光催化二氧化碳还原成烃类化合物是解决能源短缺和环境污染的重要途径。而构建复合物光催化剂可以有效地解决单一光催化剂的缺点,并且提高二氧化碳还原活性。尽管对复合物光催化剂已经做了很多研究,然而对其活性增强的内在机制还缺乏理...光催化二氧化碳还原成烃类化合物是解决能源短缺和环境污染的重要途径。而构建复合物光催化剂可以有效地解决单一光催化剂的缺点,并且提高二氧化碳还原活性。尽管对复合物光催化剂已经做了很多研究,然而对其活性增强的内在机制还缺乏理论认识。本文采用密度泛函理论计算方法研究了二维/二维BP/g-C_(3)N_(4)复合模型的电子性质和CO_(2)还原反应过程。通过对能带位置和界面电子相互作用的综合分析发现,在BP/g-C_(3)N_(4)异质结中,光生载流子的迁移遵循S型异质结光催化机制。与单一的g-C_(3)N_(4)相比,这种异质结可以实现光生载流子的高效分离并且拥有良好的氧化还原能力。此外,通过对比研究CO_(2)在g-C_(3)N_(4)和BP/g-C_(3)N_(4)还原反应过程发现,异质结使CO_(2)还原反应的最大能垒从1.48 e V降低到1.22e V。因此,BP/g-C_(3)N_(4)异质结在理论上被证明是一种优良的CO_(2)还原光催化剂。这项工作有助于了解BP改性对g-C_(3)N_(4)光催化活性的影响,也为其他高性能CO_(2)还原光催化剂的设计提供理论依据。展开更多
Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-sc...Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination methods.The as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous solution.The significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme heterojunction.Furthermore,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 composites.The built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar light.Therefore,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox ability.These results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction mechanism.This work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.展开更多
Sunlight-driven photocatalytic water-splitting for hydrogen(H2)evolution is a desirable strategy to utilize solar energy.However,this strategy is restricted by insufficient light harvesting and high photogenerated ele...Sunlight-driven photocatalytic water-splitting for hydrogen(H2)evolution is a desirable strategy to utilize solar energy.However,this strategy is restricted by insufficient light harvesting and high photogenerated electron-hole recombination rates of TiO2-based photocatalysts.Here,a graphene-modified WO3/TiO2 step-scheme heterojunction(S-scheme heterojunction)composite photocatalyst was fabricated by a facile one-step hydrothermal method.In the ternary composite,TiO2 and WO3 nanoparticles adhered closely to reduced graphene oxide(rGO)and formed a novel S-scheme heterojunction.Moreover,rGO in the composite not only supplied abundant adsorption and catalytically active sites as an ideal support but also promoted electron separation and transfer from the conduction band of TiO2 by forming a Schottky junction between TiO2 and rGO.The positive cooperative effect of the S-scheme heterojunction formed between WO3 and TiO2 and the Schottky heterojunction formed between TiO2 and graphene sheets suppressed the recombination of relatively useful electrons and holes.This effect also enhanced the light harvesting and promoted the reduction reaction at the active sites.Thus,the novel ternary WO3/TiO2/rGO composite demonstrated a remarkably enhanced photocatalytic H2 evolution rate of 245.8μmol g^-1 h^-1,which was approximately 3.5-fold that of pure TiO2.This work not only presents a low-cost graphene-based S-scheme heterojunction photocatalyst that was obtained via a feasible one-step hydrothermal approach to realize highly efficient H2 generation without using noble metals,but also provides new insights into the design of novel heterojunction photocatalysts.展开更多
Coronary artery disease （CAD） is a multifactorial disease in which inflammation plays a central role. This study aimed to investigate the association of inflammatory markers such as the neutrophil to lymphocyte rat...Coronary artery disease （CAD） is a multifactorial disease in which inflammation plays a central role. This study aimed to investigate the association of inflammatory markers such as the neutrophil to lymphocyte ratio （NLR）, the Global Registry of Acute Coronary Events （GRACE） score with in-hospital mortality of elderly patients with acute myocardial infarction （AMI） in an attempt to explore the prognostic value of these indices for elderly AMI patients. One thousand consecutive CAD patients were divided into two groups based on age 60. The laboratory and clinical characteristics were assessed retrospectively by reviewing the medical records. The NLR and GRACE score were calculated. In the elderly （〉60 years）, patients with non-ST-elevation