Weak Metal-support Interaction Research Articles

Surface engineering of carbon supported CoMoS– an effective nanocatalyst for selective deoxygenation of lignin derived phenolics to arenes

We report a viable synthesis route to prepare Co promoted MoS2 nanocatalyst supported on an activated carbon for the selective hydrodeoxygenation of lignin derived phenolics in a liquid phase. The key aspect of this strategy is to use activated carbon as support with weak metal-support interaction that promotes the formation of Co-Mo-S phase, which is inhibited in alumina supported CoMoS2 due to the strong metal-support interaction. The as-synthesized catalyst contained Co9S8 and MoS2 phases dispersed on the support, which during reduction at 450 °C formed Co-Mo-S phase that is active for deoxygenation. To validate the claim, the activity of the reduced catalyst was compared with the unreduced catalyst for guaiacol conversion. As such 92 % softwood lignin was converted after 5 h reaction time, producing 76 % liquids with 75 % deoxygenation. The loss of catalytic activity after five catalytic cycles was attributed to the reduction in catalyst surface area, sulphur leaching and metal sintering.

Partial Hydrogenation of Palm Oil-Derived Biodiesel over Ni/Electrospun Silica Fiber Catalysts

Given the high accessibility of reactants to the active metal sites of fibrous catalysts, in this research, an electrospun silica fiber was applied as a support of nickel catalysts (Ni/SF) for the partial hydrogenation of palm oil fatty acid methyl ester (FAME) in a fixed-bed reactor. The textural properties, reducibility, Ni dispersion and morphology of Ni/SF catalysts were characterized and compared to those of a Ni/porous silica ball (Ni/SB). Under 1 bar H2 pressure at 140 °C, the 30 wt% Ni/SF catalyst exhibited a high turnover frequency (TOF) of 1396 h−1 to convert methyl linoleate (C18:2) to more saturated structures. On the other hand, the system using Ni/SB catalysts showed a TOF of only 141 h−1. This result was due to the effect of the higher acidity of the silica fiber, which promoted the higher adsorption of polyunsaturated portions in FAME. The non-porous characteristics and open morphology of the Ni/SF catalysts also allowed FAME and H2 molecules to easily access the Ni active sites deposited on the surface of the silica fiber and suppressed the selectivity to cis–trans isomerization. Stability testing of the Ni/SF catalyst showed that the C18:2 conversion decreased from 71% to 60% after long-term operation for 16 h possibly due to the weak metal–support interaction that facilitated Ni particle loss from the catalyst surface.

Toluene steam reforming using nickel based catalysts made from mining residues

Two nickel-based catalysts are used for toluene steam reforming: Ni-Olivine and Ni-UGSO (Nickel-UpGraded Slug Oxides). Both catalysts are made from mining residues and prepared by incipient wetness impregnation (IWI). The activity and stability of the two catalysts in toluene steam reforming are investigated and compared, at atmospheric pressure and 800 °C in a fixed bed reactor. Reaction temperature and Ni Loading effects are evaluated for the Ni-UGSO catalyst. The physicochemical properties of the catalysts were analyzed using the following characterization techniques: X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX), X-ray absorption near edge spectroscopy (XANES), Temperature Programmed Reduction (TPR) and Brunauer-Emmett-Teller (BET) specific surface area. Results showed that toluene conversion, mainly into CO and H2, reached up to (98 w%). The catalyst activity was tested in multiple 24 h time-on-stream continuous isothermal runs and no signs of deactivation were observed. Ni in Ni-UGSO has a strong metal-support interaction, which, according to characterization results, is due to the formation of a NiO/MgO solid solution. This catalyst exhibited an elevated catalytic activity along with a high resistance to carbon formation. Ni in Ni-Olivine has shown a weak metal-support interaction leading to the formation of filamentous carbon at the catalyst’s surface.

