Production of aromatic compounds from catalytic fast pyrolysis of Jatropha residues using metal/HZSM-5 prepared by ion-exchange and impregnation methods

Metal based-zeolite catalysts were successfully prepared by two different methods including ion-exchange and wet impregnation. HZSM-5 synthesized by hydrothermal method at 160 °C was used as a support for loading metals including Co, Ni, Mo, Ga and Pd. The metal/HZSM-5 had surface area and pore size of 530–677 m²/g and 22.9-26.0 Å. Non- and catalytic fast pyrolysis of Jatropha residues using metal/HZSM-5 were studied using an analytical pyrolysis-GC/MS at 500 °C. Non-catalytic pyrolysis vapors contained primarily high levels acid (50.7%), N-containing compounds (20.3%), other oxygenated compounds including ketones, alcohols, esters, ethers, phenols and sugars (25.0%), while generated small amount of aromatic and aliphatic hydrocarbons of 3.0% and 1.0%. The addition of synthesized metal/HZSM-5 improved the aromatic selectivity up to 91–97% and decreased the undesirable oxygenated (0.6–4.0%) and N-containing compounds (1.8–4.6%). The aromatic selectivity produced by metal-ion exchanged catalysts was slightly higher than that produced by impregnated ones. At high catalyst content (biomass to catalyst ratio of 1:10), Mo/HZSM-5 showed the highest aromatic selectivity of 97% for ion-exchanged catalysts and Ga/HZSM-5 revealed the highest aromatics of 95% for impregnated catalysts. The formation of aromatic compounds could be beneficial to improve calorific values of bio-oils. The presence of metal/HZSM-5 from both preparation methods greatly enhanced MAHs selectivity including benzene, toluene, and xylene (BTX), while substantially reduced unfavorable PAHs such as napthalenes.     

Dimethyl ether synthesis on clinoptilolite zeolite and HZSM5-based hybrid catalysts in a fixed-bed reactor

In this study 4 different acid catalysts were prepared and mixed with commercial CZA catalysts and investigated in direct DME synthesis. Some of the used acid catalysts were not investigated in the literature therefore the work involves novelty. In a fixed-bed reactor, dimethyl ether (DME) was synthesized from the synthesis gas on two catalysts from, natural clinoptilolite and zeolite catalysts. The clinoptilolite (HK and DK) and two (HZSM5(117) and HZSM5(360)) catalysts mixed with commercial CuO/ZnO/Al₂O₃ (CZN) catalysts. The catalysts were also characterized by analytical chemistry techniques such as XRD, BET, TGA, and FTIR. Four different catalysts (HK, DK, HZSM5(117) and HZSM5(360)) and CZA catalysts were mixed at a ratio of 3/1, respectively, and studies were carried out in a fixed-bed reactor. Four different catalyst composition activity tests were made at temperatures 250, 275, and 300 °C. At the same time, the pressure was 30 and 40 bar and four different times (30, 60, 90, and 120 min). The composition of the gases fed to the system for DME was adjusted to N₂/CO₂/CO/H₂ = 36/10/18/36 by volume. DME selectivity (S_DME) and total carbon (X_C) conversion were calculated for each condition. The experimental results showed that the highest DME selectivity of 96.50% was observed in the reaction of the DK + CZA catalyst mixture at 250 °C and 30 min at 40 bar. In addition, high DME selectivity was obtained in all reactions of DK + CZA and HK + CZA catalyst compositions at three different temperatures. The highest DME selectivity obtained is 89.69% for the reaction of the HK + CZA catalyst mixture at 300 °C and 60 min at 30 bar. Experimental results gave insights into Dimethyl ether synthesis from syngas on clinoptilolite zeolite and HZSM5-based hybrid catalysts in a fixed-bed reactor.     

