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Advanced heterolytic H_(2) adsorption of K-added Ru/MgO catalysts for accelerating hydrogen storage into aromatic benzyltoluenes

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Journal of Energy Chemistry 2022年第8期31卷 333-343,I0009页

作者： Tae Wan Kim Hwiram Jeong Yeongin Jo Dongun Kim ji hoon park Seok Ki Kim Young-Woong Suh Department of Chemical Engineering Hanyang UniversitySeoul 04763Republic of Korea Environmental&Sustainable Resources Research Center Korea Research Institute of Chemical TechnologyDaejeon 34114Republic of Korea Department of Chemical Engineering Ajou UniversitySuwon 16499Republic of Korea

Herein,we report a highly active K-added Ru/MgO catalyst for hydrogen storage into aromatic benzyltoluenes at low temperatures to advance liquid organic hydrogen carrier *** hydrogenation activity of Ru/K/MgO catalysts exhibits a volcano-shaped dependence on the K content at the maximum with 0.02 wt%.This is in good agreement with the strength and capacity of H_(2) adsorption derived from basicity,despite a gradual decrease in the textural property and the corresponding increase in the Ru particle size with increasing the K *** functional theory calculations show that heterolytic hydrogen adsorption properties(strength and polarization)are facilitated up to a specific density of K on the Ru–MgO interface and excessive K suppresses heterolytic H_(2) adsorption by direct interaction between K and hydrogen,assuring the hydrogenation activity and H_(2) adsorption capability of Ru/K/MgO ***,the Ru/K/MgO catalyst,when K is added in an optimal amount,is highly effective to accelerate hydrogen storage kinetics at low temperatures owing to the enhanced heterolytic H_(2) adsorption.

关键词： Chemical hydrogen storage Supported Ru catalysts Ru–MgO interface Heterolytic H_(2)adsorption Charge transfer Potassium promotion

Mixed-dimensional stacked nanocomposite structures for a specific wavelength-selectable ambipolar photoresponse

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Nano Research 2024年第6期17卷 5549-5558页

作者： Young Jae park Jaeho Shim Joo Song Lee Kyu Seung Lee ji-Yeon Kim Kang Bok Ko Sang-Youp Yim Seongjun Kim hoon-Kyu Shin Donghee park Yong Ju Yun Dong Ick Son Institute of Advanced Composite Materials Korea Institute of Science and TechnologyJeollabuk-do 55324Republic of Korea National Institute for Nanomaterials Technology Pohang University of Science and TechnologyGyeongsangbuk-do 37673Republic of Korea Department of Semiconductor Science and Technology Semiconductor Physics Research CenterJeonbuk National UniversityJeonju 54896Republic of Korea Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea Center for Opto-Electronic Materials and Devices Post-Silicon Semiconductor InstituteKorea Institute of Science and TechnologySeoul 02792Republic of Korea Graduate School of Energy and Environment(KU-KIST Green School) Korea UniversitySeoul 02841Republic of Korea KIST School Department of Nanomaterials and Nano ScienceUniversity of Science and Technology(UST)Daejeon 34113Republic of Korea

Mixed-dimensional composite structures using zero-dimensional(0D)quantum dots(QDs)and two-dimensional(2D)transition metal dichalcogenides(TMDs)materials are expected to attract great interest in optoelectronics due to the potential to generate new optical ***,we report on the unique optical characteristics of a devices with mixed dimensional vertically stacked structures based on tungsten diselenide(WSe_(2))/CdSeS QDs monolayer/molybdenum disulfide(MoS_(2))(2D/0D/2D).Specifically,it exhibits an ambipolar photoresponse characteristic,with a negative photoresponse observed in the 400-600 nm wavelength range and a positive photoresponse appeared at 700 nm *** resulted in the high negative responsivity of up to 52.22 mA·W^(−1)under 400 nm,which is 163 times higher than that of the photodetector without CdSeS *** also demonstrated the negative photoresponse,which could be due to increased carrier collision probability and non-radiative *** modeling and simulation reveal that Auger recombination among the types of non-radiative recombination is the main cause of negative photocurrent ***,we discovered ambipolar photoresponse near a specific wavelength corresponding to the energy of quantum *** study revealed interesting phenomenon in the mixed low-dimensional stacked structure and paved the way to exploit it for the development of innovative photodetection materials as well as for optoelectronic applications.

