Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four plan...Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.展开更多
Single-atom catalysts(SACs),with atomically dispersed metal atoms anchored on a typical support,representing the utmost utilization effi ciency of the atoms,have recently emerged as promising catalysts for a variety o...Single-atom catalysts(SACs),with atomically dispersed metal atoms anchored on a typical support,representing the utmost utilization effi ciency of the atoms,have recently emerged as promising catalysts for a variety of catalytic applications.The electronic properties of the active center of SACs are highly dependent on the local environment constituted by the single metal atom and its surrounding coordination elements.Therefore,engineering the coordination environment near single metal sites,from the fi rst coordination shell to the second shell or higher,would be a rational way to design effi cient SACs with optimized electronic structure for catalytic applications.The wide range of coordination confi gurations,guaranteed by the multiple choices of the type and heterogeneity of the coordination element(N,O,P,S,etc.),further off er a large opportunity to rationally design SACs for satisfactory activities and investigate the structure-performance relationship.In this review,the coordination engineering of SACs by varying the type of coordination element was elaborated and the photocatalytic water splitting of SACs was highlighted.Finally,challenging issues related to the coordination engineering of SACs and their photocatalytic applications were discussed to call for more eff orts devoted to the further development of single-atom catalysis.展开更多
Due to low cost,high capacity,and high energy density,lithium–sulfur(Li–S)batteries have attracted much attention;however,their cycling performance was largely limited by the poor redox kinetics and low sulfur utili...Due to low cost,high capacity,and high energy density,lithium–sulfur(Li–S)batteries have attracted much attention;however,their cycling performance was largely limited by the poor redox kinetics and low sulfur utilization.Herein,predicted by density functional theory calculations,single‐atomic Co‐B2N2 site‐imbedded boron and nitrogen co‐doped carbon nanotubes(SA‐Co/BNC)were designed to accomplish high sulfur loading,fast kinetic,and long service period Li–S batteries.Experiments proved that Co‐B2N2 atomic sites can effectively catalyze lithium polysulfide conversion.Therefore,the electrodes delivered a specific capacity of 1106 mAh g−1 at 0.2 C after 100 cycles and exhibited an outstanding cycle performance over 1000 cycles at 1 C with a decay rate of 0.032%per cycle.Our study offers a new strategy to couple the combined effect of nanocarriers and single‐atomic catalysts in novel coordination environments for high‐performance Li–S batteries.展开更多
Coordination engineering can enhance the activity and stability of the catalyst in heterogeneous catalysis.However,the axial coordination engineering between different groups on the carbon carrier and molecular cataly...Coordination engineering can enhance the activity and stability of the catalyst in heterogeneous catalysis.However,the axial coordination engineering between different groups on the carbon carrier and molecular catalysts in the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR)has been studied rarely.Through coordination engineering strategy,a series of amino(NH_(2)),hydroxyl(OH),and carboxyl(COOH)groups functionalized carbon nanotubes(CNT)immobilized cobalt phthalocyanine(CoPc)catalysts are designed.Compared with no groups,OH groups and COOH groups,NH_(2)groups can effectively change the coordination environment of the central metal Co,thereby significantly increasing the turnover frequency(TOF)(31.4 s^(-1)at-0.6 V vs.RHE,CoPc/NH_(2)-CNT>CoPc/OH-CNT>CoPc/COOH-CN>CoPc/CNT).In the flow cell,the CoPc/NH_(2)-CNT catalyst has high carbon monoxide(CO)selectivity at high current density(~100%at-225 mA·cm^(-2),~96%at-351 mA·cm^(-2)).Importantly,the CoPc/NH_(2)-CNT catalyst can operate stably for 100 h at 225 mA·cm^(-2).Theoretical calculations reveal that CoPc/NH_(2)-CNT catalyst is beneficial to the formation of^(*)COOH and desorption of^(*)CO,thus promoting CO_(2)RR.This work provides an excellent platform for understanding the effect of coordination engineering on electrocatalytic performance and promotes a way to explore efficient and stable catalysts in other applications.展开更多
文摘Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.
基金the National Natural Science Foundation of China(Nos.21805191 and 21972094)the Guangdong Basic and Applied Basic Research Founda-tion(No.2020A1515010982)+1 种基金Shenzhen Pengcheng Scholar Program,Shenzhen Peacock Plan(No.KQTD2016053112042971)Shenzhen Science and Technology Program(Nos.KQJSCX20170727100802505 and RCJC20200714114434086).
