Oxygen Vacancy-Rich Mn–Zr Composite Oxide-Supported Ruthenium Catalyst for Base-Free Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid with High Productivity

Composite pelletized catalysts for higher one-pass conversion and productivity in the Fischer–Tropsch process are reported. The introduction of aluminum metal powder as a thermal conductor leads to the formation of a new family of composite pelletized catalysts, very different from reference systems. In particular, these catalysts retain high activity and C5+ selectivity at increasing gas-hour space velocities of up to 5,000 h−1. The productivity of these composite catalysts increases almost fourfold for fivefold GHSV increase. Composite catalysts with different types of active cobalt (conventional, introduced by impregnation, or skeletal) show similar values of one-pass conversion and productivity but give different fractional and group composition of liquid hydrocarbon products. Testing of these highly productive catalysts in reactors with different aspect ratios showed that high productivity and one-pass conversion can be achieved in industrial-size units, where feasible liquid yield of up to 140 barrels per million standard cubic feet (MMSCF) of natural gas can be reached.

A method of doping magnesium aluminum hydrotalcites, which are precursors for oxidative dehydrogenation oxide catalysts of various compositions, with copper(II) was developed, and copper(II)-containing oxide catalyst samples were synthesized. The catalytic properties of these catalysts were studied in the oxidative dehydrogenation of ethane, propane, and hexane. The conversion of ethane into ethylene on the copper-containing catalysts was established to proceed with high selectivities (90–97%) and at low temperatures (400–450°C).

Porous silica as supports for controlled fabrication of Au/CeO2/SiO2 catalysts for CO oxidation: Influence of the silica nanostructures

Heterogeneous ozone-catalyzed oxidation technology is one of the effective ways of wastewater treatment, and the development of efficient ozone oxidation catalyst is the key to this process. Herein, this work proposes the design and synthesis of an efficient multi-metal composite oxide catalyst by metal salt precursor mixing-direct granulation. The successful loading of the main active metal components, such as Mn, Cu, Fe, etc. was clarified by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and other systematic characterizations, the specific surface area of the catalyst spheres produced by pelletizing could reach 231.699 m2/g, and the pore volume was 0.414 cm3/g. And after the optimization of the catalyst preparation conditions and oxidation process conditions, the removal rate of COD could reach more than 50% for the simulated wastewater, and the catalytic activity was basically kept stable in a long-cycle operation of 1000 h, which indicated that the prepared multi-metal composite oxide catalyst had good catalytic activity and stability. Finally, the EPR characterization clarified that the degradation of organic pollutants in the catalytic process was mainly dominated by the singlet oxygen and proposed a possible catalytic oxidation mechanism, which provided a reference for the synthesis of new high-efficiency ozone oxidation catalysts.

Ceria substrate–oxide composites as catalyst for highly efficient catalytic oxidation of NO by O2

Construction of surface oxygen vacancy active sites upon MnOx/AC composite catalysts for efficient coupling adsorption and oxidation of toluene

Effects of deep eutectic solvent on Cu-Mn-C-O composite catalysts: Surface species, physical and chemical properties in methane combustion

Synthesis, characterization and performance of CuO/La 2O 3 composite catalyst for ammonia catalytic oxidation

An approach for upgrading behavior and bio-oil production using CO2-assisted cellulose pyrolysis in cobalt-based Ce/Fe/Mg composite catalyst

A new composite catalyst was constructed by immobilizing active site N,N-dihydroxypyromellitimide (NDHPI) on the co-catalyst Co-doped mesoporous sieve SBA-15 through the chemical bond with the 3-(glycidoxypropyl) trimethoxysilicane used as the silylation agent. The catalyst was characterized by various means. The new catalyst showed significantly higher activity in toluene aerobic oxidation at 90 °C with acetonitrile as a solvent or under solvent-free condition compared with the NDHPI and co-catalyst independent system. The effects of the reaction conditions such as temperature, oxygen pressure, catalyst amount on the toluene oxidation over the immobilized catalyst were also investigated. After reuse for three times, the composite catalyst kept the activity without loss of Co from SBA-15. A new composite catalyst was constructed by immobilizing active site N,N-dihydroxypyromellitimide (NDHPI) on the co-catalyst Co-doped mesoporous sieve SBA-15 through the chemical bond with the 3-(glycidoxypropyl) trimethoxysilicane used as the silylation agent. The catalyst was characterized by various means. The catalytic performance of the composite was evaluated in toluene aerobic oxidation and the reuseability of the catalyst was also investigated.

Iron(II), cobolt(II), and copper(II) phthalocyanines encapsulated inside the supercage of zeolite-Y were prepared by the in situ ligand synthesis method via heating the solid mixture of iron(II)-, cobolt(II)-, and copper(II)-exchanged NaY with phthalic anhydride and urea. Using hydrogen peroxide as the oxidant, the catalytic activity of these composite catalysts for methane selective oxidation was tested, and the reaction conditions were optimized. All these composite catalysts showed activity in selective oxidation of methane by hydrogen peroxide at room temperature. These composite catalysts were further loaded with Pd, Au, or PdAu, and their catalytic activity for methane oxidation with dioxygen as oxidant were examined. The coupling of encapsulated metallophthalocyanine catalysts with precious metal, which could catalyze the in situ generation of H(2)O(2), realized the activation of methane by molecular oxygen at room temperature. The results showed that the synergism between palladium and copper(II) phthalocyanine led to the improved catalytic activity in selective oxidation of methane at room temperature.

Inhibition of CO oxidation over Cu-Mn-Ce-O composite catalyst in the presence of dry powder fire extinguishing agent: Mechanism investigation and mitigation strategy

A novel metal oxide composite catalyst for the complete oxidation of carbon monoxide and hydrocarbons was prepared by combining oxygen ion conducting materials with active transition metals. The oxygen ion conductors used were typical fluorite-type oxides, such as ceria, zirconia, and others. Active base metal catalysts, such as copper, were used as additives to promote the catalytic properties of oxygen ion conductors. The intimate contact of the two kinds of materials gave rise to a highly active oxidation catalyst. On Cu-Ce-O composite catalysts, 95% of carbon monoxide was oxidized by air at ∼100 °C. Complete methane oxidation on the same catalyst took place at ∼550 °C. When the stoichiometric amount of sulfur dioxide was used to oxidize carbon monoxide, 96% of sulfur dioxide was reduced to elemental sulfur at temperatures above 460 °C with 99% of sulfur dioxide conversion. This type of composite catalyst also showed excellent resistance to water poisoning.

As a family of highly ordered two-dimensional anionic clay materials, layered double hydroxides (LDHs) can be used as catalyst, catalyst supported, or precursors for the synthesis of low-cost and highly dispersed supported metal catalysts with excellent catalytic activity and stability. Due to the excellent mechanical, electrical, and physicochemical properties, carbon nanomaterials can work as ideal functional components to fabricate LDHs/carbon composite catalysts with enhanced catalytic performance. This review summarizes the recent development in the controlled fabrication of functional nanocomposite materials based on layered double hydroxides and carbon-based materials, and their applications as the heterogeneous catalyst such as photocatalyst, electrocatalyst, hydrogenation and oxidation catalyst, etc. Furthermore, current challenges and prospects of LDHs/carbon composite catalysts are discussed from the viewpoint of material design and application.

Physical mixture of Ag/Al2O3 and Zn/ZSM-5 as an active catalyst component for selective catalytic reduction of NOx with n-C10H22