不同制备方法对MgFe氧化物催化吸附SO2性能的影响

用不同的制备方式得到了 3种MgFe复合氧化物和混合物 ,即机械混合的Fe2 O3 +MgO ;以MgO为载体 ,浸渍法制备的Fe2 O3 /MgO ;以MgFe水滑石类为前驱体 ,经焙烧制得MgFeOx.分别测定了 3种材料对SO2 氧化吸附的速率和硫容量 ,发现MgFeOx 脱硫性能最好 ,硫容量达到 1.4gSO2 /g吸附剂 .通过BET、XRD和IR的表征 ,分析了材料脱硫性能好的原因 .主要是高度分散状态的MgFeOx 中Mg和Fe的协同作用 ,Fe起到了催化氧化的作用 ,Mg是吸附中心 ,氧化和吸附的耦合加快了MgFeOx 对SO2 的吸附速率 ,增加了硫容量     

SO2和NO在载体γ-Al2O3上的相互作用

通过分析载体γ-Al₂O₃在423 K吸附NO和SO₂气体时的TPD和DRIFTS谱图,研究了SO₂和NO在γ-Al₂O₃上的相互作用。结果表明,在γ-Al₂O₃上SO₂促进NO氧化,NO促进SO₂吸附,O₂参与了SO₂和NO之间的相互作用。机理探讨认为,NO和SO₂在γ-Al₂O₃上吸附时至少形成两类中间体,一类中间体分解放出NO₂,另一类中间体分解产生SO₃,两类中间体分解后均产生氧空位,O₂通过（至少为途径之一）补充氧空位重新生成晶格氧或晶格缺陷吸附氧参加SO₂和NO之间的相互作用。     

3,5-二甲基苯酚甲基化合成2,3,5-三甲基苯酚的铁系催化剂研究

研究了3,5-二甲基苯酚甲醇气相催化甲基化合成2,3,5-三甲基苯酚的铁系催化剂。以Fe₂O₃为主催化剂,并通过添加Cr₂O₃、MgO、MnO、PbO₂和ZnO等为助催化剂进行性能调变。考察了催化剂组成、助催化剂含量和催化剂负载量对活性的影响。结果表明,Fe₂O₃为主催化剂,MnO和Cr₂O₃为助催化剂,Fe₂O₃、 MnO 和Cr₂O₃物质的量比为1∶0.1∶0.02,负载主、副催化剂质量分数10%效果最佳。催化剂用XRD、BET和TPD进行了表征。     

焙烧温度对橄榄石催化甲苯裂解性能的影响

以橄榄石为催化剂,通过N2物理吸附、XRD、H₂-TPR和TEM等手段研究了焙烧温度对催化剂的结构、物相、还原性能以及甲苯裂解反应活性的影响。结果表明,焙烧温度对催化剂结构和活性影响显著,低温焙烧时主要存在Mg₂SiO₄和Fe₂O₃的晶相衍射峰,随着焙烧温度的升高,Fe₂O₃的晶相衍射峰逐渐消失,随之出现了非常明显的 (Fe, Mg)SiO₃的衍射峰。选择适中的焙烧温度可以增加表面上可还原Fe₂O₃的量,从而拥有较高的甲苯裂解活性位。在实验考察范围内,900℃焙烧的橄榄石表现了最高的甲苯裂解活性。TG结果表明,该温度焙烧的橄榄石具有较好的抗积炭性能。     

固体超强酸SO42-/Fe2O3-ZrO2的声化学制备及其催化酯化性能

采用超声共沉淀法制备SO₄^2-/Fe₂O₃-ZrO₂(SFZ)固体超强酸,用流动指示剂法测定其酸强度,通过BET及IR对其进行表征,并将样品用于催化乙酸和正丁醇的酯化反应。结果表明,超声共沉淀法制备的SO₄^2-/Fe₂O₃-ZrO₂固体超强酸比表面积及酸强度大(H₀≤-16.0),催化活性高,样品表面与SO₄^2-结合较牢固,重复使用时,催化活性变化不大。     

