Catalysis is an effective means to improve the slow kinetics of hydrogen absorption and desorption,as well as the poor cycle life of the 2LiBH_(4)+MgH_(2)composite system.In this study,the TiVC MXene was obtained by e...Catalysis is an effective means to improve the slow kinetics of hydrogen absorption and desorption,as well as the poor cycle life of the 2LiBH_(4)+MgH_(2)composite system.In this study,the TiVC MXene was obtained by etching TiVAlC and introduced into 2LiH+MgB_(2)by ball milling.Products obtained were heated and hydrogenated to prepare the 2LiBH_(4)+MgH_(2)(LMBH)system,which exhibits distinguished kinetic performance and capacity retention rate.In the LMBH+6 wt%TiVC,a 9.3 wt%hydrogen is released within 35 min at 400℃as well as hydrogenation is completed within 30 min at 350℃,9 MPa.Moreover,the capacity retention rate was up to 96%after the 15th cycle.During the heating and hydrogenation process,the TiH and V_(8)C_(7)are generated in-situ as active products,and stably exist in the subsequent process to catalyze the hydrogen absorption-desorption reactions of the composite.The presence of TiH/LiH/V_(8)C_(7)/MgB_(2)interface improves the kinetic performance of the system.Reversibility is improved by inhibiting the generation of polyborane and the aggregation during the hydrogen absorption-desorption process.The interface structure-activity relationship is first elucidated that between bimetallic MXene and 2LiBH_(4)+MgH_(2)composite system during hydrogen absorption-desorption processes,providing a novel viewpoint and optimization path for the modification research of 2LiBH_(4)+MgH_(2)composites.展开更多
Light-energy-driven semiconductor catalysis offers attractive ways to address environmental and energy crises.TiO_(2) is the most promising catalyst for photocatalysis,but the lack of charge-carrier separation efficie...Light-energy-driven semiconductor catalysis offers attractive ways to address environmental and energy crises.TiO_(2) is the most promising catalyst for photocatalysis,but the lack of charge-carrier separation efficiency severely limits its catalytic performance.In this study,we carried out crystal phase engineering to prepare in situ Z-scheme hetero-phase homojunction of anatase-rutile and clarified the structure-performance relationship.The efficiency of sulfamerazine removal by hetero-phase homojunction TiO_(2) nanotube arrays in a single-compartment photocatalytic fuel cell system was improved by 1.93 times compared to conventional anatase TiO_(2) nanotube arrays and the degradation pathways were revealed by the Fukui function combined with HP-LCMS.The successful construction of Z-scheme hetero-phase homojunction was confirmed by Raman,X-ray diffraction(XRD),and electron spin resonance(ESR),which combined with density functional theory(DFT)calculations revealed the key role of crystal phase engineering in the construction of hetero-phase homojunction.This work provides a novel strategy for the scientific design of titanium dioxide photocatalysts.展开更多
Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric fo...Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric for dynamic random access memory(DRAM)applications,offering a high dielectric constant with a remarkable leakage-lowering effect by Al acceptor doping.However,ATO fabrication via conventional supercycle-based ALD suffers from severe crystallinity loss during the growth of TiO_(2) upon Al doping owing to the dopant-induced lattice disorder.In addition,Al doping cannot reduce any inherent O vacancies(V_(O))of TiO_(2),although the original purpose of doping was to address the n-type nature caused by V_(O).To resolve these limitations,we propose a single-step,in-situ Ar/O_(2) post-doping plasma(PDP)process immediately after the Al dopant incorporation.Using the PDP process,simultaneous atomic-scale dopant migration-mediated crystallization and V_(O) annihilation were successfully initiated.Thus,the surface concentration of the dopant decreased,reducing the dopant-induced lattice distortion,while promoting the highly crystallized seed layer-like surface.Consequently,strong rutile-phase recovery was accompanied by enhanced lattice-matched growth.In addition,the PDP process significantly lowers the V_(O)-to-lattice oxygen ratio by facilitating the recombination between reactive O species and V_(O),increasing the corresponding 0.4 e V of conduction band offset(CBO).Despite the common trade-off between the dielectric constant and leakage,the Pt/PDP-ATO/Ru capacitor exhibited a simultaneous 30%increase in dielectric constant and up to a 1.6-order reduction in leakage current density.展开更多
基金financed by the National Key Research and Development Plan of China[grants number 2021YFB3802400]the National Natural Science Foundation of China[grants number 52471225,52271212,52201250,51771056,52071141]Interdisciplinary Innovation Program of North China Electric Power University[grants number XM2112355].
