Coal gangue(CG),a solid waste from coal mining and processing,has raised concerns about its environmental impact.Graphitic carbon nitride(g-C_(3)N_(4))is promising for photocatalytic decomposition of organic pollutant...Coal gangue(CG),a solid waste from coal mining and processing,has raised concerns about its environmental impact.Graphitic carbon nitride(g-C_(3)N_(4))is promising for photocatalytic decomposition of organic pollutants,but its performance is hampered by its inherent defects.In this study,the compound of coal gangue and g-C_(3)N_(4)was formed by in-situ loading g-C_(3)N_(4)on the surface of coal gangue.After recombination,the morphology of g-C_(3)N_(4)changes from block structure to tremella nanosheet.This change not only increases the specific surface area of g-C_(3)N_(4),but also broadens the light absorption spectrum of g-C_(3)N_(4).Compared with original g-C_(3)N_(4),the photo-current of the complex in visible light is increased twice,and the tetracycline(TC)degradation rate is 2.1 times faster.The structure,optical properties,band structure,morphology and charge transfer mechanism of the composite were analyzed by a series of characterization techniques.It is found that coal gangue can promote the space charge transfer and separation of g-C_(3)N_(4),and the cyclic test compound has good activity stability.In this paper,a strategy of comprehensive utilization of coal gangue is proposed,which can not only reduce the envi-ronmental risk of coal gangue,but also provide carbon nitride(CN)based photocatalytic materials with superior photocatalytic properties.展开更多
[18_(T)D$IF]Ammonia(NH_(3))is considered an attractive candidate as a clean,highly efficient energy carrier.The electrocatalytic nitrogen reduction reaction(NRR)can reduce energy input and carbon footprint;therefore,r...[18_(T)D$IF]Ammonia(NH_(3))is considered an attractive candidate as a clean,highly efficient energy carrier.The electrocatalytic nitrogen reduction reaction(NRR)can reduce energy input and carbon footprint;therefore,rational design of effective electrocatalysts is essential for achieving high-efficiency electrocatalytic NH_(3)synthesis.Herein,we report that the enzymatic mechanism is the more favourable pathway for NRR,due to lower limiting potential(-0.44 V),lower free energy(only 0.02 eV)of the first hydrogenation step(*N–N to*NH–N),and more electron transfer from Fe_(2)B_(2)to the reaction species.In addition,both vacancies and dopants can be helpful in reducing the reaction energy barrier of the potential-determining step.Therefore,we have demonstrated that Fe_(2)B_(2)is a potential new candidate for effective NRR and highlighted its potential for applications in electrocatalytic NH_(3)synthesis.展开更多
The efficiency of photocatalytic pollutant removal largely depends on the ability of the photocatalytic system to produce hydroxyl radicals(·OH).However,the capability of photocatalyst to produce·OH is not s...The efficiency of photocatalytic pollutant removal largely depends on the ability of the photocatalytic system to produce hydroxyl radicals(·OH).However,the capability of photocatalyst to produce·OH is not strong at present.Advancing the capacity of photocatalytic system to produce·OH has always been a tough problem and challenge in the field of environmental science.In this research,it was found that introducing nitric oxide(NO)into the graphitic carbon nitride(g-C_(3)N_(4))photocatalytic system could memorably enhance the ability of producing·OH group.This study provides a new idea for improving the capacity of photocatalytic·OH production.展开更多
In scanning tunneling microscopy-induced luminescence(STML),the photon count is measured to reflect single-molecule properties,e.g.,the first molecular excited state.The energy of the first excited state is typically ...In scanning tunneling microscopy-induced luminescence(STML),the photon count is measured to reflect single-molecule properties,e.g.,the first molecular excited state.The energy of the first excited state is typically shown by a rise of the photon count as a function of the bias voltage between the tip and the substrate.It remains a challenge to determine the precise rise position of the current due to possible experimental noise.In this work,we propose an alternating current version of STML to resolve the fine structures in the photon count measurement.The measured photon count and the current at the long-time limit show a sinusoidal oscillation.The zero-frequency component of the current shows knee points at the precise voltage as the fraction of the detuning between the molecular gap and the DC component of the bias voltage.We propose to measure the energy level with discontinuity of the first derivative of such a zero-frequency component.The current method will extend the application of STML in terms of measuring molecular properties.展开更多
基金National Natural Science Foundation of China(Nos.21876104 and 21603109)
文摘Coal gangue(CG),a solid waste from coal mining and processing,has raised concerns about its environmental impact.Graphitic carbon nitride(g-C_(3)N_(4))is promising for photocatalytic decomposition of organic pollutants,but its performance is hampered by its inherent defects.In this study,the compound of coal gangue and g-C_(3)N_(4)was formed by in-situ loading g-C_(3)N_(4)on the surface of coal gangue.After recombination,the morphology of g-C_(3)N_(4)changes from block structure to tremella nanosheet.This change not only increases the specific surface area of g-C_(3)N_(4),but also broadens the light absorption spectrum of g-C_(3)N_(4).Compared with original g-C_(3)N_(4),the photo-current of the complex in visible light is increased twice,and the tetracycline(TC)degradation rate is 2.1 times faster.The structure,optical properties,band structure,morphology and charge transfer mechanism of the composite were analyzed by a series of characterization techniques.It is found that coal gangue can promote the space charge transfer and separation of g-C_(3)N_(4),and the cyclic test compound has good activity stability.In this paper,a strategy of comprehensive utilization of coal gangue is proposed,which can not only reduce the envi-ronmental risk of coal gangue,but also provide carbon nitride(CN)based photocatalytic materials with superior photocatalytic properties.
