氢气高温还原制备的负载型镍基催化剂用于苯酚加氢的性能

通过等体积浸渍法分别将Ni(NO₃)₂、NiCl₂、NiSO₄ 3种镍前体浸渍于A1₂O₃或SiO₂载体上,然后通过H₂高温还原法制备了负载型镍基催化剂,考察了镍前体、载体种类、镍负载量、反应条件等对镍基催化剂苯酚加氢性能的影响。结果表明,对比3种镍前体,在H₂高温还原体系中Ni(NO₃)₂最容易被还原,制备的镍基催化剂苯酚加氢活性最高。SiO₂负载的镍基催化剂活性远高于γ-Al₂O₃催化剂。适宜的Ni负载量有助于活性组分的分散和催化活性的提高。镍基催化剂的苯酚加氢产物以环己醇为主,相对缓和的反应条件更容易生成环己酮。在非极性溶剂正庚烷或环己烷存在下,苯酚加氢反应速率远远高于极性溶剂水或乙醇存在下的结果,而且环己酮的选择性更高。     

羰基镍粉焙烧制备高纯度微米氧化亚镍粉体的研究

以羰基镍粉为原料,采用焙烧法制备了氧化亚镍,并将其球磨后得到微米粉体。采用热重-差示扫描量热仪（TG-DSC）研究了羰基镍粉在空气气氛中加热时的氧化行为,利用激光粒度分析仪、等离子体光谱仪、X射线衍射仪（XRD）和扫描电镜（SEM）等分析了样品结构、成分和形貌。结果表明：空气和氧气两种气氛对产物纯度影响不明显。在两种载气条件下,通过优化焙烧温度和焙烧时间（焙烧温度为700 ℃、焙烧时间为2 h、载气流量为1.5 L/min）,羰基镍粉可直接焙烧制备得到纯度为100%、结晶度高的面心立方体氧化亚镍,球磨后得到粒度为4~19 μm的类球形微米氧化亚镍粉末。制备过程具有工艺简单、环境友好的特点。     

球形镍氧化物制备硫酸镍的方法研究

以球形镍氧化物为原料,研究了制备高纯硫酸镍的方法。首先借助X射线衍射仪（XRD）和X射线光电子能谱仪（XPS）对球形镍氧化物的主要成分进行表征,确认其主要成分为氧化镍;其次对球形镍氧化物浸取制备较高纯度的硫酸镍条件进行了优化,确立了硫酸浓度为1.84 mol/L、反应温度为200 ℃、固液比为0.3 g/mL、反应时间为6 h为最优反应条件;最后利用高温条件下（250 ℃）获得的一水合硫酸镍固体,提出了将其再次溶解生产pH和镍浓度可控的高纯硫酸镍溶液的方法。     

新型固定床Raney Ni催化剂的制备、表征及苯加氢活性评价

将镍铝合金粉、拟薄水铝石和田菁粉捏合、成型,在空气中高温焙烧,然后用苛性碱溶液充分浸取,制备出可应用于固定床加氢的活性Raney Ni催化剂.实验结果表明,成型合金焙烧过程中,富铝合金相逐渐转化为贫铝相,同时小部分金属铝氧化生成α-Al₂O₃,可提高催化剂的颗粒强度.BET和SEM分析表明,催化剂表面具有较宽的缝隙和丰富的大孔结构.苯加氢活性评价表明,在一定反应条件下,该新型固定床Raney Ni催化剂活性高于传统负载型镍催化剂,也高于按照专利方法制备的同类型催化剂.     

