芳酰基硒脲合成及其对O~2清除作用的EPR研究

芳酰基硒脲的合成试剂芳酰基异硒氰酸脂是极不稳定的化合物。通过硒氰化铅在非极性溶剂苯中同芳酰氯反应能简便、稳定和可靠地合成芳酰基异硒氰酸脂、从而与芳胺反应能合成一系列芳酰基硒脲。经EFR 研究其对超氧阴离子自由基O~2具有明显的清除作用。     

Synergistic Effect of Ta_2O_5/F-C Composites for Effective Electrosynthesis of Hydrogen Peroxide from O_2 Reduction

The electrosynthesis of H₂O₂as an environmentally friendly green process has attracted great attention due to the importance of H₂O₂in industry and human lives.In this work,a new strategy was proposed to improve the electrical conductivity and H₂O₂selectivity of transition metal oxides catalysts.F-C(F doped carbon)was coupled with Ta₂O₅by calcining polyvinylidene fluoride(PVDF)as the carbon source using one step method.The Ta₂O₅/F-C composite catalysts show an excellent H₂O₂selectivity of more than 80%as well as high reactivity at 2.52 mA/cm²,which is greatly enhanced compared to the counterparts of F-C(selectivity of 59%)and Ta₂O₅-800(current density of 0.85 mA/cm²)in 0.1 M KOH solution.The onset potential for H₂O₂production on Ta₂O₅/F-C composites is 0.78 V in 0.1 M KOH,which indicates a negligible overpotential.In addition,H₂O₂selectivity of the catalyst can be stabilized at more than 80%after 10 hours of electrolysis in alkaline electrolyte.The high performance due to the introduction of F-C increases the conductivity of Ta₂O₅and the synergistic effect between F-C and Ta₂O₅.This work proposed an efficient synergistic effect among F-doped C and Ta₂O₅for H₂O₂production.     

聚(2-甲氧基-5-丁氧基)对苯乙炔/Eu2O3纳米复合材料的合成及其光学效应

采用原位脱氯化氢缩合聚合法制备了聚(2-甲氧基-5-丁氧基)对苯乙炔/氧化铕(PMOBOPV/Eu2O3)纳米复合材料. 傅里叶变换红外(FT-IR)光谱证实了在Eu2O3表面的包覆层为PMOBOPV. 高分辨透射电子显微镜(HRTEM)观察发现, PMOBOPV/Eu2O3纳米复合材料具有核-壳结构, 直径为75-145 nm, 其中PMOBOPV包覆层厚度约为25 nm. 紫外-可见(UV-Vis)吸收光谱表明, 随着Eu2O3含量增加, PMOBOPV/Eu2O3的最大吸收峰发生红移且强度提高. 荧光光谱研究表明, 随着Eu2O3含量增加, PMOBOPV/Eu2O3的最大发射波长发生蓝移且强度提高, Eu2O3与PMOBOPV之间形成了光致电子转移体系, 使π电子离域程度增加, 并且导致荧光量子效率提高. 根据光学禁带宽度(Eg)与入射光子能量(hυ)的关系, 拟合了PMOBOPV/Eu2O3薄膜的光学禁带宽度, 发现随着Eu2O3含量增加, Eg逐步减小. 采用简并四波混频方法测试它们的三阶非线性极化率(χ(3)), 发现随着Eu2O3含量增加, PMOBOPV/Eu2O3纳米复合体的非线性光学响应逐渐增强, 这说明PMOBOPV与Eu2O3之间形成了分子间光致电子转移体系, 产生了复杂的分子间离域π电子非线性运动.     

