Effect of the support on the selective hydrogenation of benzeneover ruthenium catalysts. 1. Al2O3 and SiO2

The effect of the support on the liquid phase selective hydrogenation of benzene to cyclohexene over Ru catalysts was studied. Catalysts were prepared using RuCl₃ as precursor and characterized by hydrogen chemisorption, XPS and TPR. The reaction was carried out at 373 K and 2 MPa using a stirred tank reactor. It was found that the catalytic activity is not influenced by the Ru dispersion. More electron-deficient Ru species are present on Al₂O₃ than on SiO₂. The electronic state of Ru affects the selectivity to cyclohexene.     

Hydrogen Production by Steam Reforming of Commercially Available LPG in UAE

Steam reforming of commercially available LPG using Ru/Al₂O₃ and Ni/Al₂O₃ catalysts has been studied at temperatures between 573 and 773 K. Ru/Al₂O₃ catalyst showed higher rates of reaction and lower activation energies of the three main components of LPG, compared with Ni/Al₂O₃. However, Ni/Al₂O₃ catalyst showed a better H₂:CH₄ selectivity. The activation energy of n-butane was the lowest over Ru/Al₂O₃, whereas over Ni/Al₂O₃, propane had the lowest activation energy. The activation energy of i-butane was always the highest over both catalysts, which suggests that both catalysts performed better with unbranched molecules. A slight increase in activation energy was observed, when each component of the LPG mixture was studied separately as a pure gas, compared with being mixed in LPG. At a constant temperature of 773 K, hydrogen production yield and H₂:CH₄ selectivity were determined using Ru/Al₂O₃ at different steam:carbon (S:C) ratios and LPG flow rates. It was found that the yield and selectivity increased with the increase in S:C ratio and the decrease in the flow rate. The highest yield of 0.64 was achieved using S:C ratio of 6.5 and a LPG flow rate of 50 mL min^?1. The work provides valuable information on steam reforming of pure components of LPG, compared with when they are in the mixture. The comparison is done using conventional steam reforming catalyst, Ni/Al₂O₃, and compared with Ru/Al₂O₃. The observed trends and variations in reaction rates, in pure and mixed gases, indicated that the mechanism of steam reforming of a hydrocarbon mixture depends on its composition.     

Hydrogen production by partial oxidation of methanol over bimetallic Au–Ru/Fe2O3 catalysts

Hydrogen production by partial oxidation of methanol (POM) was investigated over Au–Ru/Fe₂O₃ catalyst, prepared by deposition–precipitation. The activity of Au–Ru/Fe₂O₃ catalyst was compared with bulk Fe₂O₃, Au/Fe₂O₃ and Ru/Fe₂O₃ catalysts. The reaction parameters, such as O₂/CH₃OH molar ratio, calcination temperature and reaction temperature were optimized. The catalysts were characterized by ICP, XRD, TEM and TPR analyses. The catalytic activity towards hydrogen formation is found to be higher over the bimetallic Au–Ru/Fe₂O₃ catalyst compared to the monometallic Au/Fe₂O₃ and Ru/Fe₂O₃ catalysts. Bulk Fe₂O₃ showed negligible activity towards hydrogen formation. The enhanced activity and stability of the bimetallic Au–Ru/Fe₂O₃ catalyst has been explained in terms of strong metal–metal and metal–support interactions. The catalytic activity was found to depend on the partial pressure of oxygen, which also plays an important role in determining the product distribution. The catalytic behavior at various calcination temperatures suggests that chemical state of the support and particle size of Au and Ru plays an important role. The optimum calcination temperature for hydrogen selectivity is 673 K. The catalytic performance at various reaction temperatures, between 433 and 553 K shows that complete consumption of oxygen is observed at 493 K. Methanol conversion increases with rise in temperature and attains 100% at 523 K; hydrogen selectivity also increases with rise in temperature and reaches 92% at 553 K. The overall reactions involved are suggested as consecutive methanol combustion, partial oxidation, steam reforming and decomposition. CO produced by methanol decomposition is subsequently transformed into CO₂ by the water gas shift and CO oxidation reactions.     

