Catalytic Activity Of Catalysts Research Articles

Surface engineered active Co3+ species in alkali doped Co3O4 spinel catalyst with superior O2 activation for efficient CO oxidation

CO oxidation is one of the most extensively investigated fields of research as it takes prime importance in environmental fortification and is highly challenging to explore efficient heterogeneous catalysts to achieve effectual conversion. In the present work, Co3O4 and alkali metal-doped Co3O4 spinel materials were obtained by the co-precipitation method and employed as suitable catalysts for CO oxidation. The catalysts were prepared by calcining the precipitated hydroxides of Co at 300°C, and 800°C (with and without the presence of water vapor) in the air atmosphere. The synthesized materials were characterized by powder X-ray diffraction, N2-sorption analysis, H2-TPR, SEM, and XPS techniques. Then the catalytic activity of catalysts is evaluated for CO oxidation using molecular O2 as an oxidizing agent. The effect of thermal treatment and also the role of alkali metal in CO oxidation are studied. The promotional effect of alkali (Li, Na, and K) in Co3O4 materials was observed with higher CO conversion, where the influence of Li ions in the Co3O4 catalyst was far greater than in other doped catalysts. Definite characteristics, nature of alkali-doped catalysts, and oxidative influence involved in CO oxidation reaction mechanism were carefully studied. In a general perspective, this work shows the influence of surface properties of alkali ion-doped Co3O4 spinel catalysts that consequently control the reactivity toward CO oxidation.

Morphology design and synthesis of magnetic microspheres as highly efficient reusable catalyst for organic dyes

Precise synthesis of magnetic particles that surface chemistry spanning is critically needed for the fundamental research. We reported a new seed emulsion interfacial polymerization, which precisely synthesized magnetic polymer particles spanning from sulfonated porous magnetic microspheres to topology structured magnetic microspheres (TPMMs). By varying the degree of cross-linking, the type of monomer, several types of magnetic polymer particles with different morphology were obtained. Then silver nanoparticles (NPs) were precipitated in situ on the surface of topology structured magnetic microspheres as catalyst (Ag@TPMMs). To estimate the catalytic activity, the reduction experiments of Rhodamine B (RhB) and 4-nitrophenol (4-NP) were studied. These toxic dyes can be reduced in a very short time, and the apparent rate coeffcients of RhB and 4-NP were 0.03156 s−1 and 0.0286 s−1 respectively, which indicated that they had a good catalytic performance. When the catalyst was used 5 cycles, the catalytic activity of catalyst was still high. The potential applications of TPMMs will be very useful in labeling, tracking, protein separation and other biomedical fields.

Green synthesis of pistachio shell-derived biochar supported cobalt catalysts and their catalytic performance in sodium borohydride hydrolysis

Pistachio shell-derived biochar supported cobalt catalysts were synthesized by using a modified impregnation-chemical reduction method. Polydopamine (PDA) and tannic acid (TA) were used as reducing and functionalizing agents. The effect of modification treatment was investigated on the physicochemical and catalytic properties. The peaks observed in XRD patterns belonged to biochar and cobalt. The surface area, total pore volume and pore diameter values of Co-PDA@BC catalyst were determined as 268 m2/g, 0.262 cm3/g and 3.03 nm, respectively. These values higher than that of Co-TA@BC catalyst. FTIR spectra exhibited bands representing the biochar structure. XPS spectra showed that cobalt was embedded in the support structure in metallic and oxide form. The use of PDA improved structural properties and catalytic activity of catalyst. The maximum hydrogen generation rate and activation energy for Co-PDA@BC was determined as 25 mL min−1gcat−1 and 31.3 kJ mol−1, respectively.