氧化铈和铈锆固溶体对Pd催化剂抗硫性能影响的研究

采用等体积浸渍法制备了质量分数为1%Pd/γ－Al₂O₃、1%Pd/10%CeO₂/γ-Al₂O₃以及1% Pd/10%Ce_0.6Zr_0.4O₂ /γ－Al₂O₃催化剂,研究了CeO₂和Ce_0.6Zr_0.4O₂ 固溶体对Pd催化剂抗硫性能的影响。利用XRD和XPS技术表征了催化剂的固相结构、表面元素组成和反应后催化剂中硫物种（或表面硫酸盐）的存在形态。利用SO₂-TPD研究了SO₂在催化剂上的吸附和脱附行为。实验结果表明,在催化剂载体中引入CeO₂和Ce_0.6Zr_0.4O₂ 降低了催化剂起燃活性;SO₂ 在Pd/Ce_0.6Zr_0.4O₂ /γ－Al₂O₃催化剂表面上发生化学反应生成Zr(SO₄)₂,其热稳定性大于在Pd/γ－Al₂O₃和Pd/CeO₂/γ－Al₂O₃催化剂表面上的硫酸盐或硫酸盐物种。     

Fe2O3对高变质程度脱灰煤热解反应性与半焦结构的影响

利用热天平研究了共混合法负载Fe₂O₃高变质程度脱灰煤的热解反应性,结果表明煤粉负载Fe₂O₃后热解反应性高于无负载的热解反应性。负载Fe₂O₃煤样在程序升温加热的马弗炉中制备出半焦,利用FTIR、XRD和RAMAN 等分析了半焦结构。由TG和FTIR可知,负载Fe₂O₃煤样热解时,热解转化率增加,热解后自由基增加。由XRD可知,Fe₂O₃没有使得煤样半焦的002峰衍射角发生明显变化,但使L_a和L_c参数明显降低,说明半焦的微晶结构石墨化程度降低。另外,在XRD分析谱图中发现部分Fe₂O₃被还原成FeO。由RAMAN可知,Fe₂O₃使半焦的G峰峰面积降低,D峰峰面积增加,说明半焦的有机结构有序化程度降低。     

Fe2O3对高变质程度脱灰煤热解反应性与半焦结构的影响

利用热天平研究了共混合法负载Fe₂O₃高变质程度脱灰煤的热解反应性，结果表明煤粉负载Fe₂O₃后热解反应性高于无负载的热解反应性。负载Fe₂O₃煤样在程序升温加热的马弗炉中制备出半焦，利用FTIR、XRD和RAMAN 等分析了半焦结构。由TG和FTIR可知，负载Fe₂O₃煤样热解时，热解转化率增加，热解后自由基增加。由XRD可知，Fe₂O₃没有使得煤样半焦的002峰衍射角发生明显变化，但使L_a和L_c参数明显降低，说明半焦的微晶结构石墨化程度降低。另外，在XRD分析谱图中发现部分Fe₂O₃被还原成FeO。由RAMAN可知，Fe₂O₃使半焦的G峰峰面积降低，D峰峰面积增加，说明半焦的有机结构有序化程度降低。     

聚苯硫醚/四氧化三铁复合材料的力学和磁性能

采用熔融共混的方法制备了聚苯硫醚（PPS）/四氧化三铁（Fe₃O₄）复合材料,考察了复合材料的形态、力学性能及磁性能。结果表明,均匀分散的Fe₃O₄粒子与PPS基体界面结合紧密;与纯PPS相比,复合体系在拉伸和弯曲强度显著提高的同时,冲击性能也有所改善;但过多的Fe₃O₄填充量反而不利于材料力学性能的提升。此外,复合体系的磁性仅依赖于Fe₃O₄的含量,而与Fe₃O₄的分散程度无关;因此,要获得既具有良好力学性能,又具有较高磁性的复合材料,30%(质量）左右的Fe₃O₄填充量较为适宜。     

