Stabilizing iridium sites via interface and reconstruction regulations for water oxidation in alkaline and acidic media

Exploring effective iridium(Ir)-based electrocatalysts with stable iridium centers is highly desirable for oxygen evolution reaction(OER).Herein,we regulated the incorporation manner of Ir in Co_(3)O_(4)support to stabilize the Ir sites for effective OER.When anchored on the surface of Co_(3)O_(4)in the form of Ir(OH)_6 species,the created Ir-OH-Co interface leads to a limited stability and poor acidic OER due to Ir leaching.When doped into Co_(3)O_(4)lattice,the analyses of X-ray absorption spectroscopy,in-situ Raman,and OER measurements show that the partially replacement of Co in Co_(3)O_(4)by Ir atoms inclines to cause strong electronic effect and activate lattice oxygen in the presence of Ir-O-Co interface,and simultaneously master the reconstruction effect to mitigate Ir dissolution,realizing the improved OER activity and stability in alkaline and acidic environments.As a result,Ir_(lat)@Co_(3)O_(4)with Ir loading of 3.67 wt%requires 294±4 mV/285±3 mV and 326±2 mV to deliver 10 mA cm^(-2)in alkaline(0.1 M KOH/1.0 M KOH)and acidic(0.5 M H_(2)SO_(4))solution,respectively,with good stability.

Comparison of the interface reaction behaviors of CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) solid-state systems based on the diffusion couple method

The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.

Interfacial reaction between AZ91D magnesium alloy melt and mild steel under high temperature

The metallurgical quality control of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and corrosion performance,while the typical used steel crucible introduces impurities and interfacial interaction during melting process.Therefore,a systematic study about impurities diffusion and interfacial interaction between molten Mg and steel is necessary.In the present study,the interfacial reaction between molten AZ91D Mg alloy and mild steel during melting process was investigated with the melting temperatures of 700℃,750℃ and 800℃.The results show that Al(Fe,Mn)intermetallic layer is the intermetallic primarily formed at the interfaces of AZ91D melt and mild steel.Meanwhile,Al_(8)(Mn,Fe)5is indexed between Al(Fe,Mn)and AZ91D.AlFe_(3)C appears between the mild steel and Al(Fe,Mn)at 700℃ and 750℃,but absent at 800℃ due to the increased solubility of carbon in Mg matrix.It is found that the growth of the intermetallic layer is controlled by diffusion mechanism,and Al and Mn are the dominant diffusing species in the whole interfacial reaction process.By measuring the thickness of different layers,the growth constant was calculated.It increases from 1.89(±0.03)×10^(-12)m^(2)·s^(-1)at 700℃ to 3.05(±0.05)×10^(-12)m^(2)·s^(-1)at 750℃,and 5.18(±0.05)×10^(-12)m^(2)·s^(-1)at 800℃.Meanwhile,the content of Fe is linearly increased in AZ91D with the increase of holding time at 700℃ and 750℃,while it shows a significantly increment after holding for 8 h at 800℃,indicating holding temperature is more crucial to determine the Fe content of AZ91D than holding time.

Cu-Zn-based alloy/oxide interfaces for enhanced electroreduction of CO_(2) to C_(2+) products

The electrochemical CO_(2)reduction reaction to produce multi-carbon(C_(2+)) hydrocarbons or oxygenate compounds is a promising route to obtain a renewable fuel of high energy density.However,producing C_(2+)at high current densities is still a challenge.Herein,we develop a Cu-Zn alloy/Cu-Zn aluminate oxide composite electrocatalytic system for enhanced conversion of CO_(2)to C_(2+)products.The Cu-Zn-Al-Layered Double Hydroxide(LDH) is used as a precursor to decompose into uniform Cu-Zn oxide/Cu-Zn aluminate pre-catalyst.Under electrochemical reduction,Cu-Zn oxide generates Cu-Zn alloy while Cu-Zn aluminate oxide remains unchanged.The alloy and oxide are closely stacked and arranged alternately,and the aluminate oxide induces the strong electron interaction of Cu,Zn and Al,creating a large number of highly active reaction interfaces composed of 0 to+3 valence metal sites.With the help of the interface effect,the optimized Cu_(9)Zn_(1)/Cu_(0.8)Zn_(0.2)Al_(2)O_(4)catalyst achieves a Faradaic efficiency of 88.5% for C_(2+)products at a current density of 400 mA cm^(-2)at-1.15 V versus reversible hydrogen electrode.The in-situ Raman and attenuate total reflectance-infrared absorption spectroscopy(ATR-IRAS) spectra show that the aluminate oxide at the interface significantly enhances the adsorption and activation of CO_(2)and the dissociation of H2O and strengthens the adsorption of CO intermediates,and the alloy promotes the C-C coupling to produce C_(2+)products.This work provides an efficient strategy to construct highly active reaction interfaces for industrial-scale electrochemical CO_(2)RR.

