Physicochemical modification of nanodiamonds

Thermal modification of nanodiamonds in the atmosphere of argon and hydrogen and their chemical modification with oleum and chlorine at different temperatures were studied. The effect of the modification conditions on the catalytic activity of palladium catalysts supported by nanodiamonds in the reaction of nitrobenzene hydrogenation and on the adsorption properties of nanodiamonds with respect to benzene, chloroform, and water was analysed.     

A nickel-substituted form of nanodiamonds and its catalytic activity in decomposition of hydrogen peroxide

Adsorption of nickel (II) ions with nanodiamonds obtained by the detonation synthesis was studied. A nickel-substituted form of nanodiamonds was obtained. The catalytic activity exhibited by nickel ions (II) in the form of the surface complexes with nanodiamond functional groups in decomposition of hydrogen peroxide was determined.     

Plasma Catalytic Synthesis of Ammonia Using Functionalized-Carbon Coatings in an Atmospheric-Pressure Non-equilibrium Discharge

We investigate the synthesis of ammonia in a non-equilibrium atmospheric-pressure plasma using functionalized-nanodiamond and diamond-like-carbon coatings on α-Al₂O₃ spheres as catalysts. Oxygenated nanodiamonds were found to increase the production yield of ammonia, while hydrogenated nanodiamonds decreased the yield. Neither type of nanodiamond affected the plasma properties significantly. Using diffuse-reflectance FT-IR and XPS, the role of different functional groups on the catalyst surface was investigated. Evidence is presented that the carbonyl group is associated with an efficient surface adsorption and desorption of hydrogen in ammonia synthesis on the surface of the nanodiamonds, and an increased production of ammonia. Conformal diamond-like-carbon coatings, deposited by plasma-enhanced chemical vapour deposition, led to a plasma with a higher electron density, and increased the production of ammonia.     

Surface chemical modifications and surface reactivity of nanodiamonds hydrogenated by CVD plasma

The present study focuses on the interaction of hydrogen microwave CVD plasma with nanodiamonds (NDs). Hydrogen treated NDs (H-NDs) were characterized using electron spectroscopies (XPS, AES) without air exposure. A surface temperature higher than 700 °C is needed to remove the oxygen present on raw NDs. The kinetics of oxygen removal were investigated. Moreover, UHV annealings of H-NDs after ageing in ambient air clearly underline that 75% of the oxygen is related to physisorbed species. Finally, H-NDs were efficiently grafted using photochemical reaction with alkenes and a spontaneous coupling of aryldiazonium salts. These results confirm similar electronic surface properties between bulk and nano diamond materials.     

Platinum- and palladium-containing carbon nanomaterials as catalysts for hydrogenation and hydrogenating amination

The catalytic activity of the carbon nanomaterials containing platinum and palladium in the model reactions of liquid-phase hydrogenation of nitrobenzene and hydrogenating amination was investigated. The catalytic systems based on nanodiamonds are more efficient than platinum-containing fullerene black, multi-walled nanotubes, and carbon nanofibers.     

Pt- and Pd-containing nanodiamonds in hydrogenation and hydroamination reactions

The catalytic activity of platinum- and palladium-containing nanodiamonds has been investigated in liquid-phase nitrobenzene, allyl alcohol, and cyclohexene hydrogenation and propanal hydroamination with 4-aminobenzoic acid as model reactions. The catalysts suggested are significantly more active than commercial Pd/C. The catalysts with a low metal weight content are the most effective in liquid phase catalytic hydrogenation.     

The chemistry of the surface of modified detonation nanodiamonds of different types

The influence of standard chemical treatment used to extract interstellar nanodiamonds from meteorites on the chemical composition of the surface of synthetic nanodiamonds with substantially different properties was studied by thermal desorption mass spectrometry and IR spectroscopy. The chemistry of the surface of nanodiamonds after treatment was substantially different from that of initial particles. The suggestion was made that the chemical structure of the surface of diamond particles in the interstellar space could be reconstructed from the data on meteorite diamonds. Mass spectrometric studies also gave information about possible mechanisms of the release of noble gases from meteorite diamonds at various temperatures.     

