The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(...The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(AR)as a precursor by regulating oil bath conditions,followed by one-step thermal decomposition to obtain carbon-coated iron-based composites.Modifying the precursor MIL-88C(Fe)preparation conditions,such as the molar ratio between metal ions and organic ligands(M/O),oil bath temperature,and oil bath time,influenced the phases,graphitization degree,and AR of the derivatives,enabling low filler loading,achieving well-matched impedance,and ensuring outstanding MA properties.The MOF-derivatives 2(MD_(2))/polyvinylidene Difluoride(PVDF),MD_(3)/PVDF,and MD4/PVDF absorbers all exhibited excellent MA properties with optimal filler loadings below 20 wt%and as low as 5 wt%.The MD_(2)/PVDF(5 wt%)achieved a maximum effective absorption bandwidth(EAB)of 5.52 GHz(1.90 mm).The MD_(3)/PVDF(10 wt%)possessed a minimum reflection loss(RL_(min))value of−67.4 at 12.56 GHz(2.13 mm).A symmetric gradient honeycomb structure(SGHS)was constructed utilizing the high-frequency structure simulator(HFSS)to further extend the EAB,achieving an EAB of 14.6 GHz and a RL_(min) of−59.0 dB.This research offers a viable inspiration to creating structures or materials with high-efficiency MA properties.展开更多
MIL-88A(Fe)@sponge(MS) was synthesized by a dip-coating method, which displayed efficient photocatalytic Cr(Ⅵ) reduction efficiency under both low power LED UV light and real solar light irradiation. It was observed ...MIL-88A(Fe)@sponge(MS) was synthesized by a dip-coating method, which displayed efficient photocatalytic Cr(Ⅵ) reduction efficiency under both low power LED UV light and real solar light irradiation. It was observed that MS(0.2 g/L) could remove 100% Cr(Ⅵ)(10 mg/L) by adding 0.4 mmol/L tartaric acid(TA) without adjusting pH(pH 5.05) within 6.0 min and 3.0 min under UV light and real solar light irradiation, respectively. Besides, the photo-induced e-and radicals(O_(2)^(·-) and CO_(2)^(·-)) were found to play the momentous roles in the MS/TA/UVL/Cr(Ⅵ) system by the scavenger experiments and electron spin resonance(ESR) tests. MS was also filled into a fixed-bed reactor to test the possibility of long-term Cr(Ⅵ)reduction operation in TA/UVL system. As expected, the results revealed that MS could still maintain 100% activity up to 60 h. These results demonstrated that MIL-88A(Fe) might be the potentially efficient catalyst for large-scale wastewater treatment in the near future.展开更多
以静电纺丝技术为基础,组装含有金属有机框架MIL-88的氮掺杂复合纳米纤维。经过高温退火制备氮掺杂的含有Fe3C的碳纳米纤维(N-Fe3C-CNFs)。通过SEM、TEM、XRD、XPS对该材料的微观形态结构进行表征,并以此材料作为锂离子电池的负极材料...以静电纺丝技术为基础,组装含有金属有机框架MIL-88的氮掺杂复合纳米纤维。经过高温退火制备氮掺杂的含有Fe3C的碳纳米纤维(N-Fe3C-CNFs)。通过SEM、TEM、XRD、XPS对该材料的微观形态结构进行表征,并以此材料作为锂离子电池的负极材料对电池的循环性能、倍率性能、CV以及阻抗(EIS)等电化学性能进行研究。结果表明,当电流密度为1 A/g时,此材料循环200圈后仍具有756. 6 m Ah/g的可逆比容量。展开更多
基金financially supported by the National Natural Science Foundation of China(51972049,52073010,and 52373259)the Projects of the Science and Technology Department of Jilin Province(20230201132GX)the Projects of the Education Department of Jilin Province(JJKH20220123KJ)。
文摘The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(AR)as a precursor by regulating oil bath conditions,followed by one-step thermal decomposition to obtain carbon-coated iron-based composites.Modifying the precursor MIL-88C(Fe)preparation conditions,such as the molar ratio between metal ions and organic ligands(M/O),oil bath temperature,and oil bath time,influenced the phases,graphitization degree,and AR of the derivatives,enabling low filler loading,achieving well-matched impedance,and ensuring outstanding MA properties.The MOF-derivatives 2(MD_(2))/polyvinylidene Difluoride(PVDF),MD_(3)/PVDF,and MD4/PVDF absorbers all exhibited excellent MA properties with optimal filler loadings below 20 wt%and as low as 5 wt%.The MD_(2)/PVDF(5 wt%)achieved a maximum effective absorption bandwidth(EAB)of 5.52 GHz(1.90 mm).The MD_(3)/PVDF(10 wt%)possessed a minimum reflection loss(RL_(min))value of−67.4 at 12.56 GHz(2.13 mm).A symmetric gradient honeycomb structure(SGHS)was constructed utilizing the high-frequency structure simulator(HFSS)to further extend the EAB,achieving an EAB of 14.6 GHz and a RL_(min) of−59.0 dB.This research offers a viable inspiration to creating structures or materials with high-efficiency MA properties.
基金supported by National Natural Science Foundation of China (Nos. 22176012, 51878023)Beijing Natural Science Foundation (No. 8202016)+1 种基金Beijing Talent Project (No. 2020A27)BUCEA Doctor Graduate Scientific Research Ability Improvement Project (No. DG2021004)。
文摘MIL-88A(Fe)@sponge(MS) was synthesized by a dip-coating method, which displayed efficient photocatalytic Cr(Ⅵ) reduction efficiency under both low power LED UV light and real solar light irradiation. It was observed that MS(0.2 g/L) could remove 100% Cr(Ⅵ)(10 mg/L) by adding 0.4 mmol/L tartaric acid(TA) without adjusting pH(pH 5.05) within 6.0 min and 3.0 min under UV light and real solar light irradiation, respectively. Besides, the photo-induced e-and radicals(O_(2)^(·-) and CO_(2)^(·-)) were found to play the momentous roles in the MS/TA/UVL/Cr(Ⅵ) system by the scavenger experiments and electron spin resonance(ESR) tests. MS was also filled into a fixed-bed reactor to test the possibility of long-term Cr(Ⅵ)reduction operation in TA/UVL system. As expected, the results revealed that MS could still maintain 100% activity up to 60 h. These results demonstrated that MIL-88A(Fe) might be the potentially efficient catalyst for large-scale wastewater treatment in the near future.
文摘以静电纺丝技术为基础,组装含有金属有机框架MIL-88的氮掺杂复合纳米纤维。经过高温退火制备氮掺杂的含有Fe3C的碳纳米纤维(N-Fe3C-CNFs)。通过SEM、TEM、XRD、XPS对该材料的微观形态结构进行表征,并以此材料作为锂离子电池的负极材料对电池的循环性能、倍率性能、CV以及阻抗(EIS)等电化学性能进行研究。结果表明,当电流密度为1 A/g时,此材料循环200圈后仍具有756. 6 m Ah/g的可逆比容量。
