Zn2+掺加的包覆型Fe2O3/SiO2颜料的制备及其呈色性能

包覆型Fe₂O₃/SiO₂颜料由于包覆完整性并不理想,该颜料高于800 ℃时呈色会产生变黑、变暗的问题。采用溶胶-凝胶法制备包覆型Fe₂O₃/SiO₂颜料,研究催化剂浓度、反应温度、硅/铁质量比等因素对包覆型Fe₂O₃/SiO₂颜料呈色性能的影响。在此基础上,通过掺加Zn²⁺,进行了Zn²⁺掺加的包覆型Fe₂O₃/SiO₂颜料的呈色性能研究。研究表明,当催化剂(氨水)浓度为0.75 mol/L,反应温度为40 ℃,硅/铁质量比m(SiO₂)/m(Fe₂O₃)为0.20,铁/锌摩尔比n(Fe)/n(Zn)为4时,制备得到的Zn²⁺掺加的包覆型Fe₂O₃/SiO₂颜料的呈色耐热性能获得明显提升,样品在850 ℃煅烧后仍然呈现出明亮的红橙色色调。     

Co2+掺杂ZnO-MgO-Al2O3-SiO2系微晶玻璃的制备及光学性能

本文采用熔融法和热处理制备了Co²⁺掺杂的ZnO-MgO-Al₂O₃-SiO₂(ZMAS)系透明微晶玻璃,基于X射线衍射的结果确定了微晶玻璃的主要晶相为ZnAl₂O₄/MgAl₂O₄,并且随着晶化处理时间的增加,微晶玻璃的物相构成没有发生明显变化,尖晶石相的结晶度和平均晶粒尺寸呈现先增大后减小的趋势。吸收光谱和发射光谱的结果表明Co²⁺进入了尖晶石相ZnAl₂O₄/MgAl₂O₄中,并取代了四面体位置(T_d)的Zn²⁺或Mg²⁺。随着晶化处理时间的增加,样品的吸收光谱强度和发射光谱强度均呈现先升高后降低的趋势,这与X射线衍射结果的变化趋势一致,说明可以通过控制微晶玻璃的结晶度来调控光学性能,这对制备性能优良的微晶玻璃材料具有一定的指导意义。对比了采用不同价态Co的氧化物原料制备的微晶玻璃,结果表明无论是掺杂CoO还是Co₂O₃,微晶玻璃尖晶石相中的Co元素均以Co²⁺形式存在。此外,将所制备的微晶玻璃材料在1 540 nm处的基态吸收截面(σ_gas)同Co掺杂的其他基体材料进行了对比,发现它有望作为可饱和吸收体应用于调Q激光器中。     

Ta、Ba共掺杂石榴石型Li7La3Zr2O12电解质的制备及性能研究

传统锂离子电池采用有机电解液体系,能量密度难以进一步提升,同时存在一定的安全隐患。采用无机固体电解质构建全固态锂电池,在提高电池能量密度同时可兼顾安全性问题。在众多无机固体电解质中,Li₇La₃Zr₂O₁₂(LLZO)石榴石电解质具有离子电导率高、与金属锂接触稳定等优势,成为受人关注的材料。为了进一步提高该材料的导电性,采用固相法合成Ta、Ba共掺杂LLZO(Li_7-x+yLa_3-yBa_yZr_2-xTa_xO₁₂)电解质,采用X射线衍射、扫描电子显微镜和电化学阻抗法分析样品的物相结构、微观形貌及离子电导率。结果表明,Ta⁵⁺掺杂能够稳定立方相结构,Ba²⁺作为掺杂剂和烧结剂,促进晶粒生长和陶瓷致密化,从而降低总电阻。其中,Li_6.45La_2.95Ba_0.05Zr_1.4Ta_0.6O₁₂样品在室温下的总电导率为1.07×10^-3 S·cm^-1,活化能为0.378 eV。Ta⁵⁺/Ba²⁺共掺杂有利于制备高致密度和高电导率的石榴石型电解质材料。     

