SO2-induced MnCeOxcatalyst severe deactivation for low-temperature deNOxremains an intractable issue.In this study,the molar ratio of Nb/Fe was innovatively tuned to enhance the SO2tolerance of Nb and Fe c...SO2-induced MnCeOxcatalyst severe deactivation for low-temperature deNOxremains an intractable issue.In this study,the molar ratio of Nb/Fe was innovatively tuned to enhance the SO2tolerance of Nb and Fe co-doped MnCeOxcatalysts.The Nb7Fe3MnCeOxcatalyst shows optimal catalytic performance advantages,achieving over 90%nitrogen oxide conversion and outstanding N2selectivity within a broad activity temperature range(150-250℃),and also admirable SO2-tolerant performance at 250℃.Detailed experimental results indicate that the strong electron transfer among Fe,Ce and Mn species helps to induce the production of surface oxygen vacancy and accelerate redox cycling,and thus improves the catalytic performance at low temperatures.Moreover,in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)experiments unveil the potential SO2tolerance mechanism of the Nb7Fe3MnCeOxcatalyst.Although the Langmuir-Hinshelwood pathway is somewhat constrained after sample sulfation,the Eley-Rideal pathway greatly facilitates the strongly adsorbed ammonia and NO molecules to undergo the selective catalytic reduction(SCR)reaction.The NO molecules are not required to be weakly adsorbed on the Nb7Fe3MnCeOxcatalyst surface as reactive nitrates,thereby relieving the negative effect of sulfation for NOxremoval.展开更多
A series of MIL-101(Fe)/Cu2O heterojunction photocatalysts was successfully constructed by coupling highly active dodecahedral Cu2O with MIL-101(Fe)through a co-precipitation method.The catalytic performance of ...A series of MIL-101(Fe)/Cu2O heterojunction photocatalysts was successfully constructed by coupling highly active dodecahedral Cu2O with MIL-101(Fe)through a co-precipitation method.The catalytic performance of these materials was systematically evaluated under visible light using tetracycline as the target pollutant.The results indicated that when the mass fraction of MIL-101(Fe)was 20%,the composite material exhibited the best catalytic performance,with a tetracycline degradation rate of up to 87.37%after 100 min of illumination,significantly enhancing the photocatalytic degradation efficiency.The significant improvement in photocatalytic performance was mainly attributed to the tight interface coupling between the two components.Transient photocurrent response and electrochemical impedance spectroscopy(EIS)demonstrated that the introduction of MIL-101(Fe)greatly enhanced the electron conduction ability of the composite system and accelerated charge migration.On the other hand,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),UV-Visible diffuse reflectance spectra(UV-Vis DRS),and Mott-Schottky characterizations,combined with electron paramagnetic resonance(EPR)tests,confirmed the formation of an effective Z-scheme heterojunction between the two components.This Z-scheme heterojunction photocatalyst not only promotes the spatial separation of photogenerated electron-hole pairs but also retains the stronger redox ability of the composite material,thereby synergistically achieving efficient degradation of pollutants.展开更多
The uniform pore size distribution and inherent particle inseparability of iron-based metal-organic frameworks(Fe-MOFs)have been shown to significantly hinder their light-harvesting capabilities and charge carrier sep...The uniform pore size distribution and inherent particle inseparability of iron-based metal-organic frameworks(Fe-MOFs)have been shown to significantly hinder their light-harvesting capabilities and charge carrier separation efficiency.These intrinsic limitations compromise catalyst recyclability and reaction kinetics in practical scenarios,thereby impeding their applicability in the degradation of antibiotic pollutants