SO2－4/Fe2O3-γ-Al2O3固体超强酸催化剂的制备

通过浸渍法制备SO^2－₄/Fe₂O₃(SF)固体超强酸，将γ-Al₂O₃纳米纤维通过粘附的方法负载到固体超强酸SO^2－₄/ Fe₂O₃上，制得SO^2－₄/Fe₂O₃-γ-Al₂O₃(SFA)固体超强酸催化剂,并选用乙酸和丁醇的酯化反应来测试SO^2－₄／Fe₂O₃-γ-Al₂O₃(SFA)固体超强酸催化剂的催化性能，在不同催化剂种类、不同γ-Al₂O₃加入量、不同焙烧温度和时间以及不同浸渍液种类和浓度的条件下，对催化活性进行了分析和讨论。     

铁氧体催化剂磁性合成及其对双氧水分解反应的影响

通过双氧水催化分解反应动力学研究,显示磁化合成铁氧体具有较高的催化速率.利用高分辨分析电镜和电子能量损失谱测试了其显微形貌、化学组成和微区晶体结构,探讨了催化作用机理.     

Effect of raw material composition on microstructures and properties of microporous MgO–Mg(Al,Fe)2O4 refractory aggregates

Microporous MgO–Mg(Al, Fe)₂O₄ refractory aggregates were prepared by the in-situ decomposition synthesis method using the magnesite, Al(OH)₃ and Fe₂O₃ as raw materials. The effect of raw material composition (theoretical Mg(Al, Fe)₂O₄ contents were 0–55 wt %) on their microstructure and strengths was investigated. When the theoretical Mg(Al, Fe)₂O₄ contents were relatively low (0–5.5 wt %), the number of neck connections between the particles in the microporous MgO–Mg(Al, Fe)₂O₄ refractory aggregates was small. As the theoretical Mg(Al, Fe)₂O₄ contents increased to be 11–22 wt %, the number of neck connections increased and the compressive strengths were enhanced. When the theoretical Mg(Al, Fe)₂O₄ contents increased to be excessive (33–55 wt %), the inter-particle pore size further increased due to the increase of volume expansion caused by the formation of more spinel, resulting in a decrease of compressive strength. Overall, when the theoretical Mg(Al, Fe)₂O₄ contents were 11–22 wt %, the microporous MgO–Mg(Al, Fe)₂O₄ refractory aggregates showed the excellent performances with the median pore sizes of 17.37–25.46 μm, the apparent porosities of 23.4–28.1%, the bulk densities of 2.57–2.79 g/cm³ as well as the compressive strengths of 41.2–75.8 MPa.     

Enhanced mechanical properties and biological responses of SLA 3D printed biphasic calcium phosphate bioceramics by doping bioactive metal elements

Favorable mechanical properties and outstanding bioactivity are necessary for bioceramics used for bone defect repair. The doping of Mg²⁺ and Fe³⁺ can improve the mechanical properties and bone regeneration capacity of calcium phosphate ceramics. In this study, magnesia oxide (MgO), ferric oxide (Fe₂O₃), and iron (Fe) powders are chosen as dopants to enhance biphasic calcium phosphate (BCP) bioceramics, and the MgO-BCP, Fe₂O₃-BCP, Fe-BCP bioceramics are prepared by stereolithography (SLA) for the first time. The effects of these dopants on the curing behavior of bioceramic slurries, mechanical properties, biodegradation, and cytocompatibility of BCP bioceramics are studied. The addition of 1 wt% Fe well enhances the flexural strength of BCP from 91.61 MPa to 122.60 MPa sintered at 1250 °C. The addition of 1 wt% MgO effectively promotes the biodegradation of BCP in simulated body solution (SBF), and enhances the proliferation of mouse pre-osteoblast (MC3T3-E1) cells in vitro. In addition, Fe powder is more suitable as a dopant for SLA 3D printed BCP than Fe₂O₃ powder, and all the performances of Fe-BCP are better than those of Fe₂O₃-BCP. The less microstructure defects and slower Fe³⁺ release rate make Fe-BCP have higher flexural strength and less cytotoxic compared with Fe₂O₃-BCP. This novel way exhibits beneficial effects of bioactive metal elements on mechanical properties and bioactivity, and indicates SLA 3D printed BCP bioceramic doped with MgO, Fe can be promising candidates for bone defect repair.     

