Boron,positioned to the left of carbon in the periodic table with one fewer electron,exhibits unique chemical properties.Tricoordinate boron compounds are typically electron-deficient,acting as strong Lewis acids in g...Boron,positioned to the left of carbon in the periodic table with one fewer electron,exhibits unique chemical properties.Tricoordinate boron compounds are typically electron-deficient,acting as strong Lewis acids in general with electrophilic behavior.In contrast,tetracoordinate boron compounds,featuring a tetrahedral geometry,display nucleophilicity and enable transformations such as migration,transmetallation,and oxidation.Boron compounds serve as versatile synthons,reagents,and catalysts in organic reactions.Incorporating boron into conjugated systems enhances chemical diversity and modulates optoelectronic properties,while the vacant p orbital of boron imparts high electron affinity and unique stimulus-responsive characteristics.Additionally,boron forms deltahedral clusters in polyhedral(car)boranes,which are air-and moisture-stable and distinct from traditional hydrocarbon structures.This review provides an overview of the fundamental properties and diverse applications of boron compounds across various fields.展开更多
Hazardous chemicals used in electronic and electrical consumer products can re-enter commerce when these products are recycled. The objectives of this study were to 1) identify the possible sources of unexpected chemi...Hazardous chemicals used in electronic and electrical consumer products can re-enter commerce when these products are recycled. The objectives of this study were to 1) identify the possible sources of unexpected chemicals and elements in consumer products, including the use of recycled E-waste plastics and 2) demonstrate bromine detection with nondestructive spectroscopy as an indicator of brominated flame retardants contaminating new products via recycled waste streams. More than 1500 consumer products of diverse types purchased in 2012-2014 were examined using X-ray fluorescence spectroscopy for correlations between bromine and other elements. New electronic products were much more likely than new non-electronics to contain greater than 1000 ppm bromine, consistent with intentionally added flame retardants, while non- electronic products were more likely to contain between 5 and 100 ppm bromine, suggesting unintentional contamination. A typical suite of elements present in E-waste was found in a majority of plastic products. Two product categories, vinyl floor tiles and beaded necklaces/garlands, were explored in more detail. Specific flame retardant chemicals in bead samples were identified by mass spectrometry and their distribution in beads was studied using scanning electron microscopy and energy dispersive spectroscopy. Five brominated chemicals typically used as flame retardants, including BDE-209, were identified in 50 of 50 Mardi Gras beads analyzed.展开更多
Low-temperature zinc batteries(LT-ZIBs)based on aqueous electrolytes show great promise for practical applications owing to their natural resource abundance and low cost.However,they suffer from sluggish kinetics with...Low-temperature zinc batteries(LT-ZIBs)based on aqueous electrolytes show great promise for practical applications owing to their natural resource abundance and low cost.However,they suffer from sluggish kinetics with elevated energy barriers due to the dissociation of bulky Zn(H2O)62+solvation structure and free Zn2+diffusion,resulting in unsatisfactory lifespan and performance.Herein,dissimilar to solvation shell tuning or layer spacing enlargement engineering,delocalized electrons in cathode through constructing intrinsic defect engineering is proposed to achieve a rapid electrocatalytic desolvation to obtain free Zn2+for insertion/extraction.As revealed by density functional theory calculations and interfacial spectroscopic characterizations,the intrinsic delocalized electron distribution propels the Zn(H2O)62+dissociation,forming a reversible interphase and facilitating Zn2+diffusion across the electrolyte/cathode interface.The as-fabricated oxygen defect-rich V2O5 on hierarchical porous carbon(ODVO@HPC)electrode exhibits high capacity robustness from 25 to20℃.Operating at-20℃,the ODVO@HPC delivers 191 mAh g-1 at 50 A g-1 and lasts for 50000 cycles at 10 A g-1,significantly enhancing the power density and lifespan under low-temperature environments in comparison to previous reports.Even with areal mass loading of-13 mg cm2,both coin cells and pouch batteries maintain excellent stability and areal capacities,realizing practical high-performance LT-ZIBs.展开更多
基金supported by the National Natural Science Foundation of China(22271105,22331005,22375106,92256304,22171246,U1804253,22371290)the National Key Research&Development Program of China(2023YFF0723900)the Natural Science Foundation of Fujian Province(2022J02009).