myocardial infarction （NSTEMI） and ST-elevation myocardial infarction （STEMI） had significantly higher NLR than did those with unstable angina （UA） and stable angina pectoris （SAP） （P〈0.01）. The NLR was considerably elevated in older AMI patients compared with their younger counterparts （〈60 years） （P〈0.05）. In elderly AMI patients, the NLR was considerably higher in the high-risk group than in both the low-risk and mediumrisk groups based on the GRACE score （P〈0.05 and P〈0.01, respectively）, and the NLR was positively correlated with the GRACE score （r=0.322, P〈0.001）. Either the NLR level or the GRACE score was significantly higher in the death group than in the surviving group （P〈0.05）. By curve receiver operator characteristic curve （ROC） analysis, the optimal cut-off levels of 9.41 for NLR and 174 for GRACE score predicted in-hospital death [ROC area under the curve （AUC） 0.771 and 0.787, respectively, P〈0.001]. It was concluded that an elevated NLR is a potential predictor of in-hospital mortality in elderly patients with AMI.展开更多
TiO2‐based Z‐scheme photocatalysts have attracted considerable attention because of the low recombination rate of their photogenerated electron–hole pairs and their high photocatalytic efficiency.In this review,the...TiO2‐based Z‐scheme photocatalysts have attracted considerable attention because of the low recombination rate of their photogenerated electron–hole pairs and their high photocatalytic efficiency.In this review,the reaction mechanism of Z‐scheme photocatalysts,recent research progress in the application of TiO2‐based Z‐scheme photocatalysts,and improved methods for photocatalytic performance enhancement are explored.Their applications,including water splitting,CO2reduction,decomposition of volatile organic compounds,and degradation of organic pollutants,are also described.The main factors affecting the photocatalytic performance of TiO2‐based Z‐scheme photocatalysts,such as pH,conductive medium,cocatalyst,architecture,and mass ratio,are discussed.Concluding remarks are presented,and some suggestions for the future development of TiO2‐based Z‐scheme photocatalysts are highlighted.展开更多
Photocatalytic hydrogen peroxide(H_(2)O_(2))production from O_(2) and H2O is an ideal process for solar‐to‐chemical energy conversion.Herein,ZnO nanorods are prepared via a simple hydrothermal method for photocataly...Photocatalytic hydrogen peroxide(H_(2)O_(2))production from O_(2) and H2O is an ideal process for solar‐to‐chemical energy conversion.Herein,ZnO nanorods are prepared via a simple hydrothermal method for photocatalytic H_(2)O_(2) production.The ZnO nanorods exhibit varied performance with different calcination temperatures.Benefiting from calcination,the separation efficiency of photo‐induced carriers is significantly improved,leading to the superior photocatalytic activity for H_(2)O_(2) production.The H_(2)O_(2) produced by ZnO calcined at 300℃ is 285μmol L^(−1),which is over 5 times larger than that produced by untreated ZnO.This work provides an insight into photocatalytic H2O2 production mechanism by ZnO nanorods,and presents a promising strategy to H2O2 production.展开更多
Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously.Herein,carbon@CdS composite hollow spheres(C@CdS-HS)are fabricated via a facil...Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously.Herein,carbon@CdS composite hollow spheres(C@CdS-HS)are fabricated via a facile hydrothermal method using porous carbon hollow spheres(C-HS)as the template.The C@CdS-HS shows an excellent photocatalytic H2-generation rate of 20.9 mmol h^(−1) g^(−1)(apparent quantum efficiency of 15.3%at 420 nm),with 1.0 wt%Pt as a cocatalyst under simulated sunlight irradiation;this rate is 69.7,13.9,and 3.9 times higher than that obtained with pure CdS hollow spheres(CdS-HS),C@CdS-HS,and CdS-HS/Pt,respectively.The enhanced photocatalytic H_(2)-evolution activity of C@CdS-HS/Pt is due to the synergistic effect of C and Pt as the bi-cocatalyst.The C-HS serves not only as an active site provider but also as an electron transporter and reservoir.Moreover,C-HS has a strong photothermal effect that is induced by near infrared light,which kinetically accelerates the H_(2)-production reaction.Additionally,the underlying charge transfer pathway and process from CdS to C−HS is revealed.This work highlights the potential application of C-HS-based nanocomposites in solar-to-chemical energy conversion.展开更多
