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Chinese Journal of Catalysis
2014, Vol. 35, No. 1
Online: 23 December 2013


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Hu and coworkers in their Article on pages 8–20 reported that CeO₂-SiO₂ composite oxides with large surface area were synthesized using a sol-gel process. The nickel catalyst supported on the as-synthesized CeO₂-SiO₂ had good properties and stability, which resulted from the weak chemical interaction between Ni and support, good dispersion of NiO, weak acidity, and low carbon deposition.

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Table of Contents for VOL.35 No.1 2014, 35 (1):  0-0.  Abstract ( 138 )   PDF (1697KB) ( 471 )

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Wet air oxidation for the decolorization of dye wastewater: An overview of the last two decades Jie Fu, George Z. Kyzas 2014, 35 (1):  1-7.  DOI: 10.1016/S1872-2067(12)60724-4 Abstract ( 248 )   [Full Text(HTML)] () PDF (426KB) ( 1121 )   Wet air oxidation (WAO), a liquid phase reaction between organic materials in water and oxygen, is one of the most economical and technologically viable advanced oxidation processes for wastewater treatment, particularly toxic and high organic content wastewater. WAO is the liquid phase oxidation of organics or oxidizable inorganic components at elevated temperatures (125-320℃) and pressures (0.5-20 MPa) using gaseous oxygen (or air) as oxidant. In the past two decades, the WAO process was widely studied and applied in the treatment of dye wastewater. Compared to conventional WAO, catalytic WAO processes have higher efficiency and use moderate reaction conditions. The catalysts included homogenous and heterogeneous types. The key points that need to be solved are recycling of homogenous catalysts and better stability of heterogeneous catalysts. In the present review, the technological processes are first introduced, then some research history and hotspots of WAO research are presented, and finally, its application in the treatment of dye wastewater in the past two decades is summarized to reveal the impressive changes in modes, trends, and conditions used. The application includes model pollutant studies and wastewater tests.

Articles

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Preparation and characterization of Ni/CeO2-SiO2 catalysts and their performance in catalytic partial oxidation of methane to syngas Jiubiao Hu, Changlin Yu, Yadong Bi, Longfu Wei, Jianchai Chen, Xirong Chen 2014, 35 (1):  8-20.  DOI: 10.1016/S1872-2067(12)60723-2 Abstract ( 340 )   [Full Text(HTML)] () PDF (1144KB) ( 993 )   Hexahydrated cerium(Ⅲ) nitrate (Ce(NO3)3·6H2O) and tetraethyl orthosilicate (C8H20O4Si) were used as the precursors for the synthesis of a series of xCeO2-(1-x)SiO2 (x = 0, 0.25, 0.5, 0.75, 1) composite oxides using a sol-gel process under acidic conditions. The active component, Ni, was loaded on the as-synthesized composite oxides, producing supported Ni catalysts for catalytic partial oxidation of methane to syngas. The properties of the as-synthesized products, such as textural structure, reduction behavior, surface acidity, and carbon deposition, were determined using N2 physical adsorption/desorption, X-ray diffraction, scanning electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, temperature-programmed reduction by H2, temperature-programmed desorption of NH3, and thermogravimetric analysis. The effects of catalyst composition, calcination temperature, and reaction time on the catalytic performance were investigated. The characterization results showed that these Ni/CeO2-SiO2 catalysts have large surface area, small CeO2 crystals, weak acidity, and low carbon deposition. Highly dispersed NiO is present and is easy to be reduced. The Ni/CeO2-SiO2 catalyst with a Ce/Si molar ratio of 1:1, w(Ni) = 10%, and calcined at 700℃ exhibited good stability and the highest CH4 conversion (~84%) and CO and H2 selectivity (> 87%).

