Effect Of Catalyst Preparation Method Research Articles

Production of Biodiesel by Transesterification of Pilot Plant Waste over Nickel (Ni)/Eggshell (CaO) Catalyst

The increment of pilot plant waste at UniKL MICET and eggshell waste cause disposal problems, such as the water and soil pollution, human health concerns, and disruption to aquatic ecosystems. Thus, to reduce the effect of disposal problem to the environment, pilot plant waste is converted into biodiesel, while eggshell is converted into catalyst in this study. This paper reports on the effect of catalyst preparation method and reaction temperature on biodiesel yield and quality. Transesterification process of pilot plant waste (olein and stearin) was conducted by using Ni/CaO (eggshell) catalyst from different preparation methods at different reaction temperatures (328 K, 333 K, 338 K and constant reaction time (5 hours), methanol-to-oil ratio (15:1), and weight of catalyst (8 wt%). The catalysts were synthesized via wet impregnation and sol–gel method and its physicochemical properties were subsequently characterized by TGA and FTIR analysis. Biodiesel analysis was done using GCMS and FTIR, while the physical properties (density, flash point, and kinematic viscosity) of biodiesel were measured according to ASTM D6751. Kissinger-Akahira-Sunose (KAS) kinetic model shows that the catalyst prepared by wet impregnation method has the lowest activation energy, which was 81.48 kJ mol–1. In addition, GCMS analysis shows that reaction temperature at 338 K produced the highest yield of biodiesel (88.26%). In conclusion, the best catalyst preparation method was wet impregnation method and the best reaction temperature was 338 K. In addition, the physical properties of the produced biodiesel corresponded to ASTM standard, thereby indicating high quality of biodiesel and can be used as petroleum-diesel substitute.

Effects of catalyst preparation methods on the performance of La2MMnO6 (M=Co, Ni) double perovskites in catalytic combustion of propane

Effects of catalyst preparation methods on the performance of La2MMnO6 (M=Co, Ni) double perovskites in catalytic combustion of propane

A Review on Catalytic Dehydration of Glycerol to Acetol

AbstractThe renewability of glycerol has made it an appealing medium for the processing of various compounds. Selective dehydration of glycerol to acetol is one of the promising glycerol valorizations. The performance and recent progress of those typical and most frequently mentioned catalysts for the synthesis of acetol from glycerol, including noble metals and transition‐based metals, are summarized in detail. A Cu‐based catalyst is identified as an appropriate catalyst for the synthesis of the glycerol dehydration route. In addition, advances in process development of several solid supports, the effects of catalyst preparation methods of suitable supports on catalytic activity, and the performance of catalysts' considering the catalytic conversion of glycerol to acetol are reviewed.

Effect of Catalyst Preparation Method on Ammonia Decomposition Reaction over Ru/MgO Catalyst

Abstract Ammonia decomposition on Ru/MgO was strongly affected by the pore structure of the MgO support. We found that highly active Ru/MgO catalysts were successfully prepared by using Ru hydroxide and hydromagnesite as catalyst precursors. The mesopores of MgO of about 3–5 nm and highly dispersed Ru species improved the catalytic performance.

Aerobic oxidation of benzyl alcohol: Influence from catalysts basicity, acidity, and preparation methods

The effect of catalyst preparation method and metal precursors on the catalyst basicity were studied in Pd catalysts supported on magnetic SBA-15 for benzyl alcohol oxidation (BzOH) to benzaldehyde (BzH). The reaction was carried out in an environmentally friendly condition, i.e, in the absence of additive and solvent, at low temperature (95 °C) in the presence of oxygen. Various techniques such as ball milling and impregnation as well as different precursors such as nitrate and chloride of palladium were applied for catalyst preparation. Among them, MPM-2 catalyst which was prepared by nitrate precursor and physical hand mixing, exhibited the most optimized basicity. The intensity of 2.9 × 10−10 of total basicity was measured by CO2-TPD experiment. The catalysts showed 50 % of BzOH conversion and 95 % of selectivity towards BzH after 3.5 h. The activation energy of the reaction was significantly decreased and reached 17.6 kJ.mol-1.