Catalytic Oligomerization of ethylene over nano-sized HZSM-5

The nano-sized HZSM-5 zeolites with different Si/Al ratios were pretreated, characterized, and tested in ethylene oligomerization performed in a fixed-bed reactor under relatively mild conditions. The effects of catalyst acidity and reaction temperature on the activity, selectivity and stability were investigated, and a possible reaction route of ethylene over acidic sites of nano-sized HZSM-5 catalyst was proposed. In comparison with micro-sized HZSM-5 zeolite, nano-sized HZSM-5 zeolites exhibited higher activity and better resistance to deactivation. Under optimal conditions (T = 275–300 °C, P = 3.0 MPa, WHSV = 1.0 h⁻¹), The average ethylene conversion was 62.5% over the nano-sized HZSM-5 with an Si/Al ratio of 80, while the selectivity to C₄₊ olefins and α-olefins was 64.3% and 13.3%, respectively. Furthermore, the products of ethylene oligomerization were a complex hydrocarbon mixture due to the acid-catalyzed secondary reactions, for which the distribution of even and odd numbered carbon atoms formed a continuous volcanic shape mainly centered on C₆–C₁₀. Furthermore, these tests demonstrate that the activity and selectivity of ethylene oligomerization depend on the operating conditions and the acidity of the catalysts. These results indicate that the Brønsted acid sites may be mainly responsible for secondary reactions and deactivation of the catalyst, whereas the Lewis acid sites may be more advantageous for ethylene oligomerization.     

Effect of Cr promoter on performance of steam reforming of dimethyl ether in a metal foam micro-reactor

The CuZnAl/HZSM-5, CuZnAlCr/HZSM-5, CuZnAlZr/HZSM-5, CuZnAlCo/HZSM-5, and CuZnAlCe/HZSM-5 catalysts that were prepared by a co-precipitation method was used for hydrogen production from steam reforming of dimethyl ether (SRD) in a metal foam micro-reactor. These catalysts were characterized by means of XRD, TPR, SEM and BET surface areas. The results showed that promoter Cr can reduce the average pore diameter and reduction temperature of catalyst. The conversion of dimethyl ether and hydrogen yield reaches 99% and 95% respectively over CuZnAlCr/HZSM-5 catalyst under a relatively lower reaction temperature. The obtained hydrogen-riched gas is easy to purify and meet the need of polymer electrolyte membrane fuel cell. The effects of reaction temperature, space velocity and steam to DME ratio on SRD were investigated in a metal foam micro-reactor. At the conditions of T = 250 °C, the space velocity of 3884 ml/(g h), steam to DME = 5, DME conversion of >97% were obtained over the CuZnAlCr/HZSM-5 catalyst without obvious deactivation during 50 h.     

Highly selective hierarchical ZSM-5 from kaolin for catalytic cracking of Calophyllum inophyllum oil to biofuel

Upgrading the inferior properties of Calophyllum inophyllum oil via catalytic cracking into biofuel required a porous heterogeneous acid catalysts. Hierarchical ZSM-5 (Hi-ZSM-5(K)) produced from desilication of kaolin-derived ZSM-5 was employed as catalyst and the activity was compared with hierarchical ZSM-5 obtained from templating method (Hi-ZSM-5(T)). Catalytic cracking of Calophyllum inophyllum oil was carried out in one-pot reaction at 475 °C for 120 min under the flow of H₂ and the products analysed using GC-MS were consisted of the mixtures of alkane, alkene, oxygenated carbon and aromatics compound. The advantages of desilication method for the formation of highly selective hierarchical ZSM-5 was observed when the catalyst exhibited enhanced acidity with mesopores diameter of 2–5 nm to give 93% conversion and high selectivity towards light C7–C9 hydrocarbons. However, Hi-ZSM-5(T) showed low acidity to give only 43% conversion, and selectivity towards C11–C12 hydrocarbons due to the mesopores diameter of 3–12 nm. The activity of hierarchical ZSM-5 was also compared with microporous ZSM-5 that produced biofuel with approximately equal distribution of C5–C18 hydrocarbons. The role of hierarchical structures was further discussed on the composition of aromatics compound, oxygenates content and alkene/alkane ratios of the biofuel.     