Analysis of CaCO3 Impregnation on HY Zeolite Surface Area, Pore Size, and Activity in the Catalytic Cracking of Palm Oil to Biofuels

Fossil energy sources are currently decreasing, requiring the development of alternative energy sources. Vegetable oil is a raw material for alternative renewable energy supplies. This study produced biofuels from vegetable oil using calcium carbonate (CaCO3)-impregnated HY catalysts. In addition, this study aimed to investigate the effect of CaCO3 impregnation on the surface area and the catalytic activity of catalysts in the palm oil cracking process to produce biofuels. The HY catalyst was modified by the wet impregnation method in 5 wt% CaCO3 solution and was further calcined at 550°C for three h. Furthermore, the catalysts were tested in a continuous fixed-bed catalytic reactor at 450°C. The catalyst properties were characterized using Brunauer–Emmett–Teller (BET) surface area, Barrett–Joyner–Halenda (BJH) for pore size distribution, and X-Ray Diffraction (XRD) for crystal structure and phases. The results showed that the addition of CaCO3 decreased surface area and pore volume; however, the pore size increased, which resulted in the production of heavy hydrocarbons. Interestingly, the introduction of CaCO3 enhanced the yield of Organic Liquid Product (OLP) and diesel-range hydrocarbons selectivity to reach 79.09% and 30.54%, respectively. Furthermore, the introduction of CaCO3 increased deoxygenation activity.

Designing of highly-efficient oxygen evolution reaction electrocatalyst FeCo-hydroxyl phosphates: Theory and experiment

The development of a physical factor to correlate the experimental methods and catalytic activity of catalysts is quite important for the design of highly-efficient catalysts. In this work, with the aid of our pre-designed correlation factor of d electron density, a new oxygen evolution reaction electrocatalyst of FeCoPO4 was designed on account of the higher electronegativity of Co atom than Fe atom. The foreign Co atom would enhance the combining capacities of the neighbouring Fe-O bonds, increase the d electron density and reduce the chemical activity of host Fe ions, and thus improve the catalytic activity of Fe based active centers. Based on the theoretical guidance, the prepared FeCoPO4 specimen exhibited low ηexp of 241 mV, fast charge transfer rate, high intrinsic activity and stable electrocatalytic activity. This strategy would be adopted to design highly-efficient catalyst by altering the d electron density of transition metal ions with suitable preparation methods.

Electrocatalytic reduction of CO2 to C1 products over bimetal catalysts: A DFT screening study

Electrochemical CO2 reduction reaction (CO2RR) to produce C1 products has received much attention in recent years. However, efficient electrocatalysts of CO2 reduction are still lacking. Herein, the theoretical screening was implemented to design bimetal catalysts (M2@M1, M1, M2 = Cu, Ag, Au, Pt, Pd, M1 ≠ M2) and the catalytic activity of catalysts was investigated systematically. A simple and rapid screening method is proposed for the design and development of electrocatalysts. Pt@Ag has good catalytic performance for CO2RR-to-HCOOH, and greatly inhibits competitive hydrogen evolution reaction (HER). Au@Pd exhibits superior performance for CO production. Its overpotential (0.448 V) required for CO production is lower than those of the many catalysts reported. Pt@Ag is also a promising catalyst to produce CH3OH, and has a better catalytic activity than the most active CO2RR-to-CH3OH catalysts. The overpotential of CO2RR-to-CH3OH is 0.393 V. This theoretical work provides a motivation for the experimental synthesis of bimetal catalysts, which are used for the electrocatalytic reduction of CO2.

Oxygen vacancies enhancing performance of Mg-Co-Ce oxide composite for the selective catalytic ozonation of ammonia in water

Catalytic ozonation based on heterogeneous metal oxides is a promising approach to removing ammonia as gaseous nitrogen from water. Herein, MgO/Co3O4/CeO2 was prepared for catalytic ozonation of ammonia in an aqueous solution. The influence of various reaction conditions was systematically investigated and optimized, in which the reaction kinetics was also analyzed. After doping Ce, the catalyst with Mg-Co-Ce molar ratio of 4:1:1 and calcined at 700 °C for 3 h, has abundant surface oxygen vacancies and exhibited excellent performance for the selective catalytic oxidation of ammonia to gaseous nitrogen by ozone. It was found that the catalytic activity of catalysts was positively related to oxygen vacancies concentration on the composites surface, which might play a vital role in selective catalytic ozonation. Under the optimal conditions, the ammonia removal rate in MgO/Co3O4/CeO2 catalytic system was 0.03328 min−1 (R2 = 0.99942), about 2.1 times greater than that of MgO/Co3O4 (0.01597 min−1, R2 = 0.99813), and the selectivity was further enhanced from 73.57% to 86.94%. Moreover, the evolution of nitrogen and chlorine species was determined to discuss the mechanism of selective oxidation of ammonia in the low chlorine-containing solution. This study might promote the understanding of catalytic ozonation of ammonia to gaseous nitrogen selectively.

