The CO methanation over NaY-zeolite supported Ni/Co3O4, Ni/ZrO2, Co3O4/ZrO2 and Ni/Co3O4/ZrO2 catalysts

The CO methanation was studied over zeolite NaY supported Ni, Co₃O₄, ZrO₂ catalysts. The XRD, N₂ physisorption and SEM analysis were used in order to characterize the catalysts. Catalytic activities were carried out under a feed composition of 1% CO, 50% H₂ and 49% He between the 125 °C to 375 °C. Except for the Ni/Co₃O₄/NaY catalyst, all catalysts gave high surface area because of the presence of zeolite NaY. Average pore diameter of the catalysts fell into the mesopore diameter range. The highest CO methanation activity was obtained with Ni/ZrO₂/NaY catalyst at which the CO methanation was started after 175 °C and 100% CO conversion was obtained at 275 °C using the same catalyst.     

Effect of CeO2 Doping on Structure and Catalytic Performance of Co3O4 Catalyst for Low-Temperature CO Oxidation

The effect of CeO₂ doping on structure and catalytic performance of Co₃O₄ catalyst was studied for low-temperature CO oxidation. The Co₃O₄ catalyst was prepared by a precipitation method and the CeO₂/Co₃O₄ catalyst was prepared by an impregnation method. Their catalytic performance had been studied with a continuous flowing micro-reactor. The results reveal that the CeO₂/Co₃O₄ catalyst exhibits much better resistance to water vapor poisoning than the Co₃O₄ catalyst for CO oxidation. The CeO₂/Co₃O₄ catalyst can maintain CO complete conversion at least 8,400 min at 110 °C with 0.6% water vapor in the feed gas, while the Co₃O₄ catalyst can maintain at 100% for only 100 min. Characterizations with XRD, TEM and TPR suggest that the CeO₂/Co₃O₄ catalyst possesses higher dispersion degree, smaller particles and larger S_BET, due to the doping of Ceria, and exists the interaction between CeO₂ and Co₃O₄, which may contribute to the excellent water resistance for low-temperature CO oxidation. Furthermore, the H₂ detected in the reactor outlet gas seems to indicate that the water–gas shift reaction is the more direct reason.     

焙烧温度对CuO/Co_3O_4-CeO_2催化剂CO优先氧化性能的影响

采用浸渍法制备了Cu O/Co3O4-Ce O2(Cu Co Ce10)催化剂,考察了在不同温度(250、300、350、400和450℃)焙烧后的样品在富氢气氛中对CO优先氧化反应的催化性能。应用BET、XRD、H2-TPR及XAFS技术详细表征了催化剂的结构与性能。结果表明,不同温度焙烧的催化剂中,铜物种均主要以Cu O相存在;350℃焙烧的Cu Co Ce10催化剂具有最大的比表面积和最好的氧化还原性能,在98~173℃的温度范围内能够将CO完全转化为CO2,呈现出最宽的CO优先氧化可操作温度窗口,以及良好的催化活性稳定性。     

ZrO2(3Y)包裹Al2O3纳米复合粉体的制备

以pH值缓冲溶液为沉淀剂,用非均匀成核和液相共沉淀相结合的方法合成出了ZrO₂（3Y）包裹Al₂O₃纳米复合粉体.用XRD、TEM对所制备粉体进行了表征.研究表明：加入分散剂使Al₂O₃悬浮液的等电点向酸性区移动,Zeta电位绝对值增大,其中pH值为9.56对应的Zeta电位绝对值最大,悬浮液最稳定.Al₂O₃悬浮液pH值为9.5,ZrOCl₂和YCl₃混合溶液浓度为0.2 mol•L^-1时前驱体的收得率最高.600℃煅烧后得到的粉体中只有α-Al₂O₃、t-ZrO₂两种物相,在Al₂O₃颗粒表面附着10 nm左右的ZrO₂（3Y）颗粒.     