关键词： mixed-dimension quantum dot heterostructure photodetector ambipolar photoresponse

Atomically Adjustable Rhodium Catalyst Synthesis with Outstanding Mass Activity via Surface-Limited Cation Exchange

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Energy & Environmental Materials 2024年第2期7卷 87-96页

作者： Hak Hyeon Lee Dong Su Kim Swagotom Sarker ji hoon Choi Ho Seong Lee Hyung Koun Cho Department of Advanced Materials Science & Engineering Sungkyunkwan University Department of Advanced Materials Science & Engineering Kyungpook National University

Rh has been widely studied as a catalyst for the promising hydrazine oxidation reaction that can replace oxygen evolution reactions for boosting hydrogen production from hydrazine-containing wastewater. Despite Rh being expensive, only a few studies have examined its electrocatalytic mass activity. Herein, surface-limited cation exchange and electrochemical activation processes are designed to remarkably enhance the mass activity of Rh. Rh atoms were readily replaced at the Ni sites on the surface of NiOOH electrodes by cation exchange, and the resulting RhOOH compounds were activated by the electrochemical reduction process. The cation exchangederived Rh catalysts exhibited particle sizes not exceeding 2 nm without agglomeration, indicating a decrease in the number of inactive inner Rh atoms. Consequently, an improved mass activity of 30 A mgRh-1was achieved at 0.4 V versus reversible hydrogen electrode. Furthermore, the two-electrode system employing the same CE-derived Rh electrodes achieved overall hydrazine splitting over 36 h at a stable low voltage. The proposed surface-limited CE process is an effective method for reducing inactive atoms of expensive noble metal catalysts.

关键词： cation exchange synthesis electrochemical metallization hydrazine oxidation reaction mass activity rhodium catalyst

Oxygen vacancy engineering for tuning the catalytic activity of LaCoO_(3) perovskite

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Journal of Rare Earths 2024年第3期42卷 506-514,I0003页

作者： Jeong Hyun Cho Minjae Kim Inchan Yang Kyung Tae park Chang Houn Rhee Hai Woong park ji Chul Jung Department of Chemical Engineering Myongji UniversityYongin 17058Republic of Korea Institute of Advanced Composite Materials Korea Institute of Science and TechnologyWanju-gunJeollabuk-do 55324Republic of Korea Iron&Steel Process Engineering Research Group POSCOPohang 37859Republic of Korea Hydrogen Research Center Research Institute of Industrial Science&Technology(RIST)Pohang 37673Republic of Korea

Herein, we attempted to engineer oxygen vacancies on the surface of LaCoO_(3) perovskite through simple post-treatments(acid or reductive thermal treatments). Acid treatment induces oxygen vacancies through the selective etching of the La cations, whereas thermal treatment in a reducing atmosphere generates oxygen vacancies by directly removing lattice oxygen. The characterization results confirm that the number of surface oxygen vacancies, which are crucial in various catalytic oxidation reactions,considerably increases in the LaCoO_(3) catalysts treated with acid or reducing gas. Acid treatment enriches the oxygen vacancies while maintaining the structure of the LaCoO_(3) catalysts, which can not be achieved through reductive thermal treatment. Therefore, the acid treatment is considered a promising technique for oxygen vacancy engineering of perovskite catalysts for tuning their catalytic activities. Furthermore,the catalytic activities of the posttreated LaCoO_(3) catalysts for CO oxidation were evaluated and are noted to be considerably better than those of the pristine LaCoO_(3) catalyst due to their abundant oxygen vacancies. Consequently, we conclude that the oxygen vacancies of perovskite catalysts can be effectively engineered via two simple methods and play a significant role in CO oxidation.

关键词： LaCoO_(3)perovskite Acid treatment Reductive thermal treatment Oxygen vacancy CO oxidation Rare earths

The Effects of Accumulated Short Bouts of Mobile-Based Physical Activity Programs on Depression,Perceived Stress,and Negative Affectivity among College Students in South Korea:Quasi-Experimental Study

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International Journal of Mental Health Promotion 2024年第7期26卷 569-578页

作者： Ye hoon Lee Yonghyun park Hyungsook Kim Division of Global Sport Industry Hankuk University of Foreign StudiesGyeonggi-doRepublic of Korea Department of Data Science Hanyang UniversitySeoulRepublic of Korea HY Digital Healthcare Center Hanyang UniversitySeoulRepublic of Korea