Quality of bio-oil from catalytic pyrolysis of microalgae Chlorella vulgaris

This study investigates the yield and quality of bio-oil produced from catalytic and non-catalytic pyrolysis of microalgae Chlorella vulgaris using Ni supported zeolite (Si/Al = 30) prepared by two different methods, ion exchange (IE) and wet impregnation (WI) to examine the effect of catalyst preparation methods on the bio-oil quality. The experiments were also conducted to investigate the effect of different temperatures (300–600 °C) and catalyst to algae ratio (1:5, 1:2, 1:1 and 2:1) on the yield and quality of bio-oil. The results showed that catalytic pyrolysis using Ni supported zeolites produced high hydrocarbon, less oxygenated and acid compounds compared to non-catalytic pyrolysis. The catalyst preparation method did not affect the yield but had an effect on the bio-oil composition. The results obtained from this study are useful in developing the catalytic pyrolysis process to refine bio-oils for commercial use.

Cobalt supported on alumina as green catalyst for Biginelli reaction in mild conditions: effect of catalyst preparation method

AbstractCobalt supported on alumina (10 wt% Co/Al

The Effect of Preparation Method on Ni/Ce/Al Catalyst for High Temperature Water-Gas Shift Reaction

High temperature water gas shift (HT-WGS) is an important catalytic process connected with reforming process in hydrogen production. Ni/CeO2-Al2O3 (or Al2O3) catalysts were studied in this work on the effect of catalyst preparation method toward the physicochemical properties and the HT-WGS activity. Ni/CeO2-Al2O3 were prepared by sol-gel and impregnation methods whereas Ni/Al2O3 was prepared by impregnation method. The catalyst samples were characterized by XRD, H2-TPR and H2-TPD techniques. The catalytic activities of HT-WGS catalysts was demonstrated at 550°C, GHSV of 2x105 mLh-1gcat-1and steam-to-CO ratio of 3. Nickel was detected as a nickel aluminate phase in the calcined catalyst. Ni strongly interacted with support in the calcined catalyst prepared by sol-gel method. The strong metal-support interaction can be resisted by preparing catalyst via impregnation and CeO2 can promote the H2O dissociation in HT-WGS mechanism. The highest metal dispersion, largest metal surface area and greatest HT-WGS activity were consequently achieved by Ni/CeO2-Al2O3 prepared from impregnation method.

Lignin Depolymerization Over CuO–MgO–Al2O3 Mixed Oxide Catalysts in Supercritical Ethanol: Effect of Catalyst Preparation Methods

Lignin Depolymerization Over CuO–MgO–Al₂O₃ Mixed Oxide Catalysts in Supercritical Ethanol: Effect of Catalyst Preparation Methods

Catalytic Activity of Bimetallic Cu-Ag/MgO-SiO2 Toward the Conversion of Ethanol to 1,3-Butadiene

Abstract In the present work, the catalytic conversion of ethanol to 1,3-butadiene (1,3-BD) was studied over monometallic of Cu and Ag, and bimetallic Cu-Ag supported on MgO-SiO2 (with MgO/SiO2 ratio of 2.0) under the temperature range from 250 to 325 °C. All catalysts were prepared by 4 different techniques including (i) conventional impregnation, (ii) microwave-assisted method, (iii) polyvinyl alcohol/sodium borohydride (PVA/NaBH4) assisted method, and (iv) benzoxaxine-assisted method to elucidate the effect of catalyst preparation method on their catalytic performance. All fresh and spent catalysts were also characterized by X-ray diffraction (XRD), N2 adsorption and Temperature-programmed reduction (TPR) techniques to understand the relation between their physical/chemical properties and catalytic performance. From the reaction test, it was found that 5 %Ag/MgO-SiO2 showed greater activity towards 1,3-BD production than 5 %Cu/MgO-SiO2; nevertheless, higher deactivation after 6 h of operation was observed from 5 %Ag/MgO-SiO2. Importantly, this study revealed that bimetallic 2.5 %Cu-2.5 %Ag/MgO-SiO2 enhanced significantly higher activity and stability towards the reaction than monometallic catalysts. In addition, 2.5 %Cu-2.5 %Ag/MgO-SiO2 prepared by benzoxaxine-assisted method enhanced significantly higher reaction activity and stability than other preparation techniques, from which 1,3-BD yield of 46.40 % after 6 h of operation can be achieved. From the characterization, the good activity of this catalyst is mainly due to the dispersion improvement of metal over MgO-SiO2 support.

