新型Rh-Ni@MOF-5催化剂催化烯烃氢甲酰化反应的研究

用新型双金属催化剂Rh-Ni@MOF-5对不同碳链长度的烯烃氢甲酰化反应进行研究。用直接法合成的MOF-5晶体作催化剂载体,将Rh、Ni元素负载在MOF-5上合成Rh-Ni@MOF-5。采用TG、XRD、SEM、TEM和FTIR等手段对其进行表征,结果表明,负载金属后的催化剂拥有规整的立方体结构且热稳定性较强。采用3种烯烃的氢甲酰化反应对其催化性能进行评价,结果表明,Rh-Ni@MOF-5对烯烃的氢甲酰化反应具有良好的催化作用并且解决了反应后催化剂的分离回收问题。在一定条件下,其反应转化率均高于70%。与单金属催化剂Rh@MOF-5进行对比发现,双金属催化剂具有更高的催化活性,其收率和选择性均较单金属催化剂有明显优势。以1-己烯氢甲酰化反应为例,考查了Rh-Ni@MOF-5的使用寿命,结果表明,多次重复利用后仍能保持稳定的晶体结构和良好的催化性能。     

生物质基含氧化合物在过渡金属碳化物上加氢脱氧研究进展

过渡金属碳化物由母体金属化合物经渗碳反应而形成,具有多变的结构组成和类贵金属的电子性质,是一类具有广泛应用前景的廉价催化材料,在催化加氢、加氢脱氧（hydrodeoxygenation,简写为HDO）和氢解等诸多重要催化反应中表现出优异的性能。近年来,对过渡金属碳化物的研究及其催化应用取得显著进展,但由于其固有的复杂性如相组成、表面缺陷与物种等导致构效关联等科学问题尚不清晰,仍有待进一步研究。本文综述了近年来过渡金属碳化物在生物质热解油中代表性含氧化合物HDO制备燃料和高附加值化学品中的研究进展,在分析了代表性含氧化合物反应路径的基础上,重点介绍了过渡金属碳化物的设计与合成策略及其结构与HDO催化性能关联,并展望了过渡金属碳化物作为生物质基含氧化合物HDO催化材料的研发方向与发展前景。     

天然气催化燃烧催化剂的研究(Ⅱ）

介绍了天然气催化燃烧钙钛矿型氧化物催化剂、六铝酸盐型催化剂以及负载型非贵金属催化剂的研究现状。对于钙钛矿型氧化物催化剂,利用A位取代或调整B位元素的种类及配比、新的技术和方法制备高比表面积或具有纳米结构的钙钛矿型氧化物,是提高其甲烷催化燃烧活性的重要手段。六铝酸盐型催化剂具有很高的热稳定性和甲烷燃烧活性,但起燃温度较高,通过采用将金属Pd负载到六铝酸盐上或改变制备方法,提高其比表面积,以提高其低温反应活性。负载型非贵金属催化剂研究最多的是过渡族金属,其氧化活性、抗毒性能和耐久性都存在问题,需进一步研究。     

用于甲苯甲醇烷基化制备对二甲苯反应的ZSM-5分子筛改性研究

甲苯甲醇烷基化制备对二甲苯具有良好的工业应用前景,ZSM-5分子筛由于其特殊的结构在该反应中展现出优异的催化性能,对ZSM-5分子筛进行改性研究,有助于提升其催化性能。本文从引入金属与非金属元素改性方面综述了国内外对ZSM-5分子筛改性用于甲苯甲醇烷基化制对二甲苯反应的研究进展。     

壳聚糖过渡金属配合物研究进展

壳聚糖分子中含有大量相邻的羟基和氨基,在合适条件下与过渡金属离子络合,能够得到具有特殊结构和性能的过渡金属配合物,因而在化学催化、吸附分离、自由基清除、材料等方面有广泛的应用。本文对壳聚糖过渡金属络合物的合成、结构表征、配位机理、热稳定性及其应用研究进行了综述,为壳聚糖过渡金属络合物的进一步发展提供科学帮助,并促进其规模化生产。     