Preparation of zinc oxide graphted nickel incorporated mesoporous SBA-16 doped graphene oxide: An efficient catalyst for transesterification of waste edible oil to biodiesel and photocatalytic degradation of organic dyes

Graphene-based composite materials a wide range of applications, including the production of electronic components and capacitors, as well as adsorption and catalysis. In this work, the ZnO/Ni-SBA-16@GO nanocatalyst was applied to synthesized biodiesel from waste edible oil (WEO) as an efficient and easily available source. The said nanomaterial was applied for the degradation of methylene blue (MB) and methyl orange (MO). The catalyst was characterized by HRTEM, XRD (small angle and wide angle), SEM, EDX, BET, N2 adsorption/desorption isotherm, and TGA. The findings illustrated that the nanostructure has well-controlled pore diameter (4.0 nm) and prominent surface area (735 m2/g). Furthermore, it was possible to reuse the catalyst up to five times; with the results indicating that the catalyst's catalytic activity was sufficient for the synthesis of WEO biodiesel for up to three cycles before diminishing. The present study used a centralized composite approach to look at the influence of numerous features on biodiesel synthesis in order to discover the optimal conditions for biodiesel production. According to the findings, the maximum biodiesel conversion yields 98% had been obtained during a 7-hour reaction time at a temperature of 70 °C. The nanostructure has also been worked as a photocatalyst to degrade MB and MO. According to the statistics, more than 90% of both dyes were degraded in less than 40 min.

Effect of Pd/Ce Loading and Catalyst Components on the Catalytic Abatement of Toluene

Monolithic catalysts are widely used in industrial catalysis. However, in the preparation of a monolithic catalyst, the traditional methods have some drawbacks such as low washcoat uploading ratio and poor uniformity. In the present work, the effects of Pd/Ce loading and catalyst components on the catalytic abatement of toluene were investigated. The acid treatment of the substrate, the particle size of the slurry and the dispersant on the uniformity of the washcoat and the catalytic performance were also explored. Characterisation was achieved via BET, SEM, zeta potential and laser grain-size analyses. The results showed that the catalytic activity of the catalyst increased with the increasing of the Ce content. It was found that the 0.2Pd-0.3Ce/γ-Al2O3 catalysts had the best toluene catalytic activity. The pretreatment of the cordierite with 20% HCl could improve the properties of the cordierite. It was also found that reducing the particle size of the washcoat and adding dispersant PAA could effectively improve the stability of the suspension and the uniformity of the washcoat. When 20% HCl pretreatment was used, the toluene catalytic activity of the monolith catalyst prepared by cordierite increased, in which T10 and T90 decreased by about 5 °C. Decreasing the particle size and dispersant also promoted the efficiency of catalytic degradation.

Three Si-substituted polyoxovanadates as efficient catalysts for Knoevenagel condensation and selective oxidation of styrene to benzaldehyde.

Three new Si-substituted polyoxovanadates (POVs), [Cd2(dien)2][Cd(dien)][Cd(Hdien)2][V15Si6O46(OH)2(H2O)]·7H2O (1), [Co(enMe)2]3[Co2(enMe)2(H2O)2][V16Si4O44(OH)2(H2O)]·6H2O (2), and [Co(teta)]4[V16Si4O42(OH)4(H2O)]·10H2O (3) (dien = diethylenetriamine; enMe = 1,2-diaminopropane; teta = triethylenetetramine) were synthesized by the hydrothermal method and characterized. Structural analysis sheds light on the fact that the {V15Si6O48}/{V16Si4O46} clusters of compounds 1-3 were formed by replacing {VO5} square pyramids in the classical {V18O42} cluster with {Si2O7} units. Compound 1 is a 2D bilayer structure formed by the [V15Si6O46(OH)2(H2O)]10- cluster and two types of bridging Cd complexes containing binuclear groups [Cd2(dien)2]4+. Compound 2 is a 3D framework constructed from the [V16Si4O44(OH)2(H2O)]10- cluster and two types of Co complex fragments including binuclear [Co2(enMe)2(H2O)2]4+. In compound 3, the [V16Si4O42(OH)4(H2O)]8- cluster is connected with bridging [Co(teta)]2+ to expand into a 2D network. Compounds 1 and 3 represent the first 2D assemblies based on a vanadosilicate cluster. 1-3 served as heterogeneous catalysts and exhibited highly efficient catalytic activities for the Knoevenagel condensation under mild ambient conditions with low catalyst loading, featuring the open Lewis base {V15Si6O48}/{V16Si4O46} sites and Lewis acid Cd2+/Co2+ sites. The conversion of benzaldehyde was up to 99.3% in 80 min at room temperature using 1 as a heterogeneous catalyst with only 0.37% catalyst loading. Moreover, compounds 1-3 as catalysts for selective oxidation of styrene to benzaldehyde exhibited excellent catalytic performance, high selectivity and could be readily recycled. Most strikingly, compound 1 showed excellent catalytic performance with 97.6% conversion of styrene and 100% selectivity of benzaldehyde in 15 min. In addition, the catalytic activity of catalyst 1 was well maintained after five cycling reactions.