The Effect of Noble Metal (M: Ir, Pt, Pd) on M/Ce2O3-γ-Al2O3 Catalysts for Hydrogen Production via the Steam Reforming of Glycerol

A promising route for the energetic valorisation of the main by-product of the biodiesel industry is the steam reforming of glycerol, as it can theoretically produce seven moles of H2 for every mole of C3H8O3. In the work presented herein, CeO2–Al2O3 was used as supporting material for Ir, Pd and Pt catalysts, which were prepared using the incipient wetness impregnation technique and characterized by employing N2 adsorption–desorption, X-Ray Diffraction (XRD), Temperature Programmed Reduction (TPR), Temperature Programmed Desorption (TPD), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The catalytic experiments aimed at identifying the effect of temperature on the total conversion of glycerol, on the conversion of glycerol to gaseous products, the selectivity towards the gaseous products (H2, CO2, CO, CH4) and the determination of the H2/CO and CO/CO2 molar ratios. The main liquid effluents produced during the reaction were quantified. The results revealed that the Pt/CeAl catalyst was more selective towards H2, which can be related to its increased number of Brønsted acid sites, which improved the hydrogenolysis and dehydrogenation–dehydration of condensable intermediates. The time-on-stream experiments, undertaken at low Water Glycerol Feed Ratios (WGFR), showed gradual deactivation for all catalysts. This is likely due to the dehydration reaction, which leads to the formation of unsaturated hydrocarbon species and eventually to carbon deposition. The weak metal–support interaction shown for the Ir/CeAl catalyst also led to pronounced sintering of the metallic particles.

Effect of Catalyst Synthesis Parameters on the Performance of CO2 Hydrogenation to Methanol over SBA-15 Supported Cu/ZnO-Based Catalysts

Bimetallic Cu-ZnO-based catalyst were systematically prepared via impregnation technique under controlled synthesis conditions of active metal loading, ratio of active metal Cu:Zn and synthesis pH. The effect of the synthesis condition on the performance of the Cu-ZnO supported catalysts with respect to the hydrogenation of CO2 to methanol in micro-activity fixed-bed reactor at 250°C, 2.25 MPa, and 75% H2/25%CO2 ratio. The synthesized catalysts were characterized by transmission electron microscopy (TEM) and temperature programmed desorption, reduction, oxidation and pulse chemisorption (TPDRO) and the surface area determination was also performed. The results demonstrate that the catalytic structure, activity, and methanol selectivity was strongly affected by the synthesis parameters. Increasing of synthesis pH from 1 to 7 shows better metal particles distribution, Cu desperation of 29%, higher BET surface area as well as Cu surface area, while further increasing on pH revealed on particles agglomeration and weak metal-support interaction. In addition, increasing of the active metal loading from 5 to 15 % resulted in dramatic increase in the conversion of CO2 and methanol production while further increase caused lower catalytic performance. Moreover, catalyst with total loading of 15%, Cu:Zn ratio of 70:30 synthesized at pH of 7 exhibit higher catalytic activity of 14%, methanol selectivity of 92%, and TOF of 1.24×103 s-1 compared with other catalyst prepared under various conditions

In situ grown metallic nickel from X–Ni (X=La, Mg, Sr) oxides for converting plastics into carbon nanotubes: Influence of metal–support interaction

The process of pyrolysis and in-line catalysis was employed for converting plastics into value-added carbon nanotubes (CNTs). The metallic nickel catalysts Ni/X (X = La, Mg, Sr) were prepared through in situ growth from parent X–Ni oxides under reductive conditions and used for the catalytic synthesis of CNTs. The results showed that the activities of nickel catalysts decreased in the order of Ni/La > Ni/Sr > Ni/Mg, which strongly depended on the degree of metal–support interaction. The strong metal–support interaction in Ni/Mg catalyst was not favorable for the exsolution of large amount of metallic Ni, resulting in the lowest yield of CNTs. On the other hand, the weak metal–support interaction in Ni/Sr was unfavorable for the high coverage of Ni nanoparticles, leading to the simultaneous growth of carbon nano-onions and CNTs. The Ni/La catalyst with moderate metal–support interaction exhibited the highest yield of CNTs due to optimized amount, size and surface coverage of Ni nanoparticles. The microstructure, graphitization degree, quality and purity of obtained carbon products were characterized using X-ray diffraction, electron microscopy, Raman spectroscopy and thermogravimetric analysis. This study demonstrated an effective and delicate approach to tune the supported metal nanoparticles, leading to enhanced catalytic activity.

