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Recent Advances in Single-Atom Catalysts for Photoelectrocatalytic Water Splitting

Carbon Energy 2025年第4期7卷 114-142页

作者： Jiao Yang Xiaoyang Zheng Syed Shoaib Ahmad Shah Chao Wang Xueyao Li Zhishuo Yan Lishan Peng Key Laboratory of Rare Earths Ganjiang Innovation Academy Chinese Academy of Sciences Institute of Applied Physics and Materials Engineering University of Macau Department of Mechanical Engineering Graduate School of Engineering The University of Tokyo Department of Chemistry School of Natural Sciences National University of Sciences and Technology Department of Chemistry University of Connecticut School of Rare Earths University of Science and Technology of China Department of Electrical and Computer Engineering North Dakota State University

Hydrogen is a highly promising energy carrier because of its renewable and clean qualities. Among the different methods for H2production, photoelectrocatalysis（PEC） water splitting has garnered significant interest, thanks to the abundant and perennial solar energy. Single-atom catalysts（SACs）, which feature well-distributed atoms anchored on supports, have gained great attention in PEC water splitting for their unique advantages in overcoming the limitations of conventional PEC ***, we comprehensively review SAC-incorporated photoelectrocatalysts for efficient PEC water splitting. We begin by highlighting the benefits of SACs in improving charge transfer, catalytic selectivity, and catalytic activity, which address the limitations of conventional PEC reactions. Next, we provide a comprehensive overview of established synthetic techniques for optimizing the properties of SACs, along with modern characterization methods to confirm their unique structures. Finally, we discuss the challenges and future directions in basic research and advancements, providing insights and guidance for this developing field.

关键词： hydrogen production photoelectrocatalysis single-atom catalysts water splitting

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Finite element analysis and experimental validation of polymer-metal contacts in block-on-ring configuration

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Friction 2024年第3期12卷 554-568页

作者： K.Y.Eayal AWWAD Khosro FALLAHNEZHAD B.F.YOUSIF Ahmad MOSTAFA Omar ALAJARMEH A.SHALWAN Xuesen ZENG Mechanical Engineering Department Faculty of EngineeringTafila Technical UniversityTafila 66110Jordan Medical Device Research Institute College of Science and EngineeringFlinders UniversitySouth Australia 5042Australia Centre for Future Materials University of Southern QueenslandToowoomba 4350Australia Department of Manufacturing Engineering Technology Public Authority for Applied Education and TrainingKuwait 13092Kuwait

The wear profile analysis,obtained by different tribometers,is essential to characterise the wear ***,most of the available methods did not take the stress distribution over the wear profile in consideration,which causes inaccurate *** this study,the wear profile of polymer–metal contact,obtained by block-on-ring configuration under dry sliding conditions,was analysed using finite element modelling(FEM)and experimental ***’s wear equation was integrated into a developed FORTRAN-UMESHMOTION code linked with Abaqus software.A varying wear coefficient(k)values covering both running-in and steady state regions,and a range of applied loads involving both mild and severe wear regions were measured and implemented in the *** FEM was in good agreement with the *** model reproduced the stress distribution profiles under variable testing conditions,while their values were affected by the sliding direction and maximum wear depth(hmax).The largest area of the wear profile,exposed to the average contact stresses,is defined as the normal *** the critical zones were characterized by high stress concentrations reaching up to 10 times of that at the normal *** wear profile was mapped to identify the critical zone where the stress concentration is the key point in this *** surface features were examined in different regions using scanning electron microscope(SEM).Ultimately,SEM analysis showed severer damage features in the critical zone than that in the normal zone as proven by ***,the literature data presented and considered the wear features the same at any point of the wear *** this study,the normal zone was determined at a stress value of about 0.5 MPa,whereas the critical zone was at about 5.5 *** wear behaviour of these two zones showed totally different features from one another.