such as levofloxacin(LEV)in aquatic environments.Here,we report an S-type heterojunction photocatalyst,MnFe2O4@MIL-101(Fe),prepared via hydrothermal coupling of magnetic MnFe2O4 nanoparticles with MIL-101(Fe).The synergistic effect of Fe3+/Fe2+and Mn3+/Mn2+redox pairs,combined with the heterojunction interface and built-in electric field,significantly enhances visible-light-driven photo-Fenton activity.The catalyst degraded over 95%of LEV with a rate constant of 0.05056 min-1 and retained 87%activity after five cycles.LC-MS analysis revealed defluorination and demethylation pathways,while toxicity assessments confirmed lower LC50,mutagenicity,and developmental toxicity of intermediates,validating the environmental viability of the photo-Fenton process.展开更多
Bi/Bi2Fe4O9nanocomposites consisting of Bi2Fe4O9nanosheets decorated with Bi nanodots were synthesized by a hydrothermal method.The formation of Bi nanodots on the Bi2Fe4O9nanosheet surfaces...Bi/Bi2Fe4O9nanocomposites consisting of Bi2Fe4O9nanosheets decorated with Bi nanodots were synthesized by a hydrothermal method.The formation of Bi nanodots on the Bi2Fe4O9nanosheet surfaces was attributed to the reducibility of 2-methoxyethanol in the precursor solution.Comparative photocatalytic evaluation reveals that the Bi/Bi2Fe4O9nanocomposites significantly enhance the degradation efficiency(99.0%)of bisphenol A compared with Bi2Fe4O9nanosheets(64.2%)under 120 min simulated solar irradiation.This remarkable enhancement can be attributed to the established Bi/Bi2Fe4O9heterojunction structure,which effectively facilitates the separation of photogenerated electron-hole pairs and accelerates interfacial charge transfer between the metallic Bi nanodots and semiconductor Bi2Fe4O9nanosheets.The synergistic effects arising from this unique architecture ultimately lead to superior photocatalytic performance.展开更多
针对光固化Al2O3陶瓷在脱脂烧结后易形成孔洞、力学性能差的问题,系统研究了石墨烯添加对陶瓷浆料流变性、沉降性、固化行为及烧结体力学性能的影响。采用γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560)对Al2O3粉体进行表面改性,并加入不同含...针对光固化Al2O3陶瓷在脱脂烧结后易形成孔洞、力学性能差的问题,系统研究了石墨烯添加对陶瓷浆料流变性、沉降性、固化行为及烧结体力学性能的影响。采用γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560)对Al2O3粉体进行表面改性,并加入不同含量的石墨烯,制备高固相、低粘度的光固化浆料。通过傅里叶红外光谱、旋转流变仪、沉降试验及Beer-Lambert模型分析,优化了浆料配方与光固化工艺参数。结果表明:当KH560含量为2.5wt%、石墨烯含量为0.01wt%时,浆料粘度最低、沉降分层最少;在曝光时间4 s条件下,添加0.01wt%石墨烯的浆料透射深度为382μm,临界曝光能量为44.3 m J/cm2。经1750℃烧结后,陶瓷零件致密度达99.7%,弯曲强度为27.61 MPa,维氏硬度为13.45GPa。石墨烯通过位阻效应及裂纹偏转机制有效促进了烧结致密化并改善了力学性能。本研究为光固化增材制造高致密、高性能氧化铝陶瓷提供了试验依据。展开更多
P2型层状过渡金属氧化物(P2-NaxTMO2)因其优异的循环稳定性和倍率性能,成为钠离子电池正极材料的有力候选者。然而,其在高电压下的不可逆相变和固有低理论容量问题,阻碍了实际应用。本研究工作提出高熵策略与双相结构的协同设计...P2型层状过渡金属氧化物(P2-NaxTMO2)因其优异的循环稳定性和倍率性能,成为钠离子电池正极材料的有力候选者。然而,其在高电压下的不可逆相变和固有低理论容量问题,阻碍了实际应用。本研究工作提出高熵策略与双相结构的协同设计来克服这些挑战。通过在P2相高熵基体中引入O3相,构建新型P2/O3双相高熵层状氧化物Na0.70Ni0.25Mn0.35Co0.15Fe0.05Ti0.20O2(简称Na0.70NMCFT)。其中,高熵设计通过构型熵稳定效应有效抑制P2相的不可逆相变,而O3相则通过协同作用弥补容量不足并提升循环稳定性。此外,双相组分之间的相互作用进一步促进P2-O3与P2-P3相变的高度可逆性。Na0.70NMCFT在1C倍率下的初始放电容量为102.08 mAhg-1,200次循环后容量保持率达88.15%,表明具有优异的循环稳定性。更重要的是,即使在10C的高倍率下,Na0.70NMCFT仍能提供85.67 mAh g-1的初始放电比容量,并在1000次循环后容量保持率达70%。本工作证实双相高熵设计在提升钠离子电池正极性能中的关键作用,为开发先进钠离子电池正极材料提供了新思路。展开更多
基金Project supported by National Natural Science Foundation of China(22076180)Key Project of Science and Technology Talent and Independent Innovation of Beibei District Science and Technology Bureau,Chongqing(2024-18)+2 种基金“Light of the West”Young Scholar Program(Class A)of Chinese Academy of SciencesSpecial Research Assistant Grant of Chinese Academy of SciencesChongqing Bayu Scholar Program(Young Scholar,YS2020048)。