Immobilizing single atom catalytic sites onto highly reduced carbon hosts: Fe–N4/CNT as a durable oxygen reduction catalyst for Na–air batteries

Immobilizing metal ions on a carbon support usually involves severe aggregation (sintering) and loose attachment of metal ions owing to a weak metal–support interaction.

Tuning the metal-support interaction of methane tri-reforming catalysts for industrial flue gas utilization

This study investigates the role of metal-support interaction (MSI) in the performance of Ni/TiO2, Ni/SBA-15, Ni/MgO, and Ni/Al2O3 catalysts for the tri-reforming of methane (TRM) reaction. To impart weak metal-support interaction (WMSI), the catalysts were calcined at 400 °C. While calcination at 850 °C or above temperature generated strong metal-support interaction (SMSI) in each catalyst. The experimental results reveal that Ni/TiO2 and Ni/MgO catalysts having WMSI displayed high initial activity due to the higher extent of reduction and Ni dispersion. However, these catalysts deactivated during 10 h reaction run. On the other hand, the performances of Ni/TiO2 and Ni/MgO catalysts having SMSI were unsatisfactory. For Ni/SBA-15 catalyst system, catalysts having weaker MSI were more active than the catalyst having stronger MSI. However, the stability of Ni/SBA-15 catalysts was governed by Ni confinement in the pores of SBA-15 rather than the strength of MSI. Ni/Al2O3 having SMSI had monodispersed Ni atoms in close association with Al2O3, which resulted in higher reforming activity compared to that of Ni/Al2O3 having WMSI. Overall, the present study asserts that the strength of MSI has a significant influence on the activity and stability of methane tri-reforming catalysts; however, the suitability of either strong or weak MSI is subject to catalyst composition.

Different Reaction Mechanisms of Ammonia Oxidation Reaction on Pt/Al2O3 and Pt/CeZrO2 with Various Pt States.

NH3 emissions were limited strictly because of the threat for human health and sustainable development. Pt/Al2O3 and Pt/CeZrO2 were prepared by the impregnation method. Differences in surface chemical states, reduction ability, acid properties, morphological properties, reaction mechanisms, and ammonia oxidation activity were studied. It indicated that Pt species states were affected by different metal-support interactions. The homogeneously dispersed Pt species over Pt/Al2O3 exposed Pt(111) because of weak metal-support interactions; there even existed an obvious interface between Pt and Al2O3. While obscure even an overlapped interface was observed over Pt/CeZrO2, resulting in the formation of PtO because of the oxygen migration from CeZrO2 to Pt species (confirmed by CO-FTIR, the cycled H2-TPR and transmission electron microscopy results). It was noteworthy that different reaction mechanisms were induced by different states of Pt species; NH was the key intermediate species for ammonia oxidation reaction over Pt/Al2O3, but two kinds of intermediates, N2H4 and HNO, were observed for Pt/CeZrO2. It consequently resulted in the obvious distinction of the NH3-SCO catalytic performance; the light-off temperatures of NH3 over Pt/Al2O3 and Pt/CeZrO2 were 231 and 275 °C, respectively, while the maximum N2 selectivity (65%) was obtained over Pt/CeZrO2, it was obviously better than that over Pt/Al2O3.

