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CoMo-catalysts modified by boron were studied. Boron was added to alumina support by kneading. Supports and catalysts were characterized by nitrogen adsorption, XPS, IR-spectroscopy of adsorbed CO. Catalysts were tested in hydrotreating of straight-run diesel fuel with 5 vol.% catalytic cracking gasoil (initial S content was 2750 ppm). It is found that boron has no significant influence on textural characteristics of catalysts. However, it increases slab length and visualization degree of active component, while stacking number remains unchanged (preferential formation of monolayers). Difference in morphology is caused by changes of Lewis acidity and generation of Brønsted acid sites. It is found that all catalysts with boron provide production of ultra-low sulfur diesel fuels (less than 10 ppm). The catalyst with a boron content of 2 wt.% combines high activity in HDS and HDN. [ABSTRACT FROM AUTHOR]

Abstract: A ferromagnetic γ-Al2O3-supported iron catalyst has been prepared and its activity and stability in catalytic wet peroxide oxidation (CWPO) have been compared with those of a previous iron-based conventional catalyst using the same support. Both catalysts were characterized by nitrogen adsorption–desorption isotherms, ICP, TXRF, XRD, XPS, elemental analysis and Mössbauer spectroscopy. The behavior of these catalysts in CWPO of chlorophenols has been related with the nature of the dominant iron species (magnetite or hematite). The results showed that the magnetic catalyst improved significantly the decomposition of H2O2 leading to an increased degradation and mineralization of chlorophenols. Complete conversion of those target pollutants and more than 75% TOC reduction were achieved after 4h under stoichiometric H2O2 dose, 100mgL−1 initial chlorophenol concentration, 1gL−1 catalyst, pH 3 and 50°C temperature. Moreover, complete dechlorination of all the chlorophenols tested was achieved, being the residual organic by-products short-chain acids without significance in terms of ecotoxicity. The catalyst showed a remarkable stability in long-term continuous experiments with limited Fe leaching, below 5% of the initial loading after 100h on stream. An additional clear advantage of the new catalyst is its easy separation and recovery from the reaction medium by applying an external magnetic field. [Copyright &y& Elsevier]

Abstract: Mono- and bimetallic Rh and Pt based NO x storage-reduction (NSR) catalysts, where the noble metals were deposited on the Al2O3 support or BaCO3 storage component, have been prepared using a twin flame spray pyrolysis setup. The catalysts were characterized by nitrogen adsorption, CO chemisorption combined with diffuse reflectance infrared Fourier transform spectroscopy, X-ray diffraction, and scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy. The NSR performance of the catalysts was investigated by fuel lean/rich cycling in the absence and presence of SO2 (25ppm) as well as after H2 desulfation at 750°C. The performance increased when Rh was located on BaCO3 enabling good catalyst regeneration during the fuel rich phase. Best performance was observed for bimetallic catalysts where the noble metals were separated, with Pt on Al2O3 and Rh on BaCO3. The Rh-containing catalysts generally showed much higher tolerance to SO2 during fuel rich conditions and lost only little activity during thermal aging at 750°C. [Copyright &y& Elsevier]

Abstract: Silica-supported MoP catalysts were prepared by temperature-programmed reduction (H2-TPR) at 550, 600 and 700°C of the corresponding dried or calcined substrates. Two catalysts were prepared by using two different synthetic approaches. A MoP catalyst was prepared using the method described in the literature that uses ammonium phosphate (NH4H2PO4) and ammonium heptamolybdate ((NH4)6Mo7O24·4H2O) precursors, calcination and subsequent H2-TPR at high temperature. A new synthetic approach was carried out to prepare another MoP catalyst using ammonium molybdate ((NH4)2MoO4) and phosphorous acid (H2PO3H) as precursors and subsequent H2-TPR. The catalytic activity was evaluated in the individual and simultaneous hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) reactions performed in a flow reactor under a hydrogen pressure of 3.0MPa. The fresh reduced and spent catalysts were characterized by ICP, N2 adsorption–desorption isotherms at −196°C, XRD, HRTEM, NH3-TPD, XPS and elemental chemical CNHS analysis. The silica-supported MoP catalysts prepared by the new synthetic method were more active in the HDS of DBT than the catalyst prepared by reduction of calcined substrate. The catalyst characterization results showed that the lower reduction temperature required to form the MoP species is responsible for the enhancement in catalytic performance. The key factors influencing on the catalytic activity are: a large specific surface area, high acidity and good dispersion of MoP phase on the support substrate. Activity measurements in simultaneous HDN–HDS showed that quinoline conversion is enhanced in the presence of a small amount of DBT whereas the HDS of DBT reaction does not appear to be inhibited by a small amount of quinoline added to the feed. [Copyright &y& Elsevier]

Abstract: This work reports the synthesis and characterization of a cerium phosphate supported gold catalyst as well as its catalytic activity for the oxidation of CO. A precipitation method in the presence of an organic modifier followed by a hydrothermal treatment was used for the support synthesis, resulting in high surface area nanometric particles. Gold/cerium phosphate catalyst with a 1% (w/w) nominal gold content was characterized using XRF, XRD, N2 adsorption–desorption measurements, TEM and DRIFTS-MS. The catalyst shows good catalytic activity at low temperature. The activity is related to the generation of oxygen vacancies in the support caused by the elimination of structural oxygen. In situ studies revealed that the reaction of the oxygen vacancies with gaseous oxygen resulted in the formation of peroxo species. These species are responsible for the activity detected at room temperature in both the catalyst and the support. Moreover, the presence of carbonate and hydrogen carbonate acting as reaction intermediates have been observed. [Copyright &y& Elsevier]