Insights into the H_2O/V_2O_5 Interface Structure for Optimizing Water-splitting

The interaction of water(H2O) with metal oxide surfaces is of fundamental importance to various fields of science, ranging from batteries to catalysis. In particular, vanadium pentoxide(V2O5) has been widely used as electrode materials for aqueous-battery and catalysts. Herein, theoretical(density functional theory) study gives atomic-scale insights into water monolayers in V2O5 and single-molecule adsorption and dissociation at three low-index surfaces and oxygen-vacancy V2O5(001) surface. The H2O/V2O5 interface structure was identified. The results show that H2O is adsorbed on the stoichiometric V2O5(001) surface with physisorption mechanism, and the dissociation hardly occurs. Water adsorbs as an intact monomer with a computed binding energy of 0.75 eV. The formation of ordered water overlayers has been observed on V2O5(001) surface, suggesting a locally ordered superstructure of molecular water. The molecular H2O adsorption on oxygen-vacancy V2O5(001) surface is stronger than that on the stoichiometric V2O5(001) surface, and H2O can undergo dissociative chemisorption to form a surface hydroxyl group and a H adatom. V2O5 can take the oxygen from H2O, which is consistent with the experimental results.     

BaO-B2O3-GeO2(BaO≤50 mo1％)三元系相图的研究

本文用X射线衍射及差热分析等方法, 研究了BaO-B_2O_3-GeO_2(BaO≤50 mol％)三元系的室温截面相图。发现了一个新的三元化合物Ba_3B_6Ge_2O_(16)(3BaO·3B_2O_3·2GeO_2)。并且研究了BaB_2O_4-Ba_3B_6Ge_2O_(16), BaGeO_3-Ba_3B_6Ge_2O_(16), BaB_2O_4-BaGeO_3三个二元系相图。它们都是共晶体系, 共晶温度分别为937±3 ℃、879±3 ℃875±3 ℃; 共晶组分分别为(BaO)_(0.42)(B_2O_3)_(0.42)(GeO_2)_(0.16), (BaO)_(0.42)(B_2O_3)_(0.24)(GeO_2)_(0.34), (BaO)_(0.50)(B_2O_3)_(0.27)(GeO_2)_(0.23)。这三个二元系组成一个三元共晶体系, 其三元共晶温度为870±3 ℃, 共晶组分为(BaO)_(0.46)(B_2O_3)_(0.27)(GeO_2)_(0.27)。     

Ce1-xNixO2/Al2O3/FeCrAl催化剂的制备及其甲烷催化燃烧性能

以FeCrA l合金薄片为基体,A l2O3为过渡载体,Ce1-xN ixO2(x=0.1-0.3)、CeO2和N iO为活性组分,制备了Ce1-xN ixO2/A l2O3/FeCrA l、CeO2/A l2O3/FeCrA l和N iO/A l2O3/FeCrA l金属基整体式催化剂,在固定床微型反应器中评价了催化剂的甲烷催化燃烧性能,用SEM、XRD、TPR等方法对催化剂的物相、表面形貌和氧化还原性进行了表征.结果表明,Ce1-xN ixO2在催化剂表面的分散性比CeO2和N iO要好;Ce1-xN ixO2/A l2O3/FeCrA l(x=0.1-0.3)催化剂具有好的催化活性和高温稳定性,CeO2/A l2O3/FeCrA l和N iO/A l2O3/FeCrA l催化剂有好的初活性但高温稳定性较差;活性组分与A l2O3和FeCrA l金属基体之间存在较强的相互作用.     

纳米Sb_2O_3表面原位(共)聚合处理对HIPS纳米复合材料力学性能的影响

通用高分子材料的工程化和工程高分子材料的高性能化是高分子材料研究与开发的主要方向之一，核心、关键技术是高分子材料的同时增强、增韧，其中利用纳米无机刚性粒子与高分子材料复合是一条最简单而又行之有效的途径．由于无机纳米填料是亲水性的、表面能极高，有机高分子不能浸润填料或与填料表面相互作用弱，导致纳米粒子在高分子基体中易于团聚而分散性差，其复合材料力学性能低下．利用硬酯酸、非离子表面活性剂、表面辐照接枝处理纳米粒子表面忙，     

Confining Li_2O_2 in tortuous pores of mesoporous cathodes to facilitate low charge overpotentials for Li-O_2 batteries

