Double transition metal nitrides and carbides(MXene)have garnered significant attention in the field of electromagnetic wave(EMW)absorption due to their distinctive structural properties.The design of efficient MXene-...Double transition metal nitrides and carbides(MXene)have garnered significant attention in the field of electromagnetic wave(EMW)absorption due to their distinctive structural properties.The design of efficient MXene-based EMW absorbers remains a formidable challenge in light of the high conductivity and strong van der Waals forces.In this work,we report for the first time the approach of the double-doping non-metal N and rare earth metal Ce-4f into Mo-MXene to construct Mo-MXene/MoO_(2)-N/Ce system.This process enables partial in-situ oxidation of Mo-MXene,thereby forming a heterostructure and enhancing the interface polarization.The introduction of Ce facilitates the hybridization between the 4f orbitals of rare earth Ce and the 4d orbitals of Mo,altering the electronic structure of Ce and Mo-MXene and promoting electron migration,which contributes to polarization loss.Furthermore,incorporating melamine into the precursor can induce N doping in Mo-MXene,thereby promoting dipolar polarization.Consequently,the double-doping of N and Ce enables the synergistic effects of interface polarization,dipole polarization,and conduction loss,leading to efficient EMW absorption.Therefore,at a frequency of 13.43 GHz and a matching thickness of 4.685 mm,the optimal reflection loss(RL)value of Mo-MXene/MoO_(2)-N/Ce reaches-57.46 dB,which exceeds a large number of reported MXene-based absorbers.This research confirms that Mo-MXene/MoO_(2)-N/Ce is a promising EMW absorption material and provides valuable insights into modulating MXene-based EMW absorbers using rare earth elements.展开更多
以硝酸铈和尿素为原料,1,3,5苯三甲酸为配体,采用简单的静电自组装法合成了铈金属有机框架(Ce-BTC)和石墨相氮化碳(g-C_(3)N_(4))的复合材料(Ce-BTC/g-C_(3)N_(4)),用于二氧化碳还原制一氧化碳的研究,并探索Ce-BTC的复合对g-C_(3)N_(4)...以硝酸铈和尿素为原料,1,3,5苯三甲酸为配体,采用简单的静电自组装法合成了铈金属有机框架(Ce-BTC)和石墨相氮化碳(g-C_(3)N_(4))的复合材料(Ce-BTC/g-C_(3)N_(4)),用于二氧化碳还原制一氧化碳的研究,并探索Ce-BTC的复合对g-C_(3)N_(4)性能的影响机制。利用X射线衍射、红外光谱、扫描电子显微镜、紫外-可见光吸收光谱、荧光光谱、阻抗、光电流测试和CO_(2)还原性能测试对复合材料的结构、形貌、光电学性能及催化性能进行研究。结果表明Ce-BTC与g-C_(3)N_(4)的复合可能使得g-C_(3)N_(4)层间距发生改变,在细化晶体颗粒的同时提高样品比表面积,使复合样品获得更高的可见光捕获能力且载流子的分离效率更高;在仅加入1 mL H2O作为质子提供源的前提下,Ce-BTC/g-C_(3)N_(4)-3拥有最优光催化性能。CO产率为19.02μmol/(h·g),是g-C_(3)N_(4)的2.25倍,循环测试后催化性能基本保持稳定。展开更多
Ce-TiO2/CA（carbon aerogel） electrode was prepared by sol impregnation approach. The XRD（X-ray diffraction） and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the op...Ce-TiO2/CA（carbon aerogel） electrode was prepared by sol impregnation approach. The XRD（X-ray diffraction） and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the optical absorption edge for Ce-TiO_2/CA is red-shifted to 535 nm compared with TiO_2/CA. Under visible light irradiation, the photocurrent density increment on Ce-TiO_2/CA is 75 times that on Ce-TiO_2/FTO（fluorine-doped tin oxide）. The electrochemical impedance spectroscopy reveals that the conductivity of CeTiO_2/CA is much better than the Ce-TiO_2/FTO. Furthermore, the Ce-TiO_2/CA can be used to the highest electrosorptive photodegradation for 4-chlorophenol wastewater degradation, which is ascribed predominantly to the efficient reduction of electron-hole pair recombination in the photocatalysts.展开更多
基金supported by the National Natural Science Foundation of China(No.22269010)the Jiangxi Provincial Natural Science Foundation(Nos.20224BAB214021 and 20244BAB28050)the Major Research Program of Jingdezhen Ceramic Industry(No.2023ZDGG002).