SrFe0.6Co0.4O3催化降解孔雀石绿的研究

具有复杂分子结构的三苯甲烷类染料孔雀石绿是一种典型的较难降解染料,是工业废水处理的难点之一。本文根据Goldschmidt半径容差规则法,设计了用于孔雀石绿降解的ABO₃型SrFe_(1-x)Co_xO₃催化剂,并选择出活性较高的SrFe_0.6Co_0.4O₃催化剂。通过XRD、SEM、BET吸附及XPS分析表明:该催化剂是纯净钙钛矿结构,颗粒形貌为无规则堆叠的“蜂窝”片状;吸附等温线没有明显的回滞环,说明没有“墨水瓶”类孔结构;XPS谱中,B位离子同时存在Fe²⁺/Fe³⁺和Co²⁺/Co³⁺ 4种价态离子,且反应前后,4种离子的分布比例有较大变化。根据实验结果,推测该催化反应机理为:催化剂B位Co³⁺与溶解氧形成活性氧[O₂]⁺和Co²⁺;活性氧[O₂]⁺完成氧化反应后其正电荷转移到B位Fe²⁺上形成Fe³⁺,Fe³⁺的正电荷可再转移到Co²⁺形成Co³⁺,完成催化过程的电荷转移与循环。     

富铈Ce1-xLaxO2催化甲烷氧氯化性能

以硝酸铈、硝酸镧为前体,用氨水共沉淀法制备了一系列Ce_1-xLa_xO₂(x≤0.5)催化剂,利用XRD、N₂吸附-脱附、SEM、Raman、H₂-TPR和OSC对催化剂的物理化学性质进行了表征,并考察其在甲烷氧氯化反应中的催化性能。结果表明:Ce_1-xLa_xO₂催化剂的氧化还原性质随着镧含量的变化发生显著改变,并且这一性质的变化与反应的转化率及产物分布具有较强的联系。Ce_1-xLa_xO₂表面氧物种的活泼性对催化剂活性影响显著,而体相氧物种容易将生成的甲烷氯化物深度氧化。在Ce_1-xLa_xO₂(x<0.3)催化剂上表面氧物种起主导作用,氯甲烷为主要反应产物,Ce_0.8La_0.2O₂催化剂上氯甲烷选择性最高为52%。在体相氧物种更活泼的Ce_0.7La_0.3O₂和Ce_0.5La_0.5O₂上产物中CO的选择性显著上升,Ce_0.5La_0.5O₂催化剂上CO选择性高达48%。稳定性测试表明Ce_0.8La_0.2O₂催化剂具有良好的稳定性。     

壳聚糖印迹聚合物对Zn2+的吸附动力学

以Zn²⁺作为模板,加入分散剂石蜡、预交联剂甲醛、交联剂环氧氯丙烷,制得特性壳聚糖印迹聚合物,用X射线衍射仪表征了聚合物的结构,考察了聚合物用量、温度等对吸附Zn²⁺的影响,研究了印迹聚合物对Zn²⁺的吸附动力学、等温吸附特性。结果表明,印迹聚合物合成过程中打破了壳聚糖原有晶体的规整性,增加了大量的配位基团,使聚合物的吸附容量大大增加,同时聚合物对Zn²⁺有很好的选择吸附性,对Zn²⁺、Cd²⁺、Mg²⁺、Mn²⁺溶液的分离因子均大于1.5;印迹聚合物能快速吸附溶液中Zn²⁺,整个吸附过程符合拟二级动力学模型：t/Q_t=8.1744+2.0186t,相关系数为0.998,吸附平衡容量模型计算值与实验值较为吻合;印迹聚合物对Zn²⁺的等温吸附过程符合Langmuir吸附等温吸附模型：C_e/Q_e=1.3297+0.02701C_e,最大吸附容量为37.023 mmol/g,吸附过程主要以单分子层的吸附形式进行。     

Cu2+和Co2+促进芬顿氧化处理垃圾渗滤液的研究

通过在传统芬顿体系中加入Cu²⁺、Co²⁺,研究Cu²⁺/Co²⁺/Fe²⁺/H₂O₂、Cu²⁺/Fe²⁺/H₂O₂、Co²⁺/Fe²⁺/H₂O₂和Fe²⁺/H₂O₂四种芬顿体系对垃圾渗滤液的处理效果,发现当初始pH分别为2、3、4、5、6时,各体系去除CODCr的效果排序为Cu²⁺/Co²⁺/Fe²⁺/H₂O₂>Cu²⁺/Fe²⁺/H₂O₂>Co²⁺/Fe^2...     