Nitrogen Tolerant Hydrodesulfurization Catalysts Based on Rh and Ru Promoted Mo/Al2O3

Rh and Ru promoted Mo/Al₂O₃ catalysts were tested in HDS of thiophene in the presence of different amounts of pyridine and compared with CoMo/Al₂O₃. The Rh and Ru promoted catalysts were more nitrogen tolerant and in the presence of pyridine showed higher HDS activities than CoMo/Al₂O₃. This was explained by higher C–N bond hydrogenolysis activity and high nitrogen tolerance of the free Rh and Ru sulfides in the promoted catalysts.     

Potential dependence of segregation and surface alloy formation of a Ru modified carbon supported Pt catalyst

Ruthenium modified carbon supported platinum catalysts have been shown to have a similar activity towards carbon monoxide oxidation as conventionally prepared bimetallic PtRu alloy catalysts. In this study the effect of the applied electrode potential and potential cycles on the location and oxidation state of the Ru species in such Ru modified Pt/C catalysts was investigated using in situ EXAFS collected at both the Ru K and Pt L₃ absorption edges. The as prepared catalyst was found to consist of a Pt core with a Ru oxy/hydroxide shell. The potential dependent data indicated alloying to form a PtRu phase at 0.05 V versus RHE and subsequent dealloying to return to the Ru oxy/hydroxide decorated Pt surface at potentials greater than 0.7 V. The Ru-O distances obtained indicate that both Ru³⁺ and Ru⁴⁺ species are present on the surface of the Pt particles at oxidising potentials; the former is characteristic of the as prepared Ru modified Pt/C catalyst and following extensive periods at potentials above 0.7 V and the latter of the Ru oxide species on the PtRu alloy.     

Effect of treatment conditions on ruthenium particle size and ammonia synthesis activity of ruthenium catalyst

Ru/Al₂O₃ catalysts with different Ru particle sizes were prepared by changing the metal loading, the treatment temperature in hydrogen or the calcination temperature in air. It is found that the catalysts obtained by different methods cannot directly be used to study the correlation between particle sizes and the catalytic activity. The difference in treatment conditions of Ru/Al₂O₃ catalysts affected the ammonia synthesis activity of Sm-promoted Ru/Al₂O₃ not only by affecting the sizes and the shapes of Ru particles, but also by changing the properties of some active sites available for gas adsorption.     

Promoting effect of rhenium on catalytic performance of Ru catalysts in hydrogenolysis of glycerol to propanediol

Ru/Al₂O₃, Ru/C and Ru/ZrO₂ catalysts were applied to the hydrogenolysis of glycerol to propanediol, and the effect of Re as an additive on the catalytic performance of Ru catalysts was examined. The catalyst systems were characterized by N₂ adsorption/desorption, XRD, TEM-EDX and XPS. The hydrogenolysis of glycerol was carried out under the conditions of 120–180 °C, 4–10 MPa hydrogen pressure and 4–8 h, and the conversion of glycerol varied from 18.7% to 29.7% over Ru/Al₂O₃, Ru/C and Ru/ZrO₂ catalysts. The reaction results indicate that Re possesses high promoting effect on the catalytic performance of Ru catalysts in glycerol hydrogenolysis.     

Production of hydrogen by steam reforming of bio-oil over Ni/Al2O3 catalysts: Effect of addition of promoter and preparation procedure

Catalytic steam reforming of bio-oil was investigated in a fixed bed tubular reactor for production of hydrogen. Two series of nickel/alumina (Ni/Al₂O₃) supported catalysts promoted with ruthenium (Ru) and magnesium (Mg) were prepared. Each catalyst of the first series (Ru–Ni/Al₂O₃) was prepared by co-impregnation of nickel and ruthenium on alumina. They were examined to investigate the effect of adding ruthenium on the performance of the catalysts for hydrogen production. The effect of the temperature, the most effective parameter in the steam reforming of bio-oil, on the activity of the catalysts was also investigated. Each catalyst of the second series (Ni–MgO/Al₂O₃) was prepared by consecutive impregnation using various preparation procedures. They were tested to determine the effect of adding magnesium as well as the effect of the preparation procedure on the outlet gas concentrations. It was shown that in both series, the catalysts were more efficient in hydrogen production as well as carbon conversion than Ni/Al₂O₃ catalysts. The highest hydrogen yield was 85% which was achieved over Ru–Ni/Al₂O₃ at 950 °C. It was also found that the effect of adding a small amount of ruthenium was superior to that of nickel on the yield of hydrogen when the nickel content was equal to or greater than 10.7%.     