文摘Single-atom catalysts(SACs),with atomically dispersed metal atoms anchored on a typical support,representing the utmost utilization effi ciency of the atoms,have recently emerged as promising catalysts for a variety of catalytic applications.The electronic properties of the active center of SACs are highly dependent on the local environment constituted by the single metal atom and its surrounding coordination elements.Therefore,engineering the coordination environment near single metal sites,from the fi rst coordination shell to the second shell or higher,would be a rational way to design effi cient SACs with optimized electronic structure for catalytic applications.The wide range of coordination confi gurations,guaranteed by the multiple choices of the type and heterogeneity of the coordination element(N,O,P,S,etc.),further off er a large opportunity to rationally design SACs for satisfactory activities and investigate the structure-performance relationship.In this review,the coordination engineering of SACs by varying the type of coordination element was elaborated and the photocatalytic water splitting of SACs was highlighted.Finally,challenging issues related to the coordination engineering of SACs and their photocatalytic applications were discussed to call for more eff orts devoted to the further development of single-atom catalysis.
基金Yunnan Expert Workstation,Grant/Award Number:202005AF150028Program for the Outstanding Young Talents of Hebei Province,China,Grant/Award Number:YGZ+6 种基金Guangdong Innovative and Entrepreneurial Team Program,Grant/Award Number:2016ZT06C517Guangdong Science and Technology Department,Grant/Award Number:2020B0909030004National Natural Science Foundation of China,Grant/Award Numbers:21601136,22075211,52071125Outstanding Youth Project of Guangdong Natural Science Foundation,Grant/Award Number:2021B1515020051Natural Science Foundation of Hebei Province,China,Grant/Award Numbers:B2020202052,B2021202028,E2020202071Chunhui Project of Ministry of Education of the People's Republic of China,Grant/Award Number:Z2017010Science and Technology Program of Guangzhou,Grant/Award Number:2019050001。
文摘Due to low cost,high capacity,and high energy density,lithium–sulfur(Li–S)batteries have attracted much attention;however,their cycling performance was largely limited by the poor redox kinetics and low sulfur utilization.Herein,predicted by density functional theory calculations,single‐atomic Co‐B2N2 site‐imbedded boron and nitrogen co‐doped carbon nanotubes(SA‐Co/BNC)were designed to accomplish high sulfur loading,fast kinetic,and long service period Li–S batteries.Experiments proved that Co‐B2N2 atomic sites can effectively catalyze lithium polysulfide conversion.Therefore,the electrodes delivered a specific capacity of 1106 mAh g−1 at 0.2 C after 100 cycles and exhibited an outstanding cycle performance over 1000 cycles at 1 C with a decay rate of 0.032%per cycle.Our study offers a new strategy to couple the combined effect of nanocarriers and single‐atomic catalysts in novel coordination environments for high‐performance Li–S batteries.
基金This work was supported by the National Natural Science Foundation of China(Nos.51772162,22001143,and 52072197)Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(No.2019KJC004)+4 种基金Outstanding Youth Foundation of Shandong Province,China(No.ZR2019JQ14)Taishan Scholar Young Talent Program,China(Nos.tsqn201909114 and tsqn201909123)Natural Science Foundation of Shandong Province,China(No.ZR2020YQ34)Major Scientific and Technological Innovation Project,China(No.2019JZZY020405)Major Basic Research Program of Natural Science Foundation of Shandong Province,China(No.ZR2020ZD09).
文摘Coordination engineering can enhance the activity and stability of the catalyst in heterogeneous catalysis.However,the axial coordination engineering between different groups on the carbon carrier and molecular catalysts in the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR)has been studied rarely.Through coordination engineering strategy,a series of amino(NH_(2)),hydroxyl(OH),and carboxyl(COOH)groups functionalized carbon nanotubes(CNT)immobilized cobalt phthalocyanine(CoPc)catalysts are designed.Compared with no groups,OH groups and COOH groups,NH_(2)groups can effectively change the coordination environment of the central metal Co,thereby significantly increasing the turnover frequency(TOF)(31.4 s^(-1)at-0.6 V vs.RHE,CoPc/NH_(2)-CNT>CoPc/OH-CNT>CoPc/COOH-CN>CoPc/CNT).In the flow cell,the CoPc/NH_(2)-CNT catalyst has high carbon monoxide(CO)selectivity at high current density(~100%at-225 mA·cm^(-2),~96%at-351 mA·cm^(-2)).Importantly,the CoPc/NH_(2)-CNT catalyst can operate stably for 100 h at 225 mA·cm^(-2).Theoretical calculations reveal that CoPc/NH_(2)-CNT catalyst is beneficial to the formation of^(*)COOH and desorption of^(*)CO,thus promoting CO_(2)RR.This work provides an excellent platform for understanding the effect of coordination engineering on electrocatalytic performance and promotes a way to explore efficient and stable catalysts in other applications.
