In the current era of renewable energy prominence,the wide operational capacity of coal-fired boilers has emerged as crucial for ensuring the sustainability of power plants.However,attaining ultra-low nitrogen oxides(...In the current era of renewable energy prominence,the wide operational capacity of coal-fired boilers has emerged as crucial for ensuring the sustainability of power plants.However,attaining ultra-low nitrogen oxides(NO_x)emissions during periods of low-load operations presents a significant and persistent challenge for coal power enterprises.While techniques such as biomass re-burning and advanced re-burning have shown promise in enhancing NO reduction effciency above 800℃,their elevated levels of chlorine(Cl)and alkali metals pose potential risks to boiler equipment integrity.Therefore,this study proposes the utilization of biomass char derived from pyrolysis as a dual-purpose solution to enhance NO reduction efficiency while safeguarding boiler integrity during low-load operations.Findings indicate that pyrolysis treatment effectively reduces the Cl and alkali metal content of biomass.Specifically,it was determined that biomass char produced through deeply pyrolysis at 300℃achieves the highest NO reduction efficiency while minimizing the presence of harmful components.At a reduction temperature of 700℃,both re-burning and advanced re-burning techniques exhibit NO reduction efficiencies of 55.90%and 62.22%,which is already an ideal deficiency at low temperatures.The addition of water vapor at 700-800℃obviously avoids the oxidation of ammonia to NO in advanced reburning.Upon further analysis,denitrification efficiency in biomass char re-burning and advanced reburning is influenced not only by volatile content but also by physicochemical properties such as porosity and surface functional group distribution under certain reaction conditions.This study provides a theoretical framework for the industrial implementation of biomass char for NO control in coal-fired power plants,offering insights into optimizing NO reduction efficiency while mitigating potential risks to boiler equipment.展开更多
To meet the growing demand for high-energy-density lithium-ion batteries(LIBs),silicon(Si)anodes have gained attention as a promising material for next-generation anodes owing to their ultrahigh gravimetric capacity.N...To meet the growing demand for high-energy-density lithium-ion batteries(LIBs),silicon(Si)anodes have gained attention as a promising material for next-generation anodes owing to their ultrahigh gravimetric capacity.Nevertheless,the Si anode faces significant challenges,particularly severe volume expansion during cycling,which leads to rapid capacity degradation and greatly hinders its commercialization potential.Although extensive research has focused on mitigating volume changes and constructing stable solid-electrolyte interphases on Si-based anodes,a crucial factor for practical application,namely the volumetric capacity,has been often overlooked.For Si-based anodes to replace conventional graphite anodes,their volumetric capacity must be thoroughly evaluated.Key factors determining the volumetric capacity include gravimetric capacity,active material mass ratio,initial Coulombic efficiency,electrode swelling ratio,and the negative-to-positive capacity ratio.This paper systematically analyzes,discusses,and summarizes each of these factors in detail.Common issues with existing strategies are identified,and future research directions concerning the commercialization of Si-based anodes are outlined.This study provides a systematic and novel perspective on effectively modifying and designing Si-based anodes,aiming to promote the volumetric capacity toward the large-scale industrialization of next-generation LIBs.展开更多
Developi ng alter native oxyge n reducti on reactio n(ORR)catalysts to replace precious Pt-based metals with abundant materials is the key challe nge of commercial application of fuel cells.Owing to their various comp...Developi ng alter native oxyge n reducti on reactio n(ORR)catalysts to replace precious Pt-based metals with abundant materials is the key challe nge of commercial application of fuel cells.Owing to their various compositi ons and tun able electronic properties,transition metal dichalcogenides(TMDs)have the great potential to realize high-efficiency catalysts for ORR.Here,various 3R-phase dichalcogenides of group VB and VIB transition metals(MX2,M=Nb,Ta,Mo,W;X=S,Se,Te)are investigated for ORR catalysts by using density functional theory calculations.The computed over-potentials of group VB TMDs are much less than those of group VIB TMDs.For group VB TMDs,a volcano-type plot of ORR catalytic activity is established on the adsorption energies of*OH,and NbS2 and TaTe2 exhibit best ORR activity with an oveepotential of 0.54 V.To achieve even better activity,strain engineering is performed to tune ORR catalytic activity,and the minimum over-potential of 0.43 V can be realized.We further dem on strate that the shift of p orbital center of surface chalcoge n elements under strain is responsible for tuning the catalytic activity of TMDs.展开更多
