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Unraveling the Harmonious Coexistence of Ruthenium States on a Self-Standing Electrode for Enhanced Hydrogen Evolution Reaction

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ENERGY & ENVIRONMENTAL MATERIALS 2024年第6期7卷 303-311页

作者： Ma, Joonhee Cho, Jin Hyuk lee, Chaehyeon Kang, Moon Sung Choi, Sungkyun Jang, Ho Won Ahn, sang hyun Back, Seoin Kim, Soo Young Korea Univ Dept Mat Sci & Engn Seoul 02841 South Korea Sogang Univ Inst Emergent Mat Dept Chem & Biomol Engn Seoul 04107 South Korea Pusan Natl Univ Coll Nanosci & Nanotechnol Dept Cogno Mechatron Engn Busan 46241 South Korea Seoul Natl Univ Res Inst Adv Mat Dept Mat Sci & Engn Seoul 08826 South Korea Chung Ang Univ Sch Chem Engn & Mat Sci Seoul 06974 South Korea

The development of cost-effective, highly efficient, and durable electrocatalysts has been a paramount pursuit for advancing the hydrogen evolution reaction (HER). Herein, a simplified synthesis protocol was designed to achieve a self-standing electrode, composed of activated carbon paper embedded with Ru single-atom catalysts and Ru nanoclusters (ACP/RuSAC+C) via acid activation, immersion, and high-temperature pyrolysis. Ab initio molecular dynamics (AIMD) calculations are employed to gain a more profound understanding of the impact of acid activation on carbon paper. Furthermore, the coexistence states of the Ru atoms are confirmed via aberration-corrected scanning transmission electron microscopy (AC-STEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). Experimental measurements and theoretical calculations reveal that introducing a Ru single-atom site adjacent to the Ru nanoclusters induces a synergistic effect, tuning the electronic structure and thereby significantly enhancing their catalytic performance. Notably, the ACP/RuSAC+C exhibits a remarkable turnover frequency (TOF) of 18 s-1 and an exceptional mass activity (MA) of 2.2 A mg-1, surpassing the performance of conventional Pt electrodes. The self-standing electrode, featuring harmoniously coexisting Ru states, stands out as a prospective choice for advancing HER catalysts, enhancing energy efficiency, productivity, and selectivity. A self-standing electrode with the coexistence of Ru single atoms and Ru nanoclusters is designed for the hydrogen evolution reaction (HER). Additional acid activation process induces defects, anchoring more Ru ions on the substrate. Detailed experimental and computational investigations suggest that the electronic coupling effect between different Ru states significantly enhanced the overall HER performance. image

关键词： electrocatalysis electronic coupling effect hydrogen evolution reaction self-standing electrode CARBON ELECTROREDUCTION CATALYSTS PAPER

Chemical and mechanical properties of stainless, environment-friendly, and nonflammable Mg alloys (SEN alloys): A review

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Journal of Magnesium and Alloys 2024年第3期12卷 841-872页

作者： Jong Un lee hyun Ji Kim sang-Cheol Jin Ye Jin Kim Young Min Kim Bong Sun You Jun Ho Bae Sung Hyuk Park Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea Department of Materials Science and Metallurgical Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Missile Research Institute Agency for Defense DevelopmentDaejeon 34060Republic of Korea

This review article provides overall understanding of stainless,environment-friendly,and nonflammable Mg alloys(SEN alloys)recently developed at the Korea Institute of Materials *** alloys are produced by adding small amounts of Ca and Y(each<1 wt%)into commercial Mg–Al based alloys,resulting in exceptional ignition and corrosion resistances and impressive mechanical *** main advantages of SEN alloys are as follows.(1)A dense multi-oxide layer of SEN alloys comprising MgO,CaO,and Y_(2)O_(3) impedes the outward dispersion of Mg vapor and the inward penetration of O_(2) during oxidation,thereby enhancing the oxidation and ignition resistances.(2)The presence of Ca-and Y-based second-phase particles in SEN alloys can enhance their corrosion resistance because Ca-containing particles prevent the spread of corrosion,and the replacement of Al-containing particles with less noble ones containing Y(e.g.,Al–Mn–Y or Al–Y particles)retards corrosion.(3)The addition of minor amounts of Ca and Y renders excellent mechanical properties due to improved strengthening *** enhanced properties are attributed to more pronounced dynamic recrystallization and grain refining behaviors caused by the second-phase particles during extrusion.(4)Despite the presence of various types of second-phase particles,the fatigue properties of SEN9 alloys are similar to those of commercial AZ91 alloys.(5)Simultaneous introduction of Ca and Y suppresses the formation of Mg17Al12 discontinuous precipitates during aging,leading to the enhanced elongation of aged SEN alloys.(6)Adding mischmetal into the SEN9 alloy leads to a six-fold enhancement in ***,the studies conducted on SEN alloys demonstrate their excellent ignition and corrosion resistances and mechanical properties,which broaden the industrial applications of Mg alloys by addressing their inherent weaknesses.

