energy was calculated using Kissinger equation. The relationship between thermal stability and rate constant of crystallization reaction is discussed on the view of crystallization kinetics, and the effect of small atom Beryllium on thermal stability of bulk amorphous alloys is also studied.展开更多
Lithium-ion batteries with LiCoO_(2)(LCO)cathodes are widely used in various electronic devices,resulting in a large amount of spent LCO(SLCO).Therefore,there is an urgent need for an efficient technique for recycling...Lithium-ion batteries with LiCoO_(2)(LCO)cathodes are widely used in various electronic devices,resulting in a large amount of spent LCO(SLCO).Therefore,there is an urgent need for an efficient technique for recycling SLCO.However,due to the presence of cobalt oxide with a spinel phase on the surface of highly-degraded LCO,the strong electrostatic repulsion from the transition metal octahedron poses a high Li replenishment barrier,making the regeneration of highly-degraded LCO a challenge.Herein,we propose a structural transformation strategy for reconstructing Li replenishment channels to aid the direct regeneration of highly-degraded LCO.In this approach,ball milling is employed to disrupt the inherent structure of highly-degraded LCO,thereby releasing the internal stress and converting the surface spinel phase into a homogeneous amorphous structure,which promotes Li insertion and regeneration.The regenerated LCO(RLCO)exhibits an outstanding discharge capacity of 179.10 mAh·g^(−1) in the voltage range of 3.0–4.5 V at 0.5 C.The proposed strategy is an effective regeneration approach for highly-degraded LCO,thereby facilitating the efficient recycling of spent lithium-ion battery cathode materials.展开更多
In general,the rapid growth of α-Fe clusters is a challenge in high Fe-content Fe-based amorphous alloys,negatively affecting their physical properties.Herein,we introduce an efficient and rapid post-treatment techni...In general,the rapid growth of α-Fe clusters is a challenge in high Fe-content Fe-based amorphous alloys,negatively affecting their physical properties.Herein,we introduce an efficient and rapid post-treatment technique known as ultrasonic vibration rapid processing(UVRP),which enables the formation of high-density strong magnetic α-Fe clusters,thereby enhancing the soft magnetic properties of Fe_(78)Si(13)B_(9) amorphous alloy ribbon.展开更多
Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru ...Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru dissolution during OER compromises the activity and stability.Amorphous materials have been identified as a viable strategy to promote the stability of RuO_(2)in acidic OER applications.This study reported a nanoporous amorphous-rich RuMnO_(x)(A-RuMnO_(x))aerogel for efficient and stable acidic OER.Compared with highly crystalline RuMnO_(x),the weakened Ru–O covalency of A-RuMnO_(x)by forming amorphous structure is favorable to inhibiting the oxidation of lattice oxygen.Meanwhile,this also optimizes the electronic structure of Ru sites from overoxidation and reduces the reaction energy barrier of the rate-determining step.As a result,A-RuMnO_(x)aerogel exhibits an ultra-low overpotential of 145 mV at 10 mA cm^(-2)and durability exceeding 100 h,as well as high mass activity up to 153 mA mg^(-1)_(Ru)at 1.5 V vs.reversible hydrogen electrode(RHE).This work provides valuable guidance for preparing highly active and stable Ru-based catalysts for acidic OER.展开更多
A suction casting experiment was conducted on Zr_(55)Cu_(30)Al_(10)Ni_(5)(at%)amorphous alloy.Using ProCAST software,numerical simulations were performed to analyze the filling and solidification processes.The velocit...A suction casting experiment was conducted on Zr_(55)Cu_(30)Al_(10)Ni_(5)(at%)amorphous alloy.Using ProCAST software,numerical simulations were performed to analyze the filling and solidification processes.The velocity field during the filling process and the temperature field during the solidification process of the alloy melt under different process parameters were obtained.Based on the simulation results,a Zr-based amorphous alloy micro-gear was prepared via casting.The results indicate that increasing the suction casting temperature enhances the fluidity of alloy melt but induces unstable flow rate during filling,which is detrimental to complete filling.Zr-based amorphous micro-gears with a module of 0.6 mm,a tooth top diameter of 8 mm,and 10 teeth were prepared through the suction casting.X-ray diffraction and differential scanning calorimetry analyses confirm that the fabricated micro-gear exhibits characteristic amorphous structural features,demonstrating well-defined geometrical contours and satisfactory forming completeness.展开更多
In order to minimize the crystal phase in Al-Cu-Ti amorphous powder,Al65Cu35-xTix amorphous powders were optimized via ball milling through adjusting the amount of Cu and Ti elements and the ball milling time.The resu...In order to minimize the crystal phase in Al-Cu-Ti amorphous powder,Al65Cu35-xTix amorphous powders were optimized via ball milling through adjusting the amount of Cu and Ti elements and the ball milling time.The results show that increasing the mole fraction of Ti can decrease the amount of Al Cu2Ti,Cu9Al4,and Al2Cu intermetallics formed during the process of ball milling;and prolonging the ball milling time can reduce the element crystalline phase to almost none.The optimal composition is determined to be Al65Cu16.5Ti18.5.TiH2 forms in all selected Al65Cu35-xTix amorphous powders during the process of optimization.H atom is decomposed from toluene and reacts with Ti during ball milling,leading to the formation of TiH2.The volume fraction of TiH2 in Al65Cu16.5Ti18.5 amorphous powder is measured to be 4.30%.展开更多