Effects of catalyst preparation route and promoters (Ce and Zr) on catalytic activity of CuZn/CNTs catalysts for hydrogen production from methanol steam reforming

Ce or Zr promoted CuZn/CNTs (carbon nanotubes) catalysts were synthesized by microwave-assisted polyol, co-precipitation and impregnation methods and were used to generate hydrogen by methanol steam reforming (MSR) process. The physico-chemical properties of the prepared catalysts were analyzed by BET, XRD, FT-IR, TEM, FE-SEM, EDX-dot mapping and H₂-TPR methods. The effect of various operating parameters on methanol conversion and selectivity of gaseous products was investigated. The results indicated that the addition of 2 wt% CeO₂ promoter on CuZn/CNTs catalyst synthesized by impregnation route (CuZn/CNTs (Imp)) increased its methanol conversion from 81.3 to 85.2%, and decreased its CO selectivity from 6.2 to 3.8% at 300 °C, WHSV of 7.5 h^?1 and S/C molar ratio of 2. In addition, the CeCuZn/CNTs catalyst prepared via the microwave-assisted polyol route (CeCuZn/CNTs (Pol)) exhibited the best catalytic activity with 98.2% hydrogen selectivity, 2.6% CO selectivity and 94.2% methanol conversion at 300 °C. Furthermore, a 48 h continuous MSR reaction at 300 °C, identified CeCuZn/CNTs (Pol) as the most stable catalyst due to its higher metal particle dispersion and better interaction between the active phase and the CNTs support.     

Steam reforming of dimethyl ether over a novel anodic γ-Al2O3 supported copper bi-functional catalyst

A novel porous alumina monolithic material was prepared through the anodization technology, and its catalytic performance for hydrolysis of dimethyl ether (DME) was investigated. The anodic γ-Al₂O₃ exhibited higher catalytic activity due to its stronger acidity, better hydrophilicity and lower activation energy than the commercial γ-Al₂O₃ and also showed good stability in a 110 h test. Meanwhile, a series of Cu/anodic γ-Al₂O₃ catalysts were prepared by impregnation method, and the mechanism of Cu loading was studied. Furthermore, the effect of Cu loading and CuO crystallite size on the activity of catalyst for DME steam reforming was investigated. The experimental results show that the conversion of DME was related to both of the Cu loading and the CuO crystallite size, while the selectivity of CO was very sensitive to the latter. In addition, the synergetic effects of different catalysts on DME steam reforming reaction system were also discussed.     

Production of hydrogen from methanol steam reforming using CuPd/ZrO2 catalysts – Influence of the catalytic surface on methanol conversion and CO selectivity

Electricity generation for mobile applications by proton exchange membrane fuel cells (PEMFCs) is typically hindered by the low volumetric energy density of hydrogen. Nevertheless, nearly pure hydrogen can be generated in-situ from methanol steam reforming (MSR), with Cu-based catalysts being the most common MSR catalysts. Cu-based catalysts display high catalytic performance, even at low temperatures (ca. 250 °C), but are easily deactivated. On the other hand, Pd-based catalysts are very stable but show poor MSR selectivity, producing high concentrations of CO as by-product. This work studies bimetallic catalysts where Cu was added as a promoter to increase MSR selectivity of Pd. Specifically, the surface composition was tuned by different sequences of Cu and Pd impregnation on a monoclinic ZrO₂ support. Both methanol conversion and MSR selectivity were higher for the catalyst with a CuPd-rich surface compared to the catalyst with a Pd-rich surface. Characterization analysis indicate that the higher MSR selectivity results from a strong interaction between the two metals when Pd is impregnated first (likely an alloy). This sequence also resulted in better metallic dispersion on the support, leading to higher methanol conversion. A H₂ production rate of 86.3 mmol h^?1 g^?1 was achieved at low temperature (220 °C) for the best performing catalyst.     