关键词： SEN magnesium alloy Corrosion resistance Ignition resistance Mechanical properties Extrudability.

Depolarization mitigated in ferroelectric Hf_(0.5)Zr_(0.5)O_(2)ultrathin films(<5 nm)on Si substrate by interface engineering

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Journal of Advanced Ceramics 2024年第3期13卷 282-292页

作者： Se hyun Kim Younghwan lee Dong hyun lee Geun Hyeong Park hyun Woo Jeong Kun Yang Yong Hyeon Cho Young Yong Kim Min Hyuk Park Department of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Research Institute of Advanced Materials College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Inter-university Semiconductor Research Center College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Pohang Accelerator Laboratory Pohang University of Science&TechnologyPohang 790784Republic of Korea

(Hf,Zr)O_(2)offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the ***,scaling this material to sub-5 nm thickness poses several challenges,including the formation of an interfacial layer and high trap *** particular,a low-k SiO_(2)interfacial layer is naturally formed when(Hf,Zr)O_(2)films are directly grown on a Si substrate,leading to high depolarization fields and rapid reduction of the remanent *** address these issues,we conducted a study to significantly improve ferroelectricity and switching endurance of(Hf,Zr)O_(2)films with sub-5 nm thicknesses by inserting a TiO_(2)interfacial *** deposition of a Ti film prior to Hf_(0.5)Zr_(0.5)O_(2)film deposition resulted in a high-k TiO_(2)interfacial layer and prevented the direct contact of Hf_(0.5)Zr_(0.5)O_(2)with *** findings show that the high-k TiO_(2)interfacial layer can reduce the SiO_(2)/Si interface trap density and the depolarization field,resulting in a switchable polarization of 60.2μC/cm^(2)for a 5 nm thick Hf_(0.5)Zr_(0.5)O_(2)***,we propose that inserting a high-k TiO_(2)interfacial layer between the Hf_(0.5)Zr_(0.5)O_(2)film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of(Hf,Zr)O_(2)grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.

关键词： ferroelectric charge trapping hafnia depolarization

Development of vehicle-recognition method on water surfaces using LiDAR data:SPD^(2)(spherically stratified point projection with diameter and distance)

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Defence Technology（防务技术） 2024年第6期36卷 95-104页

作者： Eon-ho lee Hyeon Jun Jeon Jinwoo Choi hyun-Taek Choi Sejin lee The Department of Mechanical Engineering Kongju National University1223-24 Cheonan-daeroCheonan 31080Republic of Korea Ocean System Engineering Research Division Korea Research Institute of Ships and Ocean Engineering(KRISO)Daejeon 34103Republic of Korea The Division of Mechanical&Automotive Engineering Kongju National University1223-24 Cheonan-daeroCheonan 31080Republic of Korea

Swarm robot systems are an important application of autonomous unmanned surface vehicles on water *** monitoring natural environments and conducting security activities within a certain range using a surface vehicle,the swarm robot system is more efficient than the operation of a single object as the former can reduce cost and save *** is necessary to detect adjacent surface obstacles robustly to operate a cluster of unmanned surface *** this purpose,a LiDAR(light detection and ranging)sensor is used as it can simultaneously obtain 3D information for all directions,relatively robustly and accurately,irrespective of the surrounding environmental *** the GPS(global-positioning-system)error range exists,obtaining measurements of the surface-vessel position can still ensure stability during platoon *** this study,a three-layer convolutional neural network is applied to classify types of surface *** aim of this approach is to redefine the sparse 3D point cloud data as 2D image data with a connotative meaning and subsequently utilize this transformed data for object classification ***,we have proposed a descriptor that converts the 3D point cloud data into 2D image *** use this descriptor effectively,it is necessary to perform a clustering operation that separates the point clouds for each *** developed voxel-based clustering for the point cloud ***,using the descriptor,3D point cloud data can be converted into a 2D feature image,and the converted 2D image is provided as an input value to the *** intend to verify the validity of the proposed 3D point cloud feature descriptor by using experimental data in the ***,we explore the feasibility of real-time object classification within this framework.

