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Two hybrid compounds, namely [CuI4(3atrz)4][PMoVI11MoVO40] (1) and [CuI6(3atrz)6][PMo12O40]2 (2), were synthesized through hydrothermal reactions of 3-amino-1,2,4-triazole (3atrz), phosphomolybdic acid (PMA) and appropriate copper salts. Crystal structure analysis reveals that compound 1 contains one-dimensional Cu-3atrz chains. The unit of compound 2 contains a double calyx[3]arene-shaped hexamer, which is composed of six two-coordinated CuI atoms and six 3atrz ligands. Both compounds 1 and 2 present a three-dimensional hybrid structure, which is built by the self-assembly of Cu-3atrz clusters and Keggin-type PMA units. The resulting hybrid compounds can act as highly efficient heterogeneous catalysts for the selective oxidation of olefins with molecular oxygen as the oxidant in the presence of a trace amount of tert-butyl hydroperoxide (t-BuOOH). Their excellent catalytic properties can be mainly attributed to the existence of stabilized CuI complexes with an appropriate chemical environment and a spacious structure, which can interact with t-BuOOH to form catalytic sites for the direct activation of O2. This work demonstrates that the hybrid compounds assembled from copper-3atrz complexes and phosphomolybdic acid may have great potential in molecular O2-mediated catalytic oxidation reactions, which can certainly build a platform for deep insight into the biologically relevant catalytic oxidation processes. [ABSTRACT FROM AUTHOR]

A composite of Fe3O4 nanoparticles anchored on a carbon support (Fe3O4/C), possessing both superparamagnetism and molecular oxygen activating properties, was prepared by an ammonia-assisted precipitation method. Fe3O4/C could catalyze the selective oxidation of various benzyl alcohols with air as the oxidant source, and could be easily separated and recycled with an external magnet. The small particle size and the interaction between the Fe3O4 nanoparticles and carbon support endow the Fe3O4/C catalyst with relatively high reducibility. Its oxidation state is easy to change. This intrinsic property of the Fe3O4 nanoparticles could be responsible for the high activity of Fe3O4/C in the aerobic oxidation of alcohols. [ABSTRACT FROM AUTHOR]

Two kinds of triphenylamine-based porous organic polymers (POPs) were synthesized by FeCl 3 -triggered Friedel-Crafts polymerization of triphenylamine (TPA) and formaldehyde dimethylacetal (FDA) in the absence or presence of benzene (Ph), which are denoted as POP-I (without additional Ph) and POP-II (with additional Ph as linker), respectively. Various characterization results confirm the successful synthesis of TPA-based polymers with different bridged linkers and hierarchical pore structure. Phosphomolybdic acid (HPMA) and cobalt phosphomolybdate (CoPMA) were immobilized onto the POPs, to form phosphomolybdate (PMA) functionalized POPs catalysts, and their catalytic properties were investigated for the selective oxidation of olefins with H 2 O 2 . All the PMA functionalized POPs materials are catalytically active for the epoxidation/oxidation of olefins, while CoPMA/POP-II shows the highest activity, stability and recyclability. TPA-based POPs have distinctive electron-donating and transferring ability, which can be further tuned by introducing more bridged linkers of -Ph and -CH 2 groups. Multi-interactions between PMA and POPs supports could be built through the electronic and geometric effects exerted by the 3-D POPs supports on the PMA clusters. Moreover, the existence of Co cations may further strengthen the interactions between PMA and POPs supports by forming electrostatic or coordination interactions with the TPA ligands, thus resulting in the high stability of the CoPMA/POP-II against leaching of active species during the H 2 O 2 mediated catalytic oxidation process. [ABSTRACT FROM AUTHOR]

Abstract: Three kinds of silica materials, including fumed SiO2, porous granular SiO2 and mesoporous SBA-15, were adopted to prepare supported Pt catalysts by impregnation method. The catalytic properties of these silica supported Pt catalysts (Pt/SiO2) were investigated for the complete oxidation of formaldehyde (HCHO). Among them, fumed SiO2 supported Pt catalyst (Pt/f-SiO2) shows very high catalytic activity, which could completely oxidize HCHO even at ambient temperature. According to the results of catalyst characterization, it was proposed that the nature of silica supports could affect the particle size and the chemical states of platinum species and then further influence the redox property of Pt/SiO2 catalysts. Compared with other silica supported Pt catalysts, Pt/f-SiO2 catalyst possesses higher ratio of metallic Pt species, which might be a key factor in improving its capability to activate molecular oxygen and consequently to oxidize HCHO at low temperature. [Copyright &y& Elsevier]

Abstract: The catalytic properties of iron oxide supported platinum catalysts (Pt/Fe2O3), prepared by a colloid deposition route, were investigated for the complete oxidation of formaldehyde. It is found that all the Pt/Fe2O3 catalysts calcined at different temperatures (200–500°C) were active for the oxidation of formaldehyde. Among them, the catalysts calcined at lower temperatures (i.e., 200 and 300°C) exhibited relatively high catalytic activity and stability, which could completely oxidize HCHO even at room temperature. Based on a variety of physical–chemical characterization results, it is proposed that the presence of suitable interaction between Pt particles and iron oxide supports, which is mainly in the form of Pt–O–Fe bonds, should play a positive role in determining the catalytic activity and stability of the supported Pt/Fe2O3 catalysts. [Copyright &y& Elsevier]

