Strong metal–support interaction boosts the electrocatalytic hydrogen evolution capability of Ru nanoparticles supported on titanium nitride

Ruthenium(Ru)has been regarded as one of the most promising alternatives to substitute Pt for catalyzing alkaline hydrogen evolution reaction(HER),owing to its inherent high activity and being the cheapest platinum-group metal.Herein,based on the idea of strong metal–support interaction(SMSI)regulation,Ru/TiN catalysts with different degrees of TiN overlayer over Ru nanoparticles were fabricated,which were applied to the alkaline electrolytic water.Characterizations reveal that the TiN overlayer would gradually encapsulate the Ru nanoparticles and induce more electron transfer from Ru nanoparticles to TiN support by the Ru–N–Ti bond as the SMSI degree increased.Further study shows that the exposed Ru–TiN interfaces greatly promote the H_(2) desorption capacity.Thus,the Ru/TiN-300 with a moderate SMSI degree exhibits excellent HER performance,with an overpotential of 38 mV at 10 mA cm^(−2).Also,due to the encapsulation role of TiN overlayer on Ru nanoparticles,it displays super long-term stability with a very slight potential change after 24 h.This study provides a deep insight into the influence of the SMSI effect between Ru and TiN on HER and offers a novel approach for preparing efficient and stable HER electrocatalysts through SMSI engineering.

High performance corrosion and wear resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

Composite,diffusive titanium nitride layers formed on a titanium and aluminum sub-layer were produced on the AZ91D magnesium alloy.The layers were obtained using a hybrid method which combined the PVD processes with the final sealing by a hydrothermal treatment.The microstructure,resistance to corrosion,mechanical damage,and frictional wear of the layers were examined.The properties of the AZ91D alloy covered with these layers were compared with those of the untreated alloy and of some engineering materials such as 316L stainless steel,100Cr6 bearing steel,and the AZ91D alloy subjected to commercial anodizing.It has been found that the composite diffusive nitride layer produced on the AZ91D alloy and then sealed by the hydrothermal treatment ensures the corrosion resistance comparable with that of 316L stainless steel.The layers are characterized by higher electrochemical durability which is due to the surface being overbuilt with the titanium oxides formed,as shown by the XPS examinations,from titanium nitride during the hydrothermal treatment.The composite titanium nitride layers exhibit high resistance to mechanical damage and wear,including frictional wear which is comparable with that of 100Cr6 bearing steel.The performance properties of the AZ91D magnesium alloy covered with the composite titanium nitride coating are substantially superior to those of the alloy subjected to commercial anodizing which is the dominant technique employed in industrial practice.

Pt Supported on Plasma-Chemical Titanium Nitride for Efficient Room-Temperature CO Oxidation

Catalysts of carbon monoxide oxidation were synthesized by deposition of platinum on titanium nitride (TiN). Two substrates with an average particle size of 18 and 36 nm were obtained by hydrogen reduction of titanium tetrachloride in a stream of microwave plasma of nitrogen. The surface of the catalysts was studied by X-ray photoelectron spectroscopy (XPS). The data obtained by us in the present work indicate the presence of oxynitride as a transition layer between nitride and oxide. It was found that the CO oxidation rate on the 9 - 15 wt.% Pt loaded TiN catalysts is 120 times higher than that on the platinum black with a specific surface of 30 m2/g. Increase in the reaction rate of CO oxidation on Pt/TiN catalysts as compared to platinum black can be associated with both an increase in the concentration of CO molecules adsorbed and a decrease in the activation energy of the reaction. Catalysts are promising for use in catalytic air purification systems.

Low Temperature Deposition of Titanium Nitride

Low temperature deposition (LTD) is an actual frontier in materials sicence and engineering, especially for thin film technology In this paper the fundamentals and processing of lew temperature deposition of TiN coating are reviewed. The prerequisites of a law temperature deposition process are enough good densification, hardness and adhesion of the deposited coating. The fundamentals Of low temperature deposition are Structure zone model and nonequilibrium plasma vapor growth in a combined DC and pulsed electromagnetic fields. namely a combination of a DC bias voltage superimposed by a DC pulsed bias voltage with variable frequency and peak voltage height. Low temperature deposition processing can be realized simply with only stationary eledric fields. However, sensitivity of the product quality to the process parameters is the main barrier of this processing in the way to mass production. Low temperature deposition processing using the effects of a combined DC and pulsed electromagnetic fields has attained some promising results for the future commercialization. But they need Still further Systematic and deep study The application of low temperature deposition processing is nOt limited in range of low melting substrate materials. It is also important for internal stress control, defect minimization, microstructure densification and pedermance improvement for coatings on broad spectrum of substrate materials as well as for different types of applications.