MOFs衍生镍单原子材料电催化还原化学镀镍废水中的亚磷酸盐

通过水热合成和高温煅烧制备了一种具有电催化还原活性的MOFs(金属有机骨架化合物)衍生镍单原子材料(标记为Ni@NC),将其负载于石墨毡上用作化学镀镍废水中亚磷酸盐电催化还原为次磷酸盐的阳极,以实现化学镀镍工艺中磷的循环。分析了所得Ni@NC催化材料的微观形貌、晶体结构、元素组成和电化学性能。通过电催化还原反应实验研究了反应器构型、电流密度、pH、反应时间和电极重复使用次数对Ni@NC电催化还原性能的影响。在采用阳离子交换膜的情况下,以电流密度10 mA/cm2反应120 min,pH为3的模拟废水中亚磷酸盐的还原率达到60%左右。     

金属有机框架材料催化氧化脱硫研究进展

金属有机框架(MOFs)由于其高比表面积、结构多样且孔径可调节等性能被应用于反应催化剂.研究表明,不同的制备方法和反应条件对金属有机框架材料性能有重要影响.针对不同MOFs本体以及MOFs改性材料的催化氧化脱硫性能进行了比较,探讨了影响MOFs材料性能的因素,发现材料结构中的缺陷以及复合材料中的协同作用对催化氧化脱硫性...     

水热法制备磷酸镍及其光催化性能

由于金属磷酸盐自身的结构较为多样化,使其被用到陶瓷、催化剂载体、吸附剂、离子交换剂与分子筛中。而在金属磷酸盐中磷酸镍是较为关键的一部分,其在催化、颜料、电镀等多方面的应用较为广泛,但如今对于磷酸镍在光催化方面的性能研究较少,因此,对水热法的制备技术展开简述,进而采用水热法制备了磷酸镍,最后研究磷酸镍处于紫外光照射下的光催化活性。     

应变工程调控金属材料的电催化性能研究进展

金属基催化材料在电催化反应中占有举足轻重的地位,金属催化剂的电子结构显著影响其电催化性能。应变工程能调控金属催化剂表面原子的电子结构,改变金属与吸附物分子的相互作用强度,影响电催化性能。综述了近年来金属催化剂中应变工程的引入策略,重点评述应变与金属电催化反应性能的构效关系及其作用机制,并对该领域的发展趋势进行了展望。     

多金属氧酸盐催化合成缩醛（酮）的研究进展

作为具有出色催化性能的绿色催化剂多金属氧酸盐,在催化合成缩醛（酮）反应领域展现出了广阔的应用前景。首先简要地介绍了多金属氧酸盐的性质及其应用;然后综述了近几年来多金属氧酸盐及负载多金属氧酸盐催化剂在催化合成缩醛（酮）反应中的研究现状,包括活性炭、硅胶、二氧化钛、分子筛等载体;并对其未来的发展方向进行了展望。     

Partial oxidation reactions on phosphate-based catalysts

In this work emphasis has been placed on phosphate-based catalysts used for partial oxidation reactions, such as vanadyl pyrophosphate, iron phosphates and hydrogen/hydroxy-phosphates, zirconium hydrogen phosphates as layered compounds used to stabilise/entrap Cr and V oxyhydroxy-macrocations. It is shown that, in partial oxidation reactions, the catalyst surface behave in a rather dynamic and labile way, reconstructing under activation and/or catalytic reaction conditions and adapting itself to the stereochemistry of the reactants. The active sites are shown to have a molecular size, to be isolated and to present several catalytic functions, as hydrocarbon activation, H atom abstraction, lattice oxygen incorporation and electron transfer through the solid material to allow the redox process to occur. The metal cations are the active species and the role of the phosphate tetrahedra is not only to bind the MO₆ octahedra together to constitute a dense or layered compound but also to bring some specific redox and acid–base properties. This revised version was published online in August 2006 with corrections to the Cover Date.     