Regular physical activity(PA)is known to enhance multifaceted health beneﬁts,including both physical and mental ***,traditional in-person physical activity programs have drawbacks,including time constraints for busy *** evidence suggests positive impacts on mental health through mobile-based physical activity,effects of accumulated short bouts of physical activity using mobile devices are ***,this study aims to investigate these effects,focusing on depression,perceived stress,and negative affectivity among South Korean college ***-six healthy college students were divided into the accumulated group(n=23,female=47.8%)and control group(n=23,female=47.6%).The accumulated group engaged in mobile-based physical activity,following guidelines to accumulate a minimum of two times per day and three times a *** were divided into short bouts,ensuing each bout lasted at least 10 *** control group did not engage in any speciﬁc physical *** data analysis involved comparing the scores of the intervention and control groups using several statistical techniques,such as independent sample t-test,paired sample t-tests,and 2(time)×2(group)repeated measures analysis of *** demographic characteristics at the pre-test showed no statistically signiﬁcant differences between the *** accumulated group had signiﬁcant decreases in depression(t_(40)=2.59,p=0.013,Cohen’s D=0.84)and perceived stress(t_(40)=2.06,p=0.046,Cohen’s D=0.56)from the pre-to *** control group exhibited no statistically signiﬁcant differences in any ***,there were signiﬁcant effects of time on depression scores(F1,36=4.77,p=0.036,η_(p)^(2)=0.12)while signiﬁcant interaction effects were also observed for depression(F_(1,36)=6.59,p=0.015,η_(p)^(2)=0.16).This study offers informative insights into the potential advantages of mobile-based physical activity programs with accumulated periods for enhancing mental health

关键词： Depressive symptoms mental health mobile intervention short term exercise stress

Intelligent reflecting surface for sum rate enhancement in MIMO systems

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Digital Communications and Networks 2024年第1期10卷 94-100页

作者： Chan-Yeob park ji-Sung Jung Yeong-Rong Lee Beom-Sik Shin Hyoung-Kyu Song Department of Information and Communication Engineering Sejong UniversitySeoulGwangjin-guGunja-dong 98Republic of Korea Department of Convergence Engineering for Intelligent Drone Sejong University SeoulGwangjin-guGunja-dong 98Republic of Korea

The research for the Intelligent Reflecting Surface(IRS)which has the advantages of cost and energy efficiency has been *** capacity can be effectively increased by appropriately setting the phase value of IRS elements according to the channel ***,the problem of obtaining an appropriate phase value of IRs is difficult to solve due to the non-convex *** paper proposes an iterative algorithm for the alternating optimal solution in the Single User Multiple-Input-Multiple-Output(SU-MIMO)*** proposed iterative algorithm finds an alternating optimal solution that is the phase value of IRS one by *** results show that the proposed method has better performance than that of the randomized IRS *** number of iterations for maximizing the performance of the proposed algorithm depends on the channel state between the IRS and the receiver.

关键词： Intelligent reflecting surface MIMO Sum rate

Tailoring local structures of atomically dispersed copper sites for highly selective CO_(2) electroreduction

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Carbon Energy 2024年第4期6卷 79-90页

作者： Kyung‐Jong Noh Byoung Joon park Ying Wang Yejung Choi Sang‐hoon You Yong‐Tae Kim Kug‐Seung Lee Jeong Woo Han Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)PohangGyeongbukRepublic of Korea Department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)PohangGyeongbukRepublic of Korea Pohang Accelerator Laboratory(PAL) Beamline DivisionPohangGyeongbukRepublic of Korea

Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction ***,the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites(Cu–N_(4))on carbon remains ***,we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N_(4) sites(Cu–N_(4)C_(8))located in a micropore between two graphitic sheets via a facile method to control the concentration of metal ***‐hosted Cu–N_(4)C_(8) catalysts outperformed the previously reported M–N–C catalysts for CO_(2)‐to‐CO conversion,achieving a maximum CO Faradaic efficiency(FECO)of 96%,a CO current density of–8.97 mA cm^(–2) at–0.8 V versus reversible hydrogen electrode(RHE),and over FECO of 90%from–0.6 to–1.0 V versus *** studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N_(4)C_(8) sites causes the d‐orbital energy level of the Cu atom to shift upward,which in return decreases the occupancy of antibonding states in the*COOH *** research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.