Flexible regulation engineering of titanium nitride nanofibrous membranes for efficient electromagnetic microwave absorption in wide temperature spectrum

Simultaneous development of well impedance matching and strong loss capability has become a mainstream method for achieving outstanding electromagnetic microwave absorption(EMWA)performances over wide temperature range.However,it is difficult to pursue both due to the mutual restraint of relationship between impedance matching and loss capability about temperature.Here,we propose a flexible regulation engineering of titanium nitride(TiN)nanofibrous membranes(NMs,TNMs),which could be distributed uniformly in the polydimethylsiloxane(PDMS)matrix and contributed to the formation of abundant local conductive networks,generating the local conductive loss and enhancing the loss ability of EMWs.Moreover,when the TNMs are used as functional units and dispersed in the matrix,the corresponding composites exhibit an outstanding anti-reflection effect on microwaves.As hoped,under the precondition of good impedance matching,local conductive loss and polarization loss together improve the loss capacity at room temperature,and polarization loss can compensate the local conductive loss to acquire effective dielectric response at elevated temperature.Benefiting from the reasonably synergistic loss ability caused by flexible regulation engineering,the corresponding composites exhibit the perfect EMWA performances in a wide temperature range from 298 to 573 K.This work not only elaborates the ponderable insights of independent membrane in the composition-structure-function connection,but also provides a feasible tactic for resolving coexistence of well impedance matching and strong loss capability issues in wide temperature spectrum.

Titanium nitride nanorod array/carbon cloth as flexible integrated host for highly stable lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries have been regarded as promising energy-storage systems,due to their high theoretical capacity and energy density.However,the carbonaceous sulfur hosts suffer from weak binding force between the hosts and polysulfides,restricting the cyclic stability of sulfur electrode.Meantime,the presence of binder and conductive agent in the traditional electrode reduces its energy density.This study demonstrates that titanium nitride(TiN)nanorod array on carbon cloth(CC)is employed as a flexible host for highly stable Li-S batteries via solvothermal synthesis-nitridation strategy.On the one hand,the flexible integrated network composed of three-dimensional TiN nanorod array and CC significantly improves the conductivity,increases the electron transport and electrolyte penetration of cathode.On the other hand,the 3D structure of TiN/CC and the enhanced polarity of TiN effectively strengthen the physical and chemical double adsorption for polysulfides.As a result,the combination of TiN nanorod array and CC synergistic ally promotes sulfur utilization and electrochemical performances of S@TiN/CC cathode.A discharge capacity of1015.2 mAh·g^(-1)at 0.5C after 250 cycles and 604.1mAh·g^(-1)at 3C after 250 cycles is realized.Under a larger current density of 5C,the resulting S@TiN/CC cathode maintains a high discharge capacity of 666.6 mAh·g^(-1)and the Coulombic efficiency of about 100%.

Defect-rich titanium nitride nanoparticle with high microwaveacoustic conversion efficiency for thermoacoustic imaging-guided deep tumor therapy

Pulse microwave excite thermoacoustic(TA)shockwave to destroy tumor cells in situ.This has promising applications for precise tumor therapy in deep tissue.Nanoparticle(NP)with high microwave-acoustic conversion is the key to enhance the efficiency of therapy.In this study,we firstly developed defect-rich titanium nitride nanoparticles(TiN NPs)for pulse microwave excited thermoacoustic(MTA)therapy.Due to a large number of local structural defects and charge carriers,TiN NPs exhibit excellent electromagnetic absorption through the dual mechanisms of dielectric loss and resistive loss.With pulsed microwave irradiation,it efficiently converts the microwave energy into shockwave via thermocavitation effect,achieving localized mechanical damage of mitochondria in the tumor cell and yielding a precise antitumor effect.In addition to the therapeutic function,the NP-mediated TA process also generates images that provide valuable information,including tumor size,shape,and location for treatment planning and monitoring.The experimental results showed that the TiN NPs could be efficiently accumulated in the tumor via intravenous infusion.With the deep tissue penetration characteristics of microwave,the proposed TiN-mediated MTA therapy effectively and precisely cures tumors in deep tissue without any detectable side effects.The results indicated that defect-rich TiN NPs are promising candidates for tumor therapy.

Fabrication of titanium nitride nanoparticles onto carbon nanotubes by atomic layer deposition for utilization as Pt electrocatalyst supports

Because of its good stability and conductivity,titanium nitride(TiN)is considered to be a very promising alternative support for Pt catalyst;however,the preparation of TiN supports is still challenging.In this work,atomic layer deposition was facilely adopted to fabricate TiN nanoparticles onto carbon nanotubes(CNTs),and then the prepared TiN/CNTs hybrid was used as a support of Pt catalyst.The resulting TiN/CNTs-supported Pt nanoparticles(Pt@TiN/CNTs)nanocomposite showed higher catalytic activity and long-term stability toward the oxygen reduction reaction than the commercial Pt/C,which should be due to the high conductivity and high stability of TiN support,as well as the favorable Pt-TiN strong interaction.