Synergistic“Anchor‑Capture”Enabled by Amino and Carboxyl for Constructing Robust Interface of Zn Anode

While the rechargeable aqueous zinc-ion batteries(AZIBs)have been recognized as one of the most viable batteries for scale-up application,the instability on Zn anode–electrolyte interface bottleneck the further development dramatically.Herein,we utilize the amino acid glycine(Gly)as an electrolyte additive to stabilize the Zn anode–electrolyte interface.The unique interfacial chemistry is facilitated by the synergistic“anchor-capture”effect of polar groups in Gly molecule,manifested by simultaneously coupling the amino to anchor on the surface of Zn anode and the carboxyl to capture Zn^(2+)in the local region.As such,this robust anode–electrolyte interface inhibits the disordered migration of Zn^(2+),and effectively suppresses both side reactions and dendrite growth.The reversibility of Zn anode achieves a significant improvement with an average Coulombic efficiency of 99.22%at 1 mA cm^(−2)and 0.5 mAh cm^(−2)over 500 cycles.Even at a high Zn utilization rate(depth of discharge,DODZn)of 68%,a steady cycle life up to 200 h is obtained for ultrathin Zn foils(20μm).The superior rate capability and long-term cycle stability of Zn–MnO_(2)full cells further prove the effectiveness of Gly in stabilizing Zn anode.This work sheds light on additive designing from the specific roles of polar groups for AZIBs.

INTERFACE REACTION IN MAGNETIC MULTILAYERS

Ta/NiO/NiFe/Ta multilayers were prepared by rf reactive and dc magnetron sputtering. The exchange coupling field (Hex) between NiO and NiFe reached 120O e. The composition and chemical states at the interface region of NiO/NiFe were studied using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique. The results show that there are two thermodynamically favorable reactions at NiO/NiFe interface: NiO+Fe=Ni+FeO and 3NiO+2Fe=3Ni+Fe2O3. The thickness of the chemical reaction as estimated by angle-resolved XPS was about 1-1.5 nm. These interface reaction products are magnetic defects, and we believe that the Hex and the coercivity (Hc) of NiO/NiFe are affected by these defects. Moreover, the results also show that there is an intermixing layer at the Ta/NiO (and NiO/Ta) interface due to a thermodynamically favorable reaction: 2Ta+5NiO+Ta2O5. This interface reaction has an effect on the exchange coupling as well. The thickness of the intermixing layer as estimated by XPS depth-profiles was about 8-10 nm.

INTERFACE REACTION OF TiC_p-REINFORCED Ti-MATRIX COMPOSITE

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Recent Advances in Interface Engineering for Electrocatalytic CO_(2) Reduction Reaction

Electrocatalytic CO_(2) reduction reaction(CO_(2) RR) can store and transform the intermittent renewable energy in the form of chemical energy for industrial production of chemicals and fuels,which can dramatically reduce CO_(2) emission and contribute to carbon-neutral cycle. E cient electrocatalytic reduction of chemically inert CO_(2) is challenging from thermodynamic and kinetic points of view. Therefore,low-cost,highly e cient,and readily available electrocatalysts have been the focus for promoting the conversion of CO_(2). Very recently,interface engineering has been considered as a highly e ective strategy to modulate the electrocatalytic performance through electronic and/or structural modulation,regulations of electron/proton/mass/intermediates,and the control of local reactant concentration,thereby achieving desirable reaction pathway,inhibiting competing hydrogen generation,breaking binding-energy scaling relations of intermediates,and promoting CO_(2) mass transfer. In this review,we aim to provide a comprehensive overview of current developments in interface engineering for CO_(2) RR from both a theoretical and experimental stand-point,involving interfaces between metal and metal,metal and metal oxide,metal and nonmetal,metal oxide and metal oxide,organic molecules and inorganic materials,electrode and electrolyte,molecular catalysts and electrode,etc. Finally,the opportunities and challenges of interface engineering for CO_(2) RR are proposed.

On the perturbation solution of interface-reaction controlled diffusion in solids

Insertion of species A into species B forms a product P through two kinetic processes, namely, （1） the chemical reaction between A and B that occurs at the B-P interface, and （2） the diffusion of species A in product P. These two processes are symbiotic in that the chemical reaction provides the driving force for the diffusion, while the diffusion sustains the chemical reaction by providing sufficient reactant to the reactive interface. In this paper, a math- ematical framework is developed for the coupled reaction- diffusion processes. The resulting system of boundary and initial value problem is solved analytically for the case of interface-reaction controlled diffusion, i.e., the rate of diffu- sion is much faster than the rate of chemical reaction at the interface so that the final kinetics are limited by the interface chemical reaction. Asymptotic expressions are given for the velocity of the reactive interface and the concentration of diffusing species under two different boundary conditions.

