Planar optical waveguides in single crystals of KNbOs were fabricated by MeV B and He ion implantation.The depth profiles of radiation damage in these waveguides were compared and analyzed by high resolution transmiss...Planar optical waveguides in single crystals of KNbOs were fabricated by MeV B and He ion implantation.The depth profiles of radiation damage in these waveguides were compared and analyzed by high resolution transmission electron microscope.Non leaky waveguiding modes(TEo and TMo),which are due to implantation induced increase of rib and nc,were observed in 6.0 MeV B ion implantated waveguides with a dose of 1×10^(15)cm^(-2).展开更多
In this paper,based on the developed statistical-thermodynamic model,which is based on data on the local structure of the compound and taking into account the striction interaction caused by the large sizes of the Ba ...In this paper,based on the developed statistical-thermodynamic model,which is based on data on the local structure of the compound and taking into account the striction interaction caused by the large sizes of the Ba and K cations,the formation of ferroelectric phases in BaTiO_(3)and KNbO_(3)perovskites has been studied.Based on the modified eight-minimum model,it has been possible to qualitatively identify the factors that determine the features of the thermodynamic behavior of these crystals and to reproduce the process of formation of the whole set of phase states observed in BaTiO_(3)and KNbO_(3).展开更多
The fabrication of heterojunction catalysts is an effective strategy to enhance charge separation efficiency,thus boosting the performance of photocatalysts.This work presents the synthesis and investigation of a nove...The fabrication of heterojunction catalysts is an effective strategy to enhance charge separation efficiency,thus boosting the performance of photocatalysts.This work presents the synthesis and investigation of a novel KNbO_(3)/Bi_(4)O_(5)Br_(2) heterostructure catalyst for photocatalytic N_(2)-to-NH_(3) conversion under light illumination.While morphology analysis revealed KNbO_(3) microcubes embedded within Bi_(4)O_(5)Br_(2) nanosheets,the composite exhibited no significant improvement in specific surface area or optical property compared to Bi_(4)O_(5)Br_(2) due to the relatively wide band gap and low surface area of KNbO_(3).The main contribution lies in the enhanced separation efficiency of photogenerated electrons and holes.Besides,the band structure analysis suggests that KNbO_(3) and Bi_(4)O_(5)Br_(2) exhibit suitable band potentials to form a type II heterojunction.Benefiting from the higher Fermi level of KNbO_(3) than Bi_(4)O_(5)Br_(2),the electron drift at the contact region thus occurs and leads to the formation of a built-in electric field with the direction from KNbO_(3) to Bi_(4)O_(5)Br_(2),accelerating electron migration and improving the operational efficiency of the photocatalysts.Consequently,the KNbO_(3)/Bi_(4)O_(5)Br_(2) catalyst shows an increased photoactivity,achieving an NH_(3) generation rate 1.78 and 1.58 times those of KNbO_(3) and Bi_(4)O_(5)Br_(2),respectively.This work may offer valuable insights for the design and synthesis of heterojunction composite photocatalysts.展开更多
基金Supported by the China National Nuclear Corporation,No.H7196FY003,。
文摘Planar optical waveguides in single crystals of KNbOs were fabricated by MeV B and He ion implantation.The depth profiles of radiation damage in these waveguides were compared and analyzed by high resolution transmission electron microscope.Non leaky waveguiding modes(TEo and TMo),which are due to implantation induced increase of rib and nc,were observed in 6.0 MeV B ion implantated waveguides with a dose of 1×10^(15)cm^(-2).
文摘设计低廉、高效且长稳定的析氢反应(HER)催化剂对于水分解技术的工业实施至关重要。本研究采用溶胶凝胶法结合后续热分解的方式制备出了异质纳米结构NiO KNbO_(3)催化剂,通过X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和电化学工作站(CHI660E)对NiO KNbO_(3)催化剂的晶型结构、元素价态、微观形貌和HER催化性能进行了系统分析。结果表明,NiO KNbO_(3)催化剂在1 mol L KOH电解液中表现出优异的HER催化性能,-10 mA cm 2电流密度下的析氢反应过电位仅为-217 mV,对应Tafel斜率为77.4 mV dec,在24 h恒电位析氢反应稳定性测试中,表现出良好的催化稳定性和耐腐蚀性。NiO KNbO_(3)催化剂优异的HER性能归因于NiO和KNbO_(3)的协同作用以及独特的异质纳米复合结构增大了活性位点暴露和改善了离子传输路径。
基金support of the Ministry of Science and Higher Education of the Russian Federation(State task in the field of scientific activityProject No.FENW-2023-0010/GZ0110/23-11-IF)Title of the topic:“Multicomponent intelligent structures:phase transition cross-effects and strategies for the accelerated design of eco-systems for technologies for the digital design of devices for controlling the parameters of physical media”.
文摘In this paper,based on the developed statistical-thermodynamic model,which is based on data on the local structure of the compound and taking into account the striction interaction caused by the large sizes of the Ba and K cations,the formation of ferroelectric phases in BaTiO_(3)and KNbO_(3)perovskites has been studied.Based on the modified eight-minimum model,it has been possible to qualitatively identify the factors that determine the features of the thermodynamic behavior of these crystals and to reproduce the process of formation of the whole set of phase states observed in BaTiO_(3)and KNbO_(3).
基金supported by the National Natural Science Foundation of China (Grant No.22172144)the Key Research and Development Program of Zhejiang Province (Grant No.2023C03148).
文摘The fabrication of heterojunction catalysts is an effective strategy to enhance charge separation efficiency,thus boosting the performance of photocatalysts.This work presents the synthesis and investigation of a novel KNbO_(3)/Bi_(4)O_(5)Br_(2) heterostructure catalyst for photocatalytic N_(2)-to-NH_(3) conversion under light illumination.While morphology analysis revealed KNbO_(3) microcubes embedded within Bi_(4)O_(5)Br_(2) nanosheets,the composite exhibited no significant improvement in specific surface area or optical property compared to Bi_(4)O_(5)Br_(2) due to the relatively wide band gap and low surface area of KNbO_(3).The main contribution lies in the enhanced separation efficiency of photogenerated electrons and holes.Besides,the band structure analysis suggests that KNbO_(3) and Bi_(4)O_(5)Br_(2) exhibit suitable band potentials to form a type II heterojunction.Benefiting from the higher Fermi level of KNbO_(3) than Bi_(4)O_(5)Br_(2),the electron drift at the contact region thus occurs and leads to the formation of a built-in electric field with the direction from KNbO_(3) to Bi_(4)O_(5)Br_(2),accelerating electron migration and improving the operational efficiency of the photocatalysts.Consequently,the KNbO_(3)/Bi_(4)O_(5)Br_(2) catalyst shows an increased photoactivity,achieving an NH_(3) generation rate 1.78 and 1.58 times those of KNbO_(3) and Bi_(4)O_(5)Br_(2),respectively.This work may offer valuable insights for the design and synthesis of heterojunction composite photocatalysts.