Fe-Cr-Ni-Mn系黑色陶瓷颜料的制备及呈色性能分析

以Fe₂O₃、Cr₂O₃、MnO和NiO为原料,采用固相合成法制备Fe-Cr-Ni-Mn系黑色陶瓷颜料,并使用X射线衍射仪、色度仪、扫描电子显微镜、紫外-可见分光光度计等分析手段对所制备颜料进行了表征,研究了原料配比、烧结温度、保温时间和冷却方式等对颜料呈色性能的影响。结果表明:当原料中Fe₂O₃、Cr₂O₃、MnO和NiO的摩尔比为6:1:1:1,烧结温度为1 150 ℃,保温时间为45 min,采用随炉冷却时,颜料颗粒细小,粒度分布均匀,其L^*、a^*与b^*值分别为18.02、0.20和0,禁带宽度为1.25 eV,呈纯正黑色,且物相主要由NiFe₂O₄、NiCr₂O₄和Ni[Mn_0.5Cr_1.5]O₄组成;将所制备颜料应用于黑色陶瓷釉,釉面呈纯正黑色,且光滑致密,表明所制备颜料具备优异的着色性能和应用潜力。     

脱硝协同汞氧化聚苯硫醚四元催化滤料制备方法及理化特性

采用原位氧化法（ISM）、浸渍煅烧法（ICM）和涂覆法（CM）制备聚苯硫醚（PPS）双效催化滤料,在模拟烟气固定床系统中考察了滤料低温NO_x催化协同Hg⁰氧化性能,深入分析了原位氧化滤料表面形貌、元素分布、晶态结构和Hg及NO_x赋存形态。结果表明：在相同条件下,3种制备方法对应滤料催化活性大小顺序为Mn-Ce-Fe-Co-O_x/PPS@ISM＞Mn-Ce-Fe-Co-O_x/PPS@ICM＞Mn-Ce-Fe-Co-O_x/PPS@CM。ISM对应PPS单层饱和负载量约为0.9,活性反应温度窗口为110~210℃,其中170℃时Mn-Ce-Fe-Co-O_x/PPS@ISM的非均相NO氧化、NO_x还原和Hg⁰氧化效率最高分别达到8.6%、84.6%和93.2%。程序升温脱附实验结果表明：(0.9)Mn-Ce-Fe-Co-O_x/PPS@ ISM表面NO_x吸附活性位点中弱碱位数量占优,而中碱位化学吸附NO主要以NO_y（y=2或3）结构存在,歧化态NO₂次之。同时,Hg与NO在氧气条件下以非均相反应途径转化为HgO和Hg(NO₃)₂/Hg₂(NO₃)₂。表征结果表明：ISM制备的MnO_x、CeO_x、CoO_x和Fe₂O₃复合氧化物呈弱晶相、高度分散团絮状结构赋存于PPS@ISM纤维。     