文摘Boron,positioned to the left of carbon in the periodic table with one fewer electron,exhibits unique chemical properties.Tricoordinate boron compounds are typically electron-deficient,acting as strong Lewis acids in general with electrophilic behavior.In contrast,tetracoordinate boron compounds,featuring a tetrahedral geometry,display nucleophilicity and enable transformations such as migration,transmetallation,and oxidation.Boron compounds serve as versatile synthons,reagents,and catalysts in organic reactions.Incorporating boron into conjugated systems enhances chemical diversity and modulates optoelectronic properties,while the vacant p orbital of boron imparts high electron affinity and unique stimulus-responsive characteristics.Additionally,boron forms deltahedral clusters in polyhedral(car)boranes,which are air-and moisture-stable and distinct from traditional hydrocarbon structures.This review provides an overview of the fundamental properties and diverse applications of boron compounds across various fields.
文摘Hazardous chemicals used in electronic and electrical consumer products can re-enter commerce when these products are recycled. The objectives of this study were to 1) identify the possible sources of unexpected chemicals and elements in consumer products, including the use of recycled E-waste plastics and 2) demonstrate bromine detection with nondestructive spectroscopy as an indicator of brominated flame retardants contaminating new products via recycled waste streams. More than 1500 consumer products of diverse types purchased in 2012-2014 were examined using X-ray fluorescence spectroscopy for correlations between bromine and other elements. New electronic products were much more likely than new non-electronics to contain greater than 1000 ppm bromine, consistent with intentionally added flame retardants, while non- electronic products were more likely to contain between 5 and 100 ppm bromine, suggesting unintentional contamination. A typical suite of elements present in E-waste was found in a majority of plastic products. Two product categories, vinyl floor tiles and beaded necklaces/garlands, were explored in more detail. Specific flame retardant chemicals in bead samples were identified by mass spectrometry and their distribution in beads was studied using scanning electron microscopy and energy dispersive spectroscopy. Five brominated chemicals typically used as flame retardants, including BDE-209, were identified in 50 of 50 Mardi Gras beads analyzed.
基金the National Key R&D Program of China(2021YFA1201503)National Natural Science Foundation of China(Nos.21972164,22279161,12264038,22309144)+7 种基金the Natural Science Foundation of Jiangsu Province(BK.20210130)China Postdoctoral Science Foundation(2023 M732561,2023 M731084)Innovative and Entrepreneurial Doctor in Jiangsu Province(JSSCBS20211428)J.W.and S.P.acknowledge the funding provided by the Alexander von Humboldt Foundation and the basic funding of the Helmholtz AssociationQ.Z.acknowledges the support of HZWTECH for providing computational facilitiesH.A.acknowledges the University of Hong Kong and the Hong Kong Quantum AI Lab Limited,AIR@Inno HK for supporting his fellowshipWe also thank Nano-X,Suzhou Institute of Nano-tech and Nano-bionics,Chinese Academy of Sciences for the material measurement analysisOpen Access funding enabled and organized by Projekt DEAL.
文摘Low-temperature zinc batteries(LT-ZIBs)based on aqueous electrolytes show great promise for practical applications owing to their natural resource abundance and low cost.However,they suffer from sluggish kinetics with elevated energy barriers due to the dissociation of bulky Zn(H2O)62+solvation structure and free Zn2+diffusion,resulting in unsatisfactory lifespan and performance.Herein,dissimilar to solvation shell tuning or layer spacing enlargement engineering,delocalized electrons in cathode through constructing intrinsic defect engineering is proposed to achieve a rapid electrocatalytic desolvation to obtain free Zn2+for insertion/extraction.As revealed by density functional theory calculations and interfacial spectroscopic characterizations,the intrinsic delocalized electron distribution propels the Zn(H2O)62+dissociation,forming a reversible interphase and facilitating Zn2+diffusion across the electrolyte/cathode interface.The as-fabricated oxygen defect-rich V2O5 on hierarchical porous carbon(ODVO@HPC)electrode exhibits high capacity robustness from 25 to20℃.Operating at-20℃,the ODVO@HPC delivers 191 mAh g-1 at 50 A g-1 and lasts for 50000 cycles at 10 A g-1,significantly enhancing the power density and lifespan under low-temperature environments in comparison to previous reports.Even with areal mass loading of-13 mg cm2,both coin cells and pouch batteries maintain excellent stability and areal capacities,realizing practical high-performance LT-ZIBs.
