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A series of HBeta, HZSM-5, Al2O3, MgO and hydrotalcite precursor supported Pt catalysts were prepared and used for glycerol hydrogenolysis to 1,2-propanediol (1,2-TPD) in a base-free aqueous solution. XRD, TEM, CO2-TPD and H2-TPD characterizations concluded that the activity for glycerol hydrogenolysis of the tested catalysts depends mainly on their alkalinity and particle size of Pt. A hydrotalcite precursor supported Pt catalyst with strong alkalinity and highly dispersed Pt particles exhibited the predominant performance for the desired reaction (with a 93.0% selectivity of 1,2-PDO at a conversion of 92.1%) in a base-free aqueous solution at lower pressure, and can be recycled simply by filtration. [ABSTRACT FROM AUTHOR]

The CexTi1-xO2 mixed oxides at different mole ratios (x=0.1–1.0) were prepared by co-precipitation of TiCl4 and Ce(NO3)3. The structural and reductive properties of the CexTi1-xO2 were affected by calcination temperature. At x=0.1–0.3, CeTi2O6 phase was formed and mainly as amorphous after calcination at 650°C. At x=0.3, only CeTi2O6 was formed after calcination at 750°C and CeTi2O6 crystallized completely after calcination at 800°C. TPR analyses showed that the amount of H2 consumption by CexTi1-xO2 (650°C) (except x=0.1) was greater than that by single CeO2, and the valence of CeO2 was the lowest (+3.18) at x=0.3. CuO/Ce0.3Ti0.7O2 was prepared by the impregnation method and catalytic properties were examined by means of a GC micro-reactor NO+CO reaction system, BET, TPR, XRD, XPS and NO-TPD. It was found that CuO/Ce0.3Ti0.7O2 calcined at 650°C had the highest activity in NO+CO reaction with 100% NO conversion at reaction temperature of 300°C, and at 650°C Ce0.3Ti0.7O2 just began to crystallize. The catalytic activities were largely affected by the pre-treatment conditions. At low reduction temperature (100°C), CuO species was difficult to reduce. When high degree of reductions took place, both CuO species and Ce0.3Ti0.7O2 reduced and thus a part of CuO species on the support surface would be covered. The XPS and NO-TPD analyses showed that CuO/Ce0.3Ti0.7O2 had four NO absorption centers (Cu+, Cu2+(I), Cu2+(II) and Ce3+). The CuO species involving in NO+CO reaction included Cu2+(I) and Cu+, and CeO2 species (Ce3+ and Ce4+). [ABSTRACT FROM AUTHOR]

Highlights from the article: CVD Grown MoS2 Nanoribbons on MoS2 Covered Sapphire(0001) Without Catalysts (Phys. In article no. 1900063, Fangping Ouyang, Han Huang and co-workers report on the synthesis of 1D MoS SB 2 sb nanoribbons on sapphire(0001) supported monolayer MoS SB 2 sb flakes without catalysts through an atmospheric pressure chemical vapor deposition approach. 1D MoO SB I x i sb S SB 2- I x i sb crystals are treated as precursors, which transform to MoS SB 2 sb nanoribbons through sulfurization.

Highlights: [•] Plasma-assisted CuO-based catalysts system with NO+CH4 reaction is studied. [•] CuO/CeO2/TiO2/γ-Al2O3 catalysts has the best NO removal activity among four catalysts. [•] NO conversion decreases in the order of CuO/CeO2/TiO2/γ-Al2O3 >CuO/TiO2/γ-Al2O3. [•] CuO/γ-Al2O3 >CuO/TiO2. [•] H2-TPR and NO-TPD explain the reason for CuO/CeO2/TiO2/γ-Al2O3 better NO removal. [Copyright &y& Elsevier]

Abstract: Promotional effect of Ca on the catalytic property of Pd/Ce–Zr/Al2O3 catalyst towards methane combustion is examined. The surface properties and the oxidation/reduction behavior of these catalysts are investigated by BET, TEM, XPS, TPR, TPO and TPSR techniques. Activity tests in methane combustion show that addition of Ca to Pd/Ce–Zr/Al2O3 can promote remarkably its low-temperature activity. The thermal stability of the Pd/Ce–Zr/Al2O3 catalyst to the exposure at high temperature is also enhanced by Ca loading. XPS and TEM results show that the addition of Ca to Pd/Ce–Zr/Al2O3 catalyst generates well-dispersed PdO particles on support. H2–TPR, O2–TPO and CH4/O2–TPSR experiments show that the addition of Ca improves the reduction/reoxidation properties and thermal stability of the active PdO species, which increases the catalytic activity and thermal stability of the Pd/Ce–Zr/Al2O3 catalyst. [Copyright &y& Elsevier]