摘要SO2-induced MnCeOxcatalyst severe deactivation for low-temperature deNOxremains an intractable issue.In this study,the molar ratio of Nb/Fe was innovatively tuned to enhance the SO2tolerance of Nb and Fe co-doped MnCeOxcatalysts.The Nb7Fe3MnCeOxcatalyst shows optimal catalytic performance advantages,achieving over 90%nitrogen oxide conversion and outstanding N2selectivity within a broad activity temperature range(150-250℃),and also admirable SO2-tolerant performance at 250℃.Detailed experimental results indicate that the strong electron transfer among Fe,Ce and Mn species helps to induce the production of surface oxygen vacancy and accelerate redox cycling,and thus improves the catalytic performance at low temperatures.Moreover,in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)experiments unveil the potential SO2tolerance mechanism of the Nb7Fe3MnCeOxcatalyst.Although the Langmuir-Hinshelwood pathway is somewhat constrained after sample sulfation,the Eley-Rideal pathway greatly facilitates the strongly adsorbed ammonia and NO molecules to undergo the selective catalytic reduction(SCR)reaction.The NO molecules are not required to be weakly adsorbed on the Nb7Fe3MnCeOxcatalyst surface as reactive nitrates,thereby relieving the negative effect of sulfation for NOxremoval.
摘要A series of MIL-101(Fe)/Cu2O heterojunction photocatalysts was successfully constructed by coupling highly active dodecahedral Cu2O with MIL-101(Fe)through a co-precipitation method.The catalytic performance of these materials was systematically evaluated under visible light using tetracycline as the target pollutant.The results indicated that when the mass fraction of MIL-101(Fe)was 20%,the composite material exhibited the best catalytic performance,with a tetracycline degradation rate of up to 87.37%after 100 min of illumination,significantly enhancing the photocatalytic degradation efficiency.The significant improvement in photocatalytic performance was mainly attributed to the tight interface coupling between the two components.Transient photocurrent response and electrochemical impedance spectroscopy(EIS)demonstrated that the introduction of MIL-101(Fe)greatly enhanced the electron conduction ability of the composite system and accelerated charge migration.On the other hand,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),UV-Visible diffuse reflectance spectra(UV-Vis DRS),and Mott-Schottky characterizations,combined with electron paramagnetic resonance(EPR)tests,confirmed the formation of an effective Z-scheme heterojunction between the two components.This Z-scheme heterojunction photocatalyst not only promotes the spatial separation of photogenerated electron-hole pairs but also retains the stronger redox ability of the composite material,thereby synergistically achieving efficient degradation of pollutants.
基金supported by the National Natural Science Foundation of China(No.22178325)the Research Fund of Key Laboratory of the Ministry of Education for Advanced Catalysis Materials,Zhejiang Key Laboratory of Advanced Catalysis and Adsorption Materials。
摘要The uniform pore size distribution and inherent particle inseparability of iron-based metal-organic frameworks(Fe-MOFs)have been shown to significantly hinder their light-harvesting capabilities and charge carrier separation efficiency.These intrinsic limitations compromise catalyst recyclability and reaction kinetics in practical scenarios,thereby impeding their applicability in the degradation of antibiotic pollutants such as levofloxacin(LEV)in aquatic environments.Here,we report an S-type heterojunction photocatalyst,MnFe2O4@MIL-101(Fe),prepared via hydrothermal coupling of magnetic MnFe2O4 nanoparticles with MIL-101(Fe).The synergistic effect of Fe3+/Fe2+and Mn3+/Mn2+redox pairs,combined with the heterojunction interface and built-in electric field,significantly enhances visible-light-driven photo-Fenton activity.The catalyst degraded over 95%of LEV with a rate constant of 0.05056 min-1 and retained 87%activity after five cycles.LC-MS analysis revealed defluorination and demethylation pathways,while toxicity assessments confirmed lower LC50,mutagenicity,and developmental toxicity of intermediates,validating the environmental viability of the photo-Fenton process.