羧基化磁性Fe3O4复合材料的制备及其对水体中Pb2+的吸附研究

以采用共沉淀法制备的磁性Fe₃O₄为核,通过硅烷化及酰胺化反应,制备了羧基化磁性Fe₃O₄复合材料（Fe₃O₄?SiO₂?NH?COOH）,通过红外光谱仪（FTIR）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、磁强度计（VSM）和X射线衍射仪（XRD）等对复合材料的结构进行了表征,并对不同作用条件下Fe₃O₄?SiO₂?NH?COOH吸附Pb²⁺的效果及Fe₃O₄?SiO₂?NH?COOH的重复使用效能进行了研究。结果表明,具有Fe₃O₄?SiO₂?NH?COOH结构的复合材料已被成功被制备,且该材料仍然能够实现快速磁性分离;Fe₃O₄?SiO₂?NH?COOH对Pb²⁺的静态吸附动力学数据更符合准二阶动力学,吸附时间为100 min、pH=4.5、Fe₃O₄?SiO₂?NH?COOH用量为1.0 g/L时,Fe₃O₄?SiO₂?NH?COOH对Pb²⁺的最大吸附容量为208.7 mg/g,且Langmuir方程更能描述该吸附等温过程;Fe₃O₄?SiO₂?NH?COOH对Pb²⁺的吸附是吸热过程;Fe₃O₄?SiO₂?NH?COOH对Pb²⁺的吸附量随时间延长先增加后趋于稳定,随pH值的增加先增加后减小;相比于一价阳离子,溶液中二价Ca²⁺、Mg²⁺的存在对吸附反应具有一定抑制作用;Fe₃O₄?SiO₂?NH?COOH吸附Pb²⁺后可洗脱再生,连续重复使用6次后对Pb²⁺的去除率仍大于50 %。     

Effect op the preparation conditions on the reducibility of Cu-Co based oxides

The nature of the active sites of Cu-Co-Al Catalysts used to convert synthesis gas to methanol and higher alcohols is still a matter of debate. The main difficulty to discern the nature of the synergism responsible for alcohol formation is related to the Co reducibility under reaction conditions. In this paper we studied the influence of the preparation conditions on the reducibility of Co. Binary Cu-Co, Cu-Al and Co-Al, and ternary Cu-Co-Al samples were prepared by coprecipitation and characterized by temperature-programmed reduction. X-ray powder diffraction and diffuse reflectance spectroscopy techniques. Depending on the Co/Al ratio and calcination atmosphere, the Co ions were present in three different phases before H₂ activation: CuCoO₂, GO₃O₄ and partly inverse CoAl₂O₄ spinel. The Co reducibility was in the order CuCoO₂ > Co₃O₄ > Co_oh ions in CoAl₂O₄ > Co_td ions in CoAl₂O₄. In all the cases, the presence of Cu activated the reduction of Co²⁺ and Co³⁺ ions. The mixed oxides obtained in nitrogen did not contain CO₃O₄ and the CuCoO₂ phase was formed only when the Co/Al atomic ratio was greater than 0.5. The samples calcined in air contained CO₃O₄ but not CuCoO₂. All the samples contained CoAl₂O₄, spinel phase with finely dispersed CuO. It was found that the preparative procedures and the chemical composition of the samples greatly Influence the reducibility of Co ions, thereby determining the kind of Cu-Co interaction.     

Copper doped nickel aluminate: Synthesis,characterisation, optical and colour properties

Novel environment friendly inorganic nano green pigments, Ni_1-xCu_xAl₂O₄ (x=0, 0.02, 0.04, 0.06, 0.08, 0.1) were successfully synthesised by simple, cost effective sol-gel method using citric acid as a gelling agent. Synthesised nano pigments were characterised by powder XRD, FT-IR, UV-DRS, SEM-EDX and TEM. Distribution of elements such as Ni, Cu, Al and O for the pigment Ni_0.98Cu_0.02Al₂O₄ was authenticated by elemental mapping analysis. The colour parameters were studied using CIE-LAB parameters. It is evident from the DRS measurement that the band gap energy of NiAl₂O₄ (3.11 eV) has been massively diminished to 2.63 eV when x=0.02, unexpectedly changed the colour of the pigment from cyan to green. Whilst x=0.1 the pigment colour has turned into grey and the corresponding band gap condensed into 2.17 eV. Effect of mineralisers like NaF, CaF₂, NH₄H₂PO₄ and Li₂CO₃ on the colour of Ni_0.98Cu_0.02Al₂O₄ was investigated.     