THE NiO AND MoO3 ENRICHED ZSM-5 AS CATALYST FOR THE HYDROCRACKING OF COCONUT OIL INTO BIO-JET FRACTION

ZSM-5 was enriched with NiO (nickel oxide) or MoO3 (molybdenum oxide) and used as a catalyst to increase selectivity towards the bio-jet fuel fraction from the hydrocracking of coconut oil. NiO and MoO3 were incorporated into ZSM-5 through wet impregnation at various concentrations of 0.5–5% (wt.). The catalyst material characteristics were analyzed using XRD (X-ray Diffraction), TEM (Transmission Electron Microscope), and nitrogen gas adsorption instruments. The catalyst activity was observed through a hydrocracking reaction at a temperature of 475 °C for 3 hours, using coconut oil as feed and the catalyst concentration was 2 (wt.%). The results showed that NiO and MoO3 were distributed successfully into ZSM-5. Catalyst's catalytic activity was strongly influenced by the amount of NiO and MoO3 embedded into ZSM-5. The Ni-1, Ni-5, Mo-1, Mo-3, Mo-4, and Mo-5 catalysts increased the selectivity towards the bio-jet fraction by 55%, 34%, 49%, 37%, 36%, and 62%, respectively when compared to ZSM-5.

MgO-supported CuO with encapsulated structure for enhanced peroxymonosulfate activation to remove thiamphenicol

Copper-base catalysts with high load content of CuO were commonly utilized to activate peroxymonosulfate (PMS) for removal of contaminants but limited catalytic efficiency and increased risk of copper ion leaching restricted their use. In this paper, Cu-Mg mixed metal oxides with highly dispersed minute quantities of CuO were successfully prepared by one-pot synthesis for efficiently activating PMS to remove thiamphenicol (TAP), which was economical and environmentally friendly. The catalytic activities of catalysts with different molar ratios of Cu and Mg for PMS and their characteristics were evaluated, illustrating the optimal molar ratio of Cu and Mg (1:15, named CuMg-MMO) in the catalyst. For the CuMg-MMO catalyst, MgO widely dispersed and wrapped CuO nanoparticles, minimized the copper ion leaching and promoted the generation of Cu-OH complex and non-radical species. In the CuMg-MMO/PMS system, the influence factors for TAP degradation were analyzed, including different systems, catalyst dosages, PMS concentrations, temperatures, initial pH values, TAP concentrations, anions (NO3-, HCO3-, Cl-, HPO42- and H2PO4-) and natural organic matter (NOM) concentrations. Under the optimal conditions (i.e., [catalyst]: 75 mg/L, [PMS]: 0.3 mM, temperature: 30 °C and initial pH: 6.5), TAP removal efficiency obtained by this system was 99.9%. SO4·-, ·O2- and 1O2 played more important roles than HO· in TAP degradation. Four successive repeated experiments indicated that CuMg-MMO possessed good reusability and stability. PMS decomposition, mineralization of TAP, the activation mechanism of PMS and possible degradation pathways of TAP were analyzed.