基金Funded by the National Natural Science Foundation of China(No.50902108)。
摘要Bi/Bi2Fe4O9nanocomposites consisting of Bi2Fe4O9nanosheets decorated with Bi nanodots were synthesized by a hydrothermal method.The formation of Bi nanodots on the Bi2Fe4O9nanosheet surfaces was attributed to the reducibility of 2-methoxyethanol in the precursor solution.Comparative photocatalytic evaluation reveals that the Bi/Bi2Fe4O9nanocomposites significantly enhance the degradation efficiency(99.0%)of bisphenol A compared with Bi2Fe4O9nanosheets(64.2%)under 120 min simulated solar irradiation.This remarkable enhancement can be attributed to the established Bi/Bi2Fe4O9heterojunction structure,which effectively facilitates the separation of photogenerated electron-hole pairs and accelerates interfacial charge transfer between the metallic Bi nanodots and semiconductor Bi2Fe4O9nanosheets.The synergistic effects arising from this unique architecture ultimately lead to superior photocatalytic performance.
摘要针对光固化Al2O3陶瓷在脱脂烧结后易形成孔洞、力学性能差的问题,系统研究了石墨烯添加对陶瓷浆料流变性、沉降性、固化行为及烧结体力学性能的影响。采用γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560)对Al2O3粉体进行表面改性,并加入不同含量的石墨烯,制备高固相、低粘度的光固化浆料。通过傅里叶红外光谱、旋转流变仪、沉降试验及Beer-Lambert模型分析,优化了浆料配方与光固化工艺参数。结果表明:当KH560含量为2.5wt%、石墨烯含量为0.01wt%时,浆料粘度最低、沉降分层最少;在曝光时间4 s条件下,添加0.01wt%石墨烯的浆料透射深度为382μm,临界曝光能量为44.3 m J/cm2。经1750℃烧结后,陶瓷零件致密度达99.7%,弯曲强度为27.61 MPa,维氏硬度为13.45GPa。石墨烯通过位阻效应及裂纹偏转机制有效促进了烧结致密化并改善了力学性能。本研究为光固化增材制造高致密、高性能氧化铝陶瓷提供了试验依据。
摘要P2型层状过渡金属氧化物(P2-NaxTMO2)因其优异的循环稳定性和倍率性能,成为钠离子电池正极材料的有力候选者。然而,其在高电压下的不可逆相变和固有低理论容量问题,阻碍了实际应用。本研究工作提出高熵策略与双相结构的协同设计来克服这些挑战。通过在P2相高熵基体中引入O3相,构建新型P2/O3双相高熵层状氧化物Na0.70Ni0.25Mn0.35Co0.15Fe0.05Ti0.20O2(简称Na0.70NMCFT)。其中,高熵设计通过构型熵稳定效应有效抑制P2相的不可逆相变,而O3相则通过协同作用弥补容量不足并提升循环稳定性。此外,双相组分之间的相互作用进一步促进P2-O3与P2-P3相变的高度可逆性。Na0.70NMCFT在1C倍率下的初始放电容量为102.08 mAhg-1,200次循环后容量保持率达88.15%,表明具有优异的循环稳定性。更重要的是,即使在10C的高倍率下,Na0.70NMCFT仍能提供85.67 mAh g-1的初始放电比容量,并在1000次循环后容量保持率达70%。本工作证实双相高熵设计在提升钠离子电池正极性能中的关键作用,为开发先进钠离子电池正极材料提供了新思路。