The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving ...The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving better solar light conversion and photocatalysis efficiency. For this purpose, we have designed a novel Bi quantum dots(QDs) implanted C-doped BiOCl photocatalyst(C/BOC/B) for NOx removal. The feasibility was firstly evaluated through density functional theory(DFT) calculations methods, which indicates that the enhanced photocatalytic performance could be expected owing to the synergistic effects of doped C heteroatoms and loaded Bi QDs. Then, the C/BOC/B was synthesized via a facile hydrothermal method and exhibited efficient and stable visible light photocatalytic NO removal. The results found that the doped C atoms can serve as electron guides to induce oriented charge transfer from Bi QDs to BiOCl, while the Bi QDs can act as light-capture and electron-donating sites. The reaction pathway and mechanism for NO conversion was unveiled by in situ Fourier-transform infrared spectroscopy combined with DFT calculation. The enhanced adsorption of reactants and intermediates could promote the overall reaction efficiency and selectivity in photocatalytic NO conversion. This work could provide a new perspective on the mechanistic understanding of the synergistic effects toward non-metal doping and SPR effects in semiconductor photocatalysts, and this presented technique could be extended for other semiconductor materials.展开更多
To optimize the electronic structure of photocatalyst,a facile one‐step approach is developed for the simultaneous realization of Zn‐doping and surface oxygen vacancies(SOVs)formation on SnO_(2).The Zn‐doped SnO_(2...To optimize the electronic structure of photocatalyst,a facile one‐step approach is developed for the simultaneous realization of Zn‐doping and surface oxygen vacancies(SOVs)formation on SnO_(2).The Zn‐doped SnO_(2)with abundant SOVs exhibits efficient and stable performance for photocatalytic degradation of toluene under both low and high relative humidity.Experimental and theoretical calculations results show that the synergistic effects of Zn‐doping and SOVs on SnO_(2)can considerably boost the charge transfer and separation efficiency.Utilizing the in situ DRIFTS and theoretical calculations methods,it is revealed that the benzene ring of toluene is opened at benzoic acid on the SnO_(2)surface and selectively at benzaldehyde on the Zn‐doped SnO_(2)surface.This implies that Zn‐doped SnO_(2)photocatalysts shorten the pathway of toluene degradation,and toxic intermediates can be significantly inhibited.This work could provide a promising and sustainable route for safe and efficient removal of aromatic VOCs with photocatalytic technology.展开更多
It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates.In this study,we develo...It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates.In this study,we developed a facile method to induce the La doping and cationic vacancie(V(Zn))on ZnO for the highly efficient complete NO oxidation.The photocatalytic NO removal efficiency increases from 36.2%to 53,6%.Most importantly,a significant suppressed NO2 production also has been realized.According to the DFT calculations,ESR spectra and in situ FTIR spectra,the introduction of La^3+induce the redistribution of charge carriers in La-ZnO,which promote the production of·O2^- and lead to the formation of V(Zn)for the formation of·OH,contributing to the complete oxidation of NO to nitrate.Besides,the conversion pathway of photocatalytic NO oxidation has been elaborated,This work paves a new way to simultaneously realize the photocatalytic pollutants removal and the inhibition of toxic intermediates generation for efficient and safe air purification.展开更多
This paper analyzes the unified performance of energy detection(ED) of spectrum sensing(SS) over generalized fading channels in cognitive radios(CRs). The detective performance of SS will be obviously affected by fadi...This paper analyzes the unified performance of energy detection(ED) of spectrum sensing(SS) over generalized fading channels in cognitive radios(CRs). The detective performance of SS will be obviously affected by fading channels among communication nodes, and ED has the advantages of fast implementation, no requirement of priori received information and low complexity, so it is meaningful to investigate ED over various fading channels. The probability density function(p.d.f.) of α-κ-μ distribution is derived to evaluate energy efficiency for sensing systems.The detection probability with Marcum-Q function has been derived and the close-form expressions with moment generating function(MGF) method are deduced to achieve SS.Furthermore, exact closed-form analytic expressions for average area under the receiver operating characteristics curve( AUC) also have been deduced to analyze the performance characteristics of ED over α-κ-μ fading channels.Besides, cooperative spectrum sensing(CSS) with diversity reception has been applied to improve the detection accuracy and mitigate the shadowed fading features with OR-rule. At last, the results show that the detection capacity of ED will be evidently affected by α-κ-μ fading channels, but appropriate channel parameters can improve sensing performance. In addition, the establishedED-fading pattern is approved by simulations,and it can significantly enhance the detection performance of proposed algorithms.展开更多
Mobile cloud computing（MCC） combines mobile Internet and cloud computing to improve the performance of mobile applications. However, MCC faces the problem of energy efficiency because of randomly varying channels. A...Mobile cloud computing（MCC） combines mobile Internet and cloud computing to improve the performance of mobile applications. However, MCC faces the problem of energy efficiency because of randomly varying channels. A scheduling algorithm is proposed by introducing the Lyapunov optimization, which can dynamically choose users to transmit data based on queue backlog and channel statistics. The Lyapunov analysis shows that the proposed scheduling algorithm can make a tradeoff between queue backlog and energy consumption in the channel-aware mobile cloud computing system. The simulation results verify the effectiveness of the proposed algorithm.展开更多
文摘The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving better solar light conversion and photocatalysis efficiency. For this purpose, we have designed a novel Bi quantum dots(QDs) implanted C-doped BiOCl photocatalyst(C/BOC/B) for NOx removal. The feasibility was firstly evaluated through density functional theory(DFT) calculations methods, which indicates that the enhanced photocatalytic performance could be expected owing to the synergistic effects of doped C heteroatoms and loaded Bi QDs. Then, the C/BOC/B was synthesized via a facile hydrothermal method and exhibited efficient and stable visible light photocatalytic NO removal. The results found that the doped C atoms can serve as electron guides to induce oriented charge transfer from Bi QDs to BiOCl, while the Bi QDs can act as light-capture and electron-donating sites. The reaction pathway and mechanism for NO conversion was unveiled by in situ Fourier-transform infrared spectroscopy combined with DFT calculation. The enhanced adsorption of reactants and intermediates could promote the overall reaction efficiency and selectivity in photocatalytic NO conversion. This work could provide a new perspective on the mechanistic understanding of the synergistic effects toward non-metal doping and SPR effects in semiconductor photocatalysts, and this presented technique could be extended for other semiconductor materials.