氧化镍空心壳材料的合成及其气敏特性测定

通过化学合成方法得到分散均匀的氧化亚铜方块,在此基础上以其作为硬模板采用模板技术,以六水合二氯化镍为金属源,通过“协同刻蚀”的方法获得氢氧化镍空心壳材料,并进一步热处理得到氧化镍空心壳材料。经过透射电子显微镜（TEM）,并结合广角X射线衍射等手段,证实所得材料为空心氧化镍材料。通过在旁热式气敏元件表面简单涂抹的办法制得气敏器件,并对其正丁醇气敏性能进行了测定。研究结果表明,该种材料在250 ℃下对正丁醇具有较好的敏感性,这表明该种材料是一种非常有前途的功能材料,有望获得广泛应用。     

Partial oxidation of methane to synthesis gas over some titanates based perovskite oxides

Ca_1–x - _x Sr _x TiO₃-based mixed oxide catalysts containing chromium, iron, cobalt or nickel were prepared and used in the oxidation of methane. The catalyst containing cobalt or nickel showed high activity for the synthesis gas production from methane. In the case of nickel containing catalyst, nickel oxide originally separated from the perovskite structure was easily reduced to nickel metal, which showed synthesis gas production activity. In the case of the cobalt containing catalyst, pretreatment with methane was required for high activity. Reduced metallic cobalt was formed from the perovskite structure, which revealed relatively high selectivity for the oxidative coupling of methane, and afforded synthesis gas production. Both the catalysts also catalyzed carbon dioxide reforming of methane and especially both high activity and selectivity were observed over the nickel containing catalyst.     

Colloidal nickel boride on rare earth oxides for hydrogenation of olefins

An extremely active and colloidal nickel boride was prepared by using rare earth oxide as a support in the presence of polyethylene glycol (PEG) at room temperature which could act as a catalyst in the hydrogenation of olefinic compounds, such as 4-(4'-hydroxyphenyl)-3-buten-2-one.     

Reductibility of silica supported nickel oxide

The reduction of nickel/silica catalysts was studied in parallel by temperature programmed reduction (TPR) and X-ray diffraction (XRD) methods. The calcined materials contain nickel in the form of nickel oxide and nickel hydrosilicates and a part of the oxide particles is covered with the hydrosilicate species. This oxide is reduced in the same way as unsupported nickel oxide in the absence of water, and in a similar way to nickel hydrosilicates in the presence of water.     

Hydrogenation of heptaldehyde to heptyl alcohol with nickel catalysts

Hydrogenation of heptaldehyde to heptyl alcohol was studied with W2 Raney nickel catalyst, prepared in the laboratory, commercial Raney nickel catalyst and Rufert nickel catalyst by varying temperature, catalyst concentration, hydrogen pressure and reaction time. The products were analyzed by gas-liquid chromatography on SE-30 column. The optimum conditions found for quantitative conversion (99.6%) of heptaldehyde to heptyl alcohol were: temperature, 100°C, W2 Raney nickel catalyst concentration, 2% based on heptaldehyde (w/w), hydrogen pressure, 145 psig and reaction time, 1 h. IICT Communication No. 3085.     

高活性纳米镍催化剂的制备及其催化性能研究

在液相化学还原法的基础上引入实验室自制的还原助剂M-1,制备了纳米镍粉催化剂。采用XRD,SEM,Mastersizer 2000粒径分析仪、EDS等方法对其结构及性能进行了表征,并在对硝基苯酚催化加氢反应中考察了其催化性能。结果表明,所得粉体为平均粒径57nm的纳米镍粉体;在同样的实验条件下,该催化剂的催化活性大约是工业上通常使用的Raney Ni的16倍。还原助剂的引入导致催化剂晶粒的减小,从而提高了催化剂的催化活性。     

XRD studies of evolution of catalytic nickel nanoparticles during synthesis of filamentous carbon from methane

The XDR technique was used for studying a series of high‐loaded (90%) nickel catalysts with silica as a textural promoter. These were catalysts for direct cracking of methane at 550°C. A relation between the initial average size of active catalyst particles, carbon yield and average methane conversion was demonstrated. Genesis of these catalysts was studied including oxide precursors, reduced catalysts prior to the reaction, as well as catalysts upon their contacting the reaction medium for various periods of time from 15 min to 2 h. The active catalyst particles were shown to merge or disperse at the outset of the reaction depending on their initial size. Anyway, close average sizes ranging from 30 to 40 nm were observed by the end of the first reaction hour for all the catalytic systems providing the carbon yield of 300–385 g/g Ni. The catalytic system was shown to self‐organize in the course of direct methane cracking, i.e., the catalyst particles transform in response to the reaction conditions. If the size of nickel particles cannot vary, these catalysts are inefficient for the given process. This revised version was published online in July 2006 with corrections to the Cover Date.     