Effects of alloying elements on nitrogen diffusion behavior around TiN/Ti interface α region in as-cast titanium alloys

To characterize the effects of alloying elements on inclusion dissolution of titanium nitride, the content profiles of elements around TiN/Ti boundary α phase regions in liquid titanium alloys have been experimentally carried out. Four kinds of commercial alloys of CpTi, Ti64, Ti17 and Ti6242 containing different α stabilizing or β stabilizing elements are examined through artificially embedding the TiN sponge particle into liquid alloys in VAR conditions. The content profiles of nitrogen and alloying elements around TiN/Ti boundary were measured by WDX and microprobe for as cast samples. The content profiles of nitrogen and alloying elements around N containing solid in α Ti region of these alloys show a common features of a steep change. In particular, the content profiles of elements for Ti6242 demonstrate unique change of a more gentle change tendency and further deeper into the alloy matrix. The experiment results show that, the differences among composite effects of alloying elements in different alloys within nitrogen induced diffusion α region result in different dissolution and diffusion behaviors to overcome the α phase region barriers.

The Effect of Tightening on the Corrosion Properties of the PVD Layers on Magnesium AZ91D Alloy

The corrosive properties of PVD TiN-Ti-Al type composite titanium nitride layer with titanium and aluminium sub-layers system on the AZ91D magnesium alloy and its sub-layers were investigated by using polarization method and impedance spectroscopy, specifically, in terms of the hydrothermal tightening effect. The aim was to explain the mechanisms which contribute to high anticorrosive properties obtained by hydrothermal tightening. It was stated that the hydrothermal treatment changes the surface topography of the examined layers, most probably due to the formation of a continuous titanium oxides film. Tightening significantly modifies the corrosion resistance of the particular component sub-layers of the TiN-Ti-Al layer which exhibits optimum electrochemical parameters. It was shown that the increase of the electrochemical parameters is controlled by tightening of the outside titanium nitride layer, whereas the aluminium sub-layer plays a critical role in creating proper conditions for the hydrothermal tightening of titanium nitride.

TiN nanocrystal anchored on N-doped graphene as effective sulfur hosts for high-performance lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries have become prospective candidates for next-generation energy storage owing to the high energy density and low cost.However,the sluggish kinetics of the electrochemical reaction and shuttle effect result in a rapid capacity decay.Herein,a titanium nitride nanocrystal/Ndoped graphene(TiN@NG)composite is developed to host elemental sulfur.The TiN nanoparticles decorated on graphene sheets attract Li polysulfides(LiPSx)and catalyze the electrochemical reduction and oxidation of LiPSx in the discharge and charge processes,respectively.These two effects effectively restrain the dissolution of the LiPSx and accelerate the electrochemical reactions,thereby,alleviating the shuttle effect.As a result,the cathode composed of TiN@NG/S delivers a remarkable reversible capacity(1390 mA h g^(-1) at 0.1 C)and excellent cycling performance(730 mA h g^(-1) after 300 cycles).We believe that this work can bring some inspiration for designing high-performance Li-S batteries.

Inclusion control of ultra clean ferritic stainless steel

The most important characteristics of the ultra clean ferritic stainless steel is that the carbon,nitrogen and other interstitial elements are very low.The ultra clean ferritic stainless steel has been widely used for household appliances,auto exhaust system,elevator,water treatment system,building roof and other various fields,because of its low cost,pro-environment,excellent properties.They can replace some traditional austenitic stainless steel.such 304 and 316L.The addition of titanium to liquid steel has become common for stabilizing nitrogen and carbon in steel.Titanium reacts with nitrogen,carbon,and oxygen to form titanium nitride,carbide, carbonitride and oxide.These inclusions may have a deleterious effect on the properties such as toughness, ductility,weldability and corrosion.In addition,the inclusions can also agglomerate and cause surface quality problem of the slab and clogging of the submerged entry nozzle during continuous casting process. The formation rules of inclusions in ultra clean ferritic stainless steel were investigated by the thermodynamic calculation,and methods of controlling inclusions were put forward to improve the quality of product.The composition,type,amount,size and distribution of the inclusions in the slab are investigated by optical microscope and scanning electron microscope.The results can be concluded as follows.（1） In the slab,the main original inclusions,with size of larger than 2μm,are Al2O3,TiN or Ti（CN） and complex TiN or Ti（CN） inclusion with core of MgO,MgO-Al2O3 and Ti2o3,which will not affect the performance of the steel if they are in diffusing distribution.The size of these inclusions are less than 10μm except some Al2O3 inclusions in size of 10-40μm.（2） Foreign inclusions are Ti2O3-Al2O3-MgO-SiO2 in size above 50μm covered by TiN or Ti （CN）.Although these inclusions are few,they do harm to the surface quality of stainless steel.It is able to reduce the risk of forming this kind of inclusion by aluminium deoxidation with increasing Al content to restrain the formation of Ti2O3.（3 ） TiN or Ti（CN） is easy to precipitate on inclusions such as MgO,MgO-Al2O3 and Ti2O3,except Al2O3.Controlling the content of[Ti]and[N]and the formation of the oxides can be used to control the precipitation of TiN or Ti（CN）.