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Polyvinyl amine coated Fe3O4@SiO2 magnetic microspheres for Knoevenagel condensation Farzad Zamani, Elham Izadi 2014, 35 (1):  21-27.  DOI: 10.1016/S1872-2067(12)60685-8 Abstract ( 280 )   [Full Text(HTML)] () PDF (542KB) ( 1036 )   Polyvinyl amine coated Fe3O4@SiO2 composite microspheres with a core-shell structure were prepared and employed as a magnetic catalyst for Knoevenagel condensation under mild conditions. The catalyst can be readily recovered using a magnet and reused several times without loss in activity or selectivity. The performance of the magnetic base catalyst was compared with that of polyvinyl amine functionalized mesoporous SBA-15, which showed that the magnetic nanoparticles gave improved reaction rate and yield.

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Density functional theory study of the adsorption and reaction of C2H4 on Fe3C(100) Bingyin Wang, Xiaohu Yu, Chunfang Huo, Jianguo Wang, Yongwang Li 2014, 35 (1):  28-37.  DOI: 10.1016/S1872-2067(12)60703-7 Abstract ( 330 )   [Full Text(HTML)] () PDF (823KB) ( 710 )   Spin-polarized density functional theory (DFT) and a periodic slab model were employed to investigate the adsorption of C2H4 on Fe3C(100), which is an active phase of an Fe-based catalyst for Fischer-Tropsch synthesis. The competition between dehydrogenation and cleavage of C2H4 was analyzed. The μ-bridging adsorption mode is more stable than the π or di-σ adsorption modes. Partial rehybridization of the C atoms of C2H4 (sp2→sp3) caused by the interaction of C2H4 with the Fe3C(100) surface resulted in the C atoms in C2H4 having a quasi-tetrahedron geometry. On Fe3C(100) dehydrogenation of C2H4 occurs, while C-C bond cleavage is not competitive. The calculations indicated that vinylidene (CCH2) and vinyl (CHCH2) species are the most abundant C2 species, which may be the major monomeric forms of C2H4 in the chain growth in Fischer-Tropsch synthesis.

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High performance La0.8Sr0.2MnO3-coated Ba0.5Sr0.5Co0.8Fe0.2O3 cathode prepared by a novel solid-solution method for intermediate temperature solid oxide fuel cells Li Meng, Fangzhong Wang, Ao Wang, Jian Pu, Bo Chi, Jian Li 2014, 35 (1):  38-42.  DOI: 10.1016/S1872-2067(12)60704-9 Abstract ( 277 )   [Full Text(HTML)] () PDF (623KB) ( 852 )   La0.8Sr0.2MnO3 (LSM)-coated Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF) composite powder (LSM-BSCF) was synthesized by a novel solid-solution method and investigated electrochemically as a cathode material for intermediate temperature solid oxide fuel cells. The cathode combined the merits of LSM and BSCF cathodes through an extended triple phase boundary and stabilized microstructure and demonstrated a polarization resistance between 0.61 and 0.09 Ω cm2 at 600 to 750℃. Compared with high performance cathodes prepared by solution impregnation, this LSM-BSCF cathode greatly improved performance stability.

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Poly(4-vinylpyridinium)hydrogen sulfate: A novel and efficient catalyst for the synthesis of 13-aryl-indeno[1, 2-b]naphtha[1, 2-e]pyran-12(13H)-ones under solvent-free conditions Majid Ghashang, Syed Sheik Mansoor, Krishnamoorthy Aswin 2014, 35 (1):  43-48.  DOI: 10.1016/S1872-2067(12)60707-4 Abstract ( 284 )   [Full Text(HTML)] () PDF (421KB) ( 544 )   An facile and efficient protocol for the synthesis of 13-aryl-indeno[1,2-b]naphtha[1,2-e]pyran- 12(13H)- ones has been developed that proceeds via the one-pot three-component sequential reaction of an aromatic aldehyde with β-naphthol and 2H-indene-1,3-dione under solvent-free conditions in the presence of a poly(4-vinylpyridinium)hydrogen sulfate (P(4-VPH)HSO4) catalyst. The catalyst can be reused several times, making this procedure facile, practical, and sustainable. The simple experimental procedure, solvent-free reaction conditions, use of an inexpensive catalyst, short react time, and excellent yields are some of the major advantages of this methodology.

