基于半导体氧化物的环保型直接制版印刷版材的研究

免处理激光直接制版材料足数字化制版材料发展的重要趋势.本文利用低温水热法制备具有微纳米复合结构的氧化物半导体薄膜,研究其光致浸润性的改变,并将微纳米复合结构氧化物半导体具有光致浸润性变化这一特性,作为一种新型的具有环保特性的激光直接制版材料,巧妙地应用于印刷制版材料领域中,并探索其循环使用的可能性,为一种新型的可擦除免处理印刷材料的应用做出了有益的探索.     

电解质GDC复合碳酸盐的电化学性能研究

文章在固体氧化物燃料电池的电解质(GDC)材料中分别复合10%、20%、30%质量分数的BaCO_(3)和SrCO_(3),其中BaCO_(3)和SrCO_(3)的摩尔比例为53 mol%∶47 mol%,得到掺杂碳酸盐后的复合电解质材料,并对得到的复合电解质材料进行电导率测试和微观结构(扫描电子显微镜SEM)测试,以此复合材料为电解质,用干压法制备阳极支撑的单电池,旨在测试单电池的输出性能。     

钛掺杂的α-Fe2O3-K2O系纳米湿敏陶瓷的复阻抗谱

采用硬脂酸凝胶法这种化学新工艺制备了α Fe2 O3 TiO2 K2 O复合氧化物纳米湿敏陶瓷元件 ;研究了该元件在不同湿度下的复阻抗谱 ,并建立相应的模拟等效电路 ;材料晶粒电阻、晶界电阻等特征参数计算结果表明 ,晶粒电阻基本不随湿度变化 ,晶界电阻随湿度升高而降低 .从晶界电阻角度探讨了本系材料的湿敏导电机制 ,低湿阶段导电载流子为电子和自由H ,自由H 以氢桥键过渡态机制迁移 ,中、高湿阶段导电载流子以H3O 为主 .     

碳纳米管/铁氧化物复合材料对模拟染料废水的吸附脱色效果

为获得具备优良吸附特性和磁分离性能的吸附材料,以碳纳米管(CNTs)、铁氧化物为原料制备CNTs/铁氧化物磁性复合材料。考察了复合材料吸附甲基橙的动力学、等温线及吸附剂用量的影响。实验结果表明,当吸附时间达到120 min和复合吸附材料的用量为0.2 g时,复合吸附材料对甲基橙的脱色效果达到最佳并具有良好的循环使用性能,且吸附过程更符合Langmuir等温吸附模型。利用扫描电子显微镜、傅里叶变换红外光谱和X射线衍射等分析手段对复合材料进行表征,测试结果显示,复合吸附材料与原始CNTs相比,表面官能团含量明显增加,这可能是其吸附能力显著提高的主要原因。     

硼掺杂对α-Fe2O3-K2O湿敏半导体陶瓷结构与性能的影响

用硬脂酸凝胶法工艺合成不同配比的α Fe2 O3 K2 O B2 O3复合氧化物超微粉 ,经液相烧结法制得多孔陶瓷材料 .采用XRD技术、Archimede排水法及压汞法等研究了材料物相、晶粒度及微孔结构 ;电导测试实验表明 ,B2 O3掺杂相可能以非晶态均匀包覆在主晶相晶粒表面及晶界处 ,K 被吸收包埋在B2 O3非晶相中 ;湿敏特性测试结果表明 ,硼掺杂 5% (摩尔分数 )左右 ,全湿区内材料阻 湿特性曲线线性关系良好 ,且感湿灵敏度较高、湿滞小 ,改变掺杂配比 ,可获得不同湿敏转变点的阻 湿特性曲线 ;初步探讨了材料多孔结构与湿敏性能之间的关系 ,得出通过硼掺杂调控材料微结构 ,可明显提高材料湿敏性能稳定性的结论 .     

钴氧化物/碳复合电极材料的制备及其电化学性能

金属氧化物/碳复合材料的设计与制备在超级电容器应用中具有至关重要的作用。为了研究钴氧化物对碳材料的电化学性能的影响,采用静电纺丝法对聚丙烯腈（PAN）、聚甲基丙烯酸甲酯（PMMA）和钴金属有机骨架材料（ZIF-67）的混合溶液进行纺丝,制备复合纳米纤维膜。对此纤维膜进行高温碳化与氧化处理,从而获得钴氧化物/碳复合材料,并对其形貌结构与电化学性能进行表征。结果表明：钴氧化物能明显提高碳材料的电化学性能。当ZIF-67的负载量为20%时,获得的钴氧化物/碳复合材料电化学性能最优,其在1 A/g的电流密度下比电容可达187 F/g,约是无负载钴氧化物的碳材料的4倍。     

静电纺PAN/TiO2多孔纳米复合光催化纤维的制备

为制备具有较高的光催化性能和重复使用性能的纳米二氧化钛(TiO2)光催化材料,采用静电纺丝技术制备PAN/TiO2纳米复合纤维,通过溶出致孔剂(PVP)使单根纤维表面形成孔状结构的PAN/TiO2多孔纳米复合光催化纤维,采用扫描电镜(SEM)、热重分析(TG)、比表面积分析(BET)等方法对材料进行表征.研究相同条件下...     

