Well‐Dispersed CoS Nanoparticles on a Functionalized Graphene Nanosheet Surface: A Counter Electrode of Dye‐Sensitized Solar Cells

With a facile electrophoretic deposition and chemical bath process, CoS nanoparticles have been uniformly dispersed on the surface of the functionalized graphene nanosheets (FGNS). The composite was employed as a counter electrode of dye‐sensitized solar cells (DSSCs), which yielded a power conversion efficiency of 5.54 %. It is found that this efficiency is higher than those of DSSCs based on the non‐uniform CoS nanoparticles on FGNS (4.45 %) and built on the naked CoS nanoparticles (4.79 %). The achieved efficiency of our cost‐effective DSSC is also comparable to that of noble metal Pt‐based DSSC (5.90 %). Our studies have revealed that both the exceptional electrical conductivity of the FGNS and the excellent catalytic activity of the CoS nanoparticles improve the conversion efficiency of the uniformly FGNS‐CoS composite counter electrode. The electrochemical impedance spectra, cyclic voltammetry, and Tafel polarization have evidenced the best catalytic activity and the fastest electron transport. Additionally, the dispersion condition of CoS nanoparticles on FGNS plays an important role for catalytic reduction of I₃^?.     

Effect of vanadium over NiMo/sepiolite hydrotreating catalyst

Summary Hydrotreating (HDT) and hydrodesulfuration (HDS) using an FCC feed were carried out at 673-748 K and 50 MPa total pressure. The effect of vanadium impregnated on a NiMo catalyst supported on sepiolite for HDT and HDS reactions was studied. A commercial NiMo/Al₂O₃ catalyst was used as reference. The hydrotreating conversions (wt.% HDT) is defined here as the net hydrotreating conversion into products boiling below 653 K. The results were compared with an accelerated ageing test using the catalysts on a FCC feed, with vanadium in the form of naphthenate (2000 ppm of V) added to rapidly deactivate catalysts via metal deposition. The results indicate that vanadium affects more the catalyst supported on sepiolite that the commercial catalyst. Also, at our reaction conditions, the effect of vanadium on sepiolite catalyst is similar, to those used with vanadium impregnated on the catalyst or on the catalyst where the vanadium in naphthenate form was added to FCC feed.     

Mild hydrotreating over NiMo/sepiolite catalyst

Summary In order to introduce an alternative catalyst for hydrotreating (HDT) reaction a study of NiMo supported on natural sepiolite catalysts is presented. The sepiolite catalyst has been prepared in this laboratory and a NiMo/Al₂O₃ commercial catalyst is used as a reference. The textural properties of the materials and their catalytic activity in hydrotreating (HDT) and hydrodesulfuration (HDS) using a FCC feed at 400-475°C and 50 MPa total pressure, have been evaluated. The support of the commercial catalyst is alumina containing mesopores. The sepiolite support is a hydrated magnesium phylosilicate containing micropores but with an open structure that confers the possibility to use it as a catalyst. The hydrotreating conversion (wt.% HDT) is defined here as the net hydrotreating conversion into products boiling below 380°C. For the commercial catalyst the wt.% HDT was only 5% higher than for the catalyst supported on sepiolite and the product selectivity was very similar. HDS conversion was 20% lower for the sepiolite supported catalyst. Taking into account these results the sepiolite is a suitable support of HDS catalysts.     

Heterogenized peroxopolyoxotungstate catalyst on the surface of clicked magnetite‐graphene oxide nanocomposite: Magnetically recoverable epoxidation catalyst

A new heterogeneous catalyst for the epoxidation of olefins was prepared by immobilization of peroxophosphotungstate anions on the surface of clicked magnetite‐graphene oxide as magnetically recoverable support. To prepare the heterogeneous catalyst, the clicked magnetite‐graphene oxide support was prepared by thiolene click reaction of thiol functionalized graphene oxide with vinyl modified magnetite nanoparticles. The tailored support was then modified with aminopropyl groups followed by electrostatic interaction with peroxophosphotungstate anions to achieve the desired heterogeneous catalyst. Characterization of the catalyst was performed by various physicochemical methods which confirmed the successful immobilization of peroxopolyoxotungstate species on the surface of clicked magnetite‐graphene oxide. Catalytic activity of the catalyst revealed its high catalytic activity and selectivity in the epoxidation of various olefins in the presence of H₂O₂ as green oxidant. This heterogeneous catalyst can be magnetically reused several times without significant loss of activity and selectivity.     