Establishing the structure-property relationship in amorphous materials has been a long-term grand challenge due to the lack of a unified description of the degree of disorder.In this work,we develop SPRamNet,a neural...Establishing the structure-property relationship in amorphous materials has been a long-term grand challenge due to the lack of a unified description of the degree of disorder.In this work,we develop SPRamNet,a neural network based machine-learning pipeline that effectively predicts structure-property relationship of amorphous material via global descriptors.Applying SPRamNet on the recently discovered amorphous monolayer carbon,we successfully predict the thermal and electronic properties.More importantly,we reveal that a short range of pair correlation function can readily encode sufficiently rich information of the structure of amorphous material.Utilizing powerful machine learning architectures,the encoded information can be decoded to reconstruct macroscopic properties involving many-body and long-range interactions.Establishing this hidden relationship offers a unified description of the degree of disorder and eliminates the heavy burden of measuring atomic structure,opening a new avenue in studying amorphous materials.展开更多
The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly effici...The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly efficient catalysts for the HzOR.Herein,we report amorphous ruthenium nanosheets(a-Ru NSs)with a thickness of approximately 9.6 nm.As a superior bifunctional electrocatalyst,a-Ru NSs exhibited enhanced electrocatalytic performance toward both the HzOR and hydrogen evolution reaction(HER),outperforming benchmark Pt/C catalysts,where the a-Ru NSs achieved a work-ing potential of merely-76 mV and a low overpotential of only 17 mV to attain a current density of 10 mA·cm^(-2) for the HzOR and HER,respectively.Furthermore,a-Ru NSs displayed a low cell voltage of 28 mV at 10 mA·cm^(-2) for overall hy-drazine splitting in a two-electrode electrolyzer.In situ Raman spectra revealed that the a-Ru NSs can efficiently promote N‒N bond cleavage,thereby producing more*NH_(2)and accelerating the progress of the reaction.展开更多
[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significant...[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significantly reduce energy consumption,pollution emissions and reliance on fossil fuels.Bipolar plates are the major part and key component of PEMFCs stack,which provide mechanical strength,collect and conduct current segregate oxidants and reduce agents.They contribute 70-80%weight and 20-30%cost of a whole stack,while significantly affecting the power density.There are three types plates,including metal bipolar plate,graphite bipolar plate and composite bipolar plate.Stainless steel bipolar plates,as one of metal bipolar plate,exhibit promising manufacturability,competitive cost and durability among various metal materials.However,stainless steel would be corroded in the harsh acid(pH 2-5)and humid PEMFCs environment,whereas the leached ions will contaminate the membrane.In addition,the passivated film formed on the surface will increase the interfacial contact resistance(ICR).In order to improve the corrosion resistance and electrical conductivity of steel bipolar plates,surface coatings are essential.Metal nitride coatings,metal carbide coatings,polymer coatings and carbon-based coatings have been introduced in recent years.Carbon-based coatings,mainly including a-C(amorphous Carbon),Ta-C(Tetrahedral amorphous carbon)and DLC(diamond-like carbon),have attracted considerable attention from both academia and industry,owing to their superior performance,such as chemical inertness,mechanical hardness and electrical conductivity.However,Ta-C films as protective coating of PEMFCs have been rarely reported,due to the difficulty in production for industrial application.In this paper,multi-layer Ta-C composite films were produced by using customized industrial-scale vacuum equipment to address those issues.[Methods]Multiple layered Ta-C coatings were prepared by using PIS624 equipment,which assembled filtered cathodic arc evaporation,ion beam and magnetron sputtering into one equipment,while SS304 and silicon specimens were used as substrate for testing and analysis.Adhesion layer and intermediate layer were deposited by using magnetron sputtering at deposition temperature of 150℃and pressure of 3×10^(−1) Pa,while the sputtering current was set to be 5 A and bias power to be 300 V.The Ta-C layer was coated at arc current of 80-100 A,bias voltage of 1500 V and gas flow of 75 sccm.A scanning electron microscope(CIQTEK SEM3200)was used to characterize surface morphology,coating structure and cross-section profile of the coatings.Raman spectrometer(LabRam HR Evolution,HORIBA JOBIN YVON)was used to identify the bonding valence states.Electrochemical tests were performed by using an electrochemical work station(CHI760,Shanghai Chenhua Instrument Co.,Ltd.),with the traditional three electrode system,where saturated Ag/AgCl and platinum mesh were used as the reference electrode and counter electrode,respectively.All samples were mounted in plastic tube and sealed with epoxy resin,with an exposure area of 2.25 cm^(2),serving as the working electrode.Electrochemical measurements were carried out in simulated PEMFCs cathode environment in 0.5 mol·L^(−1) H_(2)SO_(4)+5 ppm F−solution,at operating temperature of 70℃.As the cathode environment was harsher than the anode environment,all the samples are stabilized at the open-circuit potential(OCP)for approximately 30 min before the EIS measurements.ICR between bipolar plates and GDL was a key parameter affecting performance of the PEMFCs stack.The test sample sandwiched between 2 pieces of carbon paper(simulate gas diffusion layer,GDL)was placed between 2 gold-plated copper electrodes at a compaction pressure of 1.4 MPa,which was considered to be the conventional compaction pressure in the PEMFCs.Under the same conditions,the resistance of a single carbon paper was measured as well.The ICR was calculated according to the formula ICR=1/2(R2−R1)×S,where S was the contact area between GDL and coated stainless steel BPPs.All data of ICR were measured three times for averaging.