Determining atomistic structures of grain boundaries (GBs) is essential to understand structure--property interplay in oxides.Here,different GB superstructures in CuO nanosheets,including (111) and (114) twinning boun...Determining atomistic structures of grain boundaries (GBs) is essential to understand structure--property interplay in oxides.Here,different GB superstructures in CuO nanosheets,including (111) and (114) twinning boundaries (TBs) and (002)/(223) GB,are investigated.Unlike the lower-energy stoichiometric (111) TB,both experimental and first-principles investigations reveal a severe segregation of Cu and O vacancies and a nonstoichiometric property at (114) TB,which may facilitate ionic transportation and provide space for elemental segregation.More importantly,the calculated electronic structures have shown the increased conductivity as well as the unanticipated magnetism in both (114) TB and (002)/(223) GB.These findings could contribute to the race towards the property-directing structural design by GB engineering.展开更多
Atomic-scale oxidation dynamics of Cu2O nanocrystallines （NCs） are directly observed by in situ high-resolution transmission electron microscopy. A two-stage oxidation process is observed： （1）The initial oxidatio...Atomic-scale oxidation dynamics of Cu2O nanocrystallines （NCs） are directly observed by in situ high-resolution transmission electron microscopy. A two-stage oxidation process is observed： （1）The initial oxidation stage is dominated by the dislocation-mediated oxidation behavior of Cu2O NCs via solid-solid transformations, leading to the formation of a new intermediate CuOx phase. The possible crystal structure of the CuOx phase is discussed. （2） Subsequently, CuOx is transformed into CuO by layer-by-layer oxidation. These results will help in understanding the oxidation mechanisms of copper oxides and pave the way for improving their structural diversity and exploiting their potential industrial applications.展开更多
基金the National Natural Science Foundation of China (Nos.51671148,51271134,J1210061,11674251,51501132, and 51601132)the Hubei Provincial Natural Science Foundation of China (Nos.2016CFB446 and 2016CFB155)+4 种基金the Fundamental Research Funds for the Central Universitiesthe CERS-1-26 (CERSChina Equipment and Education Resources System)the China Postdoctoral Science Foundation (No.2014T70734)the Open Research Fund of Science and Technology on High Strength Structural Materials Laboratory (Central South University)the Suzhou Science and Technology project (No.SYG201619).
文摘Determining atomistic structures of grain boundaries (GBs) is essential to understand structure--property interplay in oxides.Here,different GB superstructures in CuO nanosheets,including (111) and (114) twinning boundaries (TBs) and (002)/(223) GB,are investigated.Unlike the lower-energy stoichiometric (111) TB,both experimental and first-principles investigations reveal a severe segregation of Cu and O vacancies and a nonstoichiometric property at (114) TB,which may facilitate ionic transportation and provide space for elemental segregation.More importantly,the calculated electronic structures have shown the increased conductivity as well as the unanticipated magnetism in both (114) TB and (002)/(223) GB.These findings could contribute to the race towards the property-directing structural design by GB engineering.
基金This work was supported by the National Basic Research Program of China （No. 2011CB933300）, the National Natural Science Foundation of China （Nos. 51671148, 51271134, J1210061, 11674251, 51501132, and 51601132）, the Hubei Provincial Natural Science Foundation of China （Nos. 2016CFB446 and 2016CFB155）, the Fundamental Research Funds for the Central Universities, and the CERS-1-26 （CERS-China Equip- ment and Education Resources System）, and the China Postdoctoral Science Foundation （No. 2014T70734）, and the Open Research Fund of Science and Technology on High Strength Structural Materials Laboratory （Central South University） and the Suzhou Science and Technology project （No. SYG201619）.
文摘Atomic-scale oxidation dynamics of Cu2O nanocrystallines （NCs） are directly observed by in situ high-resolution transmission electron microscopy. A two-stage oxidation process is observed： （1）The initial oxidation stage is dominated by the dislocation-mediated oxidation behavior of Cu2O NCs via solid-solid transformations, leading to the formation of a new intermediate CuOx phase. The possible crystal structure of the CuOx phase is discussed. （2） Subsequently, CuOx is transformed into CuO by layer-by-layer oxidation. These results will help in understanding the oxidation mechanisms of copper oxides and pave the way for improving their structural diversity and exploiting their potential industrial applications.