Selective hydrogenation of cinnamaldehyde to cinnamyl alcohol over palladium/zirconia in microwave protocol

Hydrogenation of aldehydes (RHO) is one of the frequently used reactions in organic synthesis and pharmaceuticals industries. In this contribution, we have synthesized control shaped and nano-sized tetragonal zirconia (t-ZrO2), palladium supported on zirconia (Pd/t-ZrO2) and nickel promoted palladium supported on zirconia (Ni-Pd/t-ZrO2) though modified microwave irradiation method. All the prepared samples were characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Diffractometry (XRD), Thermal Gravimetric Analysis (TGA), Brunauer-Emmett-Teller (BET) surface area and pore size analysis, and Fourier Transform Infrared Spectroscopy (FT-IR). Theoretical calculation (DFT) revealed high interaction of Pd with t-ZrO2(101) surface. Furthermore, adsorption energy, support relaxation and charge transfer studies confirmed the stability of Pd on t-ZrO2(101) surface. The catalytic activity of catalysts was tested for cinnamaldehyde (CAL) hydrogenation in a modified microwave reactor. The comparative study of microwave irradiated (MW) and conventional heating (C-Heating) systems show supremacy of MW over C-Heating by a factor of 46% under optimal reaction parameters for Pd/t-ZrO2 catalyst. The stability, life span, conversion and selectivity of Pd/t-ZrO2 under MW system suggest the applicability of the catalysts for a variety of organic hydrogenation reactions.

Facile fabrication of TiO2 with 3D hierarchical structure and its supported Pd catalysts for high catalytic hydrogenation performance of 4-Nitrophenol to 4-Aminophenol

TiO2 with different morphology as supports can lead to different surface properties and catalytic activities of catalysts. Herein, we reported a novel facile evaporation-induced assisted hydrothermal approach to synthesize three-dimensional hierarchical structure TiO2 assembled from needle flakes by using Brij-35 as the morphology-directing agent. The morphology of the prepared TiO2 from flower-like (TiO2-FT), sea urchin-like (TiO2-SUT), to ball-like (TiO2-BT), as well as the size of needle flakes, were controlled by adjusting the amount of Brij-35. These TiO2 supported palladium catalysts were facilely prepared using a green bio-reductive method with Catalpa Fruit extract as reducing agent, where they showed remarkable catalytic activity in selective hydrogenation of 4-nitrophenol by sodium borohydride. Especially, 1 wt%Pd/TiO2-SUT with sea urchin-like exhibited higher reaction rate constant (1.44 min−1) than 1 wt%Pd/TiO2-FT (1.08 min−1) and 1 wt%Pd/TiO2-BT (0.72 min−1). Furthermore, XRD, N2 adsorption–desorption, SEM, TEM, CO-FTIR, XPS and CO chemisorption measurements were performed to study the effects of different surface morphologies on the surface properties of catalysts. It reveals that the high catalytic performance of 1 wt%Pd/TiO2-SUT can be attributed to its specific hierarchical structure and much higher surface area, improving the uniform dispersion of Pd nanoparticles on the support to expose extra active surface Pd atoms (Pd0 species) over 1 wt%Pd/TiO2-SUT.

PROMETHEUS: A Copper-Based Polymetallic Catalyst for Automotive Applications. Part II: Catalytic Efficiency an Endurance as Compared with Original Catalysts.

PROMETHEUS catalyst, a copper-based polymetallic nano-catalyst has been proven to be suitable for automotive emission control applications. This novel catalyst consists of copper, palladium and rhodium nanoparticles as active phases, impregnated on an inorganic oxide substrate, CeO2/ZrO2 (75%, 25%). The aim of PROMETHEUS catalyst’s development is the substitution of a significant amount (85%) of Platinum Group Metals (PGMs) with copper nanoparticles while, at the same time, presenting high catalytic efficiency with respect to the commercial catalysts. In this work, an extensive investigation of the catalytic activity of full scale PROMETHEUS fresh and aged catalyst deposited on ceramic cordierites is presented and discussed. The catalytic activity was tested on an Synthetic Gas Bench (SGB) towards the oxidation of CO and CH4 and the reduction of NO. The loading of the washcoat was 2 wt% (metal content) on Cu, Pd, Rh with the corresponding metal ratio at 21:7:1. The concentration of the full-scale monolithic catalysts to be 0.032% total PGM loading for meeting Euro III standard and 0.089% for meeting Euro IV to Euro VIb standards. The catalytic activity of all catalysts was tested both in rich-burn (λ = 0.99) and lean-burn conditions (λ = 1.03).