Synthesis of hexamethylene-1,6-dicarbamate by methoxycarbonylation of 1,6-hexamethylene diamine with dimethyl carbonate over bulk and hybrid heteropoly acid catalyst

Synthesis of HDC by methoxycarbonylation of HDA with DMC was carried out over the bulk and hybrid heteropoly acid (HPA) catalyst. The catalysts were systematically characterized by XRD, FTIR, SEM and NH₃-TPD techniques. The by-products produced in the reaction were identified and a possible reaction pathway was proposed based on the by-products analysis. The performances of bulk and hybrid HPA catalysts were evaluated. The H₄[SiW₁₂O₄₀] catalyst revealed high performance compared with other catalysts and its high performance was attributed to its acidic properties. Effects of reaction parameters and reusability of the H₄[SiW₁₂O₄₀] catalyst were also investigated. Under the optimized reaction conditions, HDA conversion reached 93.2% with 64.8% HDC selectivity and only 3.8% by-product selectivity. Moreover, a possible reaction mechanism was proposed for the synthesis of HDC over H₄[SiW₁₂O₄₀] catalyst.     

Influence of the activation temperature on structural and textural properties of NiMo/Al2O3 hydrodesulfurization catalysts

Investigations of a commercial NiMo/Al₂O₃ hydrodesulfurization (HDS) catalyst are directed towards optimization of the activation procedure of HDS catalyst concerning active phase formation and thermal stability. Structural and textural data obtained with XRD, IR-FTIR, XPS and LTNA reveal that the optimal temperature for the formation of active species on the catalyst surface and an appropriate pore structure is 300°C.     

多级孔NiMo负载TS-1分子筛催化剂的制备及其加氢脱硫性能

钛硅(TS-1)分子筛的微孔孔道严重限制了其在复杂分子催化转化中的应用,为了克服这一问题,通过酸洗脱、碱刻蚀及二者相结合的方法制备了多级孔 TS-1 分子筛,并采用等体积共浸渍法制备了相应的 NiMo 负载型催化剂;使用 X 射线衍射(XRD)、N₂吸附-脱附、吡啶吸附红外光谱(Py-FTIR)、氢气程序升温还原(H₂-TPR)、X射线光电子能谱(XPS)和高分辨透射电子显微镜(HR-TEM)等方法对多级孔TS-1分子筛的理化性质进行了表征;以二苯并噻吩(DBT)为探针对催化剂的加氢脱硫(HDS)性能进行了评价。结果表明,和常规TS-1分子筛相比,多级孔TS-1分子筛保持了MFI拓扑结构,比表面积增大且具有介孔结构,分子筛表面形成了适量的Brønsted酸中心;相应催化剂上活性金属与载体间相互作用得以改善,MoS₂片晶长度和堆垛层数适宜,形成了更多的 NiMoS活性相;催化剂活性和选择性均有所提升,尤其是酸洗脱获得的 NiMo/AT-TS-1催化剂的活性相较未经处理的NiMo/TS-1催化剂提升了1.2倍,直接脱硫(DDS)路径选择性提升了22%。     

多级孔NiMo负载TS-1分子筛催化剂的制备及其加氢脱硫性能

钛硅(TS-1)分子筛的微孔孔道严重限制了其在复杂分子催化转化中的应用,为了克服这一问题,通过酸洗脱、碱刻蚀及二者相结合的方法制备了多级孔TS-1分子筛,并采用等体积共浸渍法制备了相应的NiMo负载型催化剂;使用X射线衍射(XRD)、N₂吸附-脱附、吡啶吸附红外光谱(Py-FTIR)、氢气程序升温还原(H₂-TPR)、X射线光电子能谱(XPS)和高分辨透射电子显微镜(HR-TEM)等方法对多级孔TS-1分子筛的理化性质进行了表征;以二苯并噻吩(DBT)为探针对催化剂的加氢脱硫(HDS)性能进行了评价。结果表明,和常规TS-1分子筛相比,多级孔TS-1分子筛保持了MFI拓扑结构,比表面积增大且具有介孔结构,分子筛表面形成了适量的Brønsted酸中心;相应催化剂上活性金属与载体间相互作用得以改善,MoS₂片晶长度和堆垛层数适宜,形成了更多的NiMoS活性相;催化剂活性和选择性均有所提升,尤其是酸洗脱获得的NiMo/AT-TS-1催化剂的活性相较未经处理的NiMo/TS-1催化剂提升了1.2倍,直接脱硫(DDS)路径选择性提升了22%。     