[Results]The coatings deposited by filtered cathodic arc technology were compact and smooth,which reduced coating porosity and favorable to corrosion resistance.The coating thickness of adhesion and intermediate layers were 180 nm,while the protective Ta-C coating thickness was about 300 nm,forming multiple coating to provide stronger protection for metal bipolar plates.Cr,Ti,Nb and Ta coatings were selected as adhesion layers for comparison.According to electrochemical test,Ta and Nb coatings have higher corrosion resistance.However,Ta and Nb materials would be costly when they are used for mass production.Relatively,Cr and Ti materials were cost effective.Hence,a comprehensive assessment was indispensable to decide the materials to be selected as adhesion layer.Ta-TiN and Ti-TiN combined adhesion and intermediate layer exhibited stronger corrosion resistance,with the corrosion current to be less than 10^(−6) A·cm^(−2).Ta-C protective coating deposited by using filtered cathodic arc technology indicated displayed higher corrosion resistance,with the average corrosion density to be about 1.26×10^(−7) A·cm^(−2).Ta-C coating also shown larger contact angle,with the highest hydrophobicity,which was one of the important advantages for Ta-C,in terms of corrosion resistance.According to Raman spectroscopy,the I(D)/I(G)=549.8/1126.7=0.487,with the estimated fraction of sp^(3) bonding to be in the range of 5154%.The intermediate layer TiN has higher conductivity than the CrN layer.Considering cost,corrosion performance and ICR result,the Ti-TiN layer combination is recommended for industrial scale application.[Conclusions]Multiple layer coating structure of Ta-C film had stronger corrosion resistance;with more than 50%sp^(3) content,while it also had larger water contact angle and higher corrosion resistance than DLC film.The filtered arcing deposition technology was able to make the film to be more consistent and stable than normal arcing technology in terms of the preparation of Ta-C.The coating displayed corrosion density of 1.26×10^(−7) A·cm^(−2) and ICR of less than 5 mΩ·cm^(2),far beyond technical target of 2025 DOE(US Department of Energy).This indicated that the mass-production scale coating technology for PEMFC bipolar plates is highly possible.展开更多
Noble metal-based intermetallic compounds(IMCs)with ordered atomic arrangements exhibit remarkable electrocatalytic activity owing to their unique crystal and electronic structures.During the past years,great advance ...Noble metal-based intermetallic compounds(IMCs)with ordered atomic arrangements exhibit remarkable electrocatalytic activity owing to their unique crystal and electronic structures.During the past years,great advance has been made in the development of noble metal-based IMCs.Recently,Lu and coworkers reported ultrathin“amorphous/intermetallic”(A/IMC)heterophase PtPbBi nanosheets(NSs)with a thickness of 2.5±0.3 nm.The oxidative etching effect caused by the coexistence of O_(2)and Br^(-)ions plays a crucial role in the formation of the IMC and unique two-dimensional structure with irregular shapes and curled edges.This study shows that fabricating an A/IMC heterophase structure with a multimetallic composition can effectively enhance the catalytic performances of noble metal-based electrocatalysts.展开更多
基金financially supported by the Yancheng Polytechnic College School-Level Scientific Research, China (No. ygy1903)the National Natural Science Foundation of China (Nos. 52001163, 52075237, and 52371157)+2 种基金the Open Project of Taihu Laboratory of Deep-Sea Technology Science, Key Research and Development Plan of Jiangsu Province, China (No. BE2019119)supported by the Priority Academic Program Development of Jiangsu Higher Education Institution (PAPD), Chinathe research funding for the Jiangsu Specially-Appointed Professor Program, China。
文摘Recent advancements in electrocatalysis have highlighted the exceptional application value of amorphous electrocatalysts. Withtheir unique atomic configurations, these electrocatalysts exhibit superior catalytic performance compared to that of their crystalline coun-terparts. Transition metal(TM) amorphous ribbon-shaped electrocatalysts have recently emerged as a new frontier in the catalysis field.Dealloying is widely considered a fascinating method for enhancing the electrocatalyst performance. In this review, we comprehensivelyexamine the principles of water electrolysis, discuss the prevalent methods for fabricating ribbon-configured electrocatalysts, and providean overview of amorphous alloys. Furthermore, we discuss binary, ternary, and high-entropy amorphous TM-based electrocatalysts,which satisfy the requirements necessary for effective water electrolysis. We also propose strategies to enhance the activity of amorphousTM-based ribbons, including morphology control, defect engineering, composition optimization, and heterostructure creation in differentelectrolytes. Our focus extends to the latest developments in the design of heterogeneous micro/nanostructures, management of prepara-tion techniques, and synthesis of different compositions. Finally, we address the ongoing challenges and provide a perspective on the fu-ture development of broadly applicable, self-supporting TM ribbon-shaped electrocatalysts.