Hydrogen production by steam reforming of dimethyl ether and CO-PrOx in a metal foam micro-reactor

A bi-function catalyst containing CuZnAlCr and HZSM-5 was used to generate hydrogen by stream reforming of dimethyl ether (SRD) in a metal foam micro-reactor and a fix-bed reactor. Dimethyl ether conversion of 99% and hydrogen yield of >95% was reached with HZSM-5/CuZnAlCr (mass ratio of 1:1) in the micro-reactor. A suitable balance between the dimethyl ether hydrolysis and methanol reforming steps requires the proper acidity and the metal sites. The CuZnAlCr/HZSM-5 properties, effect of CuZnAlCr to HZSM-5 mass ratio were investigated in the metal foam micro-reactor. Moreover, CO was removed from hydrogen-rich gas by preferential oxidation reaction (CO-PrOx) with PtFe/γ-Al₂O₃ catalyst in a similar metal foam micro-reactor follows the SRD stage. With the optimized O₂/CO ratio and reaction temperature, the CO concentration dropped to <10 ppm and hydrogen yield of ∼90% were achieved in the new-type SRD-COPrOx system. The SRD-COPrOx system provide a constant hydrogen production with CO concentration lower than 10 ppm during 20 h. The results indicate that metal foam micro-reactor has the great potential in the DME steam reforming to supply hydrogen for low-temperature fuel cells.     

Copper zinc oxide nanocatalysts grown on cordierite substrate for hydrogen production using methanol steam reforming

Hydrogen production from methanol rather than the traditional source, methane, is considered to be advantageous in ease of transportation and storage. However, the current copper-based catalysts utilized in methanol steam reforming are associated with challenges of sintering at high temperature and production of CO which could poison fuel cells. In addressing these challenges, ZnO nanorods were grown hydrothermally on the surface of cordierite and impregnated with Cu to produce catalysts for methanol steam reforming. The catalysts were characterized using SEM, XRD, FTIR, XPS, BET and Raman Spectroscopy. A fixed-bed reactor was used for testing the catalysts while the reaction products were characterized using a GC fitted with FID and TCD. The effects of temperature, methanol concentration and particle size of catalysts on methanol steam reforming were investigated. The experiments were carried out between 180 and 350 °C. CO selectivity of 0% was observed for temperatures between 180 and 230 °C for 0.8 MeOH:1H₂O with an average H₂ selectivity of 98% for that temperature range. XPS showed that the catalyst was relatively unchanged after reaction while Raman spectroscopy revealed coke formation on the catalyst surface for reactions carried out above 300 °C. This shows that the catalyst is active and selective for the reaction.     

Biodiesel from mutton fat using KOH impregnated MgO as heterogeneous catalysts

The use of MgO impregnated with KOH as heterogeneous catalysts for the transesterification of mutton fat with methanol has been evaluated. The mutton fat (fat) with methanol (1:22 M ratio) at 65 °C showed > 98% conversion to biodiesel with 4 wt% of MgO–KOH-20¹ (MgO impregnated with 20 wt% of KOH) in 20 min. The reaction conditions optimized were; the amount of KOH impregnation (5–20 wt%), the amount of catalyst (1.5–4 wt%, catalyst/fat), the reaction temperature (45–65 °C), fat to methanol molar ratio (1:11–1:22) and the effect of addition of water/oleic acid/palmitic acid (upto 1 wt%). Although, transesterification of fresh fat (moisture content 0.02 wt% and free fatty acids 0.002 wt%) with methanol in the presence of KOH (homogenous catalyst) resulted in the complete conversion to biodiesel, but in the presence of additional 1 wt% of either free fatty acid or moisture content, formation of soap was observed. The MgO–KOH-20 catalyst was found to tolerate additional 1 wt% of either the moisture or FFAs in the fat.     

Effect of zeolite structure on light aromatics formation during upgrading of cellulose fast pyrolysis vapor

Promising technology for the conversion of cellulose to aromatics by catalytic fast pyrolysis (CFP) was investigated using five zeolite catalysts, i.e., 5A, SAPO-34, HY, BETA and HZSM-5. The relationship between the porosity and acidity of different zeolites with product selectivity was studied. The results showed that both the acidity and pore size of the zeolite significantly affected the production of aromatics and coke, especially the bio-oil composition. The bio-oils obtained over 5A or SAPO-34 (small pore<5.5 nm) have relatively high oxygen content. The BTEXN (benzene, toluene, ethylbenzene, xylenes and naphthalene) carbon yields over weak acidic zeolites of HY and BETA are only 6.5% and 9.0%, respectively. Due to the appropriate pore size distribution and acid position, HZSM-5 gave the highest BTEXN carbon yield of 21.1%. Moreover, the coke deposited on the spent zeolites was analyzed by temperature programmed oxidation. Furthermore, three possible mechanisms that the acid sites catalyze vapor towards non-condensable gases, aromatics and coke were also studied. HZSM-5 achieved satisfactory deoxygenation and aromatic production simultaneously, made it a potential catalyst for producing light aromatics from reforming the biomass pyrolytic vapors.     