Hollow multishelled structural TiN as multi-functional catalytic host for high-performance lithium-sulfur batteries

Lithium-sulfur(Li-S)battery has attracted extensive attention because of its ultrahigh theoretical energy density and low cost.However,its commercialization is seriously hampered by its short cycling life,mainly due to the shuttle of soluble lithium polysulfides(LiPSs)and poor rate capability due to sluggish reaction kinetics.Although significant efforts have been devoted to solving the problems,it is still challenging to simultaneously address all the issues.Herein,titanium nitride hollow multishelled structure(TiN HoMS)sphere is designed as a multi-functional catalytic host for sulfur cathode.TiN,with good conductivity,can effectively catalyze the redox conversion of S and LiPSs,while its surficial oxidation passivation layer can strongly anchor LiPSs.Besides,HoMS enables TiN nanoparticle subunits to expose abundant active sites for anchoring and promoting conversion of LiPSs,while the multiple shells provide physical barriers to restrict the shuttle effect.In addition,HoMS can buffer the volume expansion of sulfur and shorten the charge transport pathway.As a result,the sulfur cathode based on triple-shelled TiN HoMS exhibits an initial specific capacity of 1016 mAh·g-1 at a high sulfur loading of 2.8 mg·cm-2 and maintains 823 mAh·g-1 after 100 cycles.Moreover,it shows a four times higher specific capacity than the one without TiN host at 2 C.

高比表面积氮化钛纳米片作为无枝晶二次水系电池的锌阳极涂层

水系锌离子电池因其能量密度高、成本低、环境友好等优点,已成为一种极具吸引力的储能设备.但由于循环过程中出现的枝晶和副反应,影响了锌金属阳极的稳定性,限制了其在二次电池中的实际应用.在这项工作中,具有高比表面积的多孔TiN纳米片被证明是一种多功能阳极涂层,以实现长循环无枝晶的水系二次锌离子电池.具有金属性质的高比表面积氮化钛纳米片优化了电子传导和锌离子通量,降低了电极表面的极化.正如预期的那样,具有氮化钛涂层的锌电极在超过600小时的时间内表现出可逆性能,没有任何树枝晶形成.此外,基于上述电极组装的全电池也表现出稳定的循环性能(超过600次,容量保留率为97.04%).本工作拓展了氮化钛材料在储能系统中的应用.

Facile molten salt synthesis of carbon-anchored TiN nanoparticles for durable high-rate lithium-ion battery anodes

Transition metal nitrides(TMNs),including titanium nitride(TiN),exhibit remarkable application prospects as anodes for durable high-rate lithium-ion batteries(LIBs).Regrettably,the absence of simple synthesis methods restricts their further development.Herein,a facile and low-cost molten salt synthesis strategy was proposed to prepare carbon-anchored TiN nanoparticles as an advanced anode material for LIBs with high rate capabilities.This nanosized TiN obtained is∼5 nm in size and well-distributed onto carbon plates,which could release a reversible capacity of∼381.5 mAh g^(−1)at 0.1 A g^(−1)after 250 cycles and∼141.5 mAh g^(−1)at 1.0 A g^(−1)after 1000 cycles.Furthermore,it was confirmed that the conversion reaction between TiN and Li-ions happened during the electrochemical reaction process,resulting in the formation of Li_(3)N and Ti.This unique microstructure attributed from TiN nanoparticles anchored by carbon could support the structural volume during cycling.This work highlights the method superiority of TiN prepared via a molten salt synthesis strategy as an anode for LIBs with impressive rate performances.

Topotactic transition of Ti_(4)AlN_(3) MAX phase in Lewis acid molten salt

MAX phases and its derived two-dimensional MXenes have attracted considerable interest because of their rich structural chemistry and multifunctional applications.Lewis acid molten salt route provides an opportunity for structure design and performance manipulation of new MAX phases and MXenes,Although a series of new MAX phases and MXenes were successfully prepared via Lewis acid melt route in recent years,few work is explored on nitride MAX phases and MXenes.Herein,a new copper-based 413-type Ti_(4)CuN_(3)MAX phase was synthesized through isomorphous replacement reaction using Ti_(4)CuN_(3)MAX phase precursor in molten CuCl2.In addition,it was found that at high temperature Ti4N3Clx MXene will transform into two-dimensional cubic TiNa nanosheets with improved structural stability.