Robust interface layers with redox shuttle reactions suppress the dendrite growth for stable solid-state Li metal batteries

Designing a durable lithium metal anode for solid state batteries requires a controllable and uniform deposition of lithium, and the metal lithium layer should maintain a good interface contact with solid state electrolyte during cycles. In this work, we construct a robust functional interface layer on the modified LiB electrode which considerably improves the electrochemical stability of lithium metal electrode in solid state batteries. It is found that the functional interface layer consisting of polydioxolane, polyiodide ion and Li TFSI effectively restrains the growth of lithium dendrites through the redox shuttle reaction of I-/I3-and maintains a good contact between lithium anode and solid electrolyte during cycles. Benefit from these two advantages, the modified Li-B anode exhibits a remarkable cyclic performance in comparison with those of the bare Li-B anode.

Interface reaction in aluminium matrix composite at laser welding

Interface reaction of SiC w/6061Al aluminium matrix composite subjected to laser welding was studied. It is pointed out that the main reason for bad weldability of the material is concerned with the interface reaction during the welding. Effects of welding parameters on interface reaction were also investigated. The results show that the interface bonding state can be improved by laser beam, and the main welding parameter affecting the strength of weld is laser output power. The smaller the output power, the lower the extent of interface reaction and the better the mechanical properties.

Recent advances in elaborate interface regulation of BiVO_(4)photoanode for photoelectrochemical water splitting

Bismuth vanadate(BiVO_(4))is an excellent photoanode material for photoelectrochemical(PEC)water splitting system,possessing high theoretical photoelectrocatalytic conversion efficiency.However,the actual PEC activity and stability of BiVO_(4)are faced with great challenges due to factors such as severe charge recombination and slow water oxidation kinetics at the interface.Therefore,various interface regulation strategies have been adopted to optimize the BiVO_(4)photoanode.This review provides an in-depth analysis for the mechanism of interface regulation strategies from the perspective of factors affecting the PEC performance of BiVO_(4)photoanodes.These interface regulation strategies improve the PEC performance of BiVO_(4)photoanode by promoting charge separation and transfer,accelerating interfacial reaction kinetics,and enhancing stability.The research on the interface regulation strategies of BiVO_(4)photoanode is of great significance for promoting the development of PEC water splitting technology.At the same time,it also has inspiration for providing new ideas and methods for designing and preparing efficient and stable catalytic materials.

Boosted Electrocatalytic Glucose Oxidation Reaction on Noble-Metal-Free MoO_(3)-Decorated Carbon Nanotubes

Electrocatalytic glucose oxidation reaction(GOR)has attracted much attention owing to its crucial role in biofuel cell fabrication.Herein,we load MoO_(3)nanoparticles on carbon nanotubes(CNTs)and use a discharge process to prepare a noblemetal-free MC-60 catalyst containing MoO_(3),Mo_(2)C,and a Mo_(2)C–MoO_(3)interface.In the GOR,MC-60 shows activity as high as 745μA/(mmol/L cm^(2)),considerably higher than those of the Pt/CNT(270μA/(mmol/L cm^(2)))and Au/CNT catalysts(110μA/(mmol/L cm^(2))).In the GOR,the response minimum on MC-60 is as low as 8μmol/L,with a steady-state response time of only 3 s.Moreover,MC-60 has superior stability and anti-interference ability to impurities in the GOR.The better performance of MC-60 in the GOR is attributed to the abundant Mo sites bonding to C and O atoms at the MoO_(3)–Mo_(2)C interface.These Mo sites create active sites for promoting glucose adsorption and oxidation,enhancing MC-60 performance in the GOR.Thus,these results help to fabricate more effi cient noble-metal-free catalysts for the fabrication of glucose-based biofuel cells.

DIFFUSION REACTION IN THE INTERFACE OF TITANIUM／MILD STEEL COMPOSITE

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Development of Sb Microelectrode and In-situ pH Measurement of Electroless Nickel Reaction Interface

Sb microelectrodes were prepared by plating. The results of testing show that they have excellent stability, quick responding speed, high pH sensitivity (35～40 mV/pH) and long useful life in high temperature acidic electroless nickel (EN) bath. By using Sb microelectrode, the pH value in EN reaction interface was measured in situ . There exists the fluctuation of pH during EN plating, and the amplitude of fluctuation tends to decrease with plating time. The largest fluctuation amplitude can reach 1～2 pH value. The in situ pH measurement provides reliable experimental results for explaining the formation of layer structure of EN deposit.