文摘To optimize the electronic structure of photocatalyst,a facile one‐step approach is developed for the simultaneous realization of Zn‐doping and surface oxygen vacancies(SOVs)formation on SnO_(2).The Zn‐doped SnO_(2)with abundant SOVs exhibits efficient and stable performance for photocatalytic degradation of toluene under both low and high relative humidity.Experimental and theoretical calculations results show that the synergistic effects of Zn‐doping and SOVs on SnO_(2)can considerably boost the charge transfer and separation efficiency.Utilizing the in situ DRIFTS and theoretical calculations methods,it is revealed that the benzene ring of toluene is opened at benzoic acid on the SnO_(2)surface and selectively at benzaldehyde on the Zn‐doped SnO_(2)surface.This implies that Zn‐doped SnO_(2)photocatalysts shorten the pathway of toluene degradation,and toxic intermediates can be significantly inhibited.This work could provide a promising and sustainable route for safe and efficient removal of aromatic VOCs with photocatalytic technology.
基金supported by the National Natural Science Foundation of China(Nos.21822601,21777011,21501016)the Innovative Research Team of Chongqing(No.yjscxx2019-101-62)+1 种基金the Natural Science Foundation of Chongqing(No.cstc2017jcyjBX0052)the Plan for“National Youth Talents”of the Organization Department of the Central Committee。
文摘It is of a great challenge to develop semiconductor photocatalysts with potential possibilities to simultaneously enhance photocatalytic efficiency and inhibit generation of toxic intermediates.In this study,we developed a facile method to induce the La doping and cationic vacancie(V(Zn))on ZnO for the highly efficient complete NO oxidation.The photocatalytic NO removal efficiency increases from 36.2%to 53,6%.Most importantly,a significant suppressed NO2 production also has been realized.According to the DFT calculations,ESR spectra and in situ FTIR spectra,the introduction of La^3+induce the redistribution of charge carriers in La-ZnO,which promote the production of·O2^- and lead to the formation of V(Zn)for the formation of·OH,contributing to the complete oxidation of NO to nitrate.Besides,the conversion pathway of photocatalytic NO oxidation has been elaborated,This work paves a new way to simultaneously realize the photocatalytic pollutants removal and the inhibition of toxic intermediates generation for efficient and safe air purification.
基金supported by the science and technology project of state grid headquarters of China (SGLNDK00KJJS1700200)
文摘This paper analyzes the unified performance of energy detection(ED) of spectrum sensing(SS) over generalized fading channels in cognitive radios(CRs). The detective performance of SS will be obviously affected by fading channels among communication nodes, and ED has the advantages of fast implementation, no requirement of priori received information and low complexity, so it is meaningful to investigate ED over various fading channels. The probability density function(p.d.f.) of α-κ-μ distribution is derived to evaluate energy efficiency for sensing systems.The detection probability with Marcum-Q function has been derived and the close-form expressions with moment generating function(MGF) method are deduced to achieve SS.Furthermore, exact closed-form analytic expressions for average area under the receiver operating characteristics curve( AUC) also have been deduced to analyze the performance characteristics of ED over α-κ-μ fading channels.Besides, cooperative spectrum sensing(CSS) with diversity reception has been applied to improve the detection accuracy and mitigate the shadowed fading features with OR-rule. At last, the results show that the detection capacity of ED will be evidently affected by α-κ-μ fading channels, but appropriate channel parameters can improve sensing performance. In addition, the establishedED-fading pattern is approved by simulations,and it can significantly enhance the detection performance of proposed algorithms.
基金supported by the National Natural Science Foundation of China(61173017)the National High Technology Research and Development Program(863 Program)(2014AA01A701)
文摘Mobile cloud computing（MCC） combines mobile Internet and cloud computing to improve the performance of mobile applications. However, MCC faces the problem of energy efficiency because of randomly varying channels. A scheduling algorithm is proposed by introducing the Lyapunov optimization, which can dynamically choose users to transmit data based on queue backlog and channel statistics. The Lyapunov analysis shows that the proposed scheduling algorithm can make a tradeoff between queue backlog and energy consumption in the channel-aware mobile cloud computing system. The simulation results verify the effectiveness of the proposed algorithm.