H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water split...H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water splitting has attracted much interest.Here,oil-soluble ZnxCd1-xS quantum dot(ZCS QD)with a uniform particle size distribution were prepared by a hot-injection method.However,no photocatalytic H2-production activity was observed for the oil-soluble ZCS QD due to its hydrophobicity.Thus,the oil-soluble ZCS QD was converted into a water-soluble ZCS QD by a ligand-exchange method.The water-soluble ZCS QD exhibited excellent photocatalytic H2-production performance in the presence of glycerin and Ni^2+,with an apparent quantum efficiency of 15.9%under irradiation of 420 nm light.Further,the photocatalytic H2-generation activity of the ZCS QD was~10.7 times higher than that of the ZnxCd1-xS relative samples prepared by the conventional co-precipitation method.This work will inspire the design and fabrication of other semiconductor QD photocatalysts because QD exhibits excellent separation efficiency for photogenerated electron-hole pairs due to its small crystallite size.展开更多
Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high...Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high energy barrier for CO_(2) photoreduction on the surface of photocatalysts com‐promise the catalytic performance.Herein,a 2D/2D Bi_(2)MoO_(6)/BiOI composite was fabricated to achieve improved CO_(2) photoreduction efficiency.Charge transfer in the composite was facilitated by the van der Waals heterojunction with a large‐area interface.Work function calculation demon‐strated that S‐scheme charge transfer is operative in the composite,and effective charge separation and strong redox capability were revealed by time‐resolved photoluminescence and electron para‐magnetic resonance spectroscopy.Moreover,the intermediates of CO_(2) photoreduction were identi‐fied based on the in situ diffuse reflectance infrared Fourier‐transform spectra.Density functional theory calculations showed that CO_(2) hydrogenation is the rate‐determining step for yielding CH_(4) and CO.Introducing Bi_(2)MoO_(6) into the composite further decreased the energy barrier for CO_(2) photoreduction on BiOI by 0.35 eV.This study verifies the synergistic effect of the S‐scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.展开更多
Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high...Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact.Herein,we develop a novel strategy to in-situ grow ultrathin/V-doped graphene(NG)layer on TiO_(2) hollow spheres(HS) with large area and intimate interfacial contact via a chemical vapor deposition(CVD).The optimized TiO^(2)/NG HS nanocomposite achieves total CO_(2)conversion rates(the sum yield of CO,CH_(3)OH and CH_(4))of 18.11μmol·g^(-1)h^(-1),which is about 4.6 times higher than blank T1O_(2)HS.Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport,realizing enhanced photocatalytic CO_(2)reduction performance.In addition,this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO_(2)conversion.展开更多
Background Pentraxin 3 （PTX3） is expressed in the heart under inflammatory conditions and plays an important role in atherogenesis. Patients with increased PTX3 levels may suffer from higher rates of cardiac events....Background Pentraxin 3 （PTX3） is expressed in the heart under inflammatory conditions and plays an important role in atherogenesis. Patients with increased PTX3 levels may suffer from higher rates of cardiac events. Regulation of specific genes by promoter methylation is important in atherogenesis. The factors influencing PTX3 levels and the association between epigenetics and PTX3 levels have not been investigated. Methods Blood samples were collected from 64 patients admitted to the Department of