Hydrocracking of Jatropha oil to aromatic compounds over the LaNiMo/ZSM-5 catalyst

The conversion of biomass to produce high-valued chemical aromatic intermediates such as benzene (B), toluene (T), ethylbenzene (E), xylene (X), naphthalene (N) has attached booming interests. Herein, in order to obtain BTEXN aromatics on the hydrocracking of Jatropha oil, several LaNiMo/ZSM-5 catalysts (La loading from 0.5 to 15 wt%) by alkali treatment and metal impregnation methods were synthesized and investigated. Fundamentally, we found the alkali treatment engendered more mesoporosity to ZSM-5 and resulted in higher catalytic activity. It bears emphasis that further metal impregnated catalyst NiMo/ZSM-5 could improve the aromatics yield due to the increase of metal active sites and acidity sites. Besides, we noted that La loading had positive effects on coke reduction, catalytic stability and catalyst lifetime. To sum up, results confirmed the favorable 1 wt% La–NiMo/ZSM-5 had maximum 75 wt% BTEXN yield, longer catalyst lifetime for 100 h and decreased carbon deposits by 1.11%.     

Ga改性HZSM-5分子筛催化2-甲基呋喃和甲醇制备芳香烃

采用等体积浸渍法在HZSM-5分子筛上引入Ga₂O₃，探究Ga改性HZSM-5分子筛对2-甲基呋喃（MF）和甲醇在固定床反应器中进行偶合反应的产物分布的影响。采用XRD、HTEM、BET和NH₃-TPD对催化剂的理化性质进行表征，结果显示，Ga的负载使得HZSM-5比表面积和孔容减小，改变了HZSM-5的酸类型及酸位强度分布。偶合反应结果表明，Ga的负载能够促进MF和甲醇的转化，Ga/HZSM-5不仅可以提高芳香烃的产率，而且提高了芳香烃产物中BTX的选择性。与HZSM-5相比，0.1%Ga/HZSM-5在反应温度为500℃、MF与甲醇摩尔比为1∶2、WHSV为2 h⁻¹反应条件下，使芳香烃产率从14.6%提高到23.7%，而BTX的选择性则从55.2%提高到67.8%。     

Catalytic activity of SBA-15 supported Ni catalyst in CH4 dry reforming: Effect of Al,Zr, and Ti co-impregnation and Al incorporation to SBA-15

In this study, the catalytic activity of the mesoporous SBA-15 supported Ni–Al, Ni–Zr, and Ni–Ti catalysts prepared by an impregnation method were investigated in dry reforming of methane. In addition, Al incorporated SBA-15 (Al–SBA-15) materials used as catalyst support were synthesized following a one-pot hydrothermal route in three different conditions: synthesis in the presence of only HCl, only NaCl, and both HCl and NaCl (denoted as A, S, and B, respectively). All catalysts were characterized by XRD, N₂ adsorption-desorption isotherms, ICP-OES, DRIFTS, SEM, TEM-EDX and TGA techniques before and/or after reaction tests. Among Al, Zr, and Ti impregnated catalysts, Ni–Al impregnated catalyst showed the highest activity in dry reforming of methane. According to activity test results, Al–SBA-15 supported Ni catalyst prepared by the one-pot hydrothermal route in the presence of both HCl and NaCl showed the best catalytic activity with high methane (81%) and carbon dioxide conversion (88%) values at 750 °C. The highest H₂ and CO selectivity values were obtained with the same catalyst with an H₂/CO molar ratio of 0.80. Therefore, these results showed that partial Al (0.11%) incorporated into the structure of SBA-15 was sufficient to improve the catalytic activity of the catalyst in dry reforming of methane.     

