NiFe2O4/g-C3N4的制备及可见光催化降解甲基橙

采用浸渍法制备不同负载量NiFe2 O4的负载型光催化剂NiFe2 O4/g-C3 N4,利用XRD、FT-IR、N2-adsorption、ICP-OES、TEM及XPS等手段表征NiFe2 O4/g-C3 N4样品,并考察其对甲基橙的可见光催化降解性能.结果表明,与NiFe2 O4和g-C3 N4样品相比,负载型NiFe2 O4/g-C3 N4样品对甲基橙具有更好的光催化降解活性,且催化活性随着NiFe2 O4负载量增大(0.5~5.0wt;)而呈现先增大再减小的趋势.NiFe2 O4负载量2.0wt;的样品2-NiFe/CN在可见光照射下对浓度5 mg·L-1的甲基橙表现出最好的降解活性和稳定性.这是因为能带宽度小(1.5 eV)的NiFe2 O4与能带宽度大(2.7 eV)的g-C3 N4形成的异质结催化剂NiFe2 O4/g-C3 N4,有效地促进光生载流子在二者界面快速传递和光生电子-空穴对的有效分离.     

Mg-LDH Nanoclays Intercalated Fennel and Green Tea Active Ingredient: Field and Laboratory Evaluation of Insecticidal Activities against Culex pipiens and Their Non-Target Organisms

(1) Background: Mosquito control with essential oils is a growing demand. This work evaluated the novel larvicidal and adulticidal activity of fennel and green tea oils and their Layered double hydroxides (LDHs) nanohybrid against Culex pipiens (Cx. pipiens) in both laboratory and field conditions and evaluated their effect against non-target organisms; (2) Methods: Two types of nanoclays, MgAl-LDH and NiAl-LDH were synthesized and characterized using PXRD, TEM and SEM, whereas their elemental analysis was accomplished by SEM-EDX; (3) Results: Mg and Ni LDHs were synthesized by the co-precipitation method. The adsorption and desorption of active ingredients were conducted using LC MS/MS, with reference to the SEM-EXD analysis. The desorption process of MgAl-LDH intercalated green tea oil was conducted using ethanol, and reveled significant peaks related to polyphenols and flavonoids like Vanillin, Catechin, Daidzein, Ellagic acid, Naringenin, Myricetin and Syringic acid with concentrations of 0.76, 0.73, 0.67, 0.59, 0.52, 0.44 and 0.42 μg/g, respectively. The larvicidal LC₅₀ values of fennel oil, Mg-LDH-F, and Ni-LDH-F were 843.88, 451.95, 550.12 ppm, respectively, whereas the corresponding values of green tea were 938.93, 530.46, and 769.94 ppm. The larval reduction percentage of fennel oil and Mg-LDH-F reached 90.1 and 96.2%, 24 h PT and their persistence reached five and seven days PT, respectively. The reduction percentage of green tea oil and Mg-LDH-GT reached 88.00 and 92.01%, 24 h PT and their persistence reached five and six days PT, respectively. Against adults, Mg-LDH-GT and Ni-LDH-GT were less effective than green tea oil as their LC₉₅ values were 5.45, 25.90, and 35.39%, respectively. The reduction in adult density PT with fennel oil, Mg-LDH-F, green tea oil, and Mg-LDH-GT reached 83.1, 100, 77.0, and 99.0%, respectively, 24 h PT and were effective for three days. Mg-LDH-GT and Mg-LDH-F increased the predation Cybister tripunctatus (71% and 69%), respectively; (4) Conclusions: For the first time, Mg-LDH-GT and Mg-LDH-F was the best system loaded with relatively good desorption release to its active ingredients and significantly affected Cx. pipiens larvae and adults in both laboratory and field circumstances, and it could be included in mosquito control.     

运动对小白鼠乳酸脱氢酶(LDH)同工酶的影响初探

经总酶活性测定和凝胶电泳图谱分析发现:剧烈运动后,小白鼠六种组织LDH总酶活性,骨骼肌有显著升高,(p<0.05),其余五种组织均变化不显著;心肌、骨骼肌、肾脏的M型LDH相对活性显著升高(P<0.05),而H型LDH相对活性显著下降(p<0.05);相应地,A亚基比例显著升高,B亚基比例显著下降,这种变化似能反应剧烈运动对小白鼠厌氧代谢的明显影响.     

NiFe双金属催化剂用于月桂酸甲酯加氢的研究

负载型Ni Fe/γ-Al₂O₃双金属催化剂的物理化学性质明显受还原温度的影响,进而影响月桂酸甲酯的加氢活性和产物选择性。金属Ni活性中心主要促进脱羰/脱羧(DOC)反应,Fe的加入能促进月桂酸甲酯发生加氢脱氧反应,促进C₁₂烷烃化合物生成。H₂-TPR、XRD、H₂-TPD和BET结果表明,高的还原温度有利于金属或合金活性中心形成,NiFe双金属催化剂的加氢活性取决于金属Ni、Fe和NiFe合金的含量;NiFe双金属催化剂吸附与活化H₂分子的能力明显受还原温度的影响。在研究的温度范围内,Ni活性中心具有优异的加氢和裂解性能,Fe物种的引入能有效抑制裂解性能。双金属催化剂的加氢活性顺序:NF420>NF360>NF450>NF300,在420℃下经H₂还原制得的NF420催化剂具有最佳的月桂酸甲酯加氢性能,在反应温度为380℃时,月桂酸甲酯加氢转化率和烷烃化合物选择性分别高达93.3%和90.0%。     