Cardiology, 35 who had coronary artery disease （CAD）, and 29 who were CAD-free. Plasma levels of PTX3 were measured by ELISA. PTX3 promoter methylation was evaluated via methyl-specific PCR. The severity of coronary artery lesion was evaluated by angiography. Results The level of PTX3 promoter methylation in the CAD group was 62.69% ± 20.57%, significantly lower than that of the CAD-free group, which was 72.45% ± 11.84% （P = 0.03）. Lower PTX3 promoter methylation levels in the CAD group were associated with higher plasma PTX3 concentrations （r = -0.29, P = 0.02）. Furthermore, lower PTX3 promoter methylation levels were associated with higher neutrophil to lymphocyte ratio （NLR） in men （r = -0.58, P = 0.002）. Conclusions The present study provides new evidence that methylation of the PTX3 promoter is associated with PTX3 plasma levels and NLR in coronary artery disease. This study also shows that modification of epigenetics by chronic inflamma- tion might be a significant molecular mechanism in the atherosclerotic processes that influence plasma PTX3 concentrations.展开更多
文摘光催化二氧化碳还原成烃类化合物是解决能源短缺和环境污染的重要途径。而构建复合物光催化剂可以有效地解决单一光催化剂的缺点,并且提高二氧化碳还原活性。尽管对复合物光催化剂已经做了很多研究,然而对其活性增强的内在机制还缺乏理论认识。本文采用密度泛函理论计算方法研究了二维/二维BP/g-C_(3)N_(4)复合模型的电子性质和CO_(2)还原反应过程。通过对能带位置和界面电子相互作用的综合分析发现,在BP/g-C_(3)N_(4)异质结中,光生载流子的迁移遵循S型异质结光催化机制。与单一的g-C_(3)N_(4)相比,这种异质结可以实现光生载流子的高效分离并且拥有良好的氧化还原能力。此外,通过对比研究CO_(2)在g-C_(3)N_(4)和BP/g-C_(3)N_(4)还原反应过程发现,异质结使CO_(2)还原反应的最大能垒从1.48 e V降低到1.22e V。因此,BP/g-C_(3)N_(4)异质结在理论上被证明是一种优良的CO_(2)还原光催化剂。这项工作有助于了解BP改性对g-C_(3)N_(4)光催化活性的影响,也为其他高性能CO_(2)还原光催化剂的设计提供理论依据。
文摘Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination methods.The as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous solution.The significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme heterojunction.Furthermore,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 composites.The built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar light.Therefore,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox ability.These results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction mechanism.This work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.
基金supported by the National Natural Science Foundation of China(U1705251,21871217,21573170,21433007)the National Key Research and Development Program of China(2018YFB1502001)~~
文摘Sunlight-driven photocatalytic water-splitting for hydrogen(H2)evolution is a desirable strategy to utilize solar energy.However,this strategy is restricted by insufficient light harvesting and high photogenerated electron-hole recombination rates of TiO2-based photocatalysts.Here,a graphene-modified WO3/TiO2 step-scheme heterojunction(S-scheme heterojunction)composite photocatalyst was fabricated by a facile one-step hydrothermal method.In the ternary composite,TiO2 and WO3 nanoparticles adhered closely to reduced graphene oxide(rGO)and formed a novel S-scheme heterojunction.Moreover,rGO in the composite not only supplied abundant adsorption and catalytically active sites as an ideal support but also promoted electron separation and transfer from the conduction band of TiO2 by forming a Schottky junction between TiO2 and rGO.The positive cooperative effect of the S-scheme heterojunction formed between WO3 and TiO2 and the Schottky heterojunction formed between TiO2 and graphene sheets suppressed the recombination of relatively useful electrons and holes.This effect also enhanced the light harvesting and promoted the reduction reaction at the active sites.Thus,the novel ternary WO3/TiO2/rGO composite demonstrated a remarkably enhanced photocatalytic H2 evolution rate of 245.8μmol g^-1 h^-1,which was approximately 3.5-fold that of pure TiO2.This work not only presents a low-cost graphene-based S-scheme heterojunction photocatalyst that was obtained via a feasible one-step hydrothermal approach to realize highly efficient H2 generation without using noble metals,but also provides new insights into the design of novel heterojunction photocatalysts.
基金This project was supported by a grant from Hubei Natural Science Foundation of China （No. 2013CKB011）.
