Open-shell graphene nanostructures(GNs)are promising candidates for future spintronics and quantum technologies.Recent progress based on on-surface synthetic approach has successfully created such GNs on metallic surf...Open-shell graphene nanostructures(GNs)are promising candidates for future spintronics and quantum technologies.Recent progress based on on-surface synthetic approach has successfully created such GNs on metallic surfaces.Meanwhile,the doping effect of metallic surfaces is inevitably present and can significantly tune their electronic and magnetic properties.Here,we investigate the zigzag end states of open-shell 7-armchair graphene nanoribbons(7-AGNRs)on Au(111),Au(100)and Ag(111)surfaces.Combined with the manipulation of a scanning tunneling microscope,we demonstrate that the end states can be tuned from empty states to singly occupied states and to doubly occupied states by substrate doping.Furthermore,the singly occupied states can be finely tuned,with the occupancy number of the states and related magnetic behaviors uncovered by experiments at different temperatures and magnetic fields.Our results provide a comprehensive study of the magnetic response of open-shell GNs on metallic surfaces at different doping levels.展开更多
Metal alloys have been widely applied for heterogeneous catalysis,especially alkane dehydrogenation.However,the catalysts always suffer from sintering and coke deposition due to the rigorous reaction conditions.Herein...Metal alloys have been widely applied for heterogeneous catalysis,especially alkane dehydrogenation.However,the catalysts always suffer from sintering and coke deposition due to the rigorous reaction conditions.Herein,we described an original approach to prepare a catalyst where highly dispersed Pt clusters alloying with copper were encapsulated in silicalite-1(S-1)zeolite for propane dehydrogenation(PDH).The introduction of Cu species significantly enhances the catalytic activity and prolongs the lifetime of the catalyst.0.1Pt0.4CuK@S-1 exhibits a propane conversion of 24.8%with 98.2%selectivity of propene,and the specific activity of propylene formation is up to 32 mol·gPt^(−1)·h^(−1)at 500℃.No obvious deactivation is observed even after 73 h on stream,affording an extremely low deactivation constant of 0.00032 h^(−1).The excellent activity and stability are ascribed to the confinement of zeolites and the stabilization of Cu species for Pt clusters.展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2021B0301030002)the National Natural Science Foundation of China(Grant Nos.11974431,and 11774434)the support from the Hundreds of Talents Program of Sun Yat-sen University and Guangdong Science and Technology Project(Grant No.2021QN02X859)。
文摘Open-shell graphene nanostructures(GNs)are promising candidates for future spintronics and quantum technologies.Recent progress based on on-surface synthetic approach has successfully created such GNs on metallic surfaces.Meanwhile,the doping effect of metallic surfaces is inevitably present and can significantly tune their electronic and magnetic properties.Here,we investigate the zigzag end states of open-shell 7-armchair graphene nanoribbons(7-AGNRs)on Au(111),Au(100)and Ag(111)surfaces.Combined with the manipulation of a scanning tunneling microscope,we demonstrate that the end states can be tuned from empty states to singly occupied states and to doubly occupied states by substrate doping.Furthermore,the singly occupied states can be finely tuned,with the occupancy number of the states and related magnetic behaviors uncovered by experiments at different temperatures and magnetic fields.Our results provide a comprehensive study of the magnetic response of open-shell GNs on metallic surfaces at different doping levels.
基金the National Key Research and Development Program of China(No.2020YFA0210900)the Science and Technology Key Project of Guangdong Province(No.2020B010188002)+1 种基金the National Natural Science Foundation of China(Nos.21905313 and 21938001)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01C102).
文摘Metal alloys have been widely applied for heterogeneous catalysis,especially alkane dehydrogenation.However,the catalysts always suffer from sintering and coke deposition due to the rigorous reaction conditions.Herein,we described an original approach to prepare a catalyst where highly dispersed Pt clusters alloying with copper were encapsulated in silicalite-1(S-1)zeolite for propane dehydrogenation(PDH).The introduction of Cu species significantly enhances the catalytic activity and prolongs the lifetime of the catalyst.0.1Pt0.4CuK@S-1 exhibits a propane conversion of 24.8%with 98.2%selectivity of propene,and the specific activity of propylene formation is up to 32 mol·gPt^(−1)·h^(−1)at 500℃.No obvious deactivation is observed even after 73 h on stream,affording an extremely low deactivation constant of 0.00032 h^(−1).The excellent activity and stability are ascribed to the confinement of zeolites and the stabilization of Cu species for Pt clusters.
基金financially supported by the National Natural Science Foundation of China (11974431, 11832019, 11622437, 61674171 and 11974422)Guangzhou Science and Technology Project (201707020002)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (XDB30000000)the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China (16XNLQ01)supported by the Outstanding Innovative Talents Cultivation Funded Programs 2017 of Renmin University of China。