基金Projects(50871061,50871062,50831003 and 50631010)supported by the National Natural Science Foundation of ChinaProject(2008BS04020)supported by the Excellent Youth Science and Technology Award of Shandong Province,China+2 种基金Project(NCET-06-584)supported by the New Century Talents Program of the Ministry of Education,ChinaProject(2007CB613901)supported by the National Basic Research Program of ChinaProject(LZUMMM2010008)supported by Open Project of Key Laboratory for Magnetism Materials of the Ministry of Education,China
文摘To study the influence of Fe addition on the Al-based amorphous alloys,the structure and properties of Al84Ni10La6 and Al84Ni9Fe1La6 alloys were investigated through various techniques.The results show that 1% Fe（molar fraction） addition increases the area of the pre-peak in the structure factor and decreases the thermal expansion coefficient difference between the crystalline and amorphous states.1% Fe addition also improves the glass forming ability（GFA）,micro-hardness,fracture toughness,electric resistivity,absolute diamagnetism and corrosion resistance of Al-Ni-La alloys,which is related to the changes of medium-range order and quench-in free volume caused by 1% Fe addition.
基金Project supported by the AVIC Unite Fund(KZ041605114)Civil Aircraft(MJ-2016-F-16)。
文摘Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) amorphous coatings were prepared using cold gas kinetic spray technology.The results show that Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) amorphous coatings are achieved with the porosity about 3.2%,thickness about 893 μm,the amount of amorphous phase about 82.5%,the hardness about 300 HV0.2.The corrosion potential and anti-corrosion life of 7075 T6 alloy aluminum are about-0.78 V and 72 h,respectively.The electrochemical analysis and neutral salt spray are about-0.69 V corrosion potential and 274 h anti-corrosion life for amorphous Al-based coatings,respectively.Therefore,the life of the Albased amorphous coatings is about 3.8 times that of 7075 T6 aluminum alloy.Besides,the failure mechanism was analyzed using TEM in this investigation.In a word,Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) coatings keep dense structure,high amorphous content,favorable amorphous phase stabilizing ability and longer anticorrosion life.That is,Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) coatings have better comprehensive properties.Therefore,these findings indicate that the present Al_(86)Ni_(8)Co_(1)La_(1)Y_(2)Gd_(2) amorphous coatings prepared using cold gas kinetic spray technique can protect aluminum alloy very well and they can be considered to be used in aviation field.
基金This work was financially supported by the National Natural Science Foundation of China （Nos. 50271070, 50323009, 50471076）.
文摘Transmission electron microscopy （TEM） is usually used to identify the amorphicity. However, some artifacts may be introduced due to improper TEM foil preparation. In this paper, three Al-rich metallic glasses with and without a glass transition were selected for characterizing the effect of the electropolishing condition on the as-quenched structure during TEM specimen preparation. It is shown that the occurrence of the modulated bright-dark structure under TEM observation is closely sensitive to the electropolishing condition, which suggests us being careful about the possible artifacts induced by specimen preparation when examining amorphous alloys under TEM.
基金National Natural Science Foundation of China(50905185)National"863"project of China(2009AA03Z342)
文摘The Al-based amorphous and nanocrystalline composite coatings with the composition of Al-Ni-Y-Co and Al-Ni-Mm-Fe were prepared on AZ91 Mg-based alloys by high velocity arc spraying technique(HVAS).The structure character of the coatings indicates that coatings contain the mixture of amorphous phases and crystalline and there are both less than 2%porosity.The electrochemical tests of the coatings and the substrate were studied.The coatings show the passivation ability during polarization,but AZ91 Mg-based alloys show little passivation.The corrosion current density of the coatings is lower than that of AZ91 Mg-based alloys.The results show that the coatings have an excellent corrosion resistance for AZ91 Mg-based alloys in 5 wt%NaCl solution.
基金financially supported by the National Natural Science Foundation of China (No. 51171091, 51471099)the Excellent Youth Project of Shandong Natural Science Foundation (No. JQ201012)the National Basic Research Program of China ("973 Program", No. 2012CB825702)
文摘The corrosion-induced crystallization of Al94 exNixGd6（x=6 and 10, in at.%） metallic glasses as well as phase separation, oxidation and cracking in good conductivity solution has been investigated by various techniques.The transmission electronic microscopy（TEM） result reveals that crystalline intermetallics and oxides present on the electrochemically thinned hole edge, and the phase separation occurs in the matrix of the as-spun ribbons with the circumferential speed Rcof 29.3 m/s. In addition, the bending and cracking of the samples occur after corrosion. The influence of Ni content on the phase separation, bending and cracking can be explained by the fact that the percolation of the backbone clusters in the amorphous alloy melts and glasses is enhanced by increasing the composition of Ni.