SiC Formation Through Interface Reaction between C_(60) and Si in Plasma Environment

The formation of SiC through the interface reaction between C60 and Si in a plasmaassisted chemical vapour deposition system （PACVD） is investigated with a C60 film previously deposited on Si wafers. The composition and structure of the deposited samples were characterized by micro-Raman spectroscopy and X-ray diffraction （XRD）. The results showed that SiC film was formed successfully in hydrogen plasma at a substrate temperature of 800℃ . The hydrogen atoms in plasma were found to enhance the production of SiC. Furthermore, the effects of the added CH4 on the formation of film were studied. Introduction of CH4 simultaneously with H2 at the beginning would suppress the formation of the initial layer of SiC due to a carbon-rich environment on the substrate, which would be disadvantageous to the further growth of the SiC film.

Interface Reaction of Ta/NiFe and NiFe/Ta and the Dead Layer

The structures of Ta/Ni81Fe19 and Ni81Fe19/Ta are commonly used in magnetoresistance multilayers. It is found that the thickness of dead layer in Ta/Ni81Fe19/Ta was about 1.6±0.2nm. X-ray photoelectron spectroscopy (XPS) was used to study the interfaces of Ta/Ni81Fe19 and Ni81Fe19/Ta. The results show that there is a reaction at the two interfaces: 2Ta+Ni=NiTa2, which caused the thinning of the effective NiFe layer. Furthermore, this reaction could also explain the phenomenon that the dead layer thickness of spin valves multilayers prepared by MBE is thinner than those prepared by magnetron sputtering.

Effect of Nb and alloying elements on interface reaction between high Nb-containing TiAl alloys and ZrO_2-based ceramic moulds

In the present study, Ti-45Al-(6, 7, 8)Nb(at%) and Ti-45Al-8Nb-0.5(Mn, Si, Y, B) alloys were prepared by arc melting and casting into Zr O2(Y2O3 stabilized) ceramic moulds to study the effect of alloying elements Nb and Mn, Si, Y, B on the interfacial reaction between casting Ti Al alloys and ceramic moulds by SEM, and the elements' distribution in the interface reaction layer by line scanning. The results showed that with an increase in Nb content, the interfacial reaction weakened and the thickness of the reaction layer decreased gradually. The interface reaction thickness of the alloys with Nb content of 6, 7, 8at% were 60, 34 and 26 μm, respectively. Clearly, the addition of 8at% Nb to Ti-45 Al is the best for the thickness of the reaction layer. The addition of Nb would form a Nb-rich film in the reaction layer, which could reduce the solubility of oxygen in the interface, and suppress further diffusion of oxygen to the matrix. If the same content of Mn, Si, Y, or B alloying elements were added respectively to Ti-45Al-8Nb, the thickness of the interface reaction layer from large to small was as follows: Mn>Si>Y>B. The interface reaction thickness increased after 0.5at% Mn added, had no obvious change after 0.5at% Si addition, and decreased after adding 0.5at% Y or B. The introduced elements, which formed a protective film or/and promoted the formation of a dense aluminum oxide layer, would be of benefit to the resistance of interfacial reaction.

FINE STRUCTURES OF BOTH INTERFACES AND INTERFACIAL REACTION PRODUCTS

The characteristic of interface depending on the atomic structure exerts an inportant,and sometime controlling,influence on performance of the interacial materials. The present paper reviews the main studies on fine structure of both the materials inter- faces and interfacial reaction products in semiconductor uperlattice,metal multilayer ceram- ics and composite materials by mean of selected area electron doffraction patterns and high resolution electron microscopy. The following features of interfaces are reviewed:the orientation relationships;the char- acteristic of steps,facets and ronghness of interfaces;atomic bonding across the interface;the degree of coherency,the structure of misfit dislocations and elastic relaxations at the inter- faces:the presence of defects at the onterfaces:the structure of the interfacial reaction prod- ucts as well as the reaction kinetics and reaetion mechanism.

Interface reactions in film materials

Interface reaction (IR) is a frequently observed phenomenon in the study ofadvanced thin film materials. It is very important to study the reaction conditions at which IRhappens and then to suppress or make use of it, the necessary conditions, including boththermodynamical and dynamical conditions of IR were discussed in detail. IRs in various systems,including oxide/silicon, oxide/metal, metal/metal, metal/semiconductor andsemiconductor/semiconductor, were reviewed. Methods to suppress and make use of IR were alsointroduced.