Studies on Gas Sensitive Materials of γ-Fe_2O_3 Doped with Rare Earth Oxides

γ-Fe_2O_3气敏材料的特点是无需贵金属掺杂即可获得实用化的灵敏度。其缺点是选择性差,稳定性不好。γ-Fe_2O_3是氧化铁的一种介稳状态,高温下会不可逆地转变为灵敏度低的α-Fe_2O_3.研究表明,采用化学共沉淀物还原氧化的方法,在γ-Fe_2O_3中掺入了Y,Ce,Eu和Tb的氧化物后,γ-Fe_2O_3的结晶度有所降低,颗粒尺寸减小,气孔率增加,气体灵敏度升高。经热分析表明,Ce-γ-Fe_2O_3,Eu-γ-Fe_2O_3的相变温度都在600℃以上,比纯γ-Fe_2O_3580℃的转变温度有所提高,即稀土氧化物掺杂后增加了γ-Fe_2O_3的相稳定性。另外选择合适的工作温度和稀土添加剂,还可使γ-Fe_2O_3材料实现对C_2H_5OH,C_2H_2和LPG的选择性检测。γ-Fe_2O_3的气敏机理属体控制型,稀土催化,陶瓷微结构等均对气敏效应有一定影响。     

BiVO_(4)/Bi_(2)MoO_(6)/g-C_(3)N_(4)复合光催化材料的制备及性能北大核心

采用水热法制备BiVO_(4)/Bi_(2)MoO_(6)/g-C_(3)N_(4)复合光催化材料。当BiVO_(4)与Bi_(2)MoO_(6)物质的量比为10∶1,g-C_(3)N_(4)对BiVO_(4)的掺杂量为1.0%,pH为3,反应温度为160℃,反应时间为6 h时,制备的BiVO_(4)/Bi_(2)MoO_(6)/g-C_(3)N_(4)复合光催化材料具有最佳的光催化活性。其对活性艳蓝KN-R染液的光催化脱色率在120 min内可达到87%以上。     

LaFeO_3系钙钛复合氧化物降低卷烟烟气中的NO_x

为降低卷烟烟气中的氮氧化物(NOx),采用TG、XRD、氮吸附和TEM等方法测定了LaFeO3钙钛矿型复合金属氧化物——LaFe0.85Pd0.05Cu0.1O3的热稳定性、比表面积、粒子的形状与大小,以及对NO的分解催化活性,并以添加于造纸法再造烟叶中的形式,考察了该氧化物对卷烟烟气中NOx等有害成分的影响。结果表明:于700℃下焙烧2h,该氧化物的比表面积为17.24m2/g,平均粒径50nm,具有较高的NO分解催化活性;与对照相比,含1.5%该复合金属氧化物的卷烟烟气中NOx含量降低13.0%,比焦油多降低约9百分点。     

Photocatalytic activity for degradation of nitrogen oxides over visible light responsive titania-based photocatalysts

This study investigates photocatalytic degradation of nitrogen oxides overtitania-based photocatalysts illuminated by ultraviolet and visible light. The TiO2 photocatalyst was synthesized in a sol-gel process using titanium butoxide as the precursor. After calcination between 150 and 300 degrees C, the synthesized TiO2 responded strongly to visible light photocatalytically degrading NO(x), probably because of the existence of carbonaceous species that act as sensitizers. The optimum calcination temperature was found to be around 200 degrees C. Additionally, platinum ion-doped TiO2 was prepared by impregnation using Pt(NH3)4(NO3)2 as a dopant, which improved the photocatalytic activity that degraded NO(x) in the visible light region. The Pt ion was doped in oxide form at the surface of TiO2 and was expected to be responsible for sensitization. At an optimum calcination temperature of around 200 degrees C, the Pt ion-doped TiO2 exhibited higher activity in the further oxidation of NO2 to NO3- clearly reducing NO2 selectivity. The TiO2 catalysts chemically prepared by either the sol-gel process or impregnation exhibited stronger activity than conventional TiO2 when illuminated under a fluorescent lamp. Rinsing with water was responsible for the restored reactivity of prepared TiO2 catalysts for NO(x) degradation.     