文摘Coronary artery disease （CAD） is a multifactorial disease in which inflammation plays a central role. This study aimed to investigate the association of inflammatory markers such as the neutrophil to lymphocyte ratio （NLR）, the Global Registry of Acute Coronary Events （GRACE） score with in-hospital mortality of elderly patients with acute myocardial infarction （AMI） in an attempt to explore the prognostic value of these indices for elderly AMI patients. One thousand consecutive CAD patients were divided into two groups based on age 60. The laboratory and clinical characteristics were assessed retrospectively by reviewing the medical records. The NLR and GRACE score were calculated. In the elderly （〉60 years）, patients with non-ST-elevation myocardial infarction （NSTEMI） and ST-elevation myocardial infarction （STEMI） had significantly higher NLR than did those with unstable angina （UA） and stable angina pectoris （SAP） （P〈0.01）. The NLR was considerably elevated in older AMI patients compared with their younger counterparts （〈60 years） （P〈0.05）. In elderly AMI patients, the NLR was considerably higher in the high-risk group than in both the low-risk and mediumrisk groups based on the GRACE score （P〈0.05 and P〈0.01, respectively）, and the NLR was positively correlated with the GRACE score （r=0.322, P〈0.001）. Either the NLR level or the GRACE score was significantly higher in the death group than in the surviving group （P〈0.05）. By curve receiver operator characteristic curve （ROC） analysis, the optimal cut-off levels of 9.41 for NLR and 174 for GRACE score predicted in-hospital death [ROC area under the curve （AUC） 0.771 and 0.787, respectively, P〈0.001]. It was concluded that an elevated NLR is a potential predictor of in-hospital mortality in elderly patients with AMI.
基金supported by the National Natural Science Foundation of China(51602207,21433007,51320105001,21573170)the Self-determined and Innovative Research Funds of SKLWUT(2017-ZD-4,2016-KF-17)the Natural Science Foundation of Hubei Province of China(2015CFA001)~~
文摘TiO2‐based Z‐scheme photocatalysts have attracted considerable attention because of the low recombination rate of their photogenerated electron–hole pairs and their high photocatalytic efficiency.In this review,the reaction mechanism of Z‐scheme photocatalysts,recent research progress in the application of TiO2‐based Z‐scheme photocatalysts,and improved methods for photocatalytic performance enhancement are explored.Their applications,including water splitting,CO2reduction,decomposition of volatile organic compounds,and degradation of organic pollutants,are also described.The main factors affecting the photocatalytic performance of TiO2‐based Z‐scheme photocatalysts,such as pH,conductive medium,cocatalyst,architecture,and mass ratio,are discussed.Concluding remarks are presented,and some suggestions for the future development of TiO2‐based Z‐scheme photocatalysts are highlighted.
文摘Photocatalytic hydrogen peroxide(H_(2)O_(2))production from O_(2) and H2O is an ideal process for solar‐to‐chemical energy conversion.Herein,ZnO nanorods are prepared via a simple hydrothermal method for photocatalytic H_(2)O_(2) production.The ZnO nanorods exhibit varied performance with different calcination temperatures.Benefiting from calcination,the separation efficiency of photo‐induced carriers is significantly improved,leading to the superior photocatalytic activity for H_(2)O_(2) production.The H_(2)O_(2) produced by ZnO calcined at 300℃ is 285μmol L^(−1),which is over 5 times larger than that produced by untreated ZnO.This work provides an insight into photocatalytic H2O2 production mechanism by ZnO nanorods,and presents a promising strategy to H2O2 production.
文摘Photocatalytic H2 production from water splitting is an effective method to solve energy crisis and environmental pollution simultaneously.Herein,carbon@CdS composite hollow spheres(C@CdS-HS)are fabricated via a facile hydrothermal method using porous carbon hollow spheres(C-HS)as the template.The C@CdS-HS shows an excellent photocatalytic H2-generation rate of 20.9 mmol h^(−1) g^(−1)(apparent quantum efficiency of 15.3%at 420 nm),with 1.0 wt%Pt as a cocatalyst under simulated sunlight irradiation;this rate is 69.7,13.9,and 3.9 times higher than that obtained with pure CdS hollow spheres(CdS-HS),C@CdS-HS,and CdS-HS/Pt,respectively.The enhanced photocatalytic H_(2)-evolution activity of C@CdS-HS/Pt is due to the synergistic effect of C and Pt as the bi-cocatalyst.The C-HS serves not only as an active site provider but also as an electron transporter and reservoir.Moreover,C-HS has a strong photothermal effect that is induced by near infrared light,which kinetically accelerates the H_(2)-production reaction.Additionally,the underlying charge transfer pathway and process from CdS to C−HS is revealed.This work highlights the potential application of C-HS-based nanocomposites in solar-to-chemical energy conversion.