Progress in vanadium complex catalysts and their catalytic behavior toward copolymerization of ethylene with α-olefins

<p indent=0mm>Ethylene-propylene rubber, linear low density polyethylene and polyolefin elastomer, which are prepared by copolymerization of ethylene with α-olefins, have an important market share of the industry due to their excellent properties. Catalyst plays important roles in the copolymerization of ethylene with α-olefins. Many vanadium complexes in the oxidation states of +3, +4 and +5 have been developed as precatalyst for the copolymerization. The progress of vanadium complex catalysts and their use in copolymerization of ethylene with α-olefins were reviewed. The effects of chelated ligands on the catalytic activity of catalysts, composition, molecular weight, molecular weight distribution and sequence of the resulting copolymers were discussed. Vanadium(III) complexes are widely used since vanadium(III) species are usually considered as active species in olefin coordination polymerization. Vanadium(III) complexes bearing monodentate <italic>N</italic>-heterocyclic carbene (NHC) ligand or bidentate β-diketonate ligands have been used as prcatalyst in copolymerization of ethylene with propylene, affording ethylene-propylene copolymers with high propylene content. Ethylene-propylene copolymers with ultra-high molecular weight were prepared by using vanadium(III) complexes containing NHC ligand. Vanadium(III) complexes bearing chelated bidentate N^N or N^O, etc. ligands show high catalytic activity up to <sc>8820 kg mol^–1 h^–1</sc> toward copolymerization of ethylene with 1-hexene. The introduction of bulky substitutes on the ligand results in an increase in the reactive ratio of ethylene and a decrease in the reactive ratio of 1-hexene, and thus a change in the sequence of monomer in the resulting copolymer. Vanadium(III) complexes containing tridentate and tetradentate ligands display relatively lower catalytic activity than their analogues containing similar bidentate ligand. Most vanadium(IV) complexes display lower catalytic activity than vanadium(III) complexes bearing similar ligands. Ethylene-propylene copolymer with high propylene content could be prepared by copolymerization of ethylene and propylene catalyzed by vanadium(IV) complexes containing monodentate amide ligands. Vanadium(V) complexes bearing chelating aryloxides have been shown to be highly active (up to <sc>144400 kg mol^–1 h^–1)</sc> in copolymerization of ethylene with propylene, affording ethylene-propylene copolymers with low propylene content (less than 15%(mol)). Ethylene-propylene copolymers with high propylene content (more than 30%(mol)) could be prepared by vanadium complexes containing monodentate or bedentate ligands. It is interesting to note that quasi-living copolymerization of ethylene with propylene was realized by using vanadium(V) complexes containing NHC ligand and ethylene-propylene copolymers with ultrahigh molecular weight and narrow molecular weight distribution were obtained. In conclusion, the vanadium complex catalysts have displayed good catalytic behavior towards the copolymerization of ethylene with α-olefins. The vanadium complexes discussed here may be an inspiration for future work in the development of vanadium complex catalyst with high catalytic activity and high comonomer incorporation for copolymerization of ethylene with α-olefins.

Investigation of LaMnO3 catalyst loaded on HZSM‐5 zeolite for CO catalytic oxidation

AbstractDue to the large amounts of CO pollutant from iron ore sintering and vehicle emissions, the control of CO emission becomes more and more important for the environment. To control the emission of CO more effectively, the catalysts of LaMnO3 perovskite with HZSM‐5 zeolite as support were prepared by sol–gel method. The structure and catalytic activities of catalysts were characterized and analyzed. According to the results of X‐ray diffraction (XRD) and energy‐dispersive X‐ray spectroscopy (EDS), the LaMnO3 perovskite phase is successfully obtained in all the supported catalysts. The average particle sizes of supported catalysts are in the range of 15–38 μm. Compared with the perovskite catalysts loaded on other kinds of supports, LaMnO3 supported with HZSM‐5 has a larger specific surface area (SSA). The SSAs of supported catalysts with different loading amount are in the range of 190–300 m2/g. The HZSM‐5 support improves the catalytic activity of LaMnO3 catalyst by increasing the SSA. The activity of supported catalyst becomes higher when the loading amount increases from 20% to 60%. The catalyst with 60% perovskite loaded shows the best activity in CO catalytic oxidation. The CO conversion of 60LM/HZSM‐5 attains 50% and 90% at 172.7°C and 201.5°C, respectively. The activities of catalysts with 80% and 100% perovskite loaded decrease due to the accumulated pores formed by too much perovskite. The supported catalysts exhibit favorable activities in consecutive reaction cycles. It turns out that HZSM‐5 support is appropriate for the synthesis of active perovskite catalysts for CO oxidation.