基金supported by the National Key Research and Development Programs-Intergovernmental International Cooperation in Science and Technology Innovation Project(Grant No.2022YFE0118400)the Natural Science Foundation of Hunan Province(2023JJ50132)+1 种基金Shenzhen Science and Technology Innovation Committee(Grants Nos.JCYJ20220818100211025,and KCXST20221021111616039)Shenzhen Science and Technology Program(No.20231128110928003)。
文摘The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results.In this study,we compared two fluorinated salts:4-(trifluoromethyl)benzamidine hydrochloride(4TF-BA·HCl)and 4-fluorobenzamidine hydrochloride(4F-BA·HCl)to engineer the 3D/2D perovskite films.Surprisingly,4F-BA formed a high-performance 3D/2D heterojunction,while4TF-BA produced an amorphous layer on the perovskite films.Our findings indicate that the balanced intramolecular charge polarization,which leads to effective hydrogen bonding,is more favorable in 4F-BA than in 4TF-BA,promoting the formation of a crystalline 2D perovskite.Nevertheless,4TF-BA managed to improve efficiency to 24%,surpassing the control device,primarily due to the natural passivation capabilities of benzamidine.Interestingly,the devices based on 4F-BA demonstrated an efficiency exceeding 25%with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.
基金supported by the National Natural Science Foundation of China(No.51631003)the Natural Science Foundation of Jiangsu Province(No.BK20191269).
文摘Exploring high-performance and cost-effective electrocatalysts that are applicable in oxygen evolution reaction(OER)is crucial for water splitting and energy storage.In this work,a facile and scalable chemical reduction strategy is developed to synthesize FeCoNiPB non-noble metal-based amorphous high-entropy oxides for the OER in alkaline media.The FeCoNiPB oxides exhibit overpotentials of 235 and 306 mV at current densities of 10 and 100 mA/cm^(2),respectively,as well as a small Tafel slope of 53 mV/dec in 1.0 M KOH solution,outperforming the performance of FeCoPB,FeNiPB,and CoNiPB oxides and the commercial RuO_(2),while maintaining excellent stability with negligible overpotential amplification over 40 h.The superior OER electrocatalytic efficiency and stability of the FeCoNiPB catalyst is primarily attributed to its unique amorphous high-entropy nanostructure,synergistic effect of the multiple components,and in situ-formed amorphous sheets with a thin(FeCoNi)OOH crystalline layer on the edge during long-term OER.This work provides new insights to design and prepare low-cost,highly efficient,and durable OER electrocatalysts.
基金the National Natural Science Foundation of China(Nos.52001222,52075361,and U21A20174)the Key National Scientific and Technological Cooperation Projects of Shanxi Province(No.202104041101008)+5 种基金the Major Science and Technology Project of Shanxi Province(No.20201102003)the Key Research and Development Projects in Shanxi Province(No.201903D421030)the Natural Science Foundation of Shanxi Province(Nos.201701D221073 and 201901D111107)the Program for the Innovative Talents of Higher Education Institutions of Shanxi(PTIT)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(STIP,No.2019L025)the Special Foundation for Youth San Jin scholars。
文摘Amorphous metal-based catalysts(AMCs)have sparked intense research interests in the field of electrocatalysis elicited by their hallmark features such as unlimited volume and morphology,manipulated electronic structures,enriched defects,and unsaturated surface atom coordination.Nevertheless,the manipulation of the amorphous phase in metal-based catalysts is so far impractical,and thus their electrocatalytic mechanism yet remains ambiguous.In this review,the latest advances in AMCs are systematically reviewed,covering amorphous-phase engineering strategy,structure manipulation,and amorphization of various material categories for electrocatalysis.Specifically,a series of applications of AMCs in electrocatalysis for the oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),and oxygen evolution reaction(OER)are summarized based on the classification criteria of substances.Finally,we put forward current challenges that have not yet been clarified in the field of AMCs,and propose possible solutions,particularly from the perspective of the evolution of electron microscopy.It is expected to promote the understanding of the amorphization-catalysis relationship and provide a guideline for designing high-performance electrocatalysts.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50231040).
文摘The Al-Ni-La-Ce-Pr-Nd amorphous ribbon with a super-thickness of 140 mm has been produced by the melt spinning technique. The thickness is as twice as that achieved by the melt spinning technique in the corresponding period (the largest thickness of 65 mm). The crystallization was characterized by using a differential scanning calorimetry. The activation energies are calculated based on the Kissinger equation and the effects of the La, Ce, Pr and Nd on the glass forming ability of Al-based alloy are discussed in the paper.