Co3O4负载纳米Au催化剂的制备

利用共沉淀法（CP）和沉积-沉淀法（DP）制备了Au／C0304催化剂,考察了制备条件及不同制备方法对金粒子大小的影响。结果表明,负载量为1wt％Au／Co3O4金粒子最小,分散度最好,而焙烧温度太高不利于金粒子的分散,另外,DP法制备的金粒子比CP法制备的要小。     

Co3O4-Bi2O2CO3催化剂的制备及其光催化性能

以Bi(NO₃)₃·5H₂O、Co(CH₃COO)₂·4H₂O为原料,采用化学沉淀-水热法制备了Co₃O₄-Bi₂O₂CO₃异质结构复合半导体光催化剂,并通过X射线衍射仪（XRD）、扫描电镜（SEM）、X射线光电子能谱（XPS）、紫外可见漫反射光谱（DRS）、荧光光谱（PL）等手段对所合成的复合型催化剂进行了理化性能表征。研究结果表明：引入Co₃O₄没有改变Bi₂O₂CO₃物相结构,但促进了Bi₂O₂CO₃ 对可见光的吸收能力,提高了Bi₂O₂CO₃表面吸附氧物种的数量,抑制了光生载流子复合。复合光催化剂对罗丹明B（RhB）的光催化脱色实验显示引入Co₃O₄能够明显提高Bi₂O₂CO₃催化剂的光催化脱色能力。尤其是Co₃O₄引入量为0.6%的Co₃O₄-Bi₂O₂CO₃样品对罗丹明B染料的光催化脱色率可达到97%（模拟日光照射30min）。本文为复合型光催化剂制备提供了简单易行的技术路线,制备的新型半导体复合光催化剂Co₃O₄-Bi₂O₂CO₃在环境净化方面表现出了较好的应用前景。     

Ceramics Based on Cubic ZrO2 (Y2O3) with Addition of a Fused Al2O3 – ZrO2 (Y2O3) Eutectic

Ceramics based on cubic zirconia with addition of crushed granules of fused or rapidly cooled Al₂O₃ – ZrO₂ (Y₂O₃) eutectic are developed and their properties (shrinkage, open porosity, apparent density, bending strength, and grain size) determined. The ceramic composites can find use in the preparation of electrolyte material for high-temperature fuel cells.     

A Novel Catalyst Pt/CoAl2O4/Al2O3 for Combination CO2 Reforming and Partial Oxidation of CH4

Pt/CoAl₂O₄/Al₂O₃, Pt/CoO_x/Al₂O₃, CoAl₂O₄/Al₂O₃ and CoO_x/Al₂O₃ catalysts were studied for combination CO₂ reforming and partial oxidation of CH₄. The results indicate that Pt/CoAl₂O₄/Al₂O₃ is the most effective, and XRD results indicate that Pt species are well dispersed over the Pt/CoAl₂O₄/Al₂O₃. High dispersion is related to the presence of CoAl₂O₄, formed during calcining at high temperature before Pt addition. In the presence of Pt, CoAl₂O₄ in the catalyst could be reduced partially at 973 K. Based on these results, it appears that zerovalent platinum with high dispersion and zerovalent cobalt resulting from CoAl₂O₄ reduction are responsible for high activity in the Pt/CoAl₂O₄/Al₂O₃ catalyst.     

Ga2O3/PAL复合催化剂的制备及催化性能研究

以凹凸棒石(PAL)为载体,沉淀法制备了Ga2OJPAL复合催化剂,采用IR、XRD、BET、TEM对催化剂结构进行表征,通过肉桂酸正丙酯的合成,由正交实验方法考察催化剂的制备条件和催化性能.结果表明,催化剂的较优制备条件是Ga2O3负载量为催化剂总质量的12％,前置液pH值为9,盐酸浸泡液浓度3.0 mol/L,焙烧温度460℃.使用所制催化剂合成肉桂酸正丙酯,产品酯化率不低于94.0％,催化剂具备良好的催化活性,可多次重复使用.     

