Solar driven nitrogen(N_(2))fixation to synthesize ammonia is a potential alternative for the traditional Haber-Bosch approach to meeting industrial demand,but is largely hampered by the difficulties in the harvesting...Solar driven nitrogen(N_(2))fixation to synthesize ammonia is a potential alternative for the traditional Haber-Bosch approach to meeting industrial demand,but is largely hampered by the difficulties in the harvesting of solar energy and activating inert N_(2).In this work,hollow CeF_(3) nanospheres co-doped with activator Tm^(3+)and sensitizer Yb^(3+)(Yb^(3+):Tm^(3+):CeF_(3))were prepared by microwave hydrothermal method.The product was employed as a catalyst for photo-driven N_(2) fixation by adjusting the molar ratio of Ce^(3+):Yb^(3+):Tm^(3+).Results show that the porous hollow structure enhances the light-harvesting by physical scattering and reflection.In addition,heteroatom doping generates abundant fluorine vacancies(F_(V))which provide abundant active sites for adsorption and activation of N_(2).The sample with molar ratio of CeF_(3):Yb^(3+):Tm^(3+)at 178:20:2 demonstrates the highest utilization of solar energy attributed to the strongest upconversion capability of near-infrared(NIR)light to visible and ultraviolet(UV)light,and the NH_(4)+concentration achieves the highest value of 15.06μmol/(gcat∙h)under simulated sunlight while nearly 6.22μmol/(gcat∙h)under NIR light.Current study offers a promising and sustainable strategy for the fixation of atmospheric N_(2) using full-spectrum solar energy.展开更多
Photocatalytic fixation of nitrogen has been recognized as a green and promising strategy for ammonia synthesis under ambient conditions.However,the efficient reduction of nitrogen remains a challenge due to high acti...Photocatalytic fixation of nitrogen has been recognized as a green and promising strategy for ammonia synthesis under ambient conditions.However,the efficient reduction of nitrogen remains a challenge due to high activation energy of nitrogen and low utilization of solar energy.Herein,lanthanum oxyfluoride with different doping content of Pr3+(LaOF:xPr3+)upconversion nanorods were synthesized by microwave hydrothermal method.Results indicated that the doping of Pr3+generated considerable defects on the surface of LaOF which acted as the adsorption and activation center for nitrogen.Meanwhile,the Pr3+ion narrowed the band gap and broadened the light response range of LaOF because LaOF:Pr3+can upconvert visible light into ultraviolet light,which excite LaOF nanorods and improve the utilization of solar light.The doping amount of Pr3+had critical effect on the photocatalytic nitrogen fixation performance which reached as high as 180μmol·L?1·ho1 when the molar ratio of Pr3+to LaOF was optimized to be 2%.展开更多
Developing photocatalysts with wide spectrum absorption and strong nitrogen activation is critical for nitrogen fixation under mild conditions.Herein,one-dimensional natural clay attapulgite(ATP)supported YFg:Sm^3+wer...Developing photocatalysts with wide spectrum absorption and strong nitrogen activation is critical for nitrogen fixation under mild conditions.Herein,one-dimensional natural clay attapulgite(ATP)supported YFg:Sm^3+were successfully synthesized via microwave hydrothermal method,and the composites were employed as the catalyst for photocatalytic nitrogen fixation under visible-light irradiation.Results indicated that the production of ammonia reached as high as 41.2 mg·L^-1 within 3 h when the molar ratio of Sm^3+and the mass fraction of YF3:Sm^3+were optimized.The enhanced fixation performance is mainly due to that the modified ATP fibber with abundant active sites and the doped fluoride with defective vacancy facilitate the adsorption and activation of N2.Furthermore,the upconversion property of YF3:Sm^3+increases the harvesting of visible-light energy,meanwhile the Z-scheme heterostructure built between YF:Sm^3+and modified ATP inhibits the recombination of charge carriers and retains high redox potentials for N2 reduction.展开更多
A series of attapulgite （ATP） supported perovskite-type La1-xCexMnO3 ix=0-0.2） nanocomposites were prepared by a sol-gel method. The samples were characterized by X-ray diffraction, transmission elec- tron microsco...A series of attapulgite （ATP） supported perovskite-type La1-xCexMnO3 ix=0-0.2） nanocomposites were prepared by a sol-gel method. The samples were characterized by X-ray diffraction, transmission elec- tron microscopy, Fourier-transform infrared spectroscopy, H2 temperature-programmed reduction, and temperature-programmed desorption of NH3. Their selective catalytic reduction of NO with NH3 was evaluated in the low-temperature range. The impact of the doping fraction of Ce4＋ on the NO conversion was investigated. The results indicated that the La1-xCexMnO3 nanoparticles with a size of ca. 15 nm were uniformly immobilized on the surface of ATP with a loading amount of 20wt%. The highest conversion rate of NO reached 98.6% when the doping fraction x was O.1, while the ATP support supplied a high surface areas facilitating the nanoparticles dispersion as well as the gas adsorption. Incorporation of an appropriate amount of Ce4＋ in the La3＋ site resulted in a high degree of reduction by the active perovskite species with enhanced catalytic activity.展开更多
