添加稀土氧化物对甲烷化催化剂中镍分散度的影响

本文对稀土氧化物的助剂作用做了进一步研究，对添加１４种稀土氧化物的催化剂进行了活性表面积、ＣＯ吸附ＩＲ谱、表观活化能的测定及ＡＥＳ表面微区分析。结果表明，添加稀土氧化物助剂，提高了镍的分散度，使镍更富集于表面，增加了反应的活性中心数目，反应活化能没有降低，具有结构效应，但不同稀土元素的作用不同。这可能与稀土元素本身的性质有关。     

稀土改性Ni/γ-Al_2O_3催化剂上甲烷化反应积碳的初步研究

本文系统考察了镧系１４种稀土氧化物对镍基甲烷化催化剂积碳的影响，发现大多数稀土的添加使催化剂活性提高，寿命延长，尤以Ｄｙ，Ｐｒ，Ｓｍ效果最佳，主要作用是稀土添加剂促进了甲烷化活性中心数的增长，有抑止积碳的能力，缩短催化剂的增活期。     

Ni/海泡石及Ni-Sm/海泡石催化剂的研究

采用海泡石为载体,金属镍为活性组份,稀土为助剂,用不同方法制备了Ｎｉ／Ｓｅｐ 和Ｎｉ－Ｓｍ ／Ｓｅｐ 催化剂,并考察了它们的苯加氢反应性能。结果表明：Ｎｉ／Ｓｅｐ 催化剂的活性明显高于Ｎｉ／Ａｌ２Ｏ３,稀土Ｓｍ 对Ｎｉ／Ｓｅｐ 催化剂有较大的改性作用。ＴＰＲ、ＴＰＤ、ＣＯ吸附结果表明,海泡石和钐能使镍的还原温度降低,氢吸附量增大,活性中心增加,同时使镍原子电子密度增高。     

稀土对Ru基加氢催化剂的改性研究

采用浸渍法制备了一系列的Ru-RE/sepiolite(海泡石)(RE=La,Ce,Tb或Y)催化剂,以二氧化碳甲烷化及苯加氢为探针反应,以TPD、TPSR、CO化学吸附和CS2中毒为手段系统地研究了RE对Ru/sepiolite催化剂的改性机制。结果表明,RE的加入显著影响Ru/sepiolite催化剂的催化性能。从机理上看,RE对CO2甲烷化性能的影响是通过对反应物活化过程中的能量因素及几何因素的调节作用来实现的。RE的加入增加了Ru/sepiolite催化剂的活性表面积、活性中心数和催化剂抗毒物的能力。研究还表明,RE的添加顺序亦对Ru/sepiolite催化剂的活性构成一定的影响。     

不同稀土及不同含量的助催化剂对重整反应的影响

考察了不同含量的稀土助剂L a对催化剂比表面积和催化活性的影响,其中以L a含量为1.5%(质量分数)时最佳。催化剂经过973K反应后得到的产物中,H2的量明显大于CO的量,≥1023K时H2/CO的值接近1,这是由于不同温度下催化剂对CH4和CO2活化的程度不同。添加不同稀土助剂催化剂的反应活性与其比表面积有正向关系,比表面积大则活性相对较高,反之则低,其中以L a和Ho为最佳。     

Study on Modification of Sm2O3 by Ni／Sepiolite Catalyst

A series of Ni-Sm/sepiolite catalysts were prepared by impregnation. The modification of Sm2O3 for Ni/sepiolite was investigated by TPR, XPS and poisoning of CS2, respectively. The results indicate that the addition of Sm2O3 improves the activity of hydrogenation and anti-poisoning ability of Ni/sepiolite catalyst, and it also increases the dispersion of nickel atoms over support and the amount of active nickel atoms in catalyst. Effect of Sm203 on Ni/sepiolite catalyst ineludes not only electronic effect but also steric effect, whereas electronic effect seems to be principal.     

变价稀土氧化物对催化剂性能的影响

本文从原子结构分析了变价稀土元素原子的结构特点 ,从机理上分析了变价稀土氧化物对催化剂原子氧化价的稳定性、贮氧能力和热稳定性等性能增强的根源 ,从理论上深入认识了稀土氧化物的助催化作用。     

不同载体对镍基催化剂的XPS影响

La掺杂的BaTiO3粉体与未掺杂BaTiO3粉体颗粒大小相仿,前者更为分散。通过XPS试验发现,Ni(2p)的结合能在Ni/B中比在Ni/A中为小,说明Ni/B中的Ni具有更大的电子密度;同样,La、Ce掺杂的镍基BaTiO3催化剂表明稀土元素的掺入能使镍基BaTiO3催化剂表面的镍电子密度增大。Ni/A表面的Ni含量少得多,表面分布较散。BaTiO3和La掺杂BaTiO3的XPS能谱基本相同。     

镍元素对炭阳极反应活性的影响

考察了煅后焦中微量元素镍对炭阳极反应活性的影响,并对炭阳极的二氧化碳反应性、空气反应性进行了测试。结果表明,适量的镍元素可以改善炭阳极在CO2中的残极率、粉化率和质量损失率;也能提高炭阳极在空气中的残极率、粉化率和质量损失率。镍元素的添加对炭阳极的CO2反应性和空气反应性均有抑制作用,可改善炭阳极质量,降低炭阳极的额外消耗。     