One-Step conversion of high FFA Crude Karanja oil (Pongamia pinnata) to Bio-diesel Using Portland cement as excellent heterogeneous catalyst

Heterogeneous catalyst was prepared from Portland cement. The prepared heterogeneous catalyst was tested for catalytic activity in the transesterification of non-edible, high free fatty acid feedstock, such as crude karanja oil (CKO), for biodiesel production, at methanol reflux temperature. Gas chromatographic (Gc) analysis technique was used to determine the fatty acid methyl ester yield. The preparation of heterogeneous catalyst from low-cost sources, and the use of non-edible feedstock, only at methanol reflux temperature, were all aimed at reducing the cost of biodiesel production. Insight into the catalytic activities of catalyst was obtained by characterizations for their textural properties, using Brunnear-Emmet-Teller (BET) analysis technique, surface scanning electron microscopy (SEM) and electron dispersive x-ray (EDX) for microstructure, surface morphology and chemical composition; x-ray diffraction (XRD) and Fourier-Transform Infra-Red (FTIR) spectroscopy for structural and functional groups analyses, respectively. Differential thermal and thermogavimetric (DTA/TGA) analyses were performed to determine the proper temperature ranges for the dehydration, decomposition, desorption and oxidation of sample via the TGA curves and their melting points and changes in crystal structures via the DTA curves, for effective determination of calcination temperature. The application of Portland Cement-derived heterogeneous catalyst in the transesterification reaction revealed excellent activity in the transesterification of crude karanja oil, with excellent fatty acid methyl ester yield of over 97.87 %. Operational conditions such as methanol/oil mole ratio (1:3 - 18), catalyst loading (3 - 9 % by wt) and reaction time (0.5 – 7 hours), were investigated to obtain the optimum reaction conditions for the feedstock, while the reaction temperature was kept constant at methanol reflux temperature, to minimise cost of production, in line with the objective of this investigation. Calcined heterogeneous catalysts gave over 80% fatty acid methyl ester yields than the raw counterpart, which were attributed to changes in crystal structures and phases of catalysts, observed in the characterization of catalysts, after calcination. Keywords: Portland cement, heterogeneous catalyst, Crude Karanja oil, transesterification reaction, Feedstock

Ceria-Molybdenum Mix Metal Oxide: A Mild and Efficient Recyclable Catalyst for One-Pot Synthesis of Polyhydroquinoline via Hantzsch Reaction

In laboratory, ceria-molybdenum mix metal oxide catalyst was synthesized by using simple grinding method and characterized by FT-IR, XRD, SEM, and EDX. Catalytic activities of catalyst were testified in Hantzsch condensation reaction for the synthesis of polyhydroquinoline by using dimedone, substituted aryl aldehydes, ethylacetoacetate and ammonium acetate with high percent yield. It is an efficient catalyst for 1,4-dihydropyridines synthesis. Cerium molybdenum mix metal oxide catalyst can be re-covered and re-used. DOI: http://dx.doi.org/10.17807/orbital.v12i1.1420

Enhancement of oxidative desulfurization performance over 3DOM H3PW12O40/TiO2 by HF treatment

Three-dimensional ordered (3DOM) H3PW12O40/TiO2 nanocomposites with anatase TiO2 exposed {001} facets are fabricated by HF treatment and applied as effective catalyst in oxidative desulfurization (ODS) process. The structure characterization results including SEM, TEM, XRD, N2 adsorption-desorption isotherms, XPS, and FT-IR confirm the different percentage of exposed {001} facets of anatase TiO2 and highly dispersion of Keggin-type phosphotungstic acid (HPW) on the 3DOM TiO2 framework. The ODS performance of as-fabricated catalysts suggests that the optimal ratio of the exposed {001} facets on anatase TiO2 is determined to be 26.83%, which exhibits superior catalytic activity for dibenzothiophene (DBT) than other catalysts. In addition, density functional theory (DFT) calculation has been applied to illustrate the influence of exposed {001} surface of anatase TiO2 on catalytic activity of catalyst.