基金Project supported by the National Natural Science Foundation of China (51674043,51702026)。
文摘Solar driven nitrogen(N_(2))fixation to synthesize ammonia is a potential alternative for the traditional Haber-Bosch approach to meeting industrial demand,but is largely hampered by the difficulties in the harvesting of solar energy and activating inert N_(2).In this work,hollow CeF_(3) nanospheres co-doped with activator Tm^(3+)and sensitizer Yb^(3+)(Yb^(3+):Tm^(3+):CeF_(3))were prepared by microwave hydrothermal method.The product was employed as a catalyst for photo-driven N_(2) fixation by adjusting the molar ratio of Ce^(3+):Yb^(3+):Tm^(3+).Results show that the porous hollow structure enhances the light-harvesting by physical scattering and reflection.In addition,heteroatom doping generates abundant fluorine vacancies(F_(V))which provide abundant active sites for adsorption and activation of N_(2).The sample with molar ratio of CeF_(3):Yb^(3+):Tm^(3+)at 178:20:2 demonstrates the highest utilization of solar energy attributed to the strongest upconversion capability of near-infrared(NIR)light to visible and ultraviolet(UV)light,and the NH_(4)+concentration achieves the highest value of 15.06μmol/(gcat∙h)under simulated sunlight while nearly 6.22μmol/(gcat∙h)under NIR light.Current study offers a promising and sustainable strategy for the fixation of atmospheric N_(2) using full-spectrum solar energy.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51674043 and 51702026)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX18_0951).
文摘Photocatalytic fixation of nitrogen has been recognized as a green and promising strategy for ammonia synthesis under ambient conditions.However,the efficient reduction of nitrogen remains a challenge due to high activation energy of nitrogen and low utilization of solar energy.Herein,lanthanum oxyfluoride with different doping content of Pr3+(LaOF:xPr3+)upconversion nanorods were synthesized by microwave hydrothermal method.Results indicated that the doping of Pr3+generated considerable defects on the surface of LaOF which acted as the adsorption and activation center for nitrogen.Meanwhile,the Pr3+ion narrowed the band gap and broadened the light response range of LaOF because LaOF:Pr3+can upconvert visible light into ultraviolet light,which excite LaOF nanorods and improve the utilization of solar light.The doping amount of Pr3+had critical effect on the photocatalytic nitrogen fixation performance which reached as high as 180μmol·L?1·ho1 when the molar ratio of Pr3+to LaOF was optimized to be 2%.
基金supported by the National Natural Science Foundation of China(Grant Nos.51674043 and 51702026)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX18_0951).
文摘Developing photocatalysts with wide spectrum absorption and strong nitrogen activation is critical for nitrogen fixation under mild conditions.Herein,one-dimensional natural clay attapulgite(ATP)supported YFg:Sm^3+were successfully synthesized via microwave hydrothermal method,and the composites were employed as the catalyst for photocatalytic nitrogen fixation under visible-light irradiation.Results indicated that the production of ammonia reached as high as 41.2 mg·L^-1 within 3 h when the molar ratio of Sm^3+and the mass fraction of YF3:Sm^3+were optimized.The enhanced fixation performance is mainly due to that the modified ATP fibber with abundant active sites and the doped fluoride with defective vacancy facilitate the adsorption and activation of N2.Furthermore,the upconversion property of YF3:Sm^3+increases the harvesting of visible-light energy,meanwhile the Z-scheme heterostructure built between YF:Sm^3+and modified ATP inhibits the recombination of charge carriers and retains high redox potentials for N2 reduction.
文摘A series of attapulgite （ATP） supported perovskite-type La1-xCexMnO3 ix=0-0.2） nanocomposites were prepared by a sol-gel method. The samples were characterized by X-ray diffraction, transmission elec- tron microscopy, Fourier-transform infrared spectroscopy, H2 temperature-programmed reduction, and temperature-programmed desorption of NH3. Their selective catalytic reduction of NO with NH3 was evaluated in the low-temperature range. The impact of the doping fraction of Ce4＋ on the NO conversion was investigated. The results indicated that the La1-xCexMnO3 nanoparticles with a size of ca. 15 nm were uniformly immobilized on the surface of ATP with a loading amount of 20wt%. The highest conversion rate of NO reached 98.6% when the doping fraction x was O.1, while the ATP support supplied a high surface areas facilitating the nanoparticles dispersion as well as the gas adsorption. Incorporation of an appropriate amount of Ce4＋ in the La3＋ site resulted in a high degree of reduction by the active perovskite species with enhanced catalytic activity.