Effect of Catalyst Preparation Method on the Characteristics of Carbon Nanospheres as Anode Materials of Lithium Secondary Batteries

Carbon nanospheres (CNSs) were synthesized from commercial activated carbons and cooking oil as carbon precursors using simple pyrolytic process and then were used as anode materials of lithium secondary batteries Prior to the synthesis of CNSs, a series of Fe catalysts supported on commercial activated carbons were prepared by two different methods, namely impregnations and adsorptions. The effect of preparation method on the characteristics of CNSs were then studied by scanning electron microscopy (SEM) , transmission electron microscope (TEM) and BET surface area measurements. Preliminary electrochemical measurements of as-synthesized CNTs were carried out using cyclic voltammetry instruments at constant scan rate to see the mechanism of Li-ion insertion and extraction into/from CNSs structures during cycle tests.

Preparation of highly dispersed W/ZrO2–Al2O3 hydrodesulfurization catalysts at high WO3 loading via a microwave hydrothermal method

Abstract A microwave hydrothermal (MWH) method was used to deposit WO 3 onto ZrO 2 –Al 2 O 3 with various ZrO 2 contents to prepare hydrodesulfurization (HDS) catalysts with high WO 3 loading (23 wt%) close to industrial hydrotreating, for achieving high W dispersion and weak W-support interaction. The catalysts with the same WO 3 and ZrO 2 contents were prepared by a conventional impregnation (IM) method as reference. The effects of catalyst preparation methods and ZrO 2 contents on the catalyst property and dibenzothiophene HDS activity were investigated. The results show that the MWH method leads to highly dispersed octahedrally coordinated W species which are weakly linked on ZrO 2 –Al 2 O 3 and easy to be reduced; no bulk WO 3 crystallites are observed even at high ZrO 2 content (50 wt%). Therefore, it causes better sulfidation and shorter WS 2 slabs. Contrarily, the IM method induces W species to agglomerate into bulk WO 3 crystallites which are poorly dispersed and hard to be reduced, which is further aggravated by ZrO 2 . The HDS activity of the MWH-prepared catalysts significantly increases with ZrO 2 up to 40 wt% ZrO 2 . This catalyst shows 2 times higher rate constant and 1.64 times higher efficiency of HDS than the IM-prepared catalyst with the same ZrO 2 content. For the IM-prepared catalysts, the HDS activity slightly increases at small amount of ZrO 2 (10 wt%) and then decreases drastically.

Hydrogen production by catalytic decalin dehydrogenation over carbon-supported platinum catalyst: Effect of catalyst preparation method

Preparation method strongly affected the platinum dispersion of carbon-supported platinum catalysts, and accordingly, their catalytic activity in the decalin dehydrogenation. The catalyst prepared by an advanced method (ion-exchange method or polyol method) exhibited a better catalytic performance than that prepared by a conventional method (impregnation method or precipitation method) in terms of initial hydrogen evolution rate and total amount of hydrogen evolution. Platinum dispersion played a key role in determining the catalytic activity in this reaction, and thus, the high platinum dispersion of the catalysts prepared by an ion-exchange method and a polyol method resulted in their high catalytic activity.

고분자 전해질 다층박막을 이용한 과산화수소 직접제조 반응 중 활성금속 용출 억제 방법

본 연구에서는 일반적인 귀금속 담지법과 담체 위에 형성한 고분자 전해질 다층 박막 내에 귀금속을 내포시키는 방법으로 촉매를 제조하고, 과산화수소 직접제조 반응에 적용하여 촉매의 제조 방법이 과산화수소 생산성 및 촉매 수명에 미치는 영향을 조사하였다. 촉매의 활성은 제조 방법에 상관없이 담체의 산세기에 크게 의존하였으며, 사용한 담체들 중 산세기가 가장 강한 HBEA(SAR=25)를 사용한 경우가 활성이 가장 우수하였다. 단순 귀금속 담지 촉매는 고분자 전해질 다층 박막을 도입한 촉매보다 과산화수소 생산성은 우수하였으나, 반응 중 활성 금속인 Pd의 용출로 인해 재사용 횟수가 증가할 때마다 활성이 급격히 감소하였다. 한편, 고분자 전해질 다층 박막의 도입은 산성 담체의 역할을 약화시켜 촉매 활성은 감소하고 과산화수소 분해능은 증가하여 전체적으로 과산화수소의 생산성이 감소되는 결과를 가져왔다. 하지만, 5회에 걸친 재사용 동안에도 촉매 활성이 유지되었으며, 이러한 비약적인 촉매 수명의 향상은 담체 위에 고분자 전해질 다층 박막을 도입하는 것이 반응 중 활성 금속의 용출 억제 측면에서 매우 효과적이라는 것을 시사한다. In this study, two types of catalysts were prepared via conventional metal supporting method and encapsulation of metal nanoparticles in the polyelectrolyte multilayers constructed on support. The resulting catalysts were applied to the direct synthesis of hydrogen peroxide, and the effect of catalyst preparation method on the catalyst life as well as hydrogen peroxide productivity was investigated. The catalytic activity was strongly dependent upon the acid strength of support regardless of the catalyst preparation methods and HBEA (SAR=25) with strong acidity was superior to other supports to promote the reaction. In the case of metal supported catalyst, while hydrogen peroxide productivity was higher than that of polyelectrolyte multilayered counterpart, the reaction performance was sharply decreased during catalyst recycling due to the metal leaching. On the other hand, construction of polyelectrolyte multilayers on support weakened the influence of acid support on the reaction medium and therefore resulted in the decrease of catalytic activity and the increase of hydrogen peroxide decomposition as well. It is noted, however, that the catalytic activity was maintained after 5 recycles, which suggests that the introduction of polyelectrolyte multilayers on the support is very effective to suppress the unfavorable metal leaching phenomenon during a reaction.