Optimal Ni loading towards efficient CH4 production from H2 and CO2 over Ni supported onto fibrous SBA-15

The transformation of SBA-15 into fibrous type SBA-15 (F-SBA-15) as well as the influence of Ni loadings (1, 3, 5, and 10 wt%) towards an efficient CH4 production from H2 and CO2 were explored. The synthesized catalysts were characterized using XRD, BET, ICP-MS, FTIR, FESEM-EDX, TEM, and in-situ FTIR adsorbed pyrrole. Increasing Ni loadings onto F-SBA-15 support promoted excellent performance towards CO2 methanation. The efficacy in CO2 methanation over Ni/F-SBA-15 increased with a sequence of 1%Ni/F-SBA-15 < 3%Ni/F-SBA-15 < 5%Ni/F-SBA-15 ≈ 10%Ni/F-SBA-15, indicating the superior performance and stability of 5%Ni/F-SBA-15. The increasing trend was due to the fibrous morphology of support which enhanced the quantity of SiONi bond, triggered better Ni dispersion, strengthen metal-support interaction, and increased the basicity. However, higher Ni loadings (10 wt%) onto F-SBA-15 slightly declined the performance and stability of CO2 methanation due to the limited spaces for substitution of Ni species with the silanol groups of F-SBA-15 upon the bulk Ni phase, poorer Ni dispersion, weaker metal-support interaction, and lower basicity. The new finding of combination between fibrous SBA-15 (F-SBA-15) with an optimum Ni loading contributed towards an outstanding performance and thus could be applied in various applications.

Steam reforming of n-dodecane over mesoporous alumina supported nickel catalysts: Effects of metal-support interaction on nickel catalysts

Developing a highly active and stable Ni-based catalyst is still a challenge for the generation of on-site hydrogen through steam reforming of long-chained hydrocarbons, such as kerosene fuels. Ni nanoparticles (ca. 5 nm) on mesoporous alumina prepared by atomic layer deposition (ALD) were employed in steam reforming of n-dodecane, and exhibited a turnover frequency (TOF) of 477.6 h−1, whereas Ni nanoparticles on commercial alumina support prepared by impregnation method exhibited a TOF of 100 h−1. The high activity of ALD Ni catalysts was ascribed to high reduction degree, as confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), and H2-chemisorption. A deactivation was also observed on the ALD prepared catalysts, which was ascribed to the weak metal-support interaction, as confirmed by H2 temperature-programmed reduction (TPR). The ALD Ni/Al2O3 catalysts were further modified with CeO2 and they showed enhanced stability with 8% deactivation degree in steam reforming of n-dodecane. Further characterizations of spent catalysts showed that the presence of CeO2 was favorable for stabilizing Ni nanoparticles by enhancing moderate metal-support interaction, and reducing the formation of coke on the interfaces of NiCeO2.

A comparison of Al2O3 and SiO2 supported Ni-based catalysts in their performance for the dry reforming of methane

Dry reforming of methane (DRM) with CO2 is of great significance in the environmental protection and the utilization of natural gas. SiO2 and Al2O3 are two typical catalyst supports used in DRM. To elucidate the effect of these two supports on the catalytic performance, in this work, Ni/SiO2 and Ni/Al2O3 catalysts are prepared by the incipient wetness method and characterized by BET, TEM, H2-TPR, XRD, TG and Raman technologies. The results indicate that the performance of Ni-based catalyst is closely related to the properties of support and the Ni/SiO2 and Ni/Al2O3 catalysts are rather different in their DRM performance. Ni/SiO2 catalyst exhibits higher initial activity but poor stability; its catalytic activity decreases rapidly in 15 h for DRM at 800°C. Because of the weak metal-support interaction, Ni species on the Ni/SiO2 catalyst is present as large Ni particles, which may promote the formation of coke precursors, viz., the multi-carbon Cn species, leading to the fast carbonaceous deposition and catalyst deactivation. In contrast, the Ni/Al2O3 catalyst displays a lower activity but a much higher stability; its activity in DRM keeps stable in 50 h. Although Ni particles in the Ni/Al2O3 catalyst is much smaller, the strong metal-support interaction promotes the formation of NiAlxOy species during the catalyst preparation process, which may lead to a decrease in the content of active Ni species and give the Ni/Al2O3 catalyst a relatively low catalytic activity in DRM; however, the strong metal-support interaction between Ni and Al2O3 is also of benefit to the formation and stabilization of small Ni particles, which can alleviate the carbanceous deposition and afford the Ni/Al2O3 catalyst a better stability.