NiMo催化剂载体中纳米HY分子筛和氧化铝混合方式对柴油加氢脱硫性能的影响

以纳米HY分子筛-氧化铝混合物为载体,根据两者混合方式的不同（溶胶凝胶法和机械混合法）制备了两种NiMo加氢脱硫催化剂,并对其进行了XRD、BET、TPD、H₂-TPR、HRTEM和FT-IR等表征。与溶胶凝胶法催化剂相比,机械混合法催化剂表现出了较好的纹理结构和更高酸量,其金属相更易还原,边角位Mo原子的分散度更高,表现出了更高的加氢脱硫性能。但溶胶凝胶法催化剂的type-Ⅱ Ni-Mo-S活性相前驱物比例更高,MoS₂晶片长度更大,堆垛程度更高,活性组分分散度较差。虽然溶胶凝胶法有利于提高type-Ⅱ Ni-Mo-S活性相前驱物比例,但是该方法导致的较差孔结构抑制了这种优势,并且降低了活性组分分散度,减弱了催化活性。     

Hydrocracking of vacuum gas oil in the presence of catalysts NiMo/Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–amorphous aluminosilicates and NiW/Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–amorphous aluminosilicates

Supported nickel–molybdenum and nickel–tungsten hydrocracking catalysts prepared using a support that consists of 70% Al₂O₃ and 30% amorphous aluminosilicate were characterized by nitrogen and mercury porosimetry, IR spectroscopy of adsorbed CO, and high-resolution electron microscopy. The catalytic tests in hydrocracking of vacuum gas oil containing 3.39% sulfur showed that the nature of the hydrogenating component (NiMo or NiW) only slightly influences the vacuum gas oil conversion and the diesel fraction yield, but noticeable influences the properties of the diesel fraction obtained. The catalyst NiMo/Al₂O₃–amorphous aluminosilicates, compared to NiW/Al₂O₃–amorphous aluminosilicates, ensures lower sulfur content in the diesel fraction obtained, whereas the catalyst NiW/Al₂O₃–amorphous aluminosilicates allows obtaining a diesel fraction with lower content of polyaromatic compounds.     

Hierarchical Structure of NiMo Hydrodesulfurization Catalysts Determined by Ptychographic X-Ray Computed Tomography

Hydrodesulphurization, the removal of sulphur from crude oils, is an essential catalytic process in the petroleum industry safeguarding the production of clean hydrocarbons. Sulphur removal is critical for the functionality of downstream processes and vital to the elimination of environmental pollutants. The effectiveness of such an endeavour is among other factors determined by the structural arrangement of the heterogeneous catalyst. Namely, the accessibility of the catalytically active molybdenum disulphide (MoS₂) slabs located on the surfaces of a porous alumina carrier. Here, we examined a series of pristine sulfided Mo and NiMo hydrodesulphurization catalysts of increasing metal loading prepared on commercial alumina carriers using ptychographic X-ray computed nanotomography. Structural analysis revealed a build consisting of two interwoven support matrix elements differing in nanoporosity. With increasing metal loading, approaching that of industrial catalysts, these matrix elements exhibit a progressively dissimilar MoS₂ surface coverage as well as MoS₂ cluster formation at the matrix element boundaries. This is suggestive of metal deposition limitations and/ or catalyst activation and following prohibitive of optimal catalytic utilization. These results will allow for diffusivity calculations, a better rationale of current generation catalyst performance as well as a better distribution of the active phase in next-generation hydrodesulphurization catalysts.     

Molecular sieves supported recyclable catalyst for atom transfer radical polymerization using hydration approach

Molecular Sieves (MS) were used as a recyclable support for atom transfer radical polymerization. The catalyst complex, CuBr₂/ligand was supported on hydrated MS and used for the polymerization of benzyl methacrylate at room temperature in anisole. The polymerization using CuBr₂/PMDETA (pentamethyl diethyltetraamine) catalyst that is physically held by the hydration of MS exhibited moderate control and produced catalyst free polymers (<0.1 ppm) with narrow molecular weight distribution (M_w/M_n ≤ 1.33). The polymerization occurred at the interface between the hydrated support and the solution containing initiator and monomer. The hydrated MS supported catalyst was recycled efficiently without a significant loss in activity. The polymerization proceeded in a “living”/controlled manner as was evident from first‐order time conversion plots. The split kinetics experiment affirmed that there was no propagation in the solution in the absence of the supported catalyst. The reaction order plot showed zero‐order dependence on the bulk initiator concentration in solution. The results of MS supported catalyst were compared to Na‐clay supported catalyst system and the improved results were attributed to high self‐diffusion coefficient and low diffusion activation energy of water on its surface. Published 2017.^§ J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3875–3883     