ＭＢ-１新型抗镍钝化剂在RFCCU上的应用试验

在研究金属型和非金属型单组分钝镍元素的基础上,通过具有协同作用元素间的复配和优化,并考虑工业应用的可行性和成本,研制了无毒、高效、稳定性好的ＭＢ-１水溶性钝镍剂,在内蒙古呼和浩特炼油厂60万吨／年RFCCU上进行了工业应用试验。结果表明,当原料油中掺渣8%～10%,平衡剂上镍含量高达11000～13000ｐｐｍ,使用ＭＢ-１钝镍剂前后相比较,轻油收率增加１.４ｗｔ％,焦炭产率相对下降１２ｗｔ％～１３ｗｔ％,氢气产率相对下降５３ｗｔ％～５４ｗｔ％,平衡剂活性指数增加３～４个单位。新型无毒ＭＢ-１钝镍剂钝化效果显著,使用方便,有显著的经济效益和社会效益。     

Preparation and characterization of nanosized nickel oxide

Nanosized nickel oxide was synthesized by a simple liquid-phase process to obtain the hydroxide precursor and then calcined to form the oxide. The precursor and the nickel oxide were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), thermal analysis (TG) and temperature-programmed reduction (TPR). The results indicated that the particle size of nickel oxide was controlled by the calcined temperature (T_C). Mixed phases of nickel oxide and nickel hydroxide were present as the T_C was lower than 300 °C. Non-stoichiometric nickel oxide (NiO_x, x = 1.2) was formed between 250 °C and 400 °C and a pure nickel oxide was formed as the T_C arrived 500 °C. The particle size of nickel oxide changed as the calcined temperature was controlled under 250 °C, 300 °C, 400 °C and 500 °C, the order was 5.6 nm, 6.5 nm, 11 nm and 17 nm, respectively.     

从失活的油脂加氢催化剂中回收镍

采用酸浸后再氨络合的方法从废油脂加氢催化剂中回收镍，镍的回收率最高可达99%以上。酸浸前先在适当温度下焙烧废催化剂样品有利于镍的溶出。使用由盐酸与硫酸以适当比例构成的混酸比使用单一盐酸或硫酸更有利于镍的溶出。加氨时，采用反加方式比正加和并流方式所得镍的回收率高。     

Interactions of supported nickel and nickel oxide catalysts with methane and steam at high temperatures

The catalytic performance of cermets made of 10% nickel or nickel oxide supported on YSZ (yttria-stabilized zirconia) for chemical looping combustion (CLC) and steam reforming (SR) of methane at 700 °C is investigated. Steam reforming of methane over the reduced catalyst resulted in a syngas containing more than 70% hydrogen and about 15% carbon monoxide. Chemical looping combustion of methane with insufficient lattice oxygen could potentially lead to 40–65% hydrogen rich gas products. Prolonged induction period (e.g. 30–80 min) in reduction of nickel oxide by methane has been observed in the presence of steam. The span of induction period increases by increasing steam partial pressure. It is hypothesized that the delayed reduction of nickel oxide is related to the retarding effect of steam on autocatalytic reactions of methane and hydrogen with lattice oxygen of nickel oxide and the subsequent reforming reactions.     