关键词： Object classification Clustering 3D point cloud data LiDAR(light detection and ranging) Surface vehicle

Novel fabrication techniques for ultra-thin silicon based flexible electronics

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International Journal of Extreme Manufacturing 2024年第4期6卷 116-149页

作者： Ju Young lee Jeong Eun Ju Chanwoo lee sang Min Won Ki Jun Yu School of Electrical and Electronic Engineering Yonsei University50 Yonsei-roSeodaemunguSeoul 03722Republic of Korea Department of Electrical and Computer Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea YU-Korea Institute of Science and Technology(KIST)Institute Yonsei University50Yonsei-roSeodaemun-guSeoul 03722Republic of Korea

Flexible electronics offer a multitude of advantages,such as flexibility,lightweight property,portability,and high *** unique properties allow for seamless applications to curved and soft surfaces,leading to extensive utilization across a wide range of fields in consumer *** applications,for example,span integrated circuits,solar cells,batteries,wearable devices,bio-implants,soft robotics,and biomimetic ***,flexible electronic devices have been developed using a variety of materials such as organic,carbon-based,and inorganic semiconducting ***(Si)owing to its mature fabrication process,excellent electrical,optical,thermal properties,and cost efficiency,remains a compelling material choice for flexible ***,the research on ultra-thin Si in the context of flexible electronics is studied rigorously *** thinning of Si is crucially important for flexible electronics as it reduces its bending stiffness and the resultant bending strain,thereby enhancing flexibility while preserving its exceptional *** review provides a comprehensive overview of the recent efforts in the fabrication techniques for forming ultra-thin Si using top-down and bottom-up approaches and explores their utilization in flexible electronics and their applications.

关键词： flexible electronics silicon fabrication technique top-down approach bottom-up approach

Anode surface engineering of zinc-ion batteries using tellurium nanobelt as a protective layer for enhancing energy storage performance

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Journal of Energy Chemistry 2024年第5期92卷 113-123页

作者： Soobeom lee Yeonjin Je Boeun Seok hyun Tae Kim Yong-Ryun Jo Soong Ju Oh Byoungyong Im Dae Guen Kim sang-Soo Chee Geon-Hyoung An Department of Energy System Engineering Gyeongsang National UniversityJinju 52725Republic of Korea Nano Convergence Materials Center Korea Institute of Ceramic Engineering and Technology(KICET)Jinju 52851Republic of Korea Department of Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea School of Materials Science and Engineering Gyeongsang National UniversityJinju 52828Republic of Korea GIST Advanced Insitute of Instrumental Analysis(GAIA) Electron Microscopy LaboratoryGwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Center for Advanced Materials and Processing Institute for Advanced EngineeringYongin 17180Republic of Korea Department of Energy Engineering Gyeongsang National UniversityJinju 52725Republic of Korea

Over the years,zinc-ion batteries(ZIBs)have attracted attention as a promising next-generation energy storage technology because of their excellent safety,long cycling performance,eco-friendliness,and high-power ***,issues,such as the corrosion and dissolution of the Zn anode,limited wet-tability,and lack of sufficient nucleation sites for Zn plating,have limited their practical *** introduction of a protective layer comprising of tellurium(Te)nanobelts onto the surface of Zn anode has emerged as a promising approach to overcome these limitations and improve the electrochemical behav-ior by enhancing the safety and wettability of ZIBs,as well as providing numerous nucleation sites for Zn *** the presence of a Te-based protective layer,the energy power density of the surface-engineered Zn anode improved significantly(ranging from 310 to 144 W h kg^(-1),over a power density range of 270 to 1,800 W kg^(-1)),and the lifespan capability was *** results demonstrate that the proposed strategy of employing Te nanobelts as a protective layer holds great promise for enhancing the energy storage performance of zIBs,making them even more attractive as a viable energy storage solution forthefuture.

关键词： Zn ion battery Anode Protective layer Tellurium Nanobelt

Acetylacetone-TiO_(2) Promoted Large Area Compatible Cascade Electron Transport Bilayer for Efficient Perovskite Solar Cells

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Energy & Environmental Materials 2024年第2期7卷 221-228页

作者： Hyong Joon lee Jin Kyoung Park Jin Hyuck Heo sang Hyuk Im Department of Chemical and Biological Engineering Korea University145 Anam-ro Seongbuk-guSeoul 17104Korea