Co-Based Catalysts Supported on Silica and Carbon Materials: Effect of Support Property on Cobalt Species and Fischer–Tropsch Synthesis Performance

The influence of different support surfaces and physical structures on cobalt species and catalytic Fischer–Tropsch synthesis (FTS) performance has been investigated by using silica or mesoporous carbon as support. All the three catalysts Co/SBA-15, Co/SiO2, and Co/CMK-3 behaved differently in the FTS test and showed characteristic cobalt species. After calcination in argon, Co3O4 was prominent on both Co/SBA-15 and Co/SiO2 because of the stronger metal–support interaction. However, the weaker metal–support interaction on Co/CMK-3 coupled with the autoreduction of cobalt oxide facilitated the formation of more CoO on the support surface. On account of the higher reducibility and specific surface area, Co/SBA-15 exhibited higher CO conversion in FTS than another two as-synthesized catalysts. SBA-15 and CMK-3 possess well-ordered channel structure which favors mass transport and diffusion while diffusion inhibits hydrocarbon chain growth. The highest C5+ and C11–17 selectivities were observed over Co/SiO2 w...

Conversion of carbon dioxide and methane to syngas over Ni/SiO2 catalyst prepared from waste palm oil fuel ash

Carbon dioxide (CO2) reforming of methane (CH4) over nickel (Ni)-supported SiO2 catalyst is a greener approach as this pathway transforms greenhouse gases into gas energy. SiO2 support was synthesized from waste palm oil fuel ash (POFA) with different Ni loading (Ni/SiO2). The SiO2(POFA) was synthesized by drying the treated POFA overnight and calcined at 600°C for 6 h. The Ni/SiO2 (POFA) catalyst with different Ni loading were synthesized by impregnation method. The physicochemical properties of the Ni/SiO2 (POFA) were characterized using nitrogen adsorption-desorption, x-ray diffraction (XRD), and fourier transform infrared (FTIR) spectroscopy. The catalytic performance of the Ni/SiO2 (POFA) was carried out at 800°C and atmospheric pressure with CO2/CH4 feed ratio of 1/1. The SiO2 (POFA) possess a good support material as it has a high surface area 6.95 m2 g−1 and assist well dispersion of Ni as evidenced by BET analysis. Higher catalytic activity was achieved at 53.10% of CO2 conversion and 67.6% of CH4 conversion over 5Ni/SiO2 (POFA). However, lower CO2 conversion of Ni/SiO2 (POFA) catalyst was due to the larger particle size of Ni and weak metal-support interaction in Ni/SiO2 (POFA). This finding proved that the waste POFA can replace the commercial SiO2 for catalytic gas reaction and solve the environmental problem.

Effect of support materials on the performance of Ni-based catalysts in tri-reforming of methane