填料型La2O3/Al2O3-Al催化剂的制备及其催化性能

以n水硝酸镧[La(NO3)3·n H2O]为原料,阳极氧化铝(Al2O3-Al)为载体,采用水热合成法将活性组分负载在Al2O3-Al上,制备了填料型固体碱催化精馏元件La2O3/Al2O3-Al,以丙酮缩合制备二丙酮醇为探针反应,考察了制备条件对催化剂性能的影响。采用XRD、SEM对催化剂的性能进行了表征。结果表明,活性组分La2O3均匀分散在载体Al2O3-Al表面上。当La(NO3)3·n H2O与氨水(NH3·H2O)的摩尔比为1∶8,油浴温度为160℃,油浴时间10 h,N2保护下焙烧温度为550℃,焙烧时间为2 h时,催化剂的活性最高,此时丙酮转化率为4.1%,二丙酮醇选择性98%。     

Ni/ZrO2/Al2O3催化剂在CO2重整CH4反应中催化性能研究

Ni/ZrO2/Al2O3催化剂在二氧化碳重整甲烷反应中,其催化活性和稳定性均优于Ni/ZrO2和Ni/Al2O3催化剂.XRD、TPD、TPR结果表明,在Ni/ZrO2/Al2O3催化剂上能形成较稳定的活性中心,负载型纳米ZrO2/Al2O3复合载体中,ZrO2以四方相形式出现,粒径为5 nm,微波和超声波的作用能诱导ZrO2和Al2O3产生新的碱性中心,有利于二氧化碳的吸附和提高活性组分的分散度.TG-DSC结果表明Ni/ZrO2/Al2O3催化剂上表面炭主要是活性较高的α炭,而Ni/ZrO2和Ni/Al2O3催化剂表面炭主要是活性较低的β炭和γ炭.     

管式反应制备氧化锆纳米晶微粉的研究

本文采用管式ＳＫ－１０／２０型表态混合反应器对ＺｒＯＣｌ２·８Ｈ２Ｏ·ＹＣｌ３与ＮＨ·Ｈ２Ｏ进行液相共沉淀反应以制备ＺｒＯ２（Ｙ２Ｏ３）纳米晶微粉。研究了表态混合器反应过程中的流速、混合特性和反应浓度对粉体粒径与粒径分布的关系,并进行了分析探讨。     

二氧化锆的制备及其应用进展

ZrO2 (Y2 O3)是重要的结构陶瓷和功能陶瓷的原材料。有关ZrO2 (Y2 O3)的研究包括ZrO2 (Y2 O3)粉体原料制备研究及应用开发研究 ,二者相互促进。本文就国内外目前ZrO2 (Y2 O3)粉体原料的制备方法及其相关应用进展进行了讨论 ,介绍了该领域的发展趋势     

Regulation of Y2O3 addition on structure and properties of Al2O3/ZrO2(Y2O3) directionally solidified eutectic ceramic

Al₂O₃/ZrO₂(Y₂O₃) directionally solidified eutectic ceramics (DSECs) with different Y₂O₃ addition were prepared. Three polymorphs of ZrO₂: m-ZrO₂, t-ZrO₂ and c-ZrO₂ appeared and disappeared in order with the increase of Y₂O₃ addition, the effects of Y₂O₃ addition amount on the mass fraction of ZrO₂ polymorphs were quantitatively analyzed. The gradual decrease of area fraction and average size of colony was attributed to the increase of constitutional undercooling region, the variation of interphase spacing in the colonies was explained via selection mechanism of dendrite tip. The maximum hardness and fracture toughness were 18.35 GPa and 8.55 MPa m^1/2 obtained at 9 mol% and 3 mol% Y₂O₃ addition, respectively. The hardness was determined by the mass fraction of m-ZrO₂ phase, the area fraction of intercolony and the residual compressive stress, and the toughening mechanisms were composed of microcrack toughening, t-m transformation toughening and residual stress toughening.     

Y2O3液相掺杂ZrO2粉体的制备及其特性

用一种新的液相掺杂技术制备Y2O3的ZrO2纳米粉体,在水－乙醇溶剂中,干燥由硝酸铝,硝酸钇和单斜相氧化锆粉体组成的悬浮液,然后在600℃热分解,可以制备出粒度小于100nm的Y2O3掺杂单斜相ZrO2粉体,这种粉体可以在0．1Pa的真空中,经1450℃热压烧结成致密化Y－TZP材料,此材料的断裂韧性（KIC)为9．9MPa.m^1/2,Vickers硬度（HV100N）为11．720GPa。     