甲醇水蒸气重整制氢CuAl2O4催化材料的研究

以γ-Al₂O₃为原料采用原位合成法制备CuAl₂O₄催化材料，通过XRF、XRD、BET和H₂-TPR等手段对催化材料进行表征，考察铜铝物质的量比对CuAl₂O₄催化材料结构、性质及其催化甲醇水蒸气重整制氢性能的影响。结果表明，不同铜铝物质的量比主要影响了铜物种的还原性能，从而影响了其催化甲醇水蒸气重整制氢的性能。当铜铝物质的量比为1：2时，CuAl₂O₄催化材料的催化性能较好，在反应温度为260℃，水醇物质的量比为1.2，甲醇气体空速为800 h^-1时，甲醇转化率为100%，产氢速率为895 mL/（kg·s）。     

Superior (de)hydrogenation properties of Mg-Ti-Pd trilayer films at room temperature

In this paper, a series of Mg-Ti-Pd trilayer films with various thicknesses of the Ti interlayer were prepared by magnetron sputtering. The trilayer films could be reversibly (de)hydrogenated at room temperature. The relationship between structure and properties of Mg-Ti-Pd trilayer films was comprehensively investigated. Our studies showed that the hydrogen storage properties of Mg-Pd films were significantly improved with the addition of a Ti interlayer. The optimal hydrogenation properties were obtained when the Ti interlayer was 1 nm. The superior hydrogenation properties achieved by introduction of the Ti interlayer could be attributed to several aspects: prevention of Mg-Pd alloying; catalytic dissociation of H(2) molecules and provision of heterogeneous nucleation sites. These results were elucidative for the development of high performance intermetallic hydrogen storage materials and thin film based functional devices.     

钙钛矿型甲醇水蒸气重整制氢催化材料的研究

采用溶胶凝胶法合成了钙钛矿复合氧化物, 负载氧化铜后得钙钛矿负载型催化材料, 通过XRD (X射线衍射分析)、BET(比表面积测试)、H₂-TPR(程序升温还原分析)、XPS (X射线光电子能谱)等手段对催化材料进行了表征, 考察了不同种类钙钛矿负载纳米铜催化材料的结构、性质对甲醇水蒸气重整制氢性能的影响. 结果显示, 钙钛矿负载纳米铜催化材料的催化活性主要与催化剂的铜比表面积、表面晶格氧缺位以及活性组分和载体间的相互作用有关. 其中, CuO/LaCrO₃钙钛矿负载型催化材料的表面氧空穴含量较多, 活性组分与载体间相互作用较强, 因此催化甲醇水蒸气重整制氢活性较好. 当反应温度为360 ℃时, CuO/LaCrO₃钙钛矿型催化剂并未出现明显失活现象, 甲醇转化率为98.6%, 产氢速率为694.9 mL•kg_cat ^–1•s ^–1.     

Development of a rational technology for synthesis of high-quality detonation nanodiamonds

Concepts concerning the structure of detonation nanodiamonds were generalized on the basis of data reported in previous publications. The pH value of the nanodiamonds in an aqueous suspension was determined. The mechanism of the longest stage, washing of nanodiamonds with water to remove excess acidity, was considered. A novel method for substantially improving the quality of nanodiamonds and the stability of aqueous suspensions of nanodiamonds was suggested.     

Study of catalytic hydrodeoxygenation performance for the Ni/KIT-6 catalysts

Ni/KIT-6 catalysts loaded with different amounts of metallic Ni were prepared by impregnation method. The prepared catalysts and their precursors were investigated through wide- and low-angle XRD, TEM, BET, H₂-TPR, and H₂-TPD analyzes. The catalytic hydrodeoxygenation performance of the catalysts was evaluated using ethyl acetate as a model bio oil compound. Results indicate that the catalytic hydrodeoxygenation performance of the prepared catalysts was directly related to hydrogen storage properties, hydrogen desorption properties, dispersion of the active component Ni, and so on. The ethyl acetate conversion and ethane selectivity of 25?wt% Ni/KIT-6 catalyst were 100 and 96.8%, respectively, at 300?°C, which shows the best performance. The hydrodeoxygenation activity of ethyl acetate was higher than that of methyl acetate and isopropyl acetate because of the effect of molecular polarity and size. And, this reaction is a structure sensitive reaction.     

PdAg/MIL-101(Fe)催化NaBH4水解制氢

将PdAg纳米颗粒负载到MIL-101(Fe)上作为硼氢化钠水解制氢的催化剂。采用XRD、TEM、HRTEM、XPS、SEM和EDS等方法对催化剂PdAg/MIL-101(Fe)的结构进行了表征。PdAg/MIL-101(Fe)在硼氢化钠水解制氢中表现出较高的催化活性,在温和的条件下水解制氢最大速率为2.60 L·min^–1·g_cat.^–1。详细研究了反应温度、催化剂用量、氢氧化钠和硼氢化钠浓度对该催化反应的影响规律。结果发现,制氢速率很大程度上依赖于反应温度,随着反应温度的升高,制氢速率明显增加,制氢的表观活化能为54.89 kJ·mol^–1。该催化剂重用性能好,5次循环后仍能保持活性。     

An active phase transformation on surface of Ni-Au/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst during partial oxidation of methane to synthesis gas

It was studied the influence of gold addition on physico-chemical properties and catalytic activity of bimetallic Ni-Au/Al₂O₃ catalyst in partial oxidation of methane (POM). The reduction behavior in hydrogen, XRD crystal structure, XPS spectra and POM catalytic activity were investigated. The reduction of Ni-Au catalyst is a prerequisite condition to catalyze POM reaction. The formation of Ni-Au alloy during high temperature reduction in hydrogen and also in the conditions of POM reaction was experimentally proved. The addition of gold to Ni/Al₂O₃ system improves catalyst stability and activity in POM reaction.     