Achieving low charge overpotentials represents one of the most critical challenges for pursuing highperformance lithium-oxygen(Li-O₂)batteries.Herein,we propose a strategy to realize low charge overpotentials by confining the growth of lithium peroxide(Li₂O₂)inside mesoporous channels of cathodes(CMK-8).The CMK-8 cathode with tortuous pore structures can extend the diffusion distance of lithium superoxide(LiO₂)in the mesoporous channels,facilitating the further reduction of LiO₂ to lithium peroxide(Li₂O₂)inside the pores and preventing them to be diffused out of the pores.Therefore,Li₂O₂ is trapped in the mesoporous channels of CMK-8 cathodes,ensuring a good Li₂O₂/CMK-8 contact interface.The CMK-8 electrode exhibits a low charge overpotential of 0.43 V and a good cycle life for 72 cycles with a fixed capacity of 500 m Ah g^-1 at 0.1 A g^-1.This study proposes a strategy to achieve a low charge overpotential by confining Li₂O₂ growth in the mesoporous channels of cathodes.     

Sm2O3改性对S2O2-8/ZrO2-SiO2固体超强酸催化剂性能的影响

硫酸促进型固体超强酸催化剂具有极强的酸性,制备简单,在酯化、烷基化、酰基化等有机反应中催化活性高,可重复使用,对设备腐蚀小,环境友好,是一类具有广阔应用前景的新型绿色催化材料,已成为固体超强酸研究的热点之一。然而,目前该类催化剂使用成本高、比表面小、含硫基团容易流失、稳定性差,阻碍了其在工业上的推广和应用。为了探索和改善其催化性能,近年来多组分氧化物的固体超强酸开始引起人们的关注。     

MoO3/TiO2-Al2O3催化剂表面结构的LRS研究

负载型Mo和Co-Mo催化剂由于工业上的广泛应用,多年来一直是催化工作者的重要研究课题.工业上应用的Mo和Co-Mo催化剂多以活性Al_2O_3和SiO_2-Al_2O_3为载体,近年来也有用TiO_2,ZrO_2和活性碳作为催化剂载体的研究报导.有关催化剂活性组分与载体之间相互作用对催化剂表面相结构和催化性能的影响方面研究已引起人们的重视。我们多年来在金属-载体相互作用研究基础上,以石油加氢精制催化剂为应用背景,开     

2MgO·2B_2O_3·MgCl_2·14H_2O-H_3BO_3-H_2O体系30℃相平衡

用相平衡方法研究了2MgO·2B_2O_3·MgCl_2·14H_2O-H_3BO_3-H_2O在30 ℃ 不同浓度H_3BO_3水溶液中的溶解转化产物及其溶解度。结果表明，氯柱硼镁石的 溶解转化产物，在H_3BO_3质量分数≤2.50%时为多水硼镁石；在2.50% ～ 5. 00%H_3BO_3范围时为库水硼镁石；当H_3BO_3量在5.00% ～ 5.60%之间时为章氏硼 镁石；而当H_3BO_3量≥5.60%时为三方硼镁石。提出了溶解相转化机理。     

Reduced Graphene Oxide Coupled Magnetic CuFe_2O_4-TiO_2 Nanoparticles with Enhanced Photocatalytic Activity for Methylene Blue Degradation

CuFe_2O_4-TiO_2/graphene nanocomposites have been prepared via a one-step hydrothermal method,and the as-prepared CuFe_2O_4-TiO_2/graphene was characterized by X-ray powder diffraction,Raman spectroscopy,scanning electron microscopy and transmission electron microscopy.The transmission electron microscopy demonstrated that CuFe_2O_4-TiO_2 nanoparticles were successfully dispersed on the graphene sheets.Photocatalytic activity of nanocomposites was evaluated in terms of degradation of methylene blue(MB) dye solution under visible light radiation.Results showed that the photocatalytic efficiency of CuFe_2O_4-TiO_2/graphene nanocomposites was higher than its individual pure oxides(CuFe_2O_4 or TiO_2) and TiO_2/graphene.The enhancing photocatalytic activity performance of the CuFe_2O_4-TiO_2/graphene nanocomposites may attributed to the mutual effect between the Cu Fe_2O_4,Ti O_2 nanoparticles and the graphene sheets.Moreover,Cu Fe_2O_4 nanoparticles have excellent magnetic property,which makes the CuFe_2O_4-TiO_2/graphene heteroarchitecture magnetically recyclable in a suspension system.     