High-performance phosphate supported on HZSM-5 catalyst for dehydration of glycerol to acrolein

The purpose of this study is to increase acrolein yield and capability of coking resistance in the reaction of glycerol dehydration to acrolein by assembling metal phosphate supported on HZSM-5 catalyst.The as-prepared catalysts were characterized by XRD,SEM,EDS,BET,NH3-TPD,CO2-TPD and Py-IR techniques.It was found that metal phosphate species were incorporated into the porous structure of HZSM-5 zeolites,thus influencing the surface and textural physico-chemical properties of the supporters.The alkaline-treated HZSM-5 catalyst promoted the dispersion of phosphate species on the carriers.Moreover,the amount of strong aridity was tremendously improved by adding the different metal hydrophosphates and the catalysts show high catalytic activity.In this present work,the Sn1/4H2PO4/HZSM-5 catalyst exhibited good performance in the catalytic activity and coking resistant ability,which resulted in a high acrolein yield of 83％ initially and acrolein yield of 68％ after 30 h.The aridity,especially the ratio of strong to weak acid,plays an important role in promoting acrolein yield and stability simultaneously.     

New catalysts for poly(butylene terephthalate) synthesis. Part 3: effect of phosphate co-catalysts

An exhaustive study of the co-catalytic activity of phosphates on titanium and titanium/hafnium based catalytic systems in poly(butylene terephthalate) synthesis was conducted in order to investigate any improvement in the process and/or in the properties of the final polymer with respect to the industrially used titanium based catalyst. Small scale polymerisation and subsequent scale up in higher capacity reactors showed a strong co-catalytic effect of phosphates. A screening on model compounds showed NaH₂PO₄ to be the most active co-catalyst. The co-catalysts had a stronger effect on titanium with respect to hafnium. Decreases in polymerisation time and tetrahydrofuran formation were observed, which in turn can improve the productivity of the whole process. Moreover, the use of phosphate improved the thermal stability of the final polymers.     

New halogen‐free fire retardant for engineering plastic applications

A comparative study of the fire‐retardant efficiency of three commercial aryl phosphates—triphenyl phosphate (TPP), resorcinol bis(diphenyl phosphate) (RDP) and bisphenol A bis(diphenyl phosphate) (BDP)—in PC/ABS blends was carried out. The thermal and hydrolytic stability of the fire‐retardant resins, as well as their physical properties, was also studied. The use of RDP and BDP is preferred over TPP because of superior properties, whereas BDP shows better fire‐retardant efficiency, hydrolytic stability, and thermal stability than RDP.     

Properties of detergent phosphates and their effects on detergent processing

Phosphates are usually key ingredients in detergent formulations ranging from liquids to free-flowing powdery material to hard cakes. Their functional properties, which contribute to the over-all detergency by controlling the alkalinity, lowering the critical micelle concentration, sequestering metal ions, and decreasing soil redeposition, are generally considered to be the reason for their wide use. Another important but less recognized reason is their versatile role in improving the handling properties and lowering the cost of the finished products. The sophistication of the phosphate manufacturing processes makes it possible to turn out a large number of phosphates with different properties and physical forms. Trisodium orthophosphate, tetrapotassium pyrophosphate, and sodium phosphate glass are for the specialties. Sodium tripolyphosphate, the work-horse of the detergent phosphates, has many grades. Some are designed to give the desired hydration properties for different detergent-processing conditions. Size and density are varied for granular grades to reduce segregation and degradation in dry-blended detergents. Sodium trimetaphosphate, which converts rapidly into tripolyphosphate, offers a new detergent-processing technology. Effervescent phosphate is an intriguing new detergent phosphate with many possible new applications. The properties of these phosphates and their effect on the detergent products and processes are discussed in detail.     

UiO-66基催化剂的制备及其在CO甲烷化中的应用

煤制天然气技术具有良好的经济和环境效益,其中CO甲烷化是煤制天然气过程的重要环节之一。本研究以UiO-66材料为载体制备了一系列具有不同Ni负载量的Ni/UiO-66催化剂,采用XRD, BET, TG, SEM, TEM, XPS等表征方法对载体和催化剂的物相结构、织构性质、热稳定性和元素分布情况进行考察,并对各催化剂上CO加氢性能进行了考察。研究结果表明,Ni金属高度分散于UiO-66载体上,且对金属有机骨架材料的物相结构和晶体形貌无显著影响。在CO甲烷化反应过程中,随Ni负载量逐渐增加,各Ni/UiO-66催化剂的起活温度逐渐降低;在相同反应温度(320℃)下,不同催化剂上Ni负载量由10%增加到30%,其CO转化率由10.7%提升到89.7%;当Ni含量为20%时,催化剂在反应过程中具有良好的稳定性。同时,Ni基催化剂上CO转化率远高于具有相同金属负载量的Fe基和Co基催化剂,表明Ni作为活性金属在合成气制甲烷反应过程中具有优异的催化性能。     