文摘Zr_~65 Al_~10 Ni_~10 Cu_~15 , Zr_~52.5 Al_~10 Ni_~10 Cu_~15 Be_~12.5 and Zr_~52.5 Al_~10 Ni_~14.6 Cu_~17.9 Ti_5 bulk amorphous alloys were prepared by copper mould casting. The crystallization kinetics was measured by differential scanning calorimeter(DSC) with different heating rates, and the activation energy was calculated using Kissinger equation. The relationship between thermal stability and rate constant of crystallization reaction is discussed on the view of crystallization kinetics, and the effect of small atom Beryllium on thermal stability of bulk amorphous alloys is also studied.
基金supported by a project of the Tsinghua Shenzhen International Graduate School-Shenzhen Pengrui Young Faculty Program of Shenzhen Pengrui Foundation(Grant No.SZPR2023007)Natural Science Foundation of Sichuan Province(Grant No.2025ZNSFSC0449)Shenzhen Science and Technology Program(Grant No.RCBS20231211090637065).
文摘Lithium-ion batteries with LiCoO_(2)(LCO)cathodes are widely used in various electronic devices,resulting in a large amount of spent LCO(SLCO).Therefore,there is an urgent need for an efficient technique for recycling SLCO.However,due to the presence of cobalt oxide with a spinel phase on the surface of highly-degraded LCO,the strong electrostatic repulsion from the transition metal octahedron poses a high Li replenishment barrier,making the regeneration of highly-degraded LCO a challenge.Herein,we propose a structural transformation strategy for reconstructing Li replenishment channels to aid the direct regeneration of highly-degraded LCO.In this approach,ball milling is employed to disrupt the inherent structure of highly-degraded LCO,thereby releasing the internal stress and converting the surface spinel phase into a homogeneous amorphous structure,which promotes Li insertion and regeneration.The regenerated LCO(RLCO)exhibits an outstanding discharge capacity of 179.10 mAh·g^(−1) in the voltage range of 3.0–4.5 V at 0.5 C.The proposed strategy is an effective regeneration approach for highly-degraded LCO,thereby facilitating the efficient recycling of spent lithium-ion battery cathode materials.
基金supported by the Major Science and Technology Project of Zhongshan City(No.2022AJ004)the Key Basic and Applied Research Program of Guangdong Province(Nos.2019B030302010 and 2022B1515120082)Guangdong Science and Technology Innovation Project(No.2021TX06C111).
文摘In general,the rapid growth of α-Fe clusters is a challenge in high Fe-content Fe-based amorphous alloys,negatively affecting their physical properties.Herein,we introduce an efficient and rapid post-treatment technique known as ultrasonic vibration rapid processing(UVRP),which enables the formation of high-density strong magnetic α-Fe clusters,thereby enhancing the soft magnetic properties of Fe_(78)Si(13)B_(9) amorphous alloy ribbon.
基金financial support from the National Natural Science Foundation of China(22478278,22308246)the Central Government Guides the Local Science and Technology Development Special Fund(YDZJSX20231A015)the Fundamental Research Program of Shanxi Province(202203021212266)。
文摘Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru dissolution during OER compromises the activity and stability.Amorphous materials have been identified as a viable strategy to promote the stability of RuO_(2)in acidic OER applications.This study reported a nanoporous amorphous-rich RuMnO_(x)(A-RuMnO_(x))aerogel for efficient and stable acidic OER.Compared with highly crystalline RuMnO_(x),the weakened Ru–O covalency of A-RuMnO_(x)by forming amorphous structure is favorable to inhibiting the oxidation of lattice oxygen.Meanwhile,this also optimizes the electronic structure of Ru sites from overoxidation and reduces the reaction energy barrier of the rate-determining step.As a result,A-RuMnO_(x)aerogel exhibits an ultra-low overpotential of 145 mV at 10 mA cm^(-2)and durability exceeding 100 h,as well as high mass activity up to 153 mA mg^(-1)_(Ru)at 1.5 V vs.reversible hydrogen electrode(RHE).This work provides valuable guidance for preparing highly active and stable Ru-based catalysts for acidic OER.
基金National Natural Science Foundation of China(51971103)Key Research and Development Program in Gansu Province(20YF8GA052)。
文摘A suction casting experiment was conducted on Zr_(55)Cu_(30)Al_(10)Ni_(5)(at%)amorphous alloy.Using ProCAST software,numerical simulations were performed to analyze the filling and solidification processes.The velocity field during the filling process and the temperature field during the solidification process of the alloy melt under different process parameters were obtained.Based on the simulation results,a Zr-based amorphous alloy micro-gear was prepared via casting.The results indicate that increasing the suction casting temperature enhances the fluidity of alloy melt but induces unstable flow rate during filling,which is detrimental to complete filling.Zr-based amorphous micro-gears with a module of 0.6 mm,a tooth top diameter of 8 mm,and 10 teeth were prepared through the suction casting.X-ray diffraction and differential scanning calorimetry analyses confirm that the fabricated micro-gear exhibits characteristic amorphous structural features,demonstrating well-defined geometrical contours and satisfactory forming completeness.