Toluene steam reforming over nickel based catalysts

Steam reforming of toluene (SRT) has been studied initially in eight nickel-based catalysts where nickel (10 wt%) was incorporated in different supports (olivine, Al2O3, MgO, LDH, ZrO₂, CeO₂ and natural sepiolite) by the incipient wetness impregnation method. Among them, nickel catalyst based on sepiolite exhibited a promising catalytic performance, with a high conversion of toluene (16%), high selectivity to hydrogen (68.4%) and low production of undesired by-products (CO, CH₄, ethylene and benzene) at low temperature (500 °C). On the other hand, the incorporation of Ni in the sepiolitic material by precipitation (PP) has been considered as alternative method to the incipient wetness impregnation method (IWI). PP method allowed to prepare a Ni-based catalyst with a very high activity (conversion of toluene ~100%), high selectivity to hydrogen (73%) and lower production of undesirable by-products (5% CO, 2% CH₄ and 0% C₆H₆) at 575 °C. In addition, catalytic deactivation due to coke deposition and nickel sinterization was clearly lower for the catalyst synthesized by PP. Characterization by different physicochemical techniques (XRD, TEM, BET surface area, ICP-OES, TPR and EA) showed that PP method allowed to obtain a sepiolite-based catalyst containing Ni with larger external surface area and smaller, highly dispersed and easily reducible Ni metal particles. The results here discussed show that the Ni incorporation method has a clear influence in the preparation of nickel catalyst supported on sepiolite with improved catalytic performance in the steam reforming of toluene.     

Catalytic upgrading pyrolysis vapors of Jatropha waste using metal promoted ZSM-5 catalysts: An analytical PY-GC/MS

HZSM-5 with high surface area of 625 m²/g was successfully synthesized by hydrothermal method at 160 °C for 72 h. The metal promoted on HZSM-5 catalyst was prepared by liquid ion exchange method. From XRD results, the addition of metals such as Co and Ni did not change the HZSM-5 structure. The metal/HZSM-5 showed lower crystallinity and surface area than the parent HZSM-5 because of the metal dispersion on the HZSM-5 surface. The metal contents of Co/HZSM-5 and Ni/HZSM-5 detected by EDX were less than 1 wt%. Catalytic fast pyrolysis of Jatropha waste using HZSM-5 and metals/HZSM-5 was investigated in terms of biomass to catalyst ratios (1:0, 1:1, 1:5 and 1:10) and types of metals (Co and Ni). From the results, it can be concluded that both biomass to catalyst ratios and the presence of metals had an effect on the increase in aromatic hydrocarbons yields as well as the decrease in the oxygenated and N-containing compounds. Both Co/HZSM-5 and Ni/HZSM-5 promoted the production of aliphatic compounds. Additionally, the PAHs compounds such as napthalenes and indenes, which caused the formation of coke, could be inhibited by metal/HZSM-5, particularly, Ni/HZSM-5. Among catalysts, Ni/HZSM-5 showed the highest hydrocarbon yield of 97.55% with N-containing compounds remained only 1.78%. The formation of hydrocarbon compounds increased the heating values of bio-oils while the elimination of the undesirable oxygenated compounds such as acids and ketones could alleviate problem regarding acidity and instability in bio oils.     

Performance analysis of hybrid catalytic conversion of CO2 to DiMethyl ether

The performance of the single-step and sequential-steps catalytic CO₂-hydrogenation to DiMethyl Ether (DME) was systematically analyzed. CuO–ZnO model-catalysts for CO₂-hydrogenation to methanol were synthesized via different methods namely co-precipitation, sequential precipitation and precipitation-impregnation of the precursors. Moreover, co-precipitation and co-impregnation methods were applied to establish bifunctional catalytic structures composed of CuO–ZnO over HZSM-5 for direct CO₂-hydrogenation to DME in a single-step.In addition, the performance of the catalytic bed made of sequential layered-arrangements of the CuO–ZnO and ZSM-5 catalysts as well as random mixture of these catalysts were also analyzed both experimentally as well as through the performed model-based study. It was observed that a faster conversion of the generated methanol to DME, secured by establishing a closer distance between the catalytic materials responsible for CO₂-hydrogenation to methanol and methanol-dehydration to DME, will improve the overall selective CO₂-conversion. This was demonstrated by obtaining the highest combined yield of methanol and DME products at the reactor outlet in those cases. Similarly, a bifunctional catalyst, for instance synthesized by co-impregnation method (made of 1:2 CuO–ZnO:ZSM-5), showed one of the most promising DME selectivity of 65% and DME yield of 12.5% under the highest reaction temperature of 260 °C, lowest tested GHSV of 200 h^?1, and maximum operating pressure 20 bar for the lowest H₂/CO₂ ratio of 3.     