关键词： polymer-to-metal contact block-on-ring wear profile wear model

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Surface stress can initiate environment-assisted fracture in metals

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Physical Review E 2024年第2期109卷 L023002-L023002页

作者： Anirudh Udupa Debapriya Pinaki Mohanty Tatsuya Sugihara James B. Mann Ronald M. Latanision Srinivasan Chandrasekar Department of Mechanical Engineering Indian Institute of Technology Madras Chennai Tamil Nadu 600036 India Center for Materials Processing and Tribology Purdue University West Lafayette Indiana 47906 USA Department of Mechanical Engineering Osaka University Suita Osaka 5650871 Japan Department of Materials Science and Engineering MIT Cambridge Massachusetts 02139 USA Exponent Inc. Natick Massachusetts 01760 USA College of Engineering Purdue University West Lafayette Indiana 47906 USA

Controlling environmental effects in surface plasticity/fracture of metals is of interest for areas as diverse as manufacturing processes, product performance, and structural safety. The key to controlling these effects is understanding the effect of adsorbates on surface energy (γ) and surface stress (f). While γ has been well studied, the role of surface stress has received much less attention. We characterize surface stress induced in metals by adsorption of organic monolayers. Linear alkanoic acids of varying chain length (3–18) are deposited by molecular self-assembly onto one side of an aluminum cantilever, several centimeters in length. The surface stress is estimated from in situ measurement of the cantilever deflection. We find that the organic adsorbates induce large surface stress of −4 to +30N/m. Furthermore, we show that f may be tuned by varying adsorbate-molecule chain length. The stress data explain beneficial embrittlement of metal surfaces by organic adsorbates in cutting and comminution processes, and point to a critical role, hitherto ignored, for f in environment assisted cracking (EAC) phenomena. Our results suggest opportunities for utilizing controlled environment-assisted fracture as an aid—fracture as a friend—to enhance material removal processes, apart from using surface stress itself as an experimental probe to explore various manifestations of EAC.

关键词： Adsorption Continuum mechanics Disclinations & dislocations Fracture Friction Tribology

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Sub-nanometer structured silicon-carbon composite nanolayers armoring on graphite for fast-charging and high-energy-density lithium-ion batteries

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Rare Metals 2023年第11期42卷 3692-3704页

作者： Zhen-Wei Li Mei-Sheng Han Jie Yu Songshan Lake Materials Laboratory Dongguan523808China Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic Systems Shenzhen Engineering Lab for Supercapacitor MaterialsSchool of Material Science and EngineeringHarbin Institute of TechnologyShenzhenShenzhen 518055China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen518055China

Silicon/carbon composites are promising alternatives to current graphite anodes in commercial lithiumion batteries(LIBs)because of their high capacity and excellent ***,the unsatisfactory fastcharging capability and cycle stability of Si/C composites caused by slow charge transport capability and huge volume change under industrial electrode conditions severely hamper their ***,a novel Si/C anode was fabricated by homogeneously depositing amorphous C-Si nanolayers on graphite(C-Si@graphite).C-Si nanolayers with uniformly dispersed sub-nanometer Si particles in 3D carbon skeleton significantly boost electron and Li-ion transport and efficiently relieve Si's agglomeration and volume *** a result,the tailored C-Si@graphite electrodes show an excellent rate capacity(760.3 mAh·g^(-1)at 5.0C)and long cycle life of over 1000 cycles at 1.0C and800 cycles at 2.0C under industrial electrode *** addition,the assembled full cells(C-Si@graphite,anode;Li[Ni_(0.8)Co_(0.1)Mn_(0.1)]O_(2),cathode)present superior fastcharging capability(240.4 Wh·kg^(-1),charging for16.2 min,3.0C)and long cycle life(80.7%capacity retention after 500 cycles at 1.0C),demonstrating the massive potential of C-Si@graphite for practical application.

关键词： Si/C anode Sub-nanometer Si Fast-charging capability Lithium-ion batteries(LIBs)

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Intergranular deformation mechanism stimulated by{10-12}extension twins in AZ81-La alloy

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Journal of Rare Earths 2024年第12期42卷 2325-2331,I0005页

作者： Biwu Zhu Jing Su Xiao Liu Changping Tang Wenhui Liu Luoxing Li Congchang Xu Pengcheng Guo College of Marine Equipment and Mechanical Engineering Jimei UniversityXiamen 361021China Research Institute of HNU in Chongqing Hunan UniversityChongqing401135China Department of Mining and Materials Engineering McGill University3610 Rue UniversityMontrealQuebec H3A 0C5Canada School of Materials Science and Engineering Hunan University of Science and TechnologyXiangtan411201China