不同压制压力下NiFe2O4纳米固体的ESR研究

 以反滴共沉定法制备了NiFe₂O₄纳米微粉，并在不同压力下将其压制成纳成米固体，然后用XRD谱和ESR谱研究了NiFe₂O₄纳米固体结构和界百状态随压制压力的变化。实验结果表明，NiFe₂O₄纳米固体的结构在高压下没有明显的变化，但其ESR谱的共振线宽和g因子值随着压力升高均表示出先逐渐增大至最大值，然手缓慢下降的规律。这种变化可以归因于纳米固体内部界面离子间的磁相互作用在压力的下所发生和变化。这引起实验结果境示，对于NiFe₂O₄纳米固体而言，最佳的成型压力是4.5 GPa，在此压力下，NiFe₂O₄纳米粒子既可以被压制成致密的纳米固体，又能够保留下它们的纳米结构和纳米性质。     

Ultrathin Mn Doped Ni-MOF Nanosheet Array for Highly Capacitive and Stable Asymmetric Supercapacitor

In this study, we demonstrate that an Mn-doped ultrathin Ni-MOF nanosheet array on nickel foam (Mn_0.1-Ni-MOF/NF) serves as a highly capacitive and stable supercapacitor positive electrode. The Mn_0.1-Ni-MOF/NF shows an areal capacity of 6.48 C cm⁻² (specific capacity C: 1178 C g⁻¹) at 2 mA cm⁻² in 6.0 m KOH, outperforming most reported MOF-based materials. More importantly, it possesses excellent cycle stability to maintain 80.6 % capacity after 5000 cycles. An asymmetric supercapacitor device utilizing Mn_0.1-Ni-MOF/NF as the positive electrode and activated carbon as the negative electrode attains a high energy density of 39.6 Wh kg⁻¹ at 143.8 Wkg⁻¹ power density with a capacitance retention of 83.6 % after 5000 cycles.     

Preparation and characterization of NiFe bimetallic micro-particles and its composite with silica shell

Magnetic NiFe particles were synthesized through hydrothermal method using hydrazine as reductant. Composite particles with core-shell structure were further achieved by depositing silicon dioxide generated via carbonation decomposition of sodium silicate solution on the surface of magnetic cores. Characterized by XRD, the Ni₉Fe particles are of fcc-type structure, and the structure of magnetic cores in composite particles was maintained despite being covered by SiO₂ shell. The existence of SiO₂ shells in the composite particles were demonstrated by SEM, EDS and IR. The results from TG and VSM indicated that the shell structure affected the physiochemical properties. The composite particles exhibited remarkable resistance to oxidation in comparison with Ni₉Fe particles due to being protected by SiO₂ shell. Meanwhile, both of them are soft magnetic materials, but Ms, Mr and Hc in Ni₉[email protected]₂ particle decreased compared with magnetic NiFe particles. The formation mechanisms of Ni₉Fe micro-particles and composite Ni₉Fe particles were discussed.     

复合磁性纳米NiFe2O4的制备及光谱特性

用微乳液化学剪裁方法制备了明胶包裹的复合纳米NiFe2 O4 。将明胶和亚铁盐以及镍盐制成凝胶 ,使该凝胶状反应物在微乳液的胶束中剪裁成微粒 ,再被还原 化合 成核长大。生成的微粒处于明胶蛋白分子的包裹之中。用XRD ,TEM ,EDS ,IR等测试表明 :微粒为明胶包裹球形纳米微粒。微球的平均粒径为 10～10 0nm ,单个微粒的粒径 3 3～ 4 6nm。每个复合微球中约有 3～ 2 2个NiFe2 O4 粒子。NiFe2 O4 复合微粉的比饱和磁化强度σs=36 31× 10 3 4π(A·m- 1 ·g- 1 ) ,矫顽力Hc=6 75 0A·m- 1 ,剩磁Br=4 39× 10 3 4π(A·m- 1 ·g- 1 )。     

层状复合金属氢氧化物-聚丙烯酸钠水分散体系的双絮凝现象及机理探讨

研究了聚丙烯酸钠(PAAS)对镁铝型层状复合金属氢氧化物(MgAl-LDH)的胶体水分散体系稳定性的影响. 利用总有机碳(TOC)分析技术测定了PAAS在LDH颗粒上的吸附量, 并利用ζ电位表征了LDH颗粒的电性质. 实验结果表明, 在质量分数为1%的LDH水分散体系中加入0.006~2.400 mmol/L PAAS, 随着PAAS浓度的增加, LDH-PAAS混合体系出现了絮凝-分散-再絮凝变化. 同时, 随着PAAS浓度的增加, PAAS在LDH颗粒上的吸附导致颗粒ζ电位由正减至0, 并进一步负向增加, 颗粒间静电斥力先减小后增加, 因此体系先絮凝再分散. 随着LDH颗粒负电性的进一步增强, 未吸附的PAAS引发颗粒间产生的空缺引力成为体系再次絮凝的主要原因. 对吸附PAAS的LDH颗粒的红外光谱分析表明, PAAS主要通过-COO-与LDH的相互作用而吸附在颗粒上.     

Oxidation ofn-butane and propene on exhydrotalcite Mg, Al, Fe mixed oxides

Oxidative dehydrogenation ofn-butane and propene has been studied on six Mg−Al−Fe oxide catalysts prepared by thermal decomposition of layered double hydroxides with a hydrotalcite-like structure, possessing Mg²⁺ and Al³⁺ ions in the brucite-like layers, and hexacyanoferrate in the interlayers. In all cases, CO₂ and H₂O are formed, together with minor amounts of ethylene and methane. On the solids prepared from hexacyanoferrate(II), formation of benzene is also observed.