High-gravity activated SHS of large bulk Al2O3/ZrO2 (Y2O3) nanocrystalline composites

Large bulk Al₂O₃/ZrO₂ (Y₂O₃) composites were in-situ prepared by SHS under varied high-gravity from ZrO₂ + Y₂O₃powder blends with an added thermit mixture. Investigated was the effect of high gravity on the microstructure, crystal growth, and properties of synthesized materials. The XRD data suggest that high gravity did not bring about any change in the phase constitution of the composite ceramics and that the ceramic matrix was composed of α-Al₂O₃, t-ZrO₂, and m-ZrO₂. SEM and EDS data show that, with increasing level of high gravity, the morphology of the ceramic microstructures transformed from the cellular eutectics to the rodshaped colonies, and the volume fraction and aspect ratio of the rod-shaped colonies increased while the rodshaped colonies were refined. Above 200 g, the microstructures of composite ceramics developed as the randomlyorientated rod-shaped colonies with a symmetrical triangular dispersion of tetragonal ZrO₂ fibers of 300 nm in the average diameter. Relative density, hardness, flexural strength and fracture toughness simultaneously reached the highest values of 98.6%, 18.6 GPa, 1248 MPa, and 15.6 MPa m^1/2 as the maximum high-gravity level of 250 g was achieved. An increase in the relative density and hardness of the ceramics with increasing gravity level was attributed to the acceleration of gas escape from SHS melts and the elimination of shrinkage cavity in the ceramics under the action of high-gravity field. The increase in fracture toughness results from the enhancement of the coupled toughening mechanisms while the increase in flexural strength comes from the refinement of the microstructures, decrease in critical defect size, and achievement of high fracture toughness.     

单质Ag修饰Co3O4的高活性Li-O2电池催化剂的制备及性能

以金属有机框架-74为模板制备了仿锤体状Co3O4,然后与单质Ag复合,通过界面工程提高了材料电导率,制备出Li-O2电池的高活性催化剂Ag/Co3O4.在100mA/g电流密度,使用Ag/Co3O4催化剂的Li-O2电池的放电比容量达到了13 945mA·h/g,即使在1000mA/g高电流密度,依然可以保持4476...     

稀土固体超强酸SO42-/SnO2-Al2O3-Sm2O3的制备及其催化性能

采用沉淀-浸渍法制备了新型稀土固体超强酸SO42-/SnO2-Al2O3-SmO3,通过IR、TG等手段对其进行了表征分析,应用于合成丁醛乙二醇缩醛,考察其催化性能,较系统地研究了稀土氧化物种类、用量、焙烧温度、焙烧时间、浸渍液浓度等因素对产品收率的影响.实验结果表明适宜的催化剂制备条件为:稀土氧化钐含量为3%,焙烧温...     

双金属异相催化剂Fe3O4@La-MOF-Schiff-Pd/Ni的制备及其催化Suzuki偶联反应

将Fe3O4纳米粒子负载到金属有机骨架La-MOF中,然后向其中引入Pd/Ni活性位点,制得含磁性纳米粒子的Pd/Ni双金属异相催化剂（Fe3O4@La-MOF-Schiff-Pd/Ni）,并通过SEM、TEM、EDS、ICP、PXRD和XPS对其进行了表征。结果表明,Fe3O4纳米粒子被成功嵌入到了La-MOF中,经过后合成修饰后,Pd和Ni活性位点被均匀分散在MOF框架中。该催化剂在Suzuki偶联反应中表现出较高的催化活性,以碘苯(1.0 mmol)和苯硼酸(1.2 mmol)为反应物时,最佳催化反应条件为：以无水乙醇为溶剂、无水碳酸钾为碱、反应温度80℃、反应时间为6 h、催化剂用量8 mg,在此条件下联苯产率达95%。该催化剂可以通过外加磁铁进行分离回收,经过5次循环使用后仍然保持较高的催化活性,产物产率为82%。Suzuki偶联反应机理探究结果表明,Pd和Ni可能具有协同催化效应。底物拓展实验表明,Fe3O4@La-MOF-Schiff-Pd/Ni双金属催化剂对含不同取代基的芳基溴化物和碘化物具有较好的普适性。