Abstract: A series of porous carbon (NC) materials were prepared by using in situ-formed aluminophosphate framework as template, and citric acid and sucrose as carbon precursors. The structure and surface chemistry properties of these carbon materials were studied by N2 adsorption, XRD, DRIFT, and XPS measurements. The catalytic properties of these NC materials were investigated in the selective oxidation of benzyl alcohol with air as oxidant source. Compared with other carbon materials, such as active carbon, mesoporous CMK-3, and carbon molecular sieves, NC materials exhibited much higher catalytic activity with nearly 100% selectivity to benzaldehyde. The presence of abundant surface quinone groups, which originates from the special preparation process of NC material, is likely responsible for the high catalytic property of these porous carbon materials. [Copyright &y& Elsevier]

Abstract: A hybrid mesoporous SBA-15 material (2a) containing an oxodiperoxo tungsten complex of the type [WO(O2)2L] (L=pyrazolylpyridine) was synthesized by a post-grafting route. The organic–inorganic hybrid catalyst was characterized by means of XRD, N2 adsorption–desorption and FT-IR. The catalytic property of 2a in the epoxidation of cyclooctene with H2O2 as the oxidant was investigated in comparison with other three kinds of hybrid tungsten containing SBA-15 materials bearing ethylenediamine, imidazole or 4,4′-bipyridine ligands. It was found that all oxodiperoxo tungsten catalysts were active at the reaction temperature of 55°C with CH3CN as solvent. However, only the catalyst with the pyrazolylpyridine ligand showed good recoverability and relatively high stability against leaching of active tungsten species. Moreover, this catalyst showed very high efficiency for H2O2 utilization, and its catalytic activity could be further improved by using solvent mixtures of CH3CN and CH3COOH. [Copyright &y& Elsevier]

Abstract: The immobilization of palladium complexes or nanoparticles in N-heterocyclic carbene (NHC) modified mesoporous SBA-15 materials was carried out by a post-grafting route. The catalytic properties of these materials were investigated for the aerobic oxidation of benzyl alcohol. Compared with the supported Pd complexes catalyst, the supported Pd nanoparticles catalyst exhibited much higher activity, recoverability and stability for the title reaction. The combination of NHC ligands and the size-restricted mesopores of SBA-15 should be responsible for the formation of active and stable supported palladium nanoparticles catalyst. [Copyright &y& Elsevier]

Abstract: Au/MeCO3 (Me=Ca, Sr, Ba) catalysts prepared by co-precipitation method were studied for low-temperature CO oxidation in the presence/absence of water in the feed stream. The type of support and the calcination temperatures have considerable effect on the activity of the catalysts. Among them, Au/BaCO3 calcined at 473 K shows the highest activity, full conversion of CO can be obtained at ambient reaction temperature in the presence of moisture. The addition of water vapor in feed stream has positive influence on the activity of Au/MeCO3 catalysts for CO oxidation, which might be due to water can participate CO oxidation reaction directly. [Copyright &y& Elsevier]

• Pt/Al 2 O 3 with 0.1 wt% Pt could completely convert toluene (1000 ppm, SV=24000 mL·g−1·h−1) to CO 2 at about 180 ℃. • TOF value calculated with the dispersion of Pt can reach 0.0685 s−1, representing a high utilization efficiency of Pt. • The reaction obeys the modified L-H mechanism and synergism of Pt nanoparticles and Al 2 O 3 support enhances the activity. • Pt nanoparticles are the active centers for O 2 activation and Al 2 O 3 support offers sites for the adsorption of toluene. A kind of highly efficient and low cost supported-Pt catalyst for oxidation of toluene is obtained through controlling both the chemical state of Pt active sites and surface properties of supports. The optimized Pt/Al 2 O 3 catalyst with Pt loading as low as 0.1 wt% could completely convert toluene (1000 ppm) to CO 2 at about 180 ℃ under a space velocity of 24,000 mL g−1 h−1. It also exhibits a high stability and moisture resistance properties under reaction atmosphere. TOF value calculated with the dispersion of Pt can reach 0.0685 s-1, representing a high utilization efficiency of Pt. A series of characterizations are carried out to investigate the key factors affecting the catalytic performance of Pt/Al 2 O 3 , and disclose the concrete role of Pt and Al 2 O 3 in the activation of molecular oxygen and toluene. In situ DRIFTS and EPR results show that Pt is the active center for O 2 activation. Metallic Pt nanoparticles (Pt0) can activate the molecular O 2 even at room temperature. Al 2 O 3 offers sites for the adsorption of toluene and desorption of CO 2 product. The weak and medium strength of acid-base sites favorite the adsorption and desorption process. The oxidation of toluene over Pt/Al 2 O 3 obeys modified L-H mechanism. The synergistic effect of metallic Pt nanoparticles and suitable Al 2 O 3 support is critical for obtaining highly efficient Pt-based catalysts with low Pt contents for toluene oxidation. [ABSTRACT FROM AUTHOR]