硅铁ZSM-48沸石的CO加氢催化性能

考察了硅铁ＺＳＭ－４８负载铁、钾催化剂在ＣＯ加氢制备低碳烯烃反应中的催化性能。结果表明,Ｆｅ（Ⅲ）离子同晶取代Ｓi（Ⅳ）后,不仅使沸石分子筛的表面能量分布更加趋 于均匀,而且明显促进了活性组分铁的还原和减弱了催化剂表面吸附氢的能力,从而大大提高了反应活性和选择性。硅铁ＺＳＭ－４８负载过量的铁、钾都不利于ＣＯ加氢合成低碳烯烃,其负载量的量侍值分别为８％和１．９％。另外,硅铁ＺＳＭ－４８的焙烧温度和焙烧     

苯环上氯取代位对四苯基金属卟啉催化烯烃环氧化性能的影响

以苯乙烯、环己烯和反式二苯乙烯为烯烃底物,以双氧水、叔丁基过氧化氢和异丙苯过氧化氢为氧化剂,以苯环上对位和邻位氯取代的四苯基金属卟啉为仿生催化剂,对烯烃的催化环氧化反应进行了对比研究.讨论了不同氯取代位的四苯基金属卟啉对烯烃环氧化性能的影响.实验结果表明,在没有助催化剂存在下,邻位氯代的四(2,6-二氯苯基)铁(锰)卟啉对烯烃的环氧化具有优异的催化性能,烯烃底物的转化率和环氧选择性都比对位氯代的四苯基铁(锰)卟啉高,且反应条件温和.其中FeⅢ(TDCPP)Cl的催化性能最好,环氧化选择性最高,催化氧化苯乙烯时,环氧苯乙烷的选择性达到了90.4%.相同金属离子不同配体的金属卟啉传递氧原子的能力为TDCPP>T(p-Cl)PP>TPP.氧化剂的结构对环氧化物的选择性有较大影响.过氧键连有吸电子基团的异丙苯过氧化氢对环氧化物的选择性最高.根据实验结果,对金属卟啉催化环氧化机理进行了分析.     

沉淀剂对镍基甲烷化催化剂性能的影响

利用尿素、碳酸铵、氨水三种沉淀剂制备了不同的镍基甲烷化催化剂,考察了沉淀条件对催化剂性能的影响。通过XRD、H₂-TPR、BET、TPO等方法对催化剂进行表征。结果表明,使用不同沉淀剂所得催化剂性能各不相同。采用尿素沉淀剂,颗粒的比表面积达到了223.55m²/g,具有较稳定的催化活性;碳酸铵沉淀颗粒粒径较大,分散也不够均匀,催化剂更容易积炭;氨水沉淀制备的催化剂粒径小,与载体结合性强,高温下活性组分易于流失。分析认为,沉淀剂影响了催化剂前驱体的形态和结构,造成了分散度、晶相结构、对氢的吸附性质以及抗积炭性等多方面的差异,表现出甲烷化反应活性和稳定性的不同。     

Interaction of shungite carbon nanoparticles with blood protein and cell components

We have analyzed and compared the effects of aqueous dispersion of shungite carbon nanoparticles, fullerene C₆₀, and nanodiamonds on structure, dynamics, and thermodynamic and redox properties of blood proteins (serum albumin and hemoglobin), proteins of erythrocyte ghost membranes as well as on erythrocyte integrity and aggregation.. All the nanomaterials dispersions have induced similar effects; however, nanodiamonds have not influences the redox properties. Basing on the results, the experimental and theoretical approaches presented can be employed to estimate the effects of biological structures contact with the nanoparticles on the bioreactivity.     

Ion chromatographic investigation of the ion-exchange properties of microdisperse sintered nanodiamonds

The possibility of using sintered diamonds as a stationary phase in ion chromatography has been evaluated. Bare sintered synthetic nanodiamonds demonstrated the properties of a weak cation-exchanger. The observed ion-exchange selectivity is similar to carboxylic type cation-exchangers. The regularities of retention of alkali, alkaline-earth and transition metal ions on a column packed with sintered nanodiamonds in dilute nitric acid were studied and the occurrence of chelating properties was noted. For the first time chromatographic separations of model mixtures of cations on diamonds have been obtained.