吸附相反应制备过渡金属离子掺杂TiO2光催化剂

利用吸附相反应制备了金属离子掺杂的TiO2光催化剂,并结合甲基橙光降解实验研究不同离子、不同离子掺杂量对复合催化剂活性的影响。TEM和紫外可见光谱分析显示,掺杂对复合光催化剂的形貌和吸收光谱均无影响。XRD表明,掺杂金属离子进入了TiO2的晶格结构而抑制其结晶。掺杂的离子大小与Ti4+越接近,掺杂量越高,其对TiO2结晶的抑制越明显。光降解实验表明,Fe3+和Cd2+的掺杂都存在最优掺杂量,但不同离子半径导致了不同的最优掺杂量。低掺杂量的Co2+对复合催化剂的活性没有影响,较高的Co2+掺杂量容易引起截流子复合而降低了其催化活性。     

纳米SnO2/TiO2/MMT制备及其光催化性能

比较不同制备方法制得的复合催化剂,由超临界干燥法制备的光催化剂具有粒径小,分散性好,光催化活性高等特点.以TiCl4为原料,采用溶胶凝胶法结合超临界流体干燥法(SCFD)制备了纳米级SnO2TiO2/MMT(蒙脱土)复合光催化剂.采用XRD和TEM对样品进行了表征.结果表明:TiO2以锐钛矿型形式存在,催化剂粒径在13～20 nm.以活性红X-3B溶液、活性橙K-NG和活性紫X-2R为反应模型,对所得催化剂的催化活性进行了评价,降解率分别达到99.9％、99.6％和99.5％,化剂循环利用时仍具有较高的催化活性.     

TiO_2光催化降解染料废水的研究进展

文章综述了TiO2光催化降解染料废水的研究现状和机理,并详细介绍了降解溶液pH值、催化剂用量、掺杂物质浓度、煅烧温度以及超声波等因素对降解效果的影响。最后对TiO2光催化降解染料废水的应用前景进行了展望。     

High-temperature adsorption of carbon dioxide on mixed oxides derived from hydrotalcite-like compounds

Various XnY(3-n)Al-hydrotalcite-like compounds (HTlcs) were synthesized by the constant pH coprecipitation method with the (X2+ + Y2+)/Al3+ molar ratio fixed at 3.0. Well-mixed oxides Xn,Y(3-n)AlO were derived from corresponding HTlcs precursors upon calcination. Physicochemical characterization with X-ray diffraction analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and the Brunauer-Emmett-Teller equation indicates that the derived oxides are of either periclase or spinel phase, with an interparticle pore diameter of 9.6-15.4 nm. These oxides generally show a high CO2 adsorption capability at 350 degrees C. For example, CaCoAlO captures 1.39 mmol/g of CO2 (i.e., 6.12 wt %) from a gas mixture (8% CO2 in N2) at 350 degrees C and 1 atm in a fixed-bed reactor within 20 min. All other mixed oxides adsorb 0.87-1.28 mmol/g (3.83-5.63 wt %) of CO2. Therefore, these mixed oxides are potential cost-effective CO2 sorbents for environmental remediation. In addition, the CO2 adsorption behavior is well-described with the deactivation model. The species of CO2 formed on the sorbents are various carbonates, as revealed by in situ IR spectra as well as TGA.     

低聚木糖作为牺牲剂在光催化产氢中的应用

目前光催化产氢的研究主要集中于修饰和改性半导体材料来提高其光催化产氢性能。在光催化分解水产氢过程中需要添加牺牲剂甲醇来消耗掉光生空穴,牺牲剂是影响半导体光催化剂产氢性能的一个重要因素。本研究选择可再生生物质低聚木糖作为牺牲剂,探讨了其光催化产氢性能,并与常用牺牲剂甲醇进行了光催化产氢性能比较。结果表明,未负载贵金属Pt时,半导体材料TiO2和C3N4进行光催化产氢时未检测到氢气。负载质量分数1%的Pt后,半导体材料Pt-TiO2和Pt-C3N4可以作为光催化剂进行产氢,经过24 h的光催化反应,基于催化剂质量,以甲醇为牺牲剂时分别产出4298. 3μmol/g和356. 5μmol/g的氢气,以低聚木糖为牺牲剂时分别产出3054. 5μmol/g和495. 6μmol/g的氢气。低聚木糖可以作为光催化产氢的牺牲剂,尤其用作Pt-C3N4的牺牲剂时,产氢性能优于甲醇。     