Renewable hydrogen from glycerol steam reforming using Co–Ni–MgO based SBA-15 nanocatalysts

Steam reforming of glycerol was carried out using Si-based mesoporous SBA-15 catalysts. Different mesoporous catalysts- Co-SBA-15, Ni-SBA-15, Co–MgO-SBA-15, Ni–MgO-SBA-15, and Co–Ni-SBA-15 were prepared using a one-pot hydrothermal method. An incipient wetness impregnation method was used only for the bimetallic Co–Ni-SBA-15 catalyst (catalyst designated as Co–Ni-SBA-15-IMPG) to compare its activity to that prepared by the one-pot method. The catalysts were characterized using XRD, TPR, TEM, TGA-DSC, ICP-OES and N₂ adsorption-desorption analytical techniques. A high surface area in the range of 540–750 m²/g was observed depending on the catalyst composition. The glycerol steam reforming (GSR) activity of the catalysts was studied in the reaction temperature range of 450 °C–700 °C for hydrogen production. Results from the GSR studies for continuous 40 h showed that both Co–Ni-SBA-15-IMPG (impregnation) and Co–Ni-SBA-15 (one-pot) were resistant to deactivation, and both yielded 100% glycerol conversion for the entire 40 h. 10%Co–5%Ni-SBA-15 and 10%Co–5%Ni-SBA-15-IMPG produced (70–78) % and (60–78) % H₂ selectivity, respectively. Addition of MgO to Co-SBA-15 and Ni-SBA-15 increased the activity and stability of the catalysts. The catalyst stability performance followed the trend 10%Co–5%Ni > 10%Co–5%MgO >10%Co–5%Ni-IMPG. > 15%Co > 10%Ni–5%MgO >15%Ni-SBA-15. Thermal analyses of the spent catalyst showed a substantial amount of coke deposition which could be the major factor responsible for catalysts deactivation. Bimetallic catalysts prepared by one-pot method (10%Co–5%Ni-SBA-15) and incipient wetness impregnation (10%Co–5%Ni-SBA-15-IMPG) exhibited remarkable GSR activity compared to their monometallic counterparts. The GSR activity was observed in the order: 10%Co–5%Ni-IMPG ≥ 10%Co–5%Ni > 10%Co–5%MgO >15%Co > 15%Ni > 10%Ni–5%MgO.     

Upgrading of a wood-derived oil over various catalysts

The upgrading of a bio-oil using a fixed bed micro-reactor operating at 1 atm, 3.6 WHSV and 330–410°C over various catalysts is reported. The catalysts used were HZSM-5, silicalite, H-mordenite, H-Y and silica-alumina. The yield of hydrocarbons as well as the extent of deoxygenation, coke formation and conversion of the non-volatile portion of the bio-oil were used as measures of catalyst performance. The maximum hydrocarbon yield when HZSM-5 was used occurred at 370°C and was 39.3 wt% of the bio-oil. For the other catalysts, the hydrocarbon yields increased with temperature and were up to 22.1 wt% for silicalite; 27.5 wt% for H-mordenite; 21.0 wt% for H-Y; and 26.2 wt% for silica-alumina at 410°C. The hydrocarbon selectivity with HZSM-5 and silicalite catalysts was mostly for gasoline range hydrocarbons (C₆ to C₁₂) and for H-mordenite and H-Y for kerosene range hydrocarbons (C₉ to C₁₅). The hydrocarbon fraction obtained with silica-alumina did not produce any defined distribution. The pore size, catalyst acidity and catalyst shape selectively affected the product distribution. The overall performance followed the order: HZSM-5 > H-mordenite > H/Y > silica-alumina, silicalite.