Tri-reforming of methane (TRM) utilizing CO2, H2O and O2 is an emerging technique for the production of synthesis gas and CO2 abatement. Nevertheless, formulation and design of low-cost, active and stable catalyst for TRM is a major challenge due to its complex reaction network and rapid catalyst deactivation. The support effect is a critical factor influencing the activity and stability of supported Ni catalyst. Thus, a series of supported Ni catalysts over different metal oxides such as Al2O3, ZrO2, TiO2, SBA-15, MgO and CeO2-ZrO2 were prepared. The catalysts were characterized by using N2 - physisorption, XRD, EDX, SEM, TEM, TPR, CO2 – TPD, NH3 – TPD, H2 – pulse chemisorption and TGA. The performance of these catalysts was evaluated at 800 °C, 1 atm, WHSV 17220 mL h−1 g−1 and molar feed composition CH4:CO2:H2O:O2:N2 = 1:0.23:0.46:0.07:0.28 in a fixed-bed reactor. The initial activity of these catalysts followed the order: Ni/Al2O3 > Ni/SBA-15 > Ni/ZrO2 > Ni/CeO2-ZrO2 > Ni/TiO2 > Ni/MgO. Ni/Al2O3 derived from spinel precursor NiAl2O4 resulted in well-dispersed smaller Ni particles, stronger metal-support interaction, a higher degree of reducibility and higher basic sites concentration, which led to its superior activity with 8.72 × 10−2 mmol/gcat·s, 2.31 × 10−2 mmol/gcat·s and 4.2 × 10−2 mmol/gcat·s CH4, CO2, and H2O conversion rate respectively. On the contrary, the stability of SBA-15 and ZrO2 supported Ni catalysts was remarkably high. Hexagonal porous network of SBA-15 confined Ni particles that resulted in high resistance against metal sintering and carbon deposition whereas Ni/ZrO2 offered resistance to Ni re-oxidation owing to its oxophilic property. Experimental investigations reveal that Ni/TiO2 and Ni/MgO resulted in poor CH4, CO2 and H2O conversion rates for TRM due to lower degree of reducibility. Furthermore, Ni/CeO2-ZrO2 catalyst had weak metal-support interaction as observed from TPR studies. Due to larger Ni crystallite size, it exhibited lower conversion compared to Ni/Al2O3, Ni/SBA-15, and Ni/ZrO2.

Synthesis of multi-walled carbon nanotubes with controlled inner and outer diameters by ethylene decomposition over Ni/MgO and Co/MgO catalysts

Abstract In this work, multi-walled carbon nanotubes (MWCNTs) with significantly different mean diameters were produced by catalytic CVD over Ni and Co-based supported catalysts. Our results indicate that Ni nanoparticles in the Ni/MgO catalyst are responsible for controlling the inner diameters of the carbon nanotubes. Contrary, Co nanoparticles in the Co/MgO catalyst control the outer diameters of MWCNTs. The “base-growth” mechanism and smaller diameters of the MWCNTs grown on the Ni/MgO catalyst are associated with a strong metal-support interaction (SMSI) resulting from NixMg1−xO mixed oxide formation. The concept of the weak metal-support interaction (WMSI) between Co nanoparticles and MgO for the Co/MgO catalyst confirms the “tip-growth” mechanism of the MWCNTs.

High temperature growth of single-walled carbon nanotubes with a narrow chirality distribution by tip-growth mode

An MgO supported Co catalyst prepared by atomic layer deposition was applied for the growth of single-walled carbon nanotubes (SWNTs). Different from other catalysts, which generally nucleate SWNTs by base-growth mode, the Co-MgO catalyst uniquely generates SWNTs by tip-growth mode, indicating a weak metal-support interaction. During chemical vapor deposition process, the lift-off of Co nanoparticles from support inhibits the aggregation of Co nanoparticles and favors the synthesis of small-diameter SWNTs with a narrow chirality distribution, even at a high reaction temperature. Particularly, product grown at 800 °C maintains a preferential synthesis of small-diameter (6, 5) SWNTs. The enrichment of (6, 5) SWNT arises from the combination of SWNT-catalyst interface thermodynamics with growth kinetic. The growth dynamics of SWNTs was further investigated by in situ Raman spectroscopy, which revealed that SWNTs with smaller diameters appeared prior to the growth of large-diameter counterparts.