关键词： atomic local structure density functional theory electrochemical CO_(2)reduction metal nitrogen‐doped carbon single‐atom catalyst

Self-supported VO_(2)on polydopamine-derived pyroprotein-based fibers for ultrastable and flexible aqueous zinc-ion batteries

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Carbon Energy 2024年第7期6卷 1-13页

作者： Jeong Seok Yeon Sul Ki park Shinik Kim Santosh VMohite Won Il Kim Gun Jang Hyun-Seok Jang jiyoung Bae Sang Moon Lee Won GHong Byung hoon Kim Yeonho Kim Ho Seok park School of Chemical Engineering College of EngineeringSungkyunkwan UniversityGyeonggi-doRepublic of Korea Department of Engineering University of CambridgeCambridgeUK Department of Applied Chemistry Konkuk UniversityChungjuRepublic of Korea Department of Chemistry Ulsan National Institute of Science and Technology(UNIST)College of Natural SciencesUlsanRepublic of Korea Department of Physics Incheon National UniversityIncheonRepublic of Korea Intelligent Sensor Convergence Research Center Incheon National UniversityIncheonRepublic of Korea Institute of Basic Science Incheon National UniversityIncheonRepublic of Korea Division of Material Analysis and Research Korea Basic Science InstituteDaejeonRepublic of Korea

A conventional electrode composite for rechargeable zinc-ion batteries(ZIBs)includes a binder for strong adhesion between the electrode material and the current ***,the introduction of a binder leads to electrochemical inactivity and low electrical conductivity,resulting in the decay of the capacity and a low rate *** present a binder-and conducting agent-free VO_(2)composite electrode using in situ polymerization of dopamine on a flexible current collector of pyroprotein-based *** as-fabricated composite electrode was used as a substrate for the direct growth of VO_(2)as a self-supported form on polydopamine-derived pyroprotein-based fibers(pp-fibers@VO_(2)(B)).It has a high conductivity and flexible nature as a current collector and moderate binding without conventional binders and conducting agents for the VO_(2)(B)*** addition,their electrochemical mechanism was *** energy storage is induced by Zn^(2+)/H^(+)coinsertion during discharging,which can be confirmed by the lattice expansion,the formation of by-products including Zn_(x)(OTf)_(y)(OH)_(2x−y)·nH_(2)O,and the reduction of V^(4+)to V^(3+).Furthermore,the assembled Zn//pp-fibers@VO_(2)(B)pouch cells have excellent flexibility and stable electrochemical performance under various bending states,showing application possibilities for portable and wearable power sources.

关键词： aqueous battery binder free conducting agent‐free flexible electrode zinc‐ion battery

Adiponectin restores the obesity-induced impaired immunomodulatory function of mesenchymal stromal cells via glycolytic reprogramming

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Acta Pharmaceutica Sinica B 2024年第1期14卷 273-291页

作者： Duc-Vinh Pham Thi-Kem Nguyen Bao-Loc Nguyen Jong-Oh Kim Jee-Heon Jeong Inho Choi Pil-hoon park Department of Pharmacology Hanoi University of PharmacyHanoi 100000Viet Nam College of Pharmacy Yeungnam UniversityGyeongsan 38541Republic of Korea Department of Medical Biotechnology Yeungnam UniversityGyeongsan 38541Republic of Korea Research Institute of Cell Culture Yeungnam UniversityGyeongsan 38541Republic of Korea Department of Precision Medicine School of MedicineSungkyunkwan UniversitySuwon 16419Republic of Korea

Obesity has been known to negatively modulate the life-span and immunosuppressive potential of mesenchymal stromal cells(MSC).However,it remains unclear what drives the compromised potency of obese *** this study,we examined the involvement of adiponectin,an adipose tissuederived hormone,in obesity-induced impaired therapeutic function of ***-induced obesity leads to a decrease in serum adiponectin,accompanied by impairment of survival and immunomodulatory effects of adipose-derived MSC(ADSC).Interestingly,priming with globular adiponectin(gAcrp)improved the immunomodulatory potential of obese *** effects were also observed in lean *** addition,gAcrp potentiated the therapeutic effectiveness of ADSC in a mouse model of DSS-induced ***,while obesity inhibited the glycolytic capacity of MSC,gAcrp treatment induced a metabolic shift toward glycolysis through activation of adiponectin receptor type 1/p38 MAPK/hypoxia inducible factor-1a *** findings suggest that activation of adiponectin signaling is a promising strategy for enhancing the therapeutic efficacy of MSC against immune-mediated disorders.

关键词： Adiponectin Adipose-derived stromal cells Colitis Glycolytic induction HIF1a Immunomodulation Mesenchymal stromal cells Obesity