Highly efficient and selective membrane transport of silver(I) using hexathia-18-crown-6 as a specific ion carrier

Hexathia-18-crown-6 (HT18C6) was used as a specific ion carrier for the transport of silver ion through a chloroform bulk liquid membrane. In the presence of thiosulfate ion as a suitable stripping agent in the receiving phase, the amount of silver transported across the liquid membrane after 60 min is 99.5±1.0%. The selectivity of Ag⁺ transport from the aqueous solutions containing other Mⁿ⁺ cations such as Tl⁺, Mg²⁺, Ca²⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺, Hg²⁺, and Cr³⁺ ions was investigated. Except with Hg²⁺ ion, non of the cations used interfere the silver transport, even at a Mⁿ⁺/Ag⁺ molar ratio of 500. The interfering effect of Hg²⁺ ion was successfully eliminated in the presence of EDTA at pH 5.     

Selective removal of iron(III) from highly salted chloride acidic solutions by solvent extraction using di(2-ethylhexyl) phosphate

Metal ions including Fe³⁺, Ca²⁺, Mg²⁺, Ni²⁺, Co²⁺ and Cu²⁺ are commonly found in the leaching solution of laterite-nickel ores, and the pre-removal of Fe³⁺ is extremely important for the recovery of nickel and cobalt. Di(2-ethylhexyl)phosphate acid (D2EHPA) showed high extraction rate and selectivity of Fe³⁺ over other metal ions. The acidity of the aqueous solution is crucial to the extraction of Fe³⁺, and the stoichiometry ratio between Fe³⁺ and the extractant is 0.86:1.54. The enthalpy for the extraction of Fe³⁺ using D2EHPA was 19.50 kJ/mol. The extraction of Fe³⁺ was ≥99% under the optimized conditions after a three-stage solvent extraction process. The iron stripping effects of different reagents showed an order of H₂C₂O₄>NH₄HCO₃>HCl>NaCl>NaHCO₃>Na₂SO₃. The stripping of Fe was ≥99% under the optimized conditions using H₂C₂O₄ as a stripping reagent.     

Synthesis of hierarchical dendritic micro–nano structure ZnFe_2O_4 and photocatalytic activities for water splitting

Hierarchical dendritic micro–nano structure Zn Fe_2O_4 have been prepared by electrochemical reduction and thermal oxidation method in this work. X-ray diffractometry, Raman spectra and field-emission scanning electron microscopy were used to characterize the crystal structure, size and morphology. The results show that the sample(S-2) is composed of pure ZnFe_2O_4 when the molar ratio of Zn~(2+)/Fe~(2+)in the electrolyte is 0.35. Decreasing the molar ratio of Zn~(2+)/Fe~(2+), the sample(S-1) is composed of ZnFe_2O_4 and α-Fe_2O_3, whereas increasing the molar ratio of Zn~(2+)/Fe~(2+), the sample(S-3) is composed of ZnFe_2O_4 and Zn O. The lattice parameters of ZnFe_2O_4 are influenced by the molar ratio of Zn~(2+)/Fe: Zn at excess decreases the cell volume whereas Fe at excess increases the cell volume of Zn Fe_2O_4. All the samples have the dendritic structure, of which S-2 has micron-sized lush branches with nano-sized leaves. UV–Vis diffuse reflectance spectra were acquired by a spectrophotometer. The absorption edges gradually blue shift with the increase of the molar ratio of Zn~(2+)/Fe~(2+). Photocatalytic activities for water splitting were investigated under Xe light irradiation in an aqueous olution containing 0.1 mol·L~(-1)Na_2S/0.02 mol·L~(-1)Na_2SO_3 in a glass reactor. The relatively highest photocatalytic activity with 1.41 μmol·h-1· 0.02 g~(-1)was achieved by pure ZnFe_2O_4sample(S-2). The photocatalytic activity of the mixture phase of Zn Fe_2O_4 and α-Fe_2O_3(S-1) is better than ZnF e_2O_4 and ZnO(S-3).     