Aerogel VOx/MgO catalysts for oxidative dehydrogenation of propane

VO_x/MgO aerogel catalysts were synthesized using three different preparation methods: by mixing the aerogel MgO support with dry ammonium vanadate, by vanadium deposition from a precursor solution in toluene, and by hydrolysis of a mixture of vanadium and magnesium alkoxides followed by co-gelation and supercritical drying. The latter aerogel technique allowed us to synthesize mixed vanadium–magnesium hydroxides with the surface areas exceeding 1300 m²/g. The synthesized catalysts were studied by a number of physicochemical methods (XRD, Raman spectroscopy, XANES and TEM). A common feature of all synthesized samples is the lack of V₂O₅ phase. In all cases vanadium was found to be a part of a surface mixed V–Mg oxide (magnesium vanadate), its structure depending on the synthesis method. The VO_x/MgO mixed aerogel sample had the highest surface area 340 m²/g, showed higher catalytic activity and selectivity in oxidative dehydrogenation of propane compared to the catalysts prepared by impregnation and dry mixing. The addition of iodine vapor to the feed in 0.1–0.25 vol.% concentrations was found to increase to propylene yield by 40–70%.     

固体酸负载Cu~Ⅰ催化剂表征及催化甲醇氧化羰基化

采用稀H2SO4和(NH4)2S2O8溶液浸渍Fe(OH)3,高温焙烧制得SO42-/Fe2O3和S2O82-/Fe2O3固体酸,然后与CuCl混合高温处理制备CuⅠ/SO42-/Fe2O3和CuI/S2O82-/Fe2O3催化剂。该催化剂在CH3OH液相氧化羰基化合成碳酸二甲酯(DMC)反应中表现出良好的催化活性,明显高于传统CuCl催化剂。载体和催化剂的XRD、NH3-TPD和XPS等表征结果表明,制备的SO42-/Fe2O3和S2O28-/Fe2O3固体酸为超强酸,与CuCl混合高温处理中发生了固体离子交换,形成了负载CuⅠ的低氯催化剂。固体酸载体酸量越多,离子交换负载的CuⅠ离子的含量越高,催化活性越好。550℃焙烧制备S2O82-/Fe2O3固体酸有较多的酸量,与CuCl热处理获得的CuⅠ/S2O82-/Fe2O3催化剂具有较好的催化活性,CH3OH转化率达到16.58%,DMC选择性和时空收率分别为97.00%和2.83g.g-1.h-1,且Cu/Cl原子比达到1.69。     

A study of the NOx storage catalyst of Ba–Fe–O complex oxide

The complex oxide Ba–Fe–O catalysts were prepared by sol–gel method. The XRD, DTA, NO-TPD, XPS and NSC measurements were used to characterize the structures, NO_x storage property and sulfur resistance ability. It is concluded that when coadsorption of NO and O₂ at 400 °C, the sample calcined at 750 °C possesses high NO_x storage capacity and sulfur resistance. The perovskite type BaFeO₃ and BaFeO_3−x phases are the active centers in the catalyst for NO_x storage.     

Nd2O3基复合氧化物上炭黑和NOx的同时催化去除特性

利用程序升温反应（TPR）技术，对同时催化去除柴油机炭黑和氮氧化物反应进行了研究.结果表明：稀土金属氧化物及其负载金属氧化物能在富氧条件下使炭黑（C）和氮氧化物（NO_x）互为氧化还原，主要生成CO₂和N₂，达到C-NO_x两者的同时催化去除.在Nd₂O₃等稀土氧化物上负载K和Mn等金属氧化物能降低炭黑的起燃温度，提高NO的还原转化率，其中K/Mn/Nd₂O₃ 上的催化反应同无催化反应相比，其炭黑起燃温度降低了170℃，最大NO→N₂转化率达到75.4％.K能显著降低起燃温度，并存在最佳负载量（2 mmol•g^-1）.K负载量过多，可能导致稀土金属氧化物上原有活性位的覆没.