Effect of Catalyst Preparation Method on Dry Reforming of Methane with Supported and Promoted Catalysts

Effect of Catalyst Preparation Method on Dry Reforming of Methane with Supported and Promoted Catalysts

Preparation of highly stable bimetallic Ni–Cu catalyst for simultaneous production of hydrogen and fish-bone carbon nanofibers: Optimization, effect of catalyst preparation methods and deactivation

This paper presents the preparation of highly stable nano-porous Ni–Cu catalysts for simultaneous production of COx–free hydrogen and carbon nano-fibers. The main features of this work focuses on the optimization, methods of catalyst preparation and application of an experimental model for deactivation. The fresh catalysts and the deposited carbon were characterized by SEM, TEM, XRD and Raman spectroscopy. Whatever to be the preparation methods, performance tests showed that the presence of Cu as promoter in Ni–Cu–MgO catalysts, enhanced the catalytic activity, substantially at higher temperatures with the best result obtained for Ni–Cu–MgO catalyst prepared by one step sol- gel method, reaching a hydrogen concentration of 70 vol% (160.51 mol H2/mol Ni-1 h) and a smaller value of ID/IG (less imperfection) for produced carbon nano-fibers at 670 °C. Detailed rate-based model for deactivation of catalyst was found to be dependent on the time, reaction temperature and partial pressure of methane and indicated that the reaction of deactivation could be modeled by a simple hyperbolic model.

Effect of preparation methods on the performance of Co/Al2O3 catalysts for dry reforming of methane

Co/Al2O3 catalysts were synthesized by dry impregnation and controlled adsorption. The effect of catalyst preparation methods on their performance in methane dry reforming was studied.

Synthesis of Methyl Acetate by Dimethyl Ether Carbonylation over Cu/HMOR: Effect of Catalyst Preparation Method

Dimethyl ether carbonylation to methyl acetate was comparatively investigated over mordenite supported copper (Cu/HMOR) catalysts prepared by different methods including evaporation, urea hydrolysis, incipient wetness impregnation and ion-exchange. The results showed that Cu/HMOR prepared via iron-exchange method exhibited the highest catalytic activity due to the synergistic effect of active-site metal and acidic molecular sieve support. Conversion of 95.3% and methyl acetate selectivity of 94.9% were achieved under conditions of 210 °C, 1.5 MPa, and GSHV of 4883 h−1. The catalysts were characterized by nitrogen absorption, X-ray diffraction, NH3 temperature program desorption, and CO temperature program desorption techniques. It was found that Cu/HMOR prepared by ion-exchange method possessed high surface area, moderate strong acid centers, and CO adsorption centers, which improved catalytic performance for the reaction of CO insertion to dimethyl ether.

Simultaneous hydrodesulfurization and hydrodenitrogenation on MoP/SiO2 catalysts: Effect of catalyst preparation method

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.

Bimetallic catalysts for the Fischer–Tropsch reaction

This short critical review summarises and analyses the developments in Fischer–Tropsch catalysis using bimetallic alloys. We introduce a simple notation for such catalysts, and monitor the reports of synergistic effects and composition/performance relationships. Special attention is given to CoFe alloys on a variety of supports, and to the effects of catalyst preparation methods and pre-treatment conditions. The key drawbacks in comparing the large amount of data available on Fischer–Tropsch catalysis are the high dimensionality of the problem and the lack of long time-on-stream studies. Based on the new understanding coming from characterisation studies of supported bimetallic particles, we propose a structured approach for effectively studying Fischer–Tropsch catalysis.