基金the National Natural Science Foundation of China for financial support(Nos.21603109,11904081 and21876104)supported by Henan Joint Funds of the National Natural Science Foundation of China(No.U1404216)+1 种基金the Special Fund of Tianshui Normal University,China(No.CXJ2020-08)the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.20JK0676)。
文摘[18_(T)D$IF]Ammonia(NH_(3))is considered an attractive candidate as a clean,highly efficient energy carrier.The electrocatalytic nitrogen reduction reaction(NRR)can reduce energy input and carbon footprint;therefore,rational design of effective electrocatalysts is essential for achieving high-efficiency electrocatalytic NH_(3)synthesis.Herein,we report that the enzymatic mechanism is the more favourable pathway for NRR,due to lower limiting potential(-0.44 V),lower free energy(only 0.02 eV)of the first hydrogenation step(*N–N to*NH–N),and more electron transfer from Fe_(2)B_(2)to the reaction species.In addition,both vacancies and dopants can be helpful in reducing the reaction energy barrier of the potential-determining step.Therefore,we have demonstrated that Fe_(2)B_(2)is a potential new candidate for effective NRR and highlighted its potential for applications in electrocatalytic NH_(3)synthesis.
基金Financial support by the National Nature Science Foundation of China(Nos.21876104 and 21603271)is gratefully appreciatedpartially supported by the General Research Fund(Nos.18300920 and 18301117)of Research Grants Council+1 种基金the Department Collaborative Fund(No.04490)Dean's Research Fund(No.FLASS/DRF04554)of the Faculty of Liberal Arts and Social Sciences,The Education Universityof Hong Kong,Hong Kong Special Administrative Region,China.
文摘The efficiency of photocatalytic pollutant removal largely depends on the ability of the photocatalytic system to produce hydroxyl radicals(·OH).However,the capability of photocatalyst to produce·OH is not strong at present.Advancing the capacity of photocatalytic system to produce·OH has always been a tough problem and challenge in the field of environmental science.In this research,it was found that introducing nitric oxide(NO)into the graphitic carbon nitride(g-C_(3)N_(4))photocatalytic system could memorably enhance the ability of producing·OH group.This study provides a new idea for improving the capacity of photocatalytic·OH production.
基金the National Natural Science Foundation of China(NSFC)(Grant No.11875049)the NSAF(Grant Nos.U1730449 and U1930403)the National Basic Research Program of China(Grant No.2016YFA0301201).
文摘In scanning tunneling microscopy-induced luminescence(STML),the photon count is measured to reflect single-molecule properties,e.g.,the first molecular excited state.The energy of the first excited state is typically shown by a rise of the photon count as a function of the bias voltage between the tip and the substrate.It remains a challenge to determine the precise rise position of the current due to possible experimental noise.In this work,we propose an alternating current version of STML to resolve the fine structures in the photon count measurement.The measured photon count and the current at the long-time limit show a sinusoidal oscillation.The zero-frequency component of the current shows knee points at the precise voltage as the fraction of the detuning between the molecular gap and the DC component of the bias voltage.We propose to measure the energy level with discontinuity of the first derivative of such a zero-frequency component.The current method will extend the application of STML in terms of measuring molecular properties.