Oxidative coupling of methane over sodium-chloride-added sodium zirconium phosphates

Monosodium zirconium phosphate or disodium zirconium phosphate by itself did not catalyze the oxidative coupling of methane and also the deep oxidation of methane. However, NaCl-added sodium zirconium phosphates showed markedly increased activity and high C₂₊ selectivity in the oxidative coupling of methane, which indicates that chlorine species or NaCl plays an essential role in the catalytic action. The catalytic performance became more stable with increasing content of NaCl. The primary reason for the catalyst deactivation is the loss of chlorine, and a possible secondary reason is the transformation of catalytic substance to the sodium zirconium phosphates having higher Na/Zr ratios or decomposition of sodium zirconium phosphates to zirconium oxide and sodium phosphate. Two kinds of surface chlorine species were observed, and the lower-binding-energy species is considered to be much more active than the higher-binding-energy species in methane activation, although the latter is present in a larger amount than the former.     

The Effect of the Structure of Trialkyl Phosphates on their Physicochemical Properties and Extraction Behavior

The density of various trialkyl phosphates (TalP) such as tri‐n‐butyl phosphate (TBP), tri‐iso‐butyl phosphate (TiBP), tri‐sec‐butyl phosphate (TsBP), tri‐n‐amyl phosphate (TAP), tri‐2‐methylbutyl phosphate (T2MBP), tri‐iso‐amyl phosphate (tri‐3‐methylbutyl phosphate, TiAP), tri‐sec‐amyl phosphate (tri‐2‐amyl phosphate, TsAP), tri‐cyclo‐amyl phosphate (TcyAP), tri‐n‐hexyl phosphate (THP), and 1.1 M solutions of some of these phosphates in various diluents, solubility of water in trialkyl phosphates, and the aqueous solubility of trialkyl phosphates have been measured. Extraction of nitric acid, Th(IV), and U(VI) by trialkyl phosphates has also been studied by the batch extraction method. Metal‐solvate stoichiometry in the extraction of Th(IV) and U(VI) by some of the phosphates has been evaluated. Data on the extraction of U(VI) by various trialkyl phosphates as a function of equilibrium aqueous‐phase nitric acid concentration at 303 K are presented in this paper. Data on the extraction of Th(IV) and U(VI) from 1 M and 5 M HNO₃ by trialkyl phosphates as a function of equilibrium aqueous‐phase metal concentration at 303 K are also presented in this paper. The effects of the structure of trialkyl phosphates on their physicochemical properties and extraction behavior are described in this paper.     

Synthesis of Metal Phosphates Using SiP2O7

A new, alternative, route to the synthesis of metal phosphates, using SiP₂O₇ as a reagent, was studied. The reaction of SiP₂O₇ with metal oxides yields a solid mixture of silica and metal phosphates; its reaction with metal fluorides yields solid metal phosphates and gaseous mixtures of SiF₄ and POF₃ .     

铁硼基海绵催化电极的制备及其高效析氢性能

采用温和化学镀法在非导电基底材料聚氨酯海绵(PU)上成功制备了NiB@Fe–B/PU催化电极，并通过掺杂少量第三种元素，如钴、钼等金属元素制备了NiB@Fe–Co–B/PU和NiB@Fe–Mo–B/PU催化电极。结果表明，掺杂钴、钼可明显提升NiB@Fe–B/PU催化电极的析氢性能，其中掺杂钴的性能更优。在0.5 mol/L缓冲液(磷酸缓冲盐溶液，PBS)中，NiB@Fe–Co–B/PU电极的析氢反应(HER)过电位仅为161 mV(电流密度, j=50 mA/cm2)，塔菲尔斜率为68.24 mV/dec，且在过电位为61 mV下能够稳定工作24 h以上，电化学稳定性良好。