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Synthesis and catalytic performance of hierarchical MCM-22 zeolite aggregates with the assistance of carbon particles and fluoride ions Jianhua Yang, Jun Chu, Jinqu Wang, Dehong Yin, Jinming Lu, Yan Zhang 2014, 35 (1):  49-57.  DOI: 10.1016/S1872-2067(12)60711-6 Abstract ( 366 )   [Full Text(HTML)] () PDF (822KB) ( 894 )   Hierarchical MCM-22 zeolite aggregates (MCM-22-FC) were prepared by one-pot hydrothermal synthesis with the assistance of carbon particles and fluoride ions. The effects of carbon particles and fluoride ions on the morphology and catalytic properties of the MCM-22 zeolite were investigated. The hierarchical MCM-22-FC zeolite aggregates were constructed by intergrown and stacked thin MCM-22 lamellas and possessed macro-/mesopores and inherent micropores. The MCM-22-FC zeolite was modified to form the Mo/MCM-22-FC catalyst, which exhibited an improved benzene yield and aromatic selectivity as well as catalyst life in the methane dehydroaromatization (MDA) reaction. Based on NH3-TPD and pyridine-Fourier transform infrared spectroscopy measurements together with thermogravimetric analysis, we found that the improved MDA catalytic performance of Mo/MCM-22-FC resulted from the formation of more active MoCx or MoOxCy species that evolved from increased amounts of Brönsted acids with the assistance of fluoride ions. This promoted the diffusion of large molecule products because of the thin MCM-22 lamellas. Less excess Brönsted acid sites were retained in the Mo/HMCM-22-FC catalyst because the formation of active centers inhibited the formation of coke, which contributed to its improved aromatic selectivity.

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H3PW12O40 catalyzed synthesis of benzoxazine and quinazoline in aqueous media Mahmood Tajbakhsh, Rahman Hosseinzadeh, Parizad Rezaee, Mahgol Tajbakhsh 2014, 35 (1):  58-65.  DOI: 10.1016/S1872-2067(12)60706-2 Abstract ( 354 )   [Full Text(HTML)] () PDF (416KB) ( 735 )   A heteropolyacid efficiently catalyzed the cyclocondensation reaction of 2-aminobenzamide and salicylamide with aldehydes and ketones to afford good yields of benzoxazine and quinazoline ring systems in an aqueous medium. The method gives clean reactions, has simple workup procedure, and uses environment friendly conditions.

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Photocatalytic removal of nitric oxide by multi-walled carbon nanotubes-supported TiO2 Hao Liu, Hairu Zhang, Hongmin Yang 2014, 35 (1):  66-77.  DOI: 10.1016/S1872-2067(12)60705-0 Abstract ( 448 )   [Full Text(HTML)] () PDF (1015KB) ( 701 )   Multi-walled carbon nanotubes (MWCNTs) coated with TiO2 were prepared by a sol-gel method and characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and UV-Vis diffuse reflectance spectroscopy. It was found that MWCNTs/TiO2 consisted mainly of anatase phase. The introduction of MWCNTs inhibited TiO2 grain growth. Moreover, the adsorption edge of MWCNTs/TiO2 shifted toward long-wavelength region compared with bare TiO2. The photocatalytic ability of MWCNTs/TiO2 for NO removal was experimentally investigated in a fixed-bed reactor. The results showed that a lower initial NO concentration was conducive to NO removal. A negative effect of SO2 on denitration was observed. In contrast, O2 and H2O played a promotional role in the photocatalytic denitration. At optimal conditions (73 mg/m3 NO, 8% O2, 5% H2O), NO removal efficiency of 46% was achieved. In addition, the reaction mechanism of denitration was proposed.