Abstract: Influence of residual on the preferential oxidation of CO in excess hydrogen (PROX) over catalysts was investigated. catalysts were characterized by BET, ICP, XRD, UV-Raman and TPR techniques. The results showed that the existence of residual made peak in TPR of catalysts shift to higher temperatures and depressed the PROX in the absence of and in the feed over catalysts. However, small amount of residual was beneficial to the catalytic performance of catalysts in the PROX in the presence of and in the feed. Consequently, residual with an appropriate content was beneficial to improve the catalytic performance of catalysts in the presence of and . [Copyright &y& Elsevier]

Abstract: A study of the liquid-phase conversion of biomass-derived sugars directly to methyl lactate catalyzed over solid base catalysts is presented. The yield of methyl lactate reached 29.45% under optimal reaction conditions. The effects of reaction time, reaction temperature, and catalysts calcination temperature were investigated. Fresh and used catalysts were characterized by XRD, CO2-TPD, and N2-adsorption techniques. MgO with the highest concentration of weakly basic sites was found to show the highest catalytic activity for the conversion of sugars to methyl lactate. [Copyright &y& Elsevier]

Abstract: Rod-like Ca x SiO x +2 catalysts were synthesized by using one-pot hydrothermal method. Catalysts calcined at 550°C were used in the transesterification reaction of soybean oil with methanol. Under methanol reflux condition, FAME yields of 82% and 95% were achieved on Ca4SiO6 in a reaction time of 1 and 2h, separately. Also, the FAME yields on different Ca x SiO x +2 catalysts were correlated with their basic properties. Besides, a FAME yield of ca. 80% can be achieved under room temperature over Ca4SiO6 catalyst. [Copyright &y& Elsevier]

Abstract: In this work, the low-boiling fraction (LBF) of bio-oil was used as feed stock. LBF is a very complex mixture, and the three groups in LBF: acids, aldehydes and phenols, are primarily responsible for deterioration in the quality. The upgrading reactions were carried out over Pt/Al2(SiO3)3, Pt/C or Pt/MgO in supercritical methanol. It is demonstrated that supercritical condition can greatly facilitate the esterification process, and after 6h reaction, all the acids can be converted into esters even without adding any catalyst. The total amount of the three groups left in products was much less exhibited on Pt supported on active carbon and MgO in the presence of hydrogen. By investigating the model reactions, the relations between the representative compounds and major products were identified, and the conversion scheme of the upgrading reactions is proposed. [Copyright &y& Elsevier]

Abstract: Hydrogenolysis of biodiesel derived glycerol to 1,2-propanediol (1,2-PDO) has attracted much attention in recent years. In this work, glycerol hydrogenolysis to 1,2-PDO was performed over CuO/MgO catalysts prepared by impregnation and coprecipitation at 180°C and 3.0MPa H2. It was found that the Cu(15)/MgO catalyst prepared by coprecipitation had the best activity. The conversion of glycerol and the selectivity of 1,2-PDO over Cu(15)/MgO reached 72.0% and 97.6%, respectively. And the conversion of glycerol was further increased to 82.0% when small amount of NaOH was added in the reaction mixture. Those highly active catalysts were characterized by X-ray diffraction, transmission electron microscopy, N2-adsorption and temperature-programmed reduction with H2. Characterization results revealed that the activity of the prepared catalysts depended strongly on the particle sizes of both Cu and MgO. Catalysts that have smaller sized Cu and MgO particles are more active for glycerol hydrogenolysis. [Copyright &y& Elsevier]

Abstract: ZrO2 supported La2O3 catalyst prepared by impregnation method was examined in the transesterification reaction of sunflower oil with methanol to produce biodiesel. It was found that the catalyst with 21wt% loaded La2O3 and calcined at 600°C showed the optimum activity. The basic property of the catalyst was studied by CO2-TPD, and the results showed that the fatty acid methyl ester (FAME) yield was related to their basicity. The catalyst was also characterized by TG–DTA, XRD, FTIR, SEM and TEM, and the mechanism for the formation of basic sites was discussed. It was also found that the crystallite size of support ZrO2 decreased by loading of La2O3, and the model of the solid-state reaction on the surface of La2O3/ZrO2 catalyst was proposed. Besides, the influence of various reaction variables on the conversion was investigated. [Copyright &y& Elsevier]