植物固体纤维丝在NiMo柴油加氢脱硫催化剂中的应用

通过在氧化铝载体加入微米级植物固体纤维丝扩孔，制备出NiMo柴油加氢脱硫催化剂。采用BET、XRD、SEM、Raman与TEM对制备的载体及催化剂进行表征研究。结果表明，植物固体纤维丝能够在催化剂中构建出部分直筒大孔，NiMo活性组分在催化剂载体上实现了高度分散，活性相MoS₂堆叠层数集中在3-5层，平均MoS₂条长度为4.49 nm。研究了催化剂载体中植物固体纤维丝含量对催化剂活性的影响，并与常规氧化铝载体催化剂进行了对比，高压微反评价结果表明，开发的含有3%（质量分数）植物固体纤维丝NiMo柴油加氢脱硫催化剂比常规NiMo催化剂活性更高，其加氢脱硫活性提高了5%-15%。     

Catalytic hydrodechlorination reaction of chlorophenols by Pd nanoparticles supported on graphene

Chlorophenols are widely used as industrial chemicals such as herbicides, insecticides, wood preservatives, and disinfectants. However, chlorophenols are very toxic materials and they have become the cause of current environmental issues. Hydrodechlorination (HDC) reaction is a more environmentally friendly removal method of chlorophenols than other methods. In this paper, Pd–modified graphene was prepared and applied to HDC reaction. Pd supported on graphene (refer to Pd/G) was prepared using the recently reported microwave irradiation method. The Pd(II)/GO was made by impregnation methods of palladium precursors in solution phase and was subsequently reduced to Pd/G by microwave irradiation. The morphological and chemical structure of the Pd/G was characterized by XRD, SEM, ICP-MS, EDS, and TEM. It was found that the graphene-based Pd catalyst showed the highest catalytic performance among Pd/Y, Pd/MCM-41, and Pd/G catalysts. This is attributed to the smaller particle size and higher dispersions of Pd nanoparticles on the graphene surface. The catalytic HDC of chlorophenols was investigated. For HDC reaction, 100 ppm solution of chlorophenols such as 4-chlorophenol, six isomers of dichlorophenol, and 2,3,5-trichlorophenol in isopropanol was treated with catalyst and base, such as Na₂CO₃ and K₂CO₃, under a hydrogen gas at ambient pressure. The progress of the chlorophenol decomposition was analyzed with GC. All chlorophenols were completely decomposed within 2 h in the 3 % Pd/G catalyst. The reaction pathway of chlorophenols was elucidated from the conversion of chlorophenols and selectivities of products. The reuse of the catalyst was also studied. The performance of the recycled catalyst in HDC reaction up to six successive runs was observed.     

Hierarchical Structure of NiMo Hydrodesulfurization Catalysts Determined by Ptychographic X‐Ray Computed Tomography

Hydrodesulphurization, the removal of sulphur from crude oils, is an essential catalytic process in the petroleum industry safeguarding the production of clean hydrocarbons. Sulphur removal is critical for the functionality of downstream processes and vital to the elimination of environmental pollutants. The effectiveness of such an endeavour is among other factors determined by the structural arrangement of the heterogeneous catalyst. Namely, the accessibility of the catalytically active molybdenum disulphide (MoS₂) slabs located on the surfaces of a porous alumina carrier. Here, we examined a series of pristine sulfided Mo and NiMo hydrodesulphurization catalysts of increasing metal loading prepared on commercial alumina carriers using ptychographic X‐ray computed nanotomography. Structural analysis revealed a build consisting of two interwoven support matrix elements differing in nanoporosity. With increasing metal loading, approaching that of industrial catalysts, these matrix elements exhibit a progressively dissimilar MoS₂ surface coverage as well as MoS₂ cluster formation at the matrix element boundaries. This is suggestive of metal deposition limitations and/ or catalyst activation and following prohibitive of optimal catalytic utilization. These results will allow for diffusivity calculations, a better rationale of current generation catalyst performance as well as a better distribution of the active phase in next‐generation hydrodesulphurization catalysts.     