In designing efficient perovskite solar cells(PSCs),the selection of suitable electron transport layers(ETLs)is critical to the final device performance as they determine the driving force for selective charge ***_(2)nanoparticles(NPs)based ETLs have been a popular choice for PSCs due to superior electron mobility,but their relatively deep-lying conduction band energy levels(ECB)result in substantial potential ***,TiO_(2)NPs establish favorable band alignment owing to shallower ECB,but their low intrinsic mobility and abundant surface trap sites impede the final *** this reason,constructing a cascaded bilayer ETL is highly desirable for efficient PSCs,as it can rearrange energy levels and exploit on advantages of an individual *** this study,we prepare SnO_(2)NPs and acetylacetone-modified TiO_(2)(Acac-TiO_(2))NPs and implement them as bilayer SnO_(2)/Acac-TiO_(2)(BST)ETL,to assemble cascaded energy band ***_(2)contributes to rapid charge carrier transport from high electron mobility while Acac-TiO_(2)minimizes band-offset and effectively suppresses interfacial ***,the optimized BST ETL generates synergistic influence and delivers power conversion efficiency(PCE)as high as 23.14%with open-circuit voltage(V_(oc))reaching 1.14 ***,the BST ETL is transferred to a large scale and the corresponding mini module demonstrates peak performance of 18.39%PCE from 25 cm^(2)aperture ***,the BST-based mini module exhibit excellent stability,maintaining 83.1%of its initial efficiency after 1000 h under simultaneous 1 Sun light-soaking and damp heat(85℃/RH 85%)environment.

关键词： acetylacetone large area perovskite solar cells TiO_(2)

Biochemical consequences of glucocerebrosidase 1 mutations in Parkinson’s disease

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Neural Regeneration Research 2024年第4期19卷 725-727页

作者： Jeong hyun Yoon Chiao-Yin lee Anthony HV Schapira Department of Clinical and Movement Neurosciences University College London Institute of Neurology Faculty of Medicine Imperial College London Aligning Science Across Parkinson's(ASAP)Collaborative Research Network

Parkinson’s disease(PD,OMIM#168600)is a common neurodegenerative disorder with a global prevalence of approximately 8.5 *** is characterized by four cardinal motor symptoms:bradykinesia,rigidity,resting tremor,and subsequently by postural *** usually involves non-motor symptoms such as rapid eye movement sleep disorder,dementia,anosmia,and autonomic *** gene glucocerebrosidase 1(GBA1),which encodes the lysosomal enzyme glucocerebrosidase(GCase)(IUBMB:EC 3.***.1.45),shows strong linkage with PD;variants of GBA1 are the commonest genetic association with PD(Sidransky et al.,2009).Several mechanisms may underlie the relationship between GBA1 mutations/variants and the molecular pathology of PD(Figure 1A and B).

关键词： cerebro consequences

Effect of Meteorological Data Assimilation on Regional Air Quality Forecasts over the Korean Peninsula

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Journal of Meteorological Research 2024年第2期38卷 262-284页

作者： Yunjae CHO hyun Mee KIM Eun-Gyeong YANG Yonghee lee Jae-Bum lee Soyoung HA Department of Atmospheric Sciences Yonsei UniversitySeoul 03722Republic of Korea Air Quality Forecasting Center National Institute of Environmental ResearchIncheon 22689Republic of Korea National Center for Atmospheric Research BoulderCO 80305USA University of Maryland Baltimore County BaltimoreMD 21250USA Global Modeling and Assimilation Office NASA Goddard Space Flight CenterGreenbeltMD 20771USA

The Weather Research and Forecasting model coupled with Chemistry(WRF-Chem),a type of online coupled chemistry-meteorology model(CCMM),considers the interaction between air quality and meteorology to improve air quality *** data assimilation(DA)can be used to reduce uncertainty in meteorological field,which is one factor causing prediction uncertainty in the *** this study,WRF-Chem and three-dimensional variational DA were used to examine the impact of meteorological DA on air quality and meteorological forecasts over the Korean *** nesting model domains were configured over East Asia(outer domain)and the Korean Peninsula(inner domain).Three experiments were conducted by using different DA domains to determine the optimal model domain for the meteorological *** the meteorological DA was performed in the outer domain or both the outer and inner domains,the root-mean-square error(RMSE),bias of the predicted particulate matter(PM)concentrations,and the RMSE of predicted meteorological variables against the observations were smaller than those in the experiment where the meteorological DA was performed only in the inner *** indicates that the improvement of the synoptic meteorological fields by DA in the outer domain enhanced the meteorological initial and boundary conditions for the inner domain,subsequently improving air quality and meteorological *** to the experiment without meteorological DA,the RMSE and bias of the meteorological and PM variables were smaller in the experiments with *** effect of meteorological DA on the improvement of PM predictions lasted for approximately 58-66 h,depending on the ***,the uncertainty reduction in the meteorological initial condition by the meteorological DA contributed to a reduction of the forecast errors of both meteorology and air quality.

关键词： meteorological data assimilation regional air quality forecast particulate matter concentration optimal model domain forecast error WRF-Chem