Uranium deposition in a weathered fractured saprolite/shale

Chemical analysis and scanning electron microscopy (SEM) microanalysis were carried out on cores of contaminated geological material collected around four closed waste disposal ponds to examine the extent of nitric acid extractable U (U(NA)) association with P, S, and extractable Fe, Al, and Mn oxides within deeply weathered fractured shale. The solid phase in many regimes on the site has been exposed to highly buffered acidic (< 3.5) groundwater and has been aggressively weathered. Higher correlations occur between U(NA) and total P and S (r2 = 0.76, 0.69, respectively), citrate bicarbonate dithionite extractable Fe (Fed) and Al (Ald) (r2 = 0.87, 0.80, respectively), and acid oxalate extractable or amorphous/poorly crystalline Fe (Feo) (r2 = 0.63) in core material from a field plot known as Area 1 compared to core material from another field plot known as Area 3. In Area 3 core material, linear regression analysis of U(NA) and total P and S, and Fed, Ald and Feo gave r2 values of 0.67, 0.4, 0.06, 0.24, and 0.45, respectively. These results showed similar relationships with SEM-wavelength dispersive spectroscopy (WDS) mapping of this material. It is noteworthy that Area 1 geological material has not been as aggressively weathered as Area 3 material due to its physical location from the waste source. In all of the cores, most of the Fe and Al oxides were crystalline, while most of the Mn oxides were amorphous. The greater adsorption and/or fixation of anion complexes of P-U (uranium phosphate) and S onto Fe and Al oxides from Area 1 cores compared to Area 3 core material is probably due to a higher amount of crystalline Fe and Al oxides compared to amorphous Fe and Al oxides and higher Al substitution in Fe oxides in Area 1. This unique study illustrates the relationships between U(NA), total P and S, and Al, Fe and Mn oxides in fractured shale under field conditions which can be used in planning remediation of this site and other similar sites.     

ZrO2-modified mesoporous nanocrystalline TiO2-xNx as efficient visible light photocatalysts

Mesoporous nanocrystalline TiO2-xNx and TiO2-xNx/ZrO2 visible-light photocatalysts have been prepared by a sol-gel method. The photocatalysts were characterized by XRD, N2 adsorption-desorption, TEM, XPS, UV/Vis, and IR spectroscopy. The photocatalytic activity of the samples was evaluated by the decomposition of ethylene in air under visible light (lambda > 450 nm) illumination. Results revealed that nitrogen was doped into the lattice of TiO2 by the thermal treatment of NH3-adsorbed TiO2 hydrous gels, converting the TiO2 into a visible-light responsive catalyst. The introduction of ZrO2 into TiO2-xNx considerably inhibits the undesirable crystal growth during calcination. Consequently, the ZrO2-modified TiO2-xNx displays higher porosity, higher specific surface area, and an improved thermal stability over the corresponding unmodified TiO2-xNx samples.     

N-TiO_2/ACF的制备及光催化降解真丝绸染色废水研究

利用扫描电镜、X射线衍射、紫外-可见漫反射等技术对采用溶胶-凝胶法制备的氮掺杂纳米TiO_2负载活性炭纤维(N-TiO_2/ACF)光催化材料进行了表征分析。以真丝绸染色废水为目标降解物,研究了光催化材料的光催化性能。研究表明:N-TiO_2/ACF光催化材料表面的N-TiO_2呈锐钛矿相,粒径约为15.3 nm,其光谱响应范围由紫外光区拓展至可见光区,吸收边带达603 nm;金卤灯照射下反应180 min,0.77 g N-TiO_2/ACF对200 m L真丝绸染色废水降解率达97.2%,2.31 g的N-TiO_2/ACF对200 mL真丝绸染色废水COD去除率达80.6%;N-TiO_2/ACF具有良好的重复使用性能。     

Impact of interactions between metal oxides to oxidative reactivity of manganese dioxide

Manganese oxides typically exist as mixtures with other metal oxides in soil-water environments; however, information is only available on their redox activity as single oxides. To bridge this gap, we examined three binary oxide mixtures containing MnO(2) and a secondary metal oxide (Al(2)O(3), SiO(2) or TiO(2)). The goal was to understand how these secondary oxides affect the oxidative reactivity of MnO(2). SEM images suggest significant heteroaggregation between Al(2)O(3) and MnO(2) and to a lesser extent between SiO(2)/TiO(2) and MnO(2). Using triclosan and chlorophene as probe compounds, pseudofirst-order kinetic results showed that Al(2)O(3) had the strongest inhibitory effect on MnO(2) reactivity, followed by SiO(2) and then TiO(2). Al(3+) ion or soluble SiO(2) had comparable inhibitory effects as Al(2)O(3) or SiO(2), indicating the dominant inhibitory mechanism was surface complexation/precipitation of Al/Si species on MnO(2) surfaces. TiO(2) inhibited MnO(2) reactivity only when a limited amount of triclosan was present. Due to strong adsorption and slow desorption of triclosan by TiO(2), precursor-complex formation between triclosan and MnO(2) was much slower and likely became the new rate-limiting step (as opposed to electron transfer in all other cases). These mechanisms can also explain the observed adsorption behavior of triclosan by the binary oxide mixtures and single oxides.