采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨...采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨道(LUMO)分析,计算了吸附构型的吸附能和最稳定吸附构型的Mulliken电荷转移与电子密度。结果表明:在15 mL模拟柴油中加入0.6 g Co_(3)O_(4),苯胺、吡啶、喹啉的最佳吸附温度分别为20、20和30℃,最佳吸附时间分别为30、30、40 min,吸附容量由大到小顺序均为苯胺>吡啶>喹啉。热力学与动力学分析表明,喹啉、吡啶、苯胺的吸附均更符合多分子层吸附的Freundlich模型和准二级动力学方程。HOMO-LUMO分析结果表明,Co_(3)O_(4)为电子接受体,3种氮化物为电子给予体,Co_(3)O_(4)对喹啉、吡啶的配位吸附结构最稳定,对苯胺的π络合吸附最稳定。电荷转移计算表明,苯胺、吡啶、喹啉向Co_(3)O_(4)团簇转移的电荷数分别为0.423、0.394、0.368,说明Co_(3)O_(4)吸附3种氮化物的吸附能力大小为苯胺>吡啶>喹啉;电子密度图结果表明,最稳定吸附结构中Co_(3)O_(4)与3种氮化物均形成了化学键。展开更多
Large-scale CO_(2)emissions have exacerbated the greenhouse effect,reinforcing the critical need for efficient CO_(2)mitigation methods.Plasma-catalytic technology enables CO_(2)conversion under mild conditions,especi...Large-scale CO_(2)emissions have exacerbated the greenhouse effect,reinforcing the critical need for efficient CO_(2)mitigation methods.Plasma-catalytic technology enables CO_(2)conversion under mild conditions,especially for CO_(2)methanation(the Sabatier reaction),which has attracted significant attention due to its economic benefits and the potential for safe energy transportation via existing natural gas pipelines.The development of high-performance CO_(2)methanation catalysts remains an ongoing and long-term objective,and there is a lack of adequate in-situ characterization techniques to investigate the mechanisms.This study focuses on the Ni/La_(2)O_(3)(LN)catalyst and introduces two CO_(2)activation strategies through F and Na modifications:the Ni-Ov-Ni site activation with electron transfer from Ni0 under low-power conditions and basic site activation under high-power conditions.The LN-NaF catalysts enhance CO_(2)methanation activity across the entire power range compared to LN,achieving a CO_(2)conversion of 86.3%and CH4 selectivity of 99.4%.Additionally,LN-F(h)reaches a CH4 yield 4.15 times higher than that of LN at low power.Furthermore,in-situ diffuse reflectance infrared Fourier transform(DRIFT)spectroscopy with a self-made reactor are performed under plasma-catalytic conditions to reveal the CO_(2)adsorption and conversion mechanisms,indicating that different dopants(F,Na,and NaF)exhibit promoting effects on different intermediates,resulting in variations in CO_(2)methanation activity.This study provides valuable insights for improving catalyst performance and a thorough comprehension of mechanisms in CO_(2)methanation.展开更多
With growing concerns regarding electromagnetic pollution,low-cost,environmentally friendly,and high-performance electromagnetic wave absorption(EWA)materials have attracted significant attention.This paper reports on...With growing concerns regarding electromagnetic pollution,low-cost,environmentally friendly,and high-performance electromagnetic wave absorption(EWA)materials have attracted significant attention.This paper reports on the synthesis of porous Fe_(3)O_(4)/C composites that incorporate dielectric and magnetic loss mechanisms via the carbothermal reduction method and optimization of waste ratio to enhance EWA performance.The Fe_(3)O_(4)/C composites with 10wt%soybean residues(Fe_(3)O_(4)/C-10),demonstrated the best EWA performance,achieving the minimum reflection loss of−56.4 dB and a bandwidth of 2.14 GHz at a thickness of 2.23 mm.This enhanced EWA performance is primarily attributable to improved impedance matching and the synergistic effect between dielectric and magnetic losses.Furthermore,radar cross-sectional simulations confirmed the practical feasibility of the porous Fe_(3)O_(4)/C composites.This study proposes a viable strategy for utilizing soybean residue and electrolytic manganese residue,highlighting their potential applications in EWA.展开更多