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Preparation of ternary Ag/Ag3PO4/g-C3N4 hybrid photocatalysts and their enhanced photocatalytic activity driven by visible light Kai Shen, Mohammed Ashraf Gondal, Rashid Ghulam Siddique, Shan Shi, Siqi Wang, Jiangbo Sun, Qingyu Xu 2014, 35 (1):  78-84.  DOI: 10.1016/S1872-2067(12)60712-8 Abstract ( 306 )   [Full Text(HTML)] () PDF (985KB) ( 1027 )   The preparation of a series of ternary Ag/Ag3PO4/g-C3N4 hybrid photocatalysts, which display enhanced photocatalytic activity, was reported. The crystal structure, morphology, composition, optical absorption, and efficient separation of charge carriers were studied by X-ray diffraction, scanning electron microscopy, absorption and photoluminescence spectroscopy measurements. Using rhodamine B as a model contaminant, the as-prepared Ag/Ag3PO4/g-C3N4 hybrid photocatalyst exhibited superior degradation performance under visible light irradiation than Ag3PO4 or binary Ag3PO4/g-C3N4 hybrid photocatalyst systems. The surface plasmon resonance of the 40 nm-silver nanoparticles formed on the surface of Ag3PO4 and the heterojunction formed at the interface between Ag3PO4 and g-C3N4, are considered to be the major physical-chemical origin and to be responsible for the enhanced photocatalytic activity.

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In situ generation of trityl carbocation (Ph3C+) as a homogeneous organocatalyst for the efficient synthesis of 4, 4’-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s Abdolkarim Zare, Maria Merajoddin, Ahmad Reza Moosavi-Zare, Mahmoud Zarei 2014, 35 (1):  85-89.  DOI: 10.1016/S1872-2067(12)60728-1 Abstract ( 219 )   [Full Text(HTML)] () PDF (406KB) ( 671 )   Trityl chloride (Ph3CCl) efficiently catalyzes the condensation of 3-methyl-1-phenyl-1H-pyrazol- 5(4H)-one and aromatic aldehydes under mild and solvent-free conditions, affording 4,4'- (arylmethylene)-bis(3-methyl-1-phenyl-1H- pyrazol-5-ol)s in high to excellent yields and in short reaction time. The presence of the requisite organocatalytic trityl carbocation (Ph3C+) species was confirmed by analysis of infrared, 1H NMR, and ultra violet spectral data. A plausible mechanism was proposed for the reaction based on the observations and literature precedent.

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Photocatalytic degradation of bisphenol A using Ti-substituted hydroxyapatite Qian Li, Xiang Feng, Xiao Zhang, Han Song, Jianwei Zhang, Jing Shang, Weiling Sun, Tong Zhu, Masato Wakamura, Mineharu Tsukada, Yingliang Lu 2014, 35 (1):  90-98.  DOI: 10.1016/S1872-2067(12)60709-8 Abstract ( 361 )   [Full Text(HTML)] () PDF (699KB) ( 763 )   Ti-substituted hydroxyapatite (TiHAP) is a new photocatalyst with high adsorption capacity and photocatalytic activity. The morphology and structure of TiHAP were characterized using transmission electron microscopy, X-ray diffraction, ultraviolet-visible spectrophotometry, and the zeta potential. The adsorption and photocatalytic degradation of bisphenol A (BPA, an environmental endocrine disrupting chemical) over TiHAP and P25 TiO2 photocatalysts were studied using liquid chromatography-mass spectrometry. The influences of fulvic acid and Fe3+ ions on the BPA degradtion rate were analyzed. The adsorption of BPA on TiHAP and TiO2 obeyed the Langmuir adsorption equation. TiHAP exhibited much higher adsorption capacity and photocatalytic degradation activity of BPA than TiO2. Fulvic acid and Fe3+ showed different effects on the photocatalytic activity of TiHAP and TiO2 films. These were explained by band structure theory, the electron transfer path, and optical absorption capacity. The results are useful for the application of TiHAP in the photocatalytic degradation of environmental endocrine disrupting chemicals.