In polycrystalline Mg-RE magnesium alloys,the lattice parameter,dislocation dynamics and critical resolved shear stress(CRSS)for various deformation modes are altered with the addition of RE atom,finally affecting deformation mode and strain accommodation mechanism among neighboring *** compression tests were performed on as-extruded AZ81-La Mg alloy samples with the c-axis of the majority of crystals vertical to the compression *** variants and dominant slip systems were examined by electron backscattered diffraction(EBSD)*** is found by in-grain misoriention axis(IGMA)analysis that the plastic deformation is mainly accommodated by a combination of the pyramidal slip and the basal *** dominant twin variant is{0112}<0111>and{1102}<1101>.Here,we applied a modified displacement gradient accommodation(m-DGA)method to evaluate the selection mechanism of twin/slip in neighbour grain stimulated by{1012}extension *** is found that the activated slip system and/or twin variant in the neighbouring grain is determined by the accommodation of the major shear strain induced by{1012}extension twin in such a way that strain concentration along grain boundaries can be relaxed.

关键词： AZ81-La alloy Twinning Slip Accommodation Rotation tensor Rare earths

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Direct CALPHAD coupling phase-field model: Closed-form expression for interface composition satisfying equal diffusion potential condition

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Physical Review E 2024年第6期109卷 065303-065303页

作者： Takumi Morino Machiko Ode Shoichi Hirosawa Department of Mechanical Engineering and Materials Science

We formulated two phase-field models to compute interfacial compositions, characterized by their high computational accuracy and efficiency. The inaugural model utilizes convergence calculations to fulfill the equal diffusion potential condition, while the subsequent model obviates the need for such calculations. Despite this, its computational outcomes strongly agree with those of the preceding model. Notably, in these models, the alteration in composition attributable to interfacial curvatures aligns with the Gibbs-Thomson effect within the equilibrium system. In this study, the solidification processes of Ni-Al-Cr and Ag-Cu-Sn alloys serve as case studies to underscore the computational precision and swiftness of the proposed models.

关键词： Microstructure Phase transitions Phase-field modeling Solidification

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Uncovering the hierarchical clusters in the heat-affected zone of an electron beam weldedα/βtitanium alloy joint

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Journal of materials science & Technology 2024年第7期174卷 120-132页

作者： C.Xu X.H.Shao H.J.Yang M.Lv H.Q.Liu X.L.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Suzhou laboratory Suzhou 215028China Department of Mechanical Engineering Kyushu UniversityFukuoka 819-0395Japan Bay Area Center for Electron Microscopy Songshan Lake Materials LaboratoryDongguan 523808China

Using high-resolution transmission Kikuchi diffraction(TKD)and transmission electron microscopy(TEM),we examined the hierarchical clusters that form in situ in the heat-affected zone(HAZ),which are com-monly referred to as“ghost”structures,of bimodal titanium alloy Ti-5Al-2Sn-2Zr-4Mo-4Cr(wt%,TC17).The ghost structures are enriched with Al elements but poor in Mo and Cr compared to the surroundingβ*** results show that the ghost structure in middle-HAZ mainly consists ofα_(L)laths with a high-angle grain boundary,which exhibits the classic Burgers orientation relationship(BOR)with the host matrix,while it encircles theα_(P)grains in *** the ghost structure is evidenced to form via in-complete martensitic *** results further confirm that the ghost structure is composed ofαL and tinyβ_(L)laths with BOR,with the former being enriched with Al and poor with Cr and Mo,while the latter is the ***,twoα_(L)variant clusters with a check-mark morphology are fre-quently observed viewed along[0001]_(αL)//[110]_(βL)directions,which are dominated by the crystallographic and geometrical relationships betweenαandβ*** on the microstructural characterization,it is hypothesized that the ghost structure is transformed from the initialα_(P)phase,due to the coupling ef-fect of high thermal stress(which induces the formation of a large number of dislocations)and element diffusion caused by sudden temperature increase and plunge cooling in the HAZ during the welding pro-cess.

关键词： TC17 titanium alloy Electron beam welding(EBW) The ghost structure Transmission Kikuchi diffraction(TKD) Transmission electron microscopy(TEM)

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Computational study of laser fragmentation in liquid:Phase explosion,inverse Leidenfrost effect at the nanoscale,and evaporation in a nanobubble

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science China(Physics,Mechanics & Astronomy) 2022年第7期65卷 99-114页

作者： Hao Huang Leonid V.Zhigilei School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Materials Science and Engineering University of VirginiaCharlottesville 22904-4745USA