Flexible supercapacitors show a great potential for applications in wearable, miniaturized, portable, large- scale transparent and flexible consumer electronics due to their significant, inherent advantages, such as b...Flexible supercapacitors show a great potential for applications in wearable, miniaturized, portable, large- scale transparent and flexible consumer electronics due to their significant, inherent advantages, such as being flexible, lightweight, low cost and environmentally friendly in comparison with the current energy storage devices. In this report, recent progress on flexible supercapacitors, flexible electrodes and electrolytes is reviewed. In addition, the future challenges and opportunities are discussed.展开更多
Since the isolation of graphene in 2004,two-dimensional(2D)materials such as transition metal dichalcogenide(TMD)have attracted numerous interests due to their unique van der Waals structure,atomically thin body,and t...Since the isolation of graphene in 2004,two-dimensional(2D)materials such as transition metal dichalcogenide(TMD)have attracted numerous interests due to their unique van der Waals structure,atomically thin body,and thickness-dependent properties.In recent years,the applications of TMD in public health have emerged due to their large surface area and high surface sensitivities,as well as their unique electrical,optical,and electrochemical properties.In this review,we focus on state-of-the-art methods to modulate the properties of 2D TMD and their applications in biosensing.Particularly,this review provides methods for designing and modulating 2D TMD via defect engineering and morphology control to achieve multi-functional surfaces for molecule capturing and sensing.Furthermore,we compare the 2D TMD-based biosensors with the traditional sensing systems,deepening our understanding of their action mechanism.Finally,we point out the challenges and opportunities of 2D TMD in this emerging area.展开更多
基金supported by the Open Topics of State Key Laboratory of Clean and Efficient Coal-Fired Power Generation and Pollution Control(D2022FK103)National Natural Science Foundation of China(22278250)+1 种基金the Shanxi Province Science and Technology Cooperation and Exchange Special Program(202104041101014)the Shanxi Province Scholarship Council。
文摘In the current era of renewable energy prominence,the wide operational capacity of coal-fired boilers has emerged as crucial for ensuring the sustainability of power plants.However,attaining ultra-low nitrogen oxides(NO_x)emissions during periods of low-load operations presents a significant and persistent challenge for coal power enterprises.While techniques such as biomass re-burning and advanced re-burning have shown promise in enhancing NO reduction effciency above 800℃,their elevated levels of chlorine(Cl)and alkali metals pose potential risks to boiler equipment integrity.Therefore,this study proposes the utilization of biomass char derived from pyrolysis as a dual-purpose solution to enhance NO reduction efficiency while safeguarding boiler integrity during low-load operations.Findings indicate that pyrolysis treatment effectively reduces the Cl and alkali metal content of biomass.Specifically,it was determined that biomass char produced through deeply pyrolysis at 300℃achieves the highest NO reduction efficiency while minimizing the presence of harmful components.At a reduction temperature of 700℃,both re-burning and advanced re-burning techniques exhibit NO reduction efficiencies of 55.90%and 62.22%,which is already an ideal deficiency at low temperatures.The addition of water vapor at 700-800℃obviously avoids the oxidation of ammonia to NO in advanced reburning.Upon further analysis,denitrification efficiency in biomass char re-burning and advanced reburning is influenced not only by volatile content but also by physicochemical properties such as porosity and surface functional group distribution under certain reaction conditions.This study provides a theoretical framework for the industrial implementation of biomass char for NO control in coal-fired power plants,offering insights into optimizing NO reduction efficiency while mitigating potential risks to boiler equipment.
基金National Natural Science Foundation of China(Grant Nos.52302249 and 12304003)Shenzhen Science and Technology Innovation Program(Grant No.KCXFZ20201221173010027).