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V2O5/hematite catalyst for low temperature selective catalytic reduction of NOx with NH3 Ping Zhang, Tianhu Chen, Xuehua Zou, Chengzhu Zhu, Dong Chen, Haibo Liu 2014, 35 (1):  99-107.  DOI: 10.1016/S1872-2067(12)60719-0 Abstract ( 267 )   [Full Text(HTML)] () PDF (859KB) ( 560 )   A series of V2O5/hematite (V/H) catalysts were prepared by impregnation of goethite with NH4VO3 solution and used in the selective catalytic reduction (SCR) of NO with NH3. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption. The effects of V2O5 loading and calcination temperature on the SCR activity were investigated. The NO conversion over 3% V/H catalysts calcined at 300℃ exceeded 95% at 250-300℃. Neither H2O nor SO2 (0.01%) had any adverse impact on the activity, but a decrease of SCR activity was observed after high concentrations (0.03% and 0.05%) of SO2 were introduced. Cutting off the SO2 supply resulted in activity restoration. The simultaneous addition of 5% H2O and 0.03% SO2 led to a synergistic poisoning effect, but when these gases were switched off, the activity was recovered. SO2 adsorption on the catalyst surface led to the decrease in SCR activity.

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Catalytic activity of Ag/SBA-15 for low-temperature gas-phase selective oxidation of benzyl alcohol to benzaldehyde Liang Ma, lihua Jia, Xiangfeng Guo, Lijun Xiang 2014, 35 (1):  108-119.  DOI: 10.1016/S1872-2067(12)60720-7 Abstract ( 426 )   [Full Text(HTML)] () PDF (1162KB) ( 763 )   Ag/SBA-15 catalysts with different Ag contents were prepared by an impregnation method and were used for the gas-phase selective oxidation of benzyl alcohol to benzaldehyde with O2 as the oxidant. These catalysts were characterized using N2 adsorption-desorption, X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, inductively coupled plasma mass spectrometry, and X-ray photoelectron spectroscopy. The effects of Ag loading, reaction temperature, and weight hourly space velocity of benzyl alcohol on the catalytic performance were investigated. The results showed that Ag was successfully incorporated into the mesoporous channels of SBA-15 and well dispersed on the surface as a result of the nano-confinement effect of SBA-15, which increased the specific surface area of the active components. Moreover, Ag/SBA-15 had a uniform pore size, a wall of thickness of 3-5 nm, and a high specific surface area of 411-541 m2/g. The catalytic activity of Ag/SBA-15 for the gas-phase selective oxidation of benzyl alcohol to benzaldehyde was enhanced by oxygen spillover of nucleophilic oxygen species from the Ag nanoparticles to the SBA-15 surface. The 5.3%Ag/SBA-15 exhibited excellent low-temperature catalytic properties; when the reaction temperature was 220℃, the conversion of benzyl alcohol and the selectivity for benzaldehyde reached 87% and 95%, respectively. At 240℃, the catalyst displayed the best catalytic properties, achieving a benzyl alcohol conversion of 94% and benzaldehyde selectivity of 97%, which remained almost constant at 240-300℃. This showed that Ag/SBA-15 had excellent thermal gradient stability. The catalyst could be used for 40 h and retained high catalytic activity for oxidation after treatment at 500℃.

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Influence of the TiO2 crystalline phase of MnOx/TiO2 catalysts for NO oxidation Zhongyi An, Yuqun Zhuo, Chao Xu, Changhe Chen 2014, 35 (1):  120-126.  DOI: 10.1016/S1872-2067(12)60726-8 Abstract ( 337 )   [Full Text(HTML)] () PDF (797KB) ( 951 )   Mn-based catalysts impregnated on TiO2 with different crystalline phases (rutile (R), anatase (A), and P25 (P)) were studied for the oxidation of NO to NO2. 10%MnOx/TiO2(P) was the most active catalyst, giving 83% of NO conversion at 300℃ and a GHSV of 20000 h-1. The catalyst activities were in the order MnOx/TiO2(P) > MnOx/TiO2(A) > MnOx/TiO2(R). The catalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, and O2 temperature-programmed desorption. Compared to anatase and rutile, P25 gave better dispersion of MnOx on the support surface, suppressed the agglomeration of catalyst particles, and also produced more Mn2O3, which was more active for the oxidation of NO. In addition, P25 enhanced the reduction of MnOx, especially for Mn2O3, and the formation of easily desorbed O2- generated from the Mn3+-O bond.