Barium-doped Pr2Ni0.6Cu0.4O4+δ with triple conducting characteristics as cathode for intermediate temperature proton conducting solid oxide fuel cell

Proton conducting solid oxide fuel cell (H-SOFC) is an emerging energy conversion device, with lower activation energy and higher energy utilization efficiency. However, the deficiency of highly active cathode materials still remains a major challenge for the development of H-SOFC. Therefore, in this work, K₂NiF₄-type cathode materials Pr_2-xBaNi_0.6Cu_0.4O_4+δ (x=0, 0.1, 0.2, 0.3), single-phase triple-conducting (e^-/O^2-/H⁺) oxides, are prepared for intermediate temperature H-SOFCs and exhibit good oxygen reduction reaction activity. The investigation demonstrates that doping Ba into Pr_2-xBaNi_0.6Cu_0.4O_4+δ can increase its electrochemical performance through enhancing electrical conductivity, oxygen vacancy concentration and proton conductivity. EIS tests are carried at 750℃ and the minimum polarization impedances are obtained when x=0.2, which are 0.068 Ω·cm² in air and 1.336 Ω·cm² in wet argon, respectively. The peak power density of the cell with Pr_1.8Ba_0.2Ni_0.6Cu_0.4O_4+δ cathode is 298 mW·cm^-2 at 750℃ in air with humidified hydrogen as fuel. Based on the above results, Ba-doped Pr_2-xBaNi_0.6Cu_0.4O_4+δ can be a good candidate material for SOFC cathode applications.     

Effects of calcium cations incorporated into magnesium vanadates on the redox behaviors and the catalytic activities for the oxidative dehydrogenation of propane

The influence of the incorporation of Ca²⁺ into MgV₂O₆, Mg₂V₂O₇ and Mg₃V₂O₈ on the catalytic activities for the oxidative dehydrogenation of propane and the mobility of lattice oxygen in those catalysts has been investigated. On Mg₂V₂O₇ and Mg₃V₂O₈ incorporated with Ca²⁺, the selectivity to propylene evidently increased with increasing the content of Ca²⁺ in those catalysts. A decrease of the conversion of propane was observed on Ca²⁺-added Mg₂V₂O₇ with increasing Ca²⁺-content; while on Ca²⁺-added Mg₃V₂O₈, no dependence on the Ca²⁺-content was observed. The incorporation of Ca²⁺ was rather insensitive to both the selectivity and the conversion on Ca²⁺-added MgV₂O₆. In order to examine the mobility of lattice oxygen in those catalysts, those catalysts were employed for the oxidative dehydrogenation in the absence of oxygen for 2.25 h, followed by the addition of gaseous oxygen into the feedstream. After the addition of gaseous oxygen under the present conditions, oxygen in the effluent was detected at 9, 3.5 and 2 min with Mg₂V₂O₇ incorporated with Ca²⁺ at these Ca/(Mg + Ca) ratios: 0, 0.05 and 0.1. The times were 1.4, 2 and 4 min with Mg₃V₂O₈ incorporated with Ca²⁺ as Mg₂V₂O₇. However, no oxygen was detected with MgV₂O₆ incorporated with Ca²⁺ even 15 min after the addition of the gaseous oxygen. The present results reveal that the mobility of the lattice oxygen in those catalysts is strongly influenced by the amount of Ca²⁺ incorporated, resulting in significant effects on the activities for the oxidative dehydrogenation of propane. ⁵¹V MAS NMR was also employed for the observation of redox behaviors of vanadium species in those catalysts during the reaction.     

Potassium-doped Co3O4 catalyst for direct decomposition of N2O

Direct decomposition of nitrous oxide (N₂O) on K-doped Co₃O₄ catalysts was examined. The K-doped Co₃O₄ catalyst showed a high activity even in the presence of water. In the durability test of the K-doped Co₃O₄ catalyst, the activity was maintained at least for 12 h. It was found that the activity of the K-doped Co₃O₄ catalyst strongly depended on the amount of K in the catalyst. In order to reveal the role of the K component on the catalytic activity, the catalyst was characterized by XRD, XPS, TPR and TPD. The results suggested that regeneration of the Co²⁺ species from the Co³⁺ species formed by oxidation of Co²⁺ with the oxygen atoms formed by N₂O decomposition was promoted by the addition of K to the Co₃O₄ catalyst.