Abstract: Ni/SiO2 and Ni–Al2O3/SiO2 catalysts were prepared by incipient wetness impregnation using citrate and nitrate precursors and tested with a reaction of combination of CO2 reforming and partial oxidation of methane to produce syngas (H2/CO). The catalytic activity of Ni/SiO2 and Ni–Al2O3/SiO2 greatly depended on interaction between NiO and support. NiO strongly interacted with support formed small nickel particles (about 4nm for NiSC which is abbreviation of Ni/SiO2 prepared with Nickel citrate precursor) after reduction. The small nickel particles over NiSC catalysts exhibited a good catalytic performance. [Copyright &y& Elsevier]

Abstract: Production of syngas via autothermal reforming of methane (MATR) in a fluidized bed reactor was investigated over a series of combined CeO2–ZrO2/SiO2 supported Ni catalysts. These combined CeO2–ZrO2/SiO2 supports and supported Ni catalysts were characterized by nitrogen adsorption, XRD, NH3-TPD, CO2-TPD and H2-TPR. It was found that the combined supports integrated the advantages of SiO2 and CeO2, ZrO2. That is, they have bigger surface area (about 300m2/g) than pure CeO2 and ZrO2, stronger acidity and alkalescence than that of pure SiO2, and enhanced the mobility of H adatoms. Ni species dispersed highly on these combined CeO2–ZrO2/SiO2 supports, and became more reducible. Ni catalysts on the combined supports possess higher CO2 adsorption ability, higher methane activation ability and exhibited higher activity for MATR. H2/CO ratio in product gas could be controlled successfully in the range of 0.99–2.21 by manipulating the relative concentrations of CO2 and O2 in feed. [Copyright &y& Elsevier]

Abstract: A series of different-sized Ni catalysts (4.5–45.0 nm) were prepared and used for methane autothermal reforming with CO2 and O2 in a fluidized-bed reactor. It was found that the activity and stability of Ni catalysts depend strongly on the particle size and the operating space velocity. Small sized Ni is more active and stable at space velocity <54,000 h−1. Characterizations disclosed that methane decomposition rate decreases with the enlarging Ni particle size, and some of the surface carbons (derived from methane decomposition) are inactive in CO2 atmosphere. As the methane decomposition rate slows on larger Ni particles and at higher space velocity to ensure complete conversion of the oxygen, surface Ni will be gradually oxidized by remaining O2, leading to Ni deactivation. [Copyright &y& Elsevier]

Abstract: The effects of ceria and zirconium additions to alumina-supported palladium catalysts on methane combustion behavior have been investigated. A series of Ce–Zr-modified Al2O3 supports and their supported Pd catalysts are prepared using impregnation method and then characterized by BET, XRD, LR, TEM, XPS techniques. The results show that the addition of Ce–Zr improves the thermal stability of alumina. The thermal stability of alumina increases with increasing the loading of Zr. The methane oxidation activity and thermal stability is found to be dependent on the Ce:Zr ratio over the Pd/Ce x Zr1−x /Al2O3 catalysts. The Pd/Ce0.2Zr0.8/Al2O3 exhibits the highest activity and thermal stability for methane oxidation. The temperatures for the 90% methane conversion are 448 and 455°C for the Pd/Ce0.2Zr0.8/Al2O3 catalysts calcined at 500 and 1100°C, respectively. TEM results show that the particle size of Pd is not the key factor influencing the activity of Pd/Ce0.2Zr0.8/Al2O3 catalyst. An induction period is present during methane combustion reaction for the Pd/Al2O3 and Pd/Ce x Zr1−x /Al2O3 catalysts (calcined at 1100°C), but the lengths of induction period are obviously different and the Pd/Ce0.2Zr0.8/Al2O3 catalyst exhibits the shortest induction period. XPS results show that comparing to Pd/Al2O3 catalyst the addition of Ce–Zr stabilizes Pd in a high oxidation state and enhances the reoxidation of metallic Pd to the active PdO under reaction conditions. Therefore the Pd/Ce x Zr1−x /Al2O3 catalysts compared to Pd/Al2O3 catalysts have higher thermal stability and shorter induction period. [Copyright &y& Elsevier]