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Thiourea dioxide: An efficient and reusable organocatalyst for the rapid one-pot synthesis of pyrano[4, 3-b]pyran derivatives in water Majid Ghashang, Syed Sheik Mansoor, Krishnamoorthy Aswin 2014, 35 (1):  127-133.  DOI: 10.1016/S1872-2067(12)60727-X Abstract ( 320 )   [Full Text(HTML)] () PDF (425KB) ( 692 )   A series of pyrano[4,3-b]pyran derivatives have been synthesized in excellent yields by the reaction of aromatic aldehydes with malononitrile or cyanoacetate and 4-hydroxy-6-methylpyran-2-one in water at 80℃, with the transformation being catalyzed by an aqueous solution of thiourea dioxide (TUD). Upon completion of the reaction, the product was isolated by filtration or extraction and the remaining aqueous TUD solution could be reused several times without any discernible impact on its catalytic activity. This procedure offers several advantages over existing procedures, including high yields, operational simplicity, the use of a non-toxic catalyst and solvent, short reaction time and minimum pollution of the environment, making it a useful and attractive process for the preparation of pyrano[4,3-b]pyran derivatives.

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Surface reactions of CuCl2 and HY zeolite during the preparation of CuY catalyst for the oxidative carbonylation of methanol Ruiyu Wang, Zhong Li 2014, 35 (1):  134-139.  DOI: 10.1016/S1872-2067(12)60735-9 Abstract ( 364 )   [Full Text(HTML)] () PDF (473KB) ( 876 )   A CuI/Y catalyst was prepared for the vapor phase oxidative carbonylation of methanol to dimethyl carbonate (DMC). The surface solid-state interactions of CuCl2 with HY zeolite were studied using thermogravimetry. The surface properties and morphologies of catalyst samples were analyzed by thermogravimetry, X-ray photoelectron spectroscopy, and elemental analysis, and their catalytic performance was assessed in a fixed-bed reactor. Both CuCl and CuCl2 were found to co-exist on the external surface of the catalyst, while ion-exchanged CuΙ along with small amounts of adsorbed CuCl were contained in the internal Y zeolite cage structures. Both the CuCl and CuCl2 were active species during the DMC synthesis. Compared with a conventional CuI/Y catalyst prepared by heating a mixture of CuCl and HY zeolite, the CuI/Y catalyst prepared by heating a mixture of CuCl2 and HY zeolite showed increased catalytic activity for the oxidative carbonylation of methanol, even though it had lower Cu and Cl contents.

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Photocatalytic degradation of methylene blue by MoO3 modified TiO2 under visible light Huabo Yang, Xiang Li, Anjie Wang, Yao Wang, Yongying Chen 2014, 35 (1):  140-147.  DOI: 10.1016/S1872-2067(12)60731-1 Abstract ( 338 )   [Full Text(HTML)] () PDF (714KB) ( 1049 )   MoO3/P25 catalysts were prepared by an impregnation method. The catalysts were characterized by X-ray diffraction, ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy, and laser Raman spectroscopy, and their photocatalytic activty was evaluated by the degradation of methylene blue dye under visible light. The monolayer dispersion threshold of MoO3 on P25 was around 0.1 g/g. The strong interaction between the monolayer-dispersed tetrahedral-coordinated molybdenum oxide species and P25 led to a decrease in the band gap of P25, thus increasing the visible light absorption of the catalyst. Crystalline MoO3 was formed on catalysts with a MoO3/P25 mass ratio above 0.1. In these cases, the visible light absorption of the catalysts decreased with increasing MoO3 content. The band gap of the catalyst was not the only factor affecting its photocatalytic activity for the degradation of methylene blue under visible light. MoO3/P25 with the MoO3 to P25 mass ratio of 0.25, which possessed not only suitable band gap but also a certain amount of crystalline MoO3, showed the best catalytic performance.