A Mixed Metal Phosphate Containing Two Types of Phosphoric Anionic Groups: Cs_2Ga_4(P_2O_7)_2(P_4O_(13))

A new mixed metal phosphate of Cs2Ga4P8O(27), which also can be written as Cs2Ga4(P2O7)2(P4O(13)), was synthesized by high temperature solid state syntheses and structurally characterized by X-ray single-crystal diffraction for the first time. The title compound crystallizes in monoclinic system with space group P21/c(No.14), and features a 3D framework which can be considered as alternating layers of {Ga2(P4O(13))}n and {Ga2(P2O7)2}n^2n- parallel to the bc plane further connected by Ga-O-P linkages, where Cs^+ cations are located in the free space between two adjacent layers to charge the valence. The Ga³⁺ cations in the compound contain two kinds of coordination models(4 and 6). Furthermore, the title compound coexists of two phospho-ric anionic groups which are non-condensed horseshoe-shaped(P4O(13)) and two(P2O7) with different symmetries. The density functional theory calculations indicate that Cs2Ga4P8O(27) is a direct band gap insulator with flat valence and dispersive conduction bands and a band gap of 4.13 eV.     

H2S对NiW/Al2O3和CoMo/Al2O3上二苯并噻吩和4,6-二甲基二苯并噻吩加氢脱硫反应的影响

 考察了H2S对NiW/Al2O3和CoMo/Al2O3上二苯并噻吩(DBT)和4,6-二甲基二苯并噻吩(DMDBT)加氢脱硫反应的影响. 结果表明,H2S同时抑制DBT和DMDBT两种硫化物的加氢脱硫反应,并且对DBT的抑制作用更为明显. 对于NiW/Al2O3和CoMo/Al2O3两种催化剂,H2S抑制了DBT和DMDBT的直接脱硫路径活性; 对于CoMo/Al2O3催化剂上DBT转化中的加氢反应也有抑制作用,但促进了DMDBT转化中加氢反应的进行. NiW/Al2O3催化剂更易受H2S的影响.     

低镍甲烷化催化剂中镍和氧化镧的分散研究

本文用X射线衍射法(XRD), 透射电镜(TEM), 配合电子衍射对Ni/Al2O3,Ni/γ-Al_2O_3-La_2O_3等催化剂中镍晶粒度和La_2O_3的分散状态进行了测量和讨论。用透射电镜测量了不同La_2O_3含量的催化剂中镍晶粒度分布, 其平均直径可与X射线宽化法测定值相比较。催化剂中随La_2O_3加入量的增加, Ni晶粒有细化趋势, 从而提高了甲烷化催化活性。对La_2O_3在γ-Al_2O_3表面作密置单层分散的模型提出了新的旁证, 并推断由于La_2O_3在γ-Al_2O_3表面高分散并产生较强相互作用, 使γ-Al_2O_3接近表层晶格发生畸变。     

Integrated Ni_2P nanosheet arrays on three-dimensional Ni foam for highly efficient water reduction and oxidation

The large-scale synthesis of efficient nonprecious bifunctional electrocatalysts for overall water splitting is a great challenge for future renewable energy conversion systems. Herein, Ni_2P nanosheet arrays directly grown on three-dimensional(3 D) Ni foam(Ni P/NF) are fabricated by hydrothermal treatment of metallic Ni foam with H_2O_2 solution and subsequent phosphidation with NaH_2PO_2. The Ni P/NF as electrocatalyst exhibits superior activities for both hydrogen evolution reaction(HER) and oxygen evolution reaction(OER). Most importantly, employing both as the cathode and anode for an alkaline water electrolyzer, Ni P/NF only requires a cell voltage of 1.63 V to reach a current density of 10 mV cm~(-2), together with stronger durability. Preliminary catalytic information suggests that the tailored 3 D superstructure and integrated electrode configurations afford improved active sties and enhanced electron/mass transfer,responding for the outstanding activity and stability.     