文摘Double transition metal nitrides and carbides(MXene)have garnered significant attention in the field of electromagnetic wave(EMW)absorption due to their distinctive structural properties.The design of efficient MXene-based EMW absorbers remains a formidable challenge in light of the high conductivity and strong van der Waals forces.In this work,we report for the first time the approach of the double-doping non-metal N and rare earth metal Ce-4f into Mo-MXene to construct Mo-MXene/MoO_(2)-N/Ce system.This process enables partial in-situ oxidation of Mo-MXene,thereby forming a heterostructure and enhancing the interface polarization.The introduction of Ce facilitates the hybridization between the 4f orbitals of rare earth Ce and the 4d orbitals of Mo,altering the electronic structure of Ce and Mo-MXene and promoting electron migration,which contributes to polarization loss.Furthermore,incorporating melamine into the precursor can induce N doping in Mo-MXene,thereby promoting dipolar polarization.Consequently,the double-doping of N and Ce enables the synergistic effects of interface polarization,dipole polarization,and conduction loss,leading to efficient EMW absorption.Therefore,at a frequency of 13.43 GHz and a matching thickness of 4.685 mm,the optimal reflection loss(RL)value of Mo-MXene/MoO_(2)-N/Ce reaches-57.46 dB,which exceeds a large number of reported MXene-based absorbers.This research confirms that Mo-MXene/MoO_(2)-N/Ce is a promising EMW absorption material and provides valuable insights into modulating MXene-based EMW absorbers using rare earth elements.
文摘以硝酸铈和尿素为原料,1,3,5苯三甲酸为配体,采用简单的静电自组装法合成了铈金属有机框架(Ce-BTC)和石墨相氮化碳(g-C_(3)N_(4))的复合材料(Ce-BTC/g-C_(3)N_(4)),用于二氧化碳还原制一氧化碳的研究,并探索Ce-BTC的复合对g-C_(3)N_(4)性能的影响机制。利用X射线衍射、红外光谱、扫描电子显微镜、紫外-可见光吸收光谱、荧光光谱、阻抗、光电流测试和CO_(2)还原性能测试对复合材料的结构、形貌、光电学性能及催化性能进行研究。结果表明Ce-BTC与g-C_(3)N_(4)的复合可能使得g-C_(3)N_(4)层间距发生改变,在细化晶体颗粒的同时提高样品比表面积,使复合样品获得更高的可见光捕获能力且载流子的分离效率更高;在仅加入1 mL H2O作为质子提供源的前提下,Ce-BTC/g-C_(3)N_(4)-3拥有最优光催化性能。CO产率为19.02μmol/(h·g),是g-C_(3)N_(4)的2.25倍,循环测试后催化性能基本保持稳定。
基金Project supported jointly by the Foundation of He'nan Educational Committee(15A150071)
文摘Ce-TiO2/CA（carbon aerogel） electrode was prepared by sol impregnation approach. The XRD（X-ray diffraction） and Raman spectra reveal that the TiO2 is anatase. The UV-vis diffuse reflectance spectra show that the optical absorption edge for Ce-TiO_2/CA is red-shifted to 535 nm compared with TiO_2/CA. Under visible light irradiation, the photocurrent density increment on Ce-TiO_2/CA is 75 times that on Ce-TiO_2/FTO（fluorine-doped tin oxide）. The electrochemical impedance spectroscopy reveals that the conductivity of CeTiO_2/CA is much better than the Ce-TiO_2/FTO. Furthermore, the Ce-TiO_2/CA can be used to the highest electrosorptive photodegradation for 4-chlorophenol wastewater degradation, which is ascribed predominantly to the efficient reduction of electron-hole pair recombination in the photocatalysts.