Low temperature gasification of brown coals catalysed by nickel

Nickel catalyst exhibited an extremely high activity in the gasification of some low rank coals at a temperature as low as 750 K. Approximately 85% of Yallourn coal was converted within 30 min in steam at 773 K. A high nickel loading, > 4 wt% was necessary. It seems essential for coal high in oxygen and low in sulphur to be gasified in this manner. Oxygen-containing functional groups on the coal surface seemed to play an important role in keeping the nickel catalyst in a finely dispersed state. Hydrogen sulphide was strongly adsorbed on the nickel catalyst and retarded this reaction. Hydrogen and carbon dioxide were the main products of low-temperature steam gasification. Similar low-temperature gasification reactions were also observed in hydrogen and in carbon dioxide.     

硫改性镍催化剂丁烯-1双键临氢异构性能

将Ni/Al_2O_3催化剂浸渍于有机多硫化物(TPS-37)中制备得到硫改性Ni/Al_2O_3催化剂。采用X射线荧光光谱(XRF)、热重-质谱(TG-MS)联用、X射线光电子能谱仪(XPS)和程序升温还原(TPR)等方法对催化剂进行表征,并考察了硫改性Ni/Al_2O_3催化剂上丁烯-1双键临氢异构性能。结果表明,硫改性Ni/Al_2O_3催化剂经高温氢气活化及甲苯萃取后,催化剂上硫含量基本不变。硫与催化剂之间存在较强的相互作用,使氧化镍在相对较低的温度下被H2还原;硫改变了Ni金属周围电子环境,从而显著改善催化剂的双键临氢异构性能。在反应温度60℃,氢压1.6 MPa,氢气和碳四烃物质的量之比(氢烃比)为0.013的条件下,硫改性Ni/Al_2O_3催化剂催化丁烯-1双键临氢异构反应,丁烯-1转化率可达92.6%,丁烯-2选择性为97.5%。催化剂稳定性实验结果表明,硫改性催化剂催化性能好,稳定性优良。     

制备方法对胶体镍催化性能的影响

通过化学还原法制备了胶体镍催化剂,并将其用于丙烯腈加氢反应。通过X射线衍射和透射电镜对催化剂进行了表征,考察了制备条件对催化性能的影响。结果表明,当c(Ni²⁺)＝10 mmol·L^-1 、温度90 ℃和n(N₂H₅ OH)∶nNi²⁺)=8时,制得的胶体镍具有较好的稳定性和催化活性,胶体镍的平均粒径为30 nm。     

超增溶自组装制备纳米氧化镍

采用超增溶自组装合成了纳米氧化镍,并通过透射电镜（TEM）、X射线衍射（XRD）、N2吸附脱附BET法和热重分析（TG）表征了其结构。结果表明,形成的纳米粒子分散性良好,粒径分布较窄(10～20 nm),晶粒度良好,微晶晶化比较完全,氧化镍纳米粒子具有较大的孔径,比表面积和孔容符合纳米粒子特性。确定了超增溶自组装制备纳米氧化镍的最佳工艺条件。     

Deactivation of fixed-bed nickel hydrogenation catalysts by sulfur

A series of fixed-bed nickel hydrogenation catalysts was tested in the dearomatization of hydrocarbon solvents. The mechanism of catalyst deactivation by aromatic sulfur compounds was studied in high-pressure micro-flow equipment by variation of the experimental conditions and the sulfur content of the feed. It is concluded that catalyst deactivation proceeds under mild but realistic conditions through formation of a surface sulfide which blocks the active surface. The rate of the disappearance of the active sites is a first-order process with rate constant 1.0 × 10⁻³ (ppm S)⁻¹ h⁻¹. Under more severe conditions, more sulfide layers are formed, but bulk Ni₃S₂ was not observed even after full deactivation of the catalysts. The poisoning of the active sites in the latter case is no longer a first-order process. Consequently, under the circumstances investigated, the sulfur resistance of nickel catalysts is determined by the nickel surface area per unit weight of catalyst.