3D porous V_2O_5 architectures for high-rate lithium storage

The discovery of novel electrode materials promises to unleash a number of technological advances in lithium-ion batteries. V_2O_5 is recognized as a high-performance cathode that capitalizes on the rich redox chemistry of vanadium to store lithium. To unlock the full potential of V_2O_5, nanotechnology solution and rational electrode design are used to imbue V_2O_5 with high energy and power density by addressing some of their intrinsic disadvantages in macroscopic crystal form. Here, we demonstrate a facile and environmental-friendly method to prepare nanorods-constructed 3D porous V_2O_5 architectures(3 D-V_2O_5)in large-scale. The 3D porous architecture is found to be responsible for the enhanced charge transfer kinetics and Li-ion diffusion rate of the 3D-V_2O_5 electrode. As the result, the 3D-V_2O_5 surpasses the conventional bulk V_2O_5 by showing enhanced discharge capacity and rate capability(delivering 154 and127 m Ah g~(-1) at 15 and 20 C, respectively).     

Electrochemical Study of Trinuclear Metal Complexes ［M_3O_2（O_2CCH_3）_6（H_2O）_3］~（2＋）（M_3＝Mo_3，MoW_2，W_3）

ＥｌｅｃｔｒｏｃｈｅｍｉｃａｌＳｔｕｄｙｏｆＴｒｉｎｕｃｌｅａｒＭｅｔａｌＣｏｍｐｌｅｘｅｓ［Ｍ_３Ｏ_２（Ｏ_２ＣＣＨ_３）_６（Ｈ_２Ｏ）_３］~（２＋）（Ｍ_３＝Ｍｏ_３，ＭｏＷ_２，Ｗ_３）ＬｉｕＨｕａｎｇ；ＸｕＬｉ；ＨｕａｎｇＪｉｎ－Ｓｈｕｎ；ＹａｎＤ...     

固体强酸催化剂S_2O_8~(2-)/ZrO_2-Al_2O_3-M_2O_3(M=Cr,Ce,La)的制备

固体强酸具有酸强度高 ,不腐蚀设备 ,不污染环境 ,与产物分离方便等特点 ,是一种对环境友好的催化剂。业已发现固体强酸对许多重要的有机反应如烃类异构化、傅克酰基化、傅克烷基化、酯化、缩合、聚合、氧化等具有良好的催化活性 ,可替代传统的浓 H2 SO4 及 Al Cl3、HF等高污染催化剂。在前文 [1]基础上 ,本文通过添加 Cr2 O3、Ce2 O3和 La2 O3对催化剂 S2 O2 - 8/Zr O2 - Al2 O3改进后制备出 S2 O2 - 8/Zr O2 -Al2 O3- M2 O3( M=Cr,Ce,La)系列固体强酸催化剂 ,用对乙酸和正丁醇的酯化转化率评价了催化活性 ,用 XRD、BET、流…     

不同晶型Bi2O3可见光光催化降解罗丹明B的研究

采用化学沉淀法制备了α、β、γ 3种晶体结构的Bi₂O₃光催化剂。利用XRD、TEM、氮气吸附、TG-DSC、紫外-可见漫反射光谱对样品的晶体结构、微观形貌、光学吸收特性进行了表征,并以罗丹明B(RhB)作为模型污染物,研究了不同的粉体光催化剂在可见光(λ>420 nm)照射下的光催化能力。结果表明：制备的α-Bi₂O₃为长3 μm、宽1 μm的板条状颗粒,带隙为2.84 eV;β-Bi₂O₃为粒径约150 nm的不规则颗粒,带隙为2.75 eV;γ-Bi₂O₃为直径6 nm、长度150~200 nm的纳米管,带隙为2.68 eV。在可见光照射下Bi₂O₃光催化降解RhB的活性如下：γ-Bi₂O₃>β-Bi₂O₃>α-Bi₂O₃,其中γ-Bi₂O₃在辐照60 min后对罗丹明B的脱色率可达97%以上。