Nitrogen-rich mesoporous carbon supported iron catalyst with superior activity for Fischer-Tropsch synthesis

Superior iron-based Fischer-Tropsch synthesis (FTS) catalysts (Fe/NMCs) were developed by impregnating high amount of iron (40 wt%) over nitrogen-rich mesoporous carbons (NMCs) with high porosities. The large pore volumes and specific surface areas of NMCs realized the high loadings and proper dispersions of iron while the nitrogen-containing groups enhanced the basicities of the catalysts. Weak metal-support interactions were observed in Fe/NMCs, which improved the reduction, carburization of iron, and further the FTS activities. FTS tests indicated a medium amount of nitrogen (≤8.3 wt%) did not show obvious effect on the activity of the catalyst, but a much higher amount of nitrogen (≥16.5 wt%) could result in a significant decrease of activity. Nitrogen-containing groups could effectively suppress the methane selectivity and improve the lower olefins selectivity in the FTS reaction. The hydrocarbon productivity of the Fe/NMCs was up to 0.62 g HC/(h·g cat.) at 260 °C, 1 MPa, and H2/CO ratio of 1, much higher than that of any other iron catalyst reported under similar conditions. As a result of the superior performance, Fe/NMCs could be one of ideal candidates for iron-based FTS catalysts in the future.

Synthesis of Ni/SBA-15 for CO2 reforming of CH4: Utilization of palm oil fuel ash as silica source

In this study, Ni/SBA-15 was synthesized using Palm Oil Fuel Ash (POFA) as the silica source and was applied in the CO2 reforming of CH4. The preparation of POFA sodium silicate (POFA-Na2SiO3) was done using sodium hydroxide (NaOH) fusion method under several parameters including NaOH/POFA mass ratio, fusion temperature and H2O/ NaOH-fused POFA mass ratio. The optimum condition was achieved at NaOH/POFA mass ratio of 2:1, fusion temperature of 550°C and H2O/ NaOH-fused POFA mass ratio of 4:1, with maximum silica content of 40570 ppm. The obtained POFA-Na2SiO3 was used as the silica source for the synthesis of Ni/SBA-15(POFA), and its properties and catalytic performance were compared with Ni/SBA-15(TEOS). The physicochemical properties of the catalysts were characterized using XRD, BET and FTIR, meanwhile the catalytic performance of the catalyst was carried out in a fixed bed reactor at 800°C, atmospheric pressure and CO2/CH4 feed ratio of 1/1. The characterization results revealed that the physicohemical properties of Ni/SBA-15(POFA) were comparable with Ni/SBA-15(TEOS), except for the size of Ni and the strength of metal-support interaction. The catalytic performance results showed that Ni/SBA-15(POFA) has comparable CO2 conversion (around 89%), but lower in CH4 conversion (differences around 31.5%) and stability, which might be due to the larger Ni size and weak metal-support interaction in Ni/SBA-15(POFA) as compared to Ni/SBA-15(TEOS). Although Ni/SBA-15(POFA) showed lower catalytic performance towards CO2 reforming of CH4, POFA can be considered as an alternative silica source to synthesis Ni/SBA-15 owing to the fact that the deficiency observed in the present catalyst can be improved via metal loading method.

Vapour phase selective hydrogenation of benzaldehyde to benzyl alcohol using Cu supported Mg-Al hydrotalicite catalyst

The vapour phase catalytic hydrogenation of benzaldehyde to benzyl alcohol using copper supported Magnesium-Alumina (Mg-Al) hydrotalicite (CuHT) catalyst was studied. The effect of various copper metal loadings, reaction temperature and different preparatory methods on the activity of catalysts was determined. A better catalytic performance was observed for 12.5CuHT catalyst prepared by impregnation method at 250°C. The maximum conversion of about 68% with 93% benzyl alcohol selectivity was obtained at the optimized conditions. The catalyst was active upto 87h with time-on-stream. The activity of CuHT was influenced by high surface area, smaller crystallite size and weak metal support interaction.