文摘H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water splitting has attracted much interest.Here,oil-soluble ZnxCd1-xS quantum dot(ZCS QD)with a uniform particle size distribution were prepared by a hot-injection method.However,no photocatalytic H2-production activity was observed for the oil-soluble ZCS QD due to its hydrophobicity.Thus,the oil-soluble ZCS QD was converted into a water-soluble ZCS QD by a ligand-exchange method.The water-soluble ZCS QD exhibited excellent photocatalytic H2-production performance in the presence of glycerin and Ni^2+,with an apparent quantum efficiency of 15.9%under irradiation of 420 nm light.Further,the photocatalytic H2-generation activity of the ZCS QD was~10.7 times higher than that of the ZnxCd1-xS relative samples prepared by the conventional co-precipitation method.This work will inspire the design and fabrication of other semiconductor QD photocatalysts because QD exhibits excellent separation efficiency for photogenerated electron-hole pairs due to its small crystallite size.
文摘Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high energy barrier for CO_(2) photoreduction on the surface of photocatalysts com‐promise the catalytic performance.Herein,a 2D/2D Bi_(2)MoO_(6)/BiOI composite was fabricated to achieve improved CO_(2) photoreduction efficiency.Charge transfer in the composite was facilitated by the van der Waals heterojunction with a large‐area interface.Work function calculation demon‐strated that S‐scheme charge transfer is operative in the composite,and effective charge separation and strong redox capability were revealed by time‐resolved photoluminescence and electron para‐magnetic resonance spectroscopy.Moreover,the intermediates of CO_(2) photoreduction were identi‐fied based on the in situ diffuse reflectance infrared Fourier‐transform spectra.Density functional theory calculations showed that CO_(2) hydrogenation is the rate‐determining step for yielding CH_(4) and CO.Introducing Bi_(2)MoO_(6) into the composite further decreased the energy barrier for CO_(2) photoreduction on BiOI by 0.35 eV.This study verifies the synergistic effect of the S‐scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.
文摘Photocatalytic CO_(2)conversion efficiency is hampered by the rapid recombination of photogenerated charge carriers.It is effective to suppress the recombination by constructing cocatalysts on photocatalysts with high-quality interfacial contact.Herein,we develop a novel strategy to in-situ grow ultrathin/V-doped graphene(NG)layer on TiO_(2) hollow spheres(HS) with large area and intimate interfacial contact via a chemical vapor deposition(CVD).The optimized TiO^(2)/NG HS nanocomposite achieves total CO_(2)conversion rates(the sum yield of CO,CH_(3)OH and CH_(4))of 18.11μmol·g^(-1)h^(-1),which is about 4.6 times higher than blank T1O_(2)HS.Experimental results demonstrate that intimate interfacial contact and abundant pyridinic N sites can effectively facilitate photogenerated charge carrier separation and transport,realizing enhanced photocatalytic CO_(2)reduction performance.In addition,this work provides an effective strategy for in-situ construction of graphene-based photocatalysts for highly efficient photocatalytic CO_(2)conversion.
文摘Background Pentraxin 3 （PTX3） is expressed in the heart under inflammatory conditions and plays an important role in atherogenesis. Patients with increased PTX3 levels may suffer from higher rates of cardiac events. Regulation of specific genes by promoter methylation is important in atherogenesis. The factors influencing PTX3 levels and the association between epigenetics and PTX3 levels have not been investigated. Methods Blood samples were collected from 64 patients admitted to the Department of Cardiology, 35 who had coronary artery disease （CAD）, and 29 who were CAD-free. Plasma levels of PTX3 were measured by ELISA. PTX3 promoter methylation was evaluated via methyl-specific PCR. The severity of coronary artery lesion was evaluated by angiography. Results The level of PTX3 promoter methylation in the CAD group was 62.69% ± 20.57%, significantly lower than that of the CAD-free group, which was 72.45% ± 11.84% （P = 0.03）. Lower PTX3 promoter methylation levels in the CAD group were associated with higher plasma PTX3 concentrations （r = -0.29, P = 0.02）. Furthermore, lower PTX3 promoter methylation levels were associated with higher neutrophil to lymphocyte ratio （NLR） in men （r = -0.58, P = 0.002）. Conclusions The present study provides new evidence that methylation of the PTX3 promoter is associated with PTX3 plasma levels and NLR in coronary artery disease. This study also shows that modification of epigenetics by chronic inflamma- tion might be a significant molecular mechanism in the atherosclerotic processes that influence plasma PTX3 concentrations.