Laser fragmentation in liquid is an effective and environment-friendly processing technique capable of yielding colloidal nanoparticles and atomic clusters with a narrow size distribution. The advancement of this technique can be facilitated by an improved understanding of processes that control the sizes, shapes, and structures of the produced nanoparticles. In this work, the dependence of the fragmentation mechanisms on the energy density deposited by the laser pulse is investigated in atomistic simulations performed for 20 nm Au nanoparticles irradiated in water by 10 ps laser pulses. The simulations reveal that the decrease in the absorbed laser energy leads to sequential transitions from the regime of “strong” phase explosion, when all products of an explosive phase decomposition of the irradiated nanoparticle are promptly injected into the water surrounding a nanobubble formed around the nanoparticle, to two distinct regimes of nanoparticle fragmentation leading to the formation of a large central nanoparticle surrounded by smaller satellite fragments. First, in the regime of “mild” phase explosion, the central nanoparticle is produced by the reflection of some of the hot metal droplets generated by the explosive decomposition of the nanoparticle from the boundary of the nanobubble. This reflection is attributed to the inverse Leidenfrost effect acting at the nanoscale. The reflected droplets converge in the center of the nanobubble and coalesce into a single droplet that solidifies shortly after the collapse of the nanobubble. Further decrease in the absorbed laser energy brings the irradiation conditions below the threshold for the phase explosion and results in the formation of a core-satellite structure of the fragmentation products through an interplay of the intense evaporation from the surface of the irradiated nanoparticle, evolution of the nanobubble, and condensation of the metal vapor into clusters and small satellite nanoparticles. The computationa

关键词： laser fragmentation in liquid molecular dynamics simulations phase explosion inverse Leidenfrost effect nanobubble nanoparticles

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Microstructural evolution and its influence on the wear resistance of a laser directed energy deposited Ni-based single crystal superalloy

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材料科学技术（英文版） 2025年第2期205卷 127-138页

作者： Chenyu Ren Kai Chen Jingjing Liang R.Lakshmi Narayan Upadrasta Ramamurty Jinguo Li Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano) State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an 710049China Superalloys Division Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Department of Materials Science and Engineering Indian Institute of TechnologyDelhiNew Delhi 110016India School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

The wear behavior of Ni-based single crystal(NBSC)superalloy SRR99 fabricated by laser-directed energy deposition(LDED)is investigated and compared with that of its cast *** γ'precipitate size in the latter is＞400 nm,that in the former is an order of magnitude *** sliding wear tests reveal that the wear rate and coefficient of friction of the LDED alloy are 75％and 20％lower than that of its cast counterpart,*** transmission electron microscopy investigation of the wear-tested cast alloy indicates that there is orientation change and formation of nanoscale grains only at the top layer of the worn surface,whereas regions below undergo moderate plastic deformation via dislocation *** contrast,the sub-surface of the worn LDED alloy has a graded microstructure,with a composite of NiO/γ-Ni on the top,γ'free nano-grains in the middle,and a highly deformed nanoscale layer at the *** improved wear behavior of the LDED alloy is attributed to its higher dislocation density,finer γ'precipitates,and the formation of this graded ***,a detailed description of mechanisms that lead to the formation of this unique graded microstructure is provided.

关键词： In-situ formed gradient nanostructure Enhanced wear resistance Laser-directed energy deposition additive manufacturing Ni-based single crystal superalloys Plastic deformation

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Recent research progress in the mechanism and suppression of fusion welding-induced liquation cracking of nickel based superalloys

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International Journal of Minerals,Metallurgy and materials 2024年第5期31卷 1072-1088页

作者： Zongli Yi Jiguo Shan Yue Zhao Zhenlin Zhang Aiping Wu Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China College of Engineering China Agricultural UniversityBeijing 100091China State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China School of Material Science and Engineering Southwest Jiaotong UniversityChengdu 610031China

Nickel-based superalloys are extensively used in the crucial hot-section components of industrial gas turbines,aeronautics,and astronautics because of their excellent mechanical properties and corrosion resistance at high *** welding serves as an effective means for joining and repairing these alloys;however,fusion welding-induced liquation cracking has been a challenging *** paper comprehensively reviewed recent liquation cracking,discussing the formation mechanisms,cracking criteria,and *** recent investigations,regulating material composition,changing the preweld heat treatment of the base metal,optimizing the welding process parameters,and applying auxiliary control methods are effective strategies for mitigating *** promote the application of nickel-based superalloys,further research on the combination impact of multiple elements on cracking prevention and specific quantitative criteria for liquation cracking is necessary.

关键词： nickel-based superalloy fusion welding liquation cracking cracking mechanism cracking suppression

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