基金Projects(51271036,51471035,51101018)supported by the National Natural Science Foundation of ChinaProject supported by the Program of"One Hundred Talented People"of the Chinese Academy of Sciences
文摘In order to minimize the crystal phase in Al-Cu-Ti amorphous powder,Al65Cu35-xTix amorphous powders were optimized via ball milling through adjusting the amount of Cu and Ti elements and the ball milling time.The results show that increasing the mole fraction of Ti can decrease the amount of Al Cu2Ti,Cu9Al4,and Al2Cu intermetallics formed during the process of ball milling;and prolonging the ball milling time can reduce the element crystalline phase to almost none.The optimal composition is determined to be Al65Cu16.5Ti18.5.TiH2 forms in all selected Al65Cu35-xTix amorphous powders during the process of optimization.H atom is decomposed from toluene and reacts with Ti during ball milling,leading to the formation of TiH2.The volume fraction of TiH2 in Al65Cu16.5Ti18.5 amorphous powder is measured to be 4.30%.
基金supported by the National Key R&D Program of China under Grant No.2021YFA1400500the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No.XDB33000000+1 种基金the National Natural Science Foundation of China under Grant No.12334003the Beijing Municipal Natural Science Foundation under Grant Nos.JQ22001 and QY23014。
文摘Establishing the structure-property relationship in amorphous materials has been a long-term grand challenge due to the lack of a unified description of the degree of disorder.In this work,we develop SPRamNet,a neural network based machine-learning pipeline that effectively predicts structure-property relationship of amorphous material via global descriptors.Applying SPRamNet on the recently discovered amorphous monolayer carbon,we successfully predict the thermal and electronic properties.More importantly,we reveal that a short range of pair correlation function can readily encode sufficiently rich information of the structure of amorphous material.Utilizing powerful machine learning architectures,the encoded information can be decoded to reconstruct macroscopic properties involving many-body and long-range interactions.Establishing this hidden relationship offers a unified description of the degree of disorder and eliminates the heavy burden of measuring atomic structure,opening a new avenue in studying amorphous materials.
基金supported by the National Key R&D Program of China(2018YFA0702001)National Natural Science Foundation of China(22371268,22301287)+3 种基金Fundamental Research Funds for the Central Universities(WK2060000016)Anhui Provincial Natural Science Foundation(2208085J09,2208085QB33)Collaborative Innovation Program of Hefei Science Center,CAS(2022HSC-CIP020)Youth Innovation Promotion Association of the Chinese Academy of Science(2018494)and USTC Tang Scholar.
文摘The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly efficient catalysts for the HzOR.Herein,we report amorphous ruthenium nanosheets(a-Ru NSs)with a thickness of approximately 9.6 nm.As a superior bifunctional electrocatalyst,a-Ru NSs exhibited enhanced electrocatalytic performance toward both the HzOR and hydrogen evolution reaction(HER),outperforming benchmark Pt/C catalysts,where the a-Ru NSs achieved a work-ing potential of merely-76 mV and a low overpotential of only 17 mV to attain a current density of 10 mA·cm^(-2) for the HzOR and HER,respectively.Furthermore,a-Ru NSs displayed a low cell voltage of 28 mV at 10 mA·cm^(-2) for overall hy-drazine splitting in a two-electrode electrolyzer.In situ Raman spectra revealed that the a-Ru NSs can efficiently promote N‒N bond cleavage,thereby producing more*NH_(2)and accelerating the progress of the reaction.
基金Major Science and technology projects of Anhui Province (202103a05020003)。
文摘[Background and purposes]Proton exchange membrane fuel cells(PEMFCs),which convert hydrogen energy directly into electrical energy and water,have received overwhelming attention,owing to their potential to significantly reduce energy consumption,pollution emissions and reliance on fossil fuels.Bipolar plates are the major part and key component of PEMFCs stack,which provide mechanical strength,collect and conduct current segregate oxidants and reduce agents.They contribute 70-80%weight and 20-30%cost of a whole stack,while significantly affecting the power density.There are three types plates,including metal bipolar plate,graphite bipolar plate and composite bipolar plate.Stainless steel bipolar plates,as one of metal bipolar plate,exhibit promising manufacturability,competitive cost and durability among various metal materials.However,stainless steel would be corroded in the harsh acid(pH 2-5)and humid PEMFCs environment,whereas the leached ions will contaminate the membrane.In addition,the passivated film formed on the surface will increase the interfacial contact resistance(ICR).In order to improve the corrosion resistance and electrical conductivity of steel bipolar plates,surface coatings are essential.Metal nitride coatings,metal carbide coatings,polymer coatings and carbon-based coatings have been introduced in recent years.Carbon-based coatings,mainly including a-C(amorphous Carbon),Ta-C(Tetrahedral amorphous carbon)and DLC(diamond-like carbon),have attracted considerable attention from both academia and industry,owing to their superior performance,such as chemical inertness,mechanical hardness and electrical conductivity.However,Ta-C films as protective coating of PEMFCs have been rarely reported,due to the difficulty in production for industrial application.In this paper,multi-layer Ta-C composite films were produced by using customized industrial-scale vacuum equipment to address those issues.