文摘To meet the growing demand for high-energy-density lithium-ion batteries(LIBs),silicon(Si)anodes have gained attention as a promising material for next-generation anodes owing to their ultrahigh gravimetric capacity.Nevertheless,the Si anode faces significant challenges,particularly severe volume expansion during cycling,which leads to rapid capacity degradation and greatly hinders its commercialization potential.Although extensive research has focused on mitigating volume changes and constructing stable solid-electrolyte interphases on Si-based anodes,a crucial factor for practical application,namely the volumetric capacity,has been often overlooked.For Si-based anodes to replace conventional graphite anodes,their volumetric capacity must be thoroughly evaluated.Key factors determining the volumetric capacity include gravimetric capacity,active material mass ratio,initial Coulombic efficiency,electrode swelling ratio,and the negative-to-positive capacity ratio.This paper systematically analyzes,discusses,and summarizes each of these factors in detail.Common issues with existing strategies are identified,and future research directions concerning the commercialization of Si-based anodes are outlined.This study provides a systematic and novel perspective on effectively modifying and designing Si-based anodes,aiming to promote the volumetric capacity toward the large-scale industrialization of next-generation LIBs.
基金National Key Research and Development Program of China(No.2017YFB0701600)National Natural Science Foundation of China(Nos.11874036,51622103,and 21573123)+2 种基金Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01N111)Shenzhen Projects for Basic Research(No.JCYJ20170412171430026)National Program for Thousand Young Talents of China.
文摘Developi ng alter native oxyge n reducti on reactio n(ORR)catalysts to replace precious Pt-based metals with abundant materials is the key challe nge of commercial application of fuel cells.Owing to their various compositi ons and tun able electronic properties,transition metal dichalcogenides(TMDs)have the great potential to realize high-efficiency catalysts for ORR.Here,various 3R-phase dichalcogenides of group VB and VIB transition metals(MX2,M=Nb,Ta,Mo,W;X=S,Se,Te)are investigated for ORR catalysts by using density functional theory calculations.The computed over-potentials of group VB TMDs are much less than those of group VIB TMDs.For group VB TMDs,a volcano-type plot of ORR catalytic activity is established on the adsorption energies of*OH,and NbS2 and TaTe2 exhibit best ORR activity with an oveepotential of 0.54 V.To achieve even better activity,strain engineering is performed to tune ORR catalytic activity,and the minimum over-potential of 0.43 V can be realized.We further dem on strate that the shift of p orbital center of surface chalcoge n elements under strain is responsible for tuning the catalytic activity of TMDs.
基金financial support from the National Nature Science Foundation of China under Grants(no. 51102139 and no.50972065)the Shenzhen Technical Plan Projects(no.JC201105201100A)+1 种基金support from Guangdong Province Innovation R&D Team Plan(2009010025)the China Postdoctoral Science Foundation (no.2012M510022)
文摘Flexible supercapacitors show a great potential for applications in wearable, miniaturized, portable, large- scale transparent and flexible consumer electronics due to their significant, inherent advantages, such as being flexible, lightweight, low cost and environmentally friendly in comparison with the current energy storage devices. In this report, recent progress on flexible supercapacitors, flexible electrodes and electrolytes is reviewed. In addition, the future challenges and opportunities are discussed.
基金We acknowledge the supports by the National Natural Science Foundation of China(Nos.51991343,51991340,and 52188101)the National Science Fund for Distinguished Young Scholars(No.52125309)+3 种基金Guangdong Innovative and Entrepreneurial Research Team Program(No.2017ZT07C341)the Shenzhen Basic Research Project(Nos.JCYJ20190809180605522,WDZC20200819095319002,and JCYJ20200109144616617)Y.L.and Y-C.B.would also like to acknowledge the Scientific Research Start-up Funds(No.QD2021033C)at Tsinghua Shenzhen International Graduate SchoolShenzhen Basic Research Project(No.JCYJ20220530142816037).
文摘Since the isolation of graphene in 2004,two-dimensional(2D)materials such as transition metal dichalcogenide(TMD)have attracted numerous interests due to their unique van der Waals structure,atomically thin body,and thickness-dependent properties.In recent years,the applications of TMD in public health have emerged due to their large surface area and high surface sensitivities,as well as their unique electrical,optical,and electrochemical properties.In this review,we focus on state-of-the-art methods to modulate the properties of 2D TMD and their applications in biosensing.Particularly,this review provides methods for designing and modulating 2D TMD via defect engineering and morphology control to achieve multi-functional surfaces for molecule capturing and sensing.Furthermore,we compare the 2D TMD-based biosensors with the traditional sensing systems,deepening our understanding of their action mechanism.Finally,we point out the challenges and opportunities of 2D TMD in this emerging area.