ZnO与骨架NiMo物理混合用于丙三醇催化重整-氢解制1,2-丙二醇

以骨架NiMo以及与氧化物物理混合, 考察了其在连续固定床反应器中无外加氢气条件下的丙三醇一锅法重整-氢解制1,2-丙二醇(1,2-PDO)的性能.研究发现, 骨架NiMo自身催化活性高, 但对1,2-PDO的选择性一般.当将其与MgO, SiO₂, Al₂O₃, HZSM-5, TiO₂, ZrO₂或CeO₂机械混合时, 丙三醇转化率和1,2-PDO选择性均发生下降.但当与ZnO物理混合时, 催化活性和选择性均有所提高, 1,2-PDO得率可达52.0%, 优于贵金属催化剂在该一锅法反应中得到的结果.物理混合的ZnO与骨架NiMo之间这种独特的协同作用, 归因于重整过程中产生的CO₂在ZnO上发生化学吸附, 原位增强了ZnO的路易斯酸性.这不仅促进了丙三醇在ZnO上脱水生成中间产物丙酮醇, 也促进了丙酮醇在骨架NiMo上加氢生成1,2-PDO.     

The industrial hydroformylation of olefins with a rhodium-based supported liquid phase catalyst: I: Description of the catalyst system,catalyst characterization and preparation,together with some orienting hydroformylation experiments with propyl

Hydridocarbonyltris(triphenylphosphine)-rhodium(I) (RhHCO(PPh₃)₃), dissolved in liquid triphenylphosphine and immobilized in a porous support b The hydroformylation reaction proceeds in the following way for propylene: CH₃CHCH₂ + CO + H₂ → CH₃CH₂CH₂CHOIn order to assess the industrial applicability of the above-mentioned catalyst a number of support materials were investigated. The influence of the rIt is concluded that supports based on α-alumina show the best results if these are pure and have an inert surface. SCS9 and SA5202 and also an experIn the range 25 – 100 (mol Rh) (m³ PPh₃)⁻¹ the reaction rate is first order with respect to the rhodium concentration. The selectivityThe degree of propylene conversion can be as high as 16.8% without an adverse effect on the catalyst performance. In this range of degrees of conversio     

Theoretical investigation of novel silsesquioxane-supported Phillips-type catalyst by density functional theory (DFT) method

In spite of great commercial importance of the Phillips CrO_x/SiO₂ catalyst and long term research efforts, the precise physicochemical nature of active sites and polymerization mechanisms still remains unclear. The difficulties in a clear mechanistic understanding of this catalyst mainly come from the complexity of the surface chemistry of the amorphous silica gel support. In this work, novel silsesquioxane-supported Phillips Cr catalysts are utilized as realistic models of the industrial catalyst for theoretical investigation using the density functional theory (DFT) method in order to elucidate the effects of surface chemistry of silica gel in terms of supporting of chromium compounds and fluorination of the silica surface on the catalytic properties of the Phillips catalyst. Both qualitative and quantitative aspects with respect to various electronic properties and thermodynamic characteristics of the model catalysts were achieved. The future prospects of a state-of-the-art catalyst design and mechanistic approaches for the heterogeneous SiO₂-supported Phillips catalyst has been demonstrated. The text was submitted by the authors in English.     

Oxidation of ammonia using modified TiO<Subscript>2</Subscript> catalyst and UV-VIS irradiation

The impact of UV and VIS irradiation and specific nitrogen modification on a 5%Cu/5%TiO₂/SiO₂ catalyst in the course of oxidation of ammonia was investigated. It was demonstrated that both UV and VIS irradiation increased the conversion of the reactant in the reaction studied. Due to a good distribution of titanium dioxide and copper on the surface of the support, higher ammonia conversion was achieved. Physico-chemical characterisation of the catalysts studied using methods such as BET, SEM-EDS, TPD (NH₃), and TPD (CO₂) was carried out.     

贵金属铱对氨分解用镍基催化剂的促进作用研究

用湿式浸渍法制备了不同贵金属质量分数的镍-铱双金属催化剂,以氨分解为模型反应对其催化性能进行考察.结果表明,贵金属铱的添加提高了10%Ni/γ-Al2O3的低温活性.在铱的质量分数不高于1%时,氨分解反应活性随铱质量分数的增加出现最大值(相应的Ir质量分数为0.7%),对应的10%Ni-0.7%Ir/γ-Al2O3催化剂在400 ℃时,氨分解率为43.55%,较单组分的Ni催化剂高40.0%.用H2-TPR、H2-TPD 、BET和XRD表征方法对催化剂进行了表征.结果表明,Ir与活性组分Ni之间存在协同作用.铱的添加促进了活性组分的分散、减小了镍的晶粒尺寸,且增加了催化剂活性位的数量,从而提高了催化剂的氨分解性能.