文摘采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨道(LUMO)分析,计算了吸附构型的吸附能和最稳定吸附构型的Mulliken电荷转移与电子密度。结果表明:在15 mL模拟柴油中加入0.6 g Co_(3)O_(4),苯胺、吡啶、喹啉的最佳吸附温度分别为20、20和30℃,最佳吸附时间分别为30、30、40 min,吸附容量由大到小顺序均为苯胺>吡啶>喹啉。热力学与动力学分析表明,喹啉、吡啶、苯胺的吸附均更符合多分子层吸附的Freundlich模型和准二级动力学方程。HOMO-LUMO分析结果表明,Co_(3)O_(4)为电子接受体,3种氮化物为电子给予体,Co_(3)O_(4)对喹啉、吡啶的配位吸附结构最稳定,对苯胺的π络合吸附最稳定。电荷转移计算表明,苯胺、吡啶、喹啉向Co_(3)O_(4)团簇转移的电荷数分别为0.423、0.394、0.368,说明Co_(3)O_(4)吸附3种氮化物的吸附能力大小为苯胺>吡啶>喹啉;电子密度图结果表明,最稳定吸附结构中Co_(3)O_(4)与3种氮化物均形成了化学键。
文摘水热法在FTO导电玻璃表面制备了Co_(3)O_(4)掺杂不同摩尔比例石墨烯的Co_(3)O_(4)/G(Graphene)薄膜,筛选出掺杂石墨烯比例最合适的Co_(3)O_(4)/G薄膜样品作为基底,使用旋涂法将Bi VO_(4)旋涂在其表面,成功制备出了(Co_(3)O_(4)/G)@BiVO_(4)复合薄膜结构的光电探测器。利用电化学工作站(CHI760E型)和氙灯(CEL-S500型)模拟太阳光对样品进行光电性能测试,利用拉曼光谱来检测石墨烯的存在,使用场发射扫描电子显微镜和透射电子显微镜对样品的微观形貌结构进行分析,使用X射线衍射和X射线光电子能谱对样品进行物相以及化学键态的分析,并采用了UV-3600紫外-可见分光光度计对样品的光吸收性能进行了测试。结果显示:Co_(3)O_(4)与石墨烯掺杂比例为1∶2时,Co_(3)O_(4)/G薄膜光电流最优,是纯Co_(3)O_(4)薄膜光电流的10.8倍;相对于纯Co_(3)O_(4)薄膜,(Co_(3)O_(4)/G)薄膜的形貌从均匀、致密的草状生长为了类似石墨烯的网状结构;利用旋涂法制备的(Co_(3)O_(4)/G)@Bi VO_(4)复合薄膜具有更高的光电流和光吸收能力,其光电流为Co_(3)O_(4)/G薄膜的6.3倍,响应度为2.52 m A·W^(-1),探测率可达2.693×10^(12)Jones。
基金supported by the National Natural Science Foundation of China(No.51878292).
文摘Large-scale CO_(2)emissions have exacerbated the greenhouse effect,reinforcing the critical need for efficient CO_(2)mitigation methods.Plasma-catalytic technology enables CO_(2)conversion under mild conditions,especially for CO_(2)methanation(the Sabatier reaction),which has attracted significant attention due to its economic benefits and the potential for safe energy transportation via existing natural gas pipelines.The development of high-performance CO_(2)methanation catalysts remains an ongoing and long-term objective,and there is a lack of adequate in-situ characterization techniques to investigate the mechanisms.This study focuses on the Ni/La_(2)O_(3)(LN)catalyst and introduces two CO_(2)activation strategies through F and Na modifications:the Ni-Ov-Ni site activation with electron transfer from Ni0 under low-power conditions and basic site activation under high-power conditions.The LN-NaF catalysts enhance CO_(2)methanation activity across the entire power range compared to LN,achieving a CO_(2)conversion of 86.3%and CH4 selectivity of 99.4%.Additionally,LN-F(h)reaches a CH4 yield 4.15 times higher than that of LN at low power.Furthermore,in-situ diffuse reflectance infrared Fourier transform(DRIFT)spectroscopy with a self-made reactor are performed under plasma-catalytic conditions to reveal the CO_(2)adsorption and conversion mechanisms,indicating that different dopants(F,Na,and NaF)exhibit promoting effects on different intermediates,resulting in variations in CO_(2)methanation activity.This study provides valuable insights for improving catalyst performance and a thorough comprehension of mechanisms in CO_(2)methanation.
基金supported by the National Natural Science Foundation of China(No.52471221)the Natural Science Foundation of Hunan Province,China(No.2024JJ7145)the National Sustainable Development Agenda Innovation Demonstration Zone Hunan special project,China(No.2022sfq09).
文摘With growing concerns regarding electromagnetic pollution,low-cost,environmentally friendly,and high-performance electromagnetic wave absorption(EWA)materials have attracted significant attention.This paper reports on the synthesis of porous Fe_(3)O_(4)/C composites that incorporate dielectric and magnetic loss mechanisms via the carbothermal reduction method and optimization of waste ratio to enhance EWA performance.The Fe_(3)O_(4)/C composites with 10wt%soybean residues(Fe_(3)O_(4)/C-10),demonstrated the best EWA performance,achieving the minimum reflection loss of−56.4 dB and a bandwidth of 2.14 GHz at a thickness of 2.23 mm.This enhanced EWA performance is primarily attributable to improved impedance matching and the synergistic effect between dielectric and magnetic losses.Furthermore,radar cross-sectional simulations confirmed the practical feasibility of the porous Fe_(3)O_(4)/C composites.This study proposes a viable strategy for utilizing soybean residue and electrolytic manganese residue,highlighting their potential applications in EWA.