文摘Catalysis is an effective means to improve the slow kinetics of hydrogen absorption and desorption,as well as the poor cycle life of the 2LiBH_(4)+MgH_(2)composite system.In this study,the TiVC MXene was obtained by etching TiVAlC and introduced into 2LiH+MgB_(2)by ball milling.Products obtained were heated and hydrogenated to prepare the 2LiBH_(4)+MgH_(2)(LMBH)system,which exhibits distinguished kinetic performance and capacity retention rate.In the LMBH+6 wt%TiVC,a 9.3 wt%hydrogen is released within 35 min at 400℃as well as hydrogenation is completed within 30 min at 350℃,9 MPa.Moreover,the capacity retention rate was up to 96%after the 15th cycle.During the heating and hydrogenation process,the TiH and V_(8)C_(7)are generated in-situ as active products,and stably exist in the subsequent process to catalyze the hydrogen absorption-desorption reactions of the composite.The presence of TiH/LiH/V_(8)C_(7)/MgB_(2)interface improves the kinetic performance of the system.Reversibility is improved by inhibiting the generation of polyborane and the aggregation during the hydrogen absorption-desorption process.The interface structure-activity relationship is first elucidated that between bimetallic MXene and 2LiBH_(4)+MgH_(2)composite system during hydrogen absorption-desorption processes,providing a novel viewpoint and optimization path for the modification research of 2LiBH_(4)+MgH_(2)composites.
基金supported by the National Natural Science Foundation of China(Nos.52370025,52372212)BUCEA Postgraduate Education and Teaching Quality Improvement Project(No.J2023016)the BUCEA Post Graduate Innovation Project(Nos.DG2023012 and PG2024073).
文摘Light-energy-driven semiconductor catalysis offers attractive ways to address environmental and energy crises.TiO_(2) is the most promising catalyst for photocatalysis,but the lack of charge-carrier separation efficiency severely limits its catalytic performance.In this study,we carried out crystal phase engineering to prepare in situ Z-scheme hetero-phase homojunction of anatase-rutile and clarified the structure-performance relationship.The efficiency of sulfamerazine removal by hetero-phase homojunction TiO_(2) nanotube arrays in a single-compartment photocatalytic fuel cell system was improved by 1.93 times compared to conventional anatase TiO_(2) nanotube arrays and the degradation pathways were revealed by the Fukui function combined with HP-LCMS.The successful construction of Z-scheme hetero-phase homojunction was confirmed by Raman,X-ray diffraction(XRD),and electron spin resonance(ESR),which combined with density functional theory(DFT)calculations revealed the key role of crystal phase engineering in the construction of hetero-phase homojunction.This work provides a novel strategy for the scientific design of titanium dioxide photocatalysts.
基金supported by the Samsung Electronics Co.,Ltd.(ISO230414-05954-01)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF2021R1A6A1A03039981)+2 种基金the Korea Institute for Advancement of Technology(KIAT)Grant,funded by the Korea Government(MOTIE)(P0023703,HRD Program for Industrial Innovation)The computations were performed at the Korea Institute of Science and Technology Information(KISTI)National Supercomputing Center(KSC-2024-CRE-0316)the UNIST Supercomputing Center。
文摘Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric for dynamic random access memory(DRAM)applications,offering a high dielectric constant with a remarkable leakage-lowering effect by Al acceptor doping.However,ATO fabrication via conventional supercycle-based ALD suffers from severe crystallinity loss during the growth of TiO_(2) upon Al doping owing to the dopant-induced lattice disorder.In addition,Al doping cannot reduce any inherent O vacancies(V_(O))of TiO_(2),although the original purpose of doping was to address the n-type nature caused by V_(O).To resolve these limitations,we propose a single-step,in-situ Ar/O_(2) post-doping plasma(PDP)process immediately after the Al dopant incorporation.Using the PDP process,simultaneous atomic-scale dopant migration-mediated crystallization and V_(O) annihilation were successfully initiated.Thus,the surface concentration of the dopant decreased,reducing the dopant-induced lattice distortion,while promoting the highly crystallized seed layer-like surface.Consequently,strong rutile-phase recovery was accompanied by enhanced lattice-matched growth.In addition,the PDP process significantly lowers the V_(O)-to-lattice oxygen ratio by facilitating the recombination between reactive O species and V_(O),increasing the corresponding 0.4 e V of conduction band offset(CBO).Despite the common trade-off between the dielectric constant and leakage,the Pt/PDP-ATO/Ru capacitor exhibited a simultaneous 30%increase in dielectric constant and up to a 1.6-order reduction in leakage current density.