Abstract: Selective oxidation of glycerol with molecular oxygen was studied over different functionalized MWNTs supported Pt catalysts in base-free aqueous solution. N2 adsorption, IR, Raman and SEM–EDS analysis confirmed that the tubular structure of MWNTs is stable during HNO3 and H2O2 pretreatment and the surface of MWNTs was successfully functionalized by HNO3, H2O2 and NH2–CH2–CH2–SH. XRD, SEM and TEM analysis demonstrated that unique sized Pt particles formed on S-pretreated MWNTs. Pt/S-MWNTs catalyst with small Pt particles was more active than Pt/MWNTs, Pt/HNO3-MWNTs and Pt/H2O2-MWNTs for glycerol oxidation in base-free aqueous solution. Free glyceric acid formed (with 68.3% selectivity and 90.4% conversion of glycerol) on Pt/S-MWNTs in base-free solution. While dihydroxyacetone formed firstly in an aqueous solution of NaOH/glycerol=2:1 and the cleavage C–C bonds (catalyzed by alkali) arise severely. [Copyright &y& Elsevier]

Abstract: Vanadia supported on zeolites were prepared and characterized by N2 physisorption, FTIR, XRPD, and NH3-TPD methods. The influence of the Si/Al ratio on the total surface acidity of the catalysts as well as the optimum V2O5 content were studied and compared with the catalytic activity in the selective catalytic reduction (SCR) of NO with ammonia. The SCR activity was found to correlate directly with the total acidity of the catalysts and showed high poisoning resistivity after doping with potassium oxide (100μmol/g). The poisoning resistance was due to unique combination of high surface area, acidity and micropore structure of the support. Apparently the support hosted the potassium oxide on the acid sites, thereby protecting the active vanadium species from poisoning. Zeolite based catalysts might therefore prove useful for SCR of NO in alkali- containing flue gases from, e.g. biomass fired power plants. [Copyright &y& Elsevier]

Abstract: Na-montmorillonite (Na-mmt) and different pillared interlayered clays (Al-PILC, Zr-PILC, Ti-PILC and Al2O3/Ti-PILC) supported CrCe catalysts for the deep oxidation of nitrogen-containing VOCs (NVOCs) are synthesized and characterized by a combination of X-ray diffraction, N2 adsorption/desorption, high resolution transmission electron microscopy, temperature-programmed reduction, temperature-programmed desorption and adsorption capacity tests techniques. The results indicate that a porous structure named “house of cards” forms during the pillaring and calcination processes. Both porous structure and acidity play important roles in deep oxidation of NVOCs. The mesoporous structure and the proper acid sites improve the catalytic activity of supported CrCe catalysts. Among all these catalysts, CrCe/Ti-PILC and CrCe/Al2O3/Ti-PILC exhibit higher catalytic activity than other catalysts. N-butylamine and ethylenediamine with –NH2 groups are easier to be destructed may be involved in the stronger adsorption on the acid sites of the catalysts. Much too strong adsorption of ethylenediamine on the acid sites leads to a lower activity compared with n-butylamine. Acetonitrile with C≡N bond and little interaction with acid sites is the most difficult to be decomposed. All the catalysts show a good control quality of NO x , and the yield of NO x is limited within 2% during the whole experimental temperature range. [Copyright &y& Elsevier]

Abstract: Nanotitania supported on mesoporous silica systems were synthesized by a reliable procedure based on an incipient wetness impregnation post-synthetic approach. Characterization by X-ray diffraction, N2 physisorption, TEM, X-ray photoelectron spectroscopy, ICP has been carried out in order to investigate the chemical–physical properties of the catalysts with particular attention to the chemical nature of the titanium species. The photocatalytic activity of the samples was evaluated for the degradation of NOx in the gas phase. The influence of both the textural properties and the nature of titanium species on the photocatalytic activity is discussed. [Copyright &y& Elsevier]

Abstract: A series of Co–Mo–Mg/Al2O3, K–Co–Mo–Mg/Al2O3, and Co–Mo/silica catalysts were prepared and characterized by means of N2 adsorption, temperature-programmed desorption of ammonia (NH3-TPD), high-resolution transmission electron microscopy (HRTEM), and Fourier transformed infrared (FT-IR) spectra of adsorbed NO. The physicochemical properties of the catalysts were correlated with their hydrodesulfurization and olefin hydrogenation activities. The results showed that the dispersion and stacking of supported MoS2 were more important in influencing the selectivity of FCC gasoline hydrodesulfurization than the catalyst pore diameter and acidity. The compromise between the dispersion and the stacking of supported MoS2 slabs was crucial to form the sufficient and accessible Co–Mo–S phases for achieving optimal hydrodesulfurization selectivity. The present results form a fundamental basis for developing highly effective catalysts for the selective hydrodesulfurization of fluid catalytic cracking gasoline to meet the strict regulations for ultra-low sulfur gasoline. [Copyright &y& Elsevier]