Ag–Al2O3 catalysts prepared by impregnation, co-precipitation and single sol–gel methods were used for selective catalytic reduction of NOx by propene in the presence of oxygen. Ag(5)–Al2O3(SG) catalyst was found to be the most active catalyst for selective reduction of NOx, especially the activity in the low-temperature range, which may be ascribed to synergistic effect of BET surface area, pore size distribution, Ag species dispersion, the valence and morphology of the Ag species of the catalyst. The conversion of NOx increased with the oxygen concentration in the low-temperature region, whereas the NOx conversion decreased with the oxygen concentration in the high-temperature region. The differences of oxygen concentration on the catalyst from the previous report on impregnation Ag/Al2O3 catalyst with 2 wt.% Ag loading were discussed in detail. [Copyright &y& Elsevier]

The activities of CuO/TiO2 and ZrO2-modified CuO/TiO2 in the NO reduction by CO were examined with a microreactor-gas chromatography (GC) NO+CO reaction system, and the catalysts were characterized by physical adsorption, TG-DTA, XRD and NO-TPD techniques. The results showed that the NO conversion temperatures of 6% CuO/TiO2 were 280 °C at T50% and 450 °C at T99%, compared to 325 °C at T99% for 6% CuO–10% ZrO2/TiO2. The 6% CuO–10% ZrO2/TiO2 calcined at 500 and 750 °C had similar catalytic activities (T99% at 300 °C) in H2 atmosphere. The nitrogen adsorption–desorption isotherm and pore-size distribution curve of TiO2 represented type IV of the BDDT system and a typical mesoporous sample, respectively. After ZrO2 addition, the diffraction peak of ZrO2 was not detected and the diffraction peak intensity of CuO did not increase either, likely due to the strong interaction between CuO and ZrO2 that enhanced the catalytic activity and stability. In the H2 atmosphere, CuO produced dispersed Cu0 species. Four desorption species (NO, N2O, N2 and O2) were detected during the thermal desorption of NO by CuO/TiO2 and CuO–ZrO2/TiO2 treated in both air and H2. Addition of ZrO2 onto CuO/TiO2 shifted the NO dissociation peaks towards low temperature, indicating that the activity of NO decomposition was higher by CuO–ZrO2/TiO2 than by CuO/TiO2. The NO+CO reaction formed intermediary product N2O at low temperature but formed N2 at high temperature. In addition, the peak temperature of NO desorption was related to the catalytic activity under both air and H2, and the dissociation of NO on catalysts surface was a rate-determining step in NO+CO reaction. [Copyright &y& Elsevier]

Four perovskite-type precursors (LaNiO3, La2NiO4, LaCoO3 and La2CoO4) were successfully prepared by Pechini method and were characterized by X-ray powder diffraction (XRD), temperature-programmed reduction technique (TPR) and X-ray photoelectron spectroscopy (XPS). After reduction, their catalytic activity toward CO2 reforming of CH4 was tested in a fixed-bed reactor. It was found that Ni-based La2NiO4 catalyst, after calcinations at 850 or 1100 °C, was quite active and stable with CH4 conversion of 72% and 75%, respectively. It was proposed that the well-defined structure and La2O2CO3 phase might be responsible for the unusual catalytic behavior observed over the catalyst. [Copyright &y& Elsevier]

Silica-supported poly-γ-aminopropylsilane transition metal (Ni2+, Cu2+, Co2+) complexes have been prepared. These catalysts are highly active and stereoselective for Heck vinylation reaction of aryl iodide with olefines at 130–150 °C, and can be reused after washing without loss in activity. An induction period of more than 2 h was observed. [Copyright &y& Elsevier]

Abstract: A novel palladium supported on cerium, lanthanum, praseodymium and zirconium-pillared montmorillonite (MMT) catalysts are prepared and for the catalytic combustion of toluene, acetone and ethyl acetate. The order of catalytic activity is consistent with the different support: La–Zr/MMT≈Ce–Zr/MMT>Pr–Zr/MMT. X-ray diffraction (XRD) experiment revealed that the basal spacing of MMT enhanced from 0.97 nm to 1.73 nm after Zr-pillared treatment. After doping of Ce, La and Pr, the interlayer spacing increased to 1.94, 2.02 and 1.85 nm on Ce–Zr/MMT, La–Zr/MMT and Pr–Zr/MMT support. N2 adsorption–desorption method and scanning electron microscopy (SEM) helped to understand the catalytic performance of these palladium supported and rare earth oxides doped MMT catalysts. [Copyright &y& Elsevier]