Effect of La_2O_3on Methanation of CO and CO_2over Ni-Mo/γ-Al_2O_3Catalyst

In the early 1980s, it was reported thatrare earth oxide can improve the properties ofnickel catalysts['J. In this paper, the effect ofLaZO3 on activity of methanation of CO andCOb over Ni-Mo/Y-A12O3 was studied. The relationship between catalytic activity, surfacebehaviour and the role of LaZO3 in Mi-Mo-La/Y-Allot catalyst were investigated by means oftransmission electron microscope (TEM ), Xray photoelectron spectroscopy (XPS ), andchemisorption of CO.1 Experimental1. I Prepara…     

Study on Roast Reaction Kinetics of Baotou Concentrate of Rare Earth with 15% Na_2CO_3 Additions

ＴｈｅｒｅｓｅａｒｃｈｏｎｔｈｅｒｏａｓｔｒｅａｃｔｉｏｎｏｆＢａｏｔｏｕｃｏｎｃｅｎｔｒａｔｅｏｆｒａｒｅｅａｒｔｈｗｉｔｈＮａ２ＣＯ３ａｄｄｉｔｉｏｎｓｂｅｇａｎｉｎ１９６３ａｎｄｔｈｅｉｎｄｕｓｔｒｉａｌｓｃａｌｅｅｘｐｅｒｉｍｅｎｔｓ...     

Ca(OH)_2改性活性炭及其吸附CO_2的研究

采用Ca(OH)2为化学活化剂,对颗粒活性炭进行改性。结果表明,在Ca(OH)2用量为100mL、改性温度80℃、改性时间2h、干燥时间6h时,改性后的活性炭吸附容量达到最大,为3.91mmol/g。     

稀土掺杂锂离子电池正极材料LiCoO2的影响研究

在合成LiCoO2的基础上,采用共沉淀法掺杂稀土La、Ce、Lu、Y等合成制备了LiRExCo1-xo2,并对其进行了XRD、SEM表征及电性能测试.结果表明,合成的LiRE、Co1-xO2具有LiCoO2结构,当稀土La的加入量x＜0.05时,稀土能完全形成单一LiRExCo1-xO2相;稀土的掺入能促进LiCoO2结晶,同时使104面的相对衍射强度增加;LiRExCo1-xO2首次放电容量达147.4 mA·h/g,循环稳定性有所提高.     

NiO-La2O3/γ-Al2O3催化剂中各组分间的相互作用

本文采用差热分析、X射线衍射、透射电镜和选区电子衍射对催化剂的物种情况及形貌加以研究 ,结合催化剂焙烧过程的相变情况 ,从而获得催化剂焙烧过程的化学反应情况。发现稀土助剂的加入使载体的晶体结构发生变化 ,从而使载体表面改性 ,抑制了 Ni Al2 O4的生成 ,提高了 Ni O的分散度。而且发现有 L a2 O2 CO3晶体存在于载体表面 ,L a2 O3以高度分散的状态存在     

Dimethyl ether synthesis from CO2 hydrogenation on La-modified CuO-ZnO-Al2O3/HZSM-5 bifunctional catalysts

A series of CuO-ZnO-Al2O3-La2O3 /HZSM-5 bifunctional catalysts with various La loadings for dimethyl ether (DME) directly synthesized from CO2 hydrogenation were prepared. The catalysts were characterized with N2 adsorption-desorption, X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), NH3 temperature-programmed desorption (NH3-TPD) and N2O titration techniques, and tested for the synthesis of DME directly from CO2 hydrogenation in a fixed-bed reactor. The results showed that the reducibility, dispersion of bifunctional catalysts were strongly dependent on the addition of La. With the addition of appropriate amount of La, the crystallite size of CuO was decreased and the dispersion of Cu on the surface was enhanced, which resulted in the increased conversion of CO2 . It was also found that the selectivity to DME was related to the intensity and amount of strong acid site on the catalyst surface. The presence of La favored the production of DME, and the optimum catalytic activity was obtained when the amount of La was 2.0 wt.%.     

Promotional effect of CO pretreatment on CuO/CeO2 catalyst for catalytic reduction of NO by CO

The CuO/CeO2 catalysts were investigated by means of X-ray diffraction(XRD),laser Raman spectroscopy(LRS),X-ray photoelectronic spectroscopy(XPS),temperature-programmed reduction(TPR),in situ Fourier transform infrared spectroscopy(FTIR) and NO+CO reaction.The results revealed that the low temperature(150 °C) catalytic performances were enhanced for CO pretreated samples.During CO pretreatment,the surface Cu+/Cu0 and oxygen vacancies on ceria surface were present.The low valence copper species activated the adsorbed CO and surface oxygen vacancies facilitated the NO dissociation.These effects in turn led to higher activities of CuO/CeO2 for NO reduction.The current study provided helpful understandings of active sites and reaction mechanism in NO+CO reaction.     

利用CO2减少炼钢烟尘的实验研究

炼钢过程每冶炼1 t钢产生约10～20 kg烟尘,烟尘量的增加既降低金属收得率又增加了除尘负荷.炼钢烟尘的治理,传统方式是在烟尘产生后再进行回收处理利用;然而如何在冶炼过程中减少烟尘产生的工艺方法还未见文献报道.通过热力学计算和理论分析,进行了利用CO2减少炼钢烟尘产生的探索性实验,实验结果表明,随着混合喷吹中二氧化碳比例的提高,烟尘的产生量逐步减少,铁损呈明显的下降趋势.     

包头稀土精矿添加25%碳酸钠焙烧反应动力学研究

采用XRD、DTA-TG及化学分析等方法,对包头稀土精矿添加25%碳酸钠焙烧反应进行了研究。分解反应分两个阶段进行,第一阶段348℃～455℃,稀土氟碳酸盐分解为稀土氟氧化物,铈被氧化得到CeO