[Methods]Multiple layered Ta-C coatings were prepared by using PIS624 equipment,which assembled filtered cathodic arc evaporation,ion beam and magnetron sputtering into one equipment,while SS304 and silicon specimens were used as substrate for testing and analysis.Adhesion layer and intermediate layer were deposited by using magnetron sputtering at deposition temperature of 150℃and pressure of 3×10^(−1) Pa,while the sputtering current was set to be 5 A and bias power to be 300 V.The Ta-C layer was coated at arc current of 80-100 A,bias voltage of 1500 V and gas flow of 75 sccm.A scanning electron microscope(CIQTEK SEM3200)was used to characterize surface morphology,coating structure and cross-section profile of the coatings.Raman spectrometer(LabRam HR Evolution,HORIBA JOBIN YVON)was used to identify the bonding valence states.Electrochemical tests were performed by using an electrochemical work station(CHI760,Shanghai Chenhua Instrument Co.,Ltd.),with the traditional three electrode system,where saturated Ag/AgCl and platinum mesh were used as the reference electrode and counter electrode,respectively.All samples were mounted in plastic tube and sealed with epoxy resin,with an exposure area of 2.25 cm^(2),serving as the working electrode.Electrochemical measurements were carried out in simulated PEMFCs cathode environment in 0.5 mol·L^(−1) H_(2)SO_(4)+5 ppm F−solution,at operating temperature of 70℃.As the cathode environment was harsher than the anode environment,all the samples are stabilized at the open-circuit potential(OCP)for approximately 30 min before the EIS measurements.ICR between bipolar plates and GDL was a key parameter affecting performance of the PEMFCs stack.The test sample sandwiched between 2 pieces of carbon paper(simulate gas diffusion layer,GDL)was placed between 2 gold-plated copper electrodes at a compaction pressure of 1.4 MPa,which was considered to be the conventional compaction pressure in the PEMFCs.Under the same conditions,the resistance of a single carbon paper was measured as well.The ICR was calculated according to the formula ICR=1/2(R2−R1)×S,where S was the contact area between GDL and coated stainless steel BPPs.All data of ICR were measured three times for averaging.[Results]The coatings deposited by filtered cathodic arc technology were compact and smooth,which reduced coating porosity and favorable to corrosion resistance.The coating thickness of adhesion and intermediate layers were 180 nm,while the protective Ta-C coating thickness was about 300 nm,forming multiple coating to provide stronger protection for metal bipolar plates.Cr,Ti,Nb and Ta coatings were selected as adhesion layers for comparison.According to electrochemical test,Ta and Nb coatings have higher corrosion resistance.However,Ta and Nb materials would be costly when they are used for mass production.Relatively,Cr and Ti materials were cost effective.Hence,a comprehensive assessment was indispensable to decide the materials to be selected as adhesion layer.Ta-TiN and Ti-TiN combined adhesion and intermediate layer exhibited stronger corrosion resistance,with the corrosion current to be less than 10^(−6) A·cm^(−2).Ta-C protective coating deposited by using filtered cathodic arc technology indicated displayed higher corrosion resistance,with the average corrosion density to be about 1.26×10^(−7) A·cm^(−2).Ta-C coating also shown larger contact angle,with the highest hydrophobicity,which was one of the important advantages for Ta-C,in terms of corrosion resistance.According to Raman spectroscopy,the I(D)/I(G)=549.8/1126.7=0.487,with the estimated fraction of sp^(3) bonding to be in the range of 5154%.The intermediate layer TiN has higher conductivity than the CrN layer.Considering cost,corrosion performance and ICR result,the Ti-TiN layer combination is recommended for industrial scale application.[Conclusions]Multiple layer coating structure of Ta-C film had stronger corrosion resistance;with more than 50%sp^(3) content,while it also had larger water contact angle and higher corrosion resistance than DLC film.The filtered arcing deposition technology was able to make the film to be more consistent and stable than normal arcing technology in terms of the preparation of Ta-C.The coating displayed corrosion density of 1.26×10^(−7) A·cm^(−2) and ICR of less than 5 mΩ·cm^(2),far beyond technical target of 2025 DOE(US Department of Energy).This indicated that the mass-production scale coating technology for PEMFC bipolar plates is highly possible.
文摘Noble metal-based intermetallic compounds(IMCs)with ordered atomic arrangements exhibit remarkable electrocatalytic activity owing to their unique crystal and electronic structures.During the past years,great advance has been made in the development of noble metal-based IMCs.Recently,Lu and coworkers reported ultrathin“amorphous/intermetallic”(A/IMC)heterophase PtPbBi nanosheets(NSs)with a thickness of 2.5±0.3 nm.The oxidative etching effect caused by the coexistence of O_(2)and Br^(-)ions plays a crucial role in the formation of the IMC and unique two-dimensional structure with irregular shapes and curled edges.This study shows that fabricating an A/IMC heterophase structure with a multimetallic composition can effectively enhance the catalytic performances of noble metal-based electrocatalysts.