Synthesis and Microscopic Characterization of Dendrimer-Derived Ru/Al2O3 Catalysts

Fourth generation poly(amidoamine) dendrimers have been used to template and stabilize Ru nanoparticles in solution. UV-visible spectroscopic results indicate that Ru³⁺ ions from a RuCl₃ precursor can complex with functional groups within the dendrimer structure. Subsequent reduction of the Ru³⁺ ions yields finely dispersed Ru nanoparticles with a narrow particle size distribution. These dendrimer-stabilized nanoparticles were deposited onto an alumina support and thermally activated to remove the dendrimer “shell”, as indicated by in situ Fourier transform infrared (FTIR) spectroscopic measurements. High resolution transmission electron microscopy (HRTEM) measurements indicate that the resulting Ru/Al₂O₃ catalyst has a smaller mean metal particle size and a narrower particle size distribution than a similar catalyst prepared by a traditional wet impregnation from the same RuCl₃ precursor.     

Activity,selectivity, and adsorbed reaction intermediates/reaction side products in the selective methanation of CO in reformate gases on supported Ru catalysts

The reaction behavior and mechanistic aspects of the selective methanation of CO over two supported Ru catalysts, a Ru/zeolite catalyst and a Ru/Al₂O₃ catalyst, in CO₂ containing reaction gas mixtures were investigated by temperature-screening measurements, kinetic measurements and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements. The influence of other components present in realistic reformate gases, such as H₂O and high amounts of CO₂, on the reaction behavior was evaluated via measurements in increasingly realistic gas mixtures. Temperature screening and kinetic measurements revealed a high activity of both catalysts, with the Ru mass-normalized activity of the Ru/zeolite catalyst exceeding that of the Ru/Al₂O₃ catalyst by about one order of magnitude. Approaching more realistic conditions, the conversion–temperature curve was shifted slightly upwards for the Ru/Al₂O₃ catalyst, whereas for the Ru/zeolite catalyst it remained unaffected. The selectivity was highest for the Ru/zeolite catalyst, where in parallel to full conversion of CO the conversion of CO₂ remained below 10% over a 40 °C temperature window. During selective methanation on the Ru/Al₂O₃ catalyst, CO₂ was converted even though CO was not completely removed from the feed. Transient DRIFTS measurements, following the build-up and decomposition of adsorbed surface species in different reaction atmospheres and in the corresponding CO-free gas mixtures, respectively, provide information on the formation and removal/stability of the respective adsorbed species and, by comparison with the kinetic data, on their role in the reaction mechanism. Consequences on the mechanism and physical reasons underlying the observed selectivity are discussed.     

Effect of Chlorine on the Chemisorptive Properties and Ammonia Synthesis Activity of Alumina-Supported Ru Catalysts

Abstract  

A series of Ru/Al₂O₃ catalysts were prepared to study the effect of the amount and the origin of residual chlorine on chemisorptive property and the ammonia synthesis activity. The catalysts were characterized by X-ray fluorescence, CO chemisorption, transmission Electron Microscopy, X-ray photoelectron spectroscopy, hydrogen temperature-programmed desorption, hydrogen temperature-programmed reduction. It is found that the presence of chlorine had a limited impact on Ru particle size. Residual chlorine originated from RuCl₃ would not influence on Ru 3d_5/2 binding energy, but chlorine from HCl solution significantly increased Ru 3d_5/2 binding energy. Regardless of their source, the presence of chlorine severely reduced the amount of hydrogen species corresponding to the desorption peak at medium temperature. The inhibition effect of chlorine on hydrogen adsorption was more strong for Ru catalyst with residual chlorine from the RuCl₃ precursor. With a similar amount of residual chlorine, the catalysts with chlorine originated from the RuCl₃ precursor showed much lower catalytic activity than those prepared by impregnation of HCl. These results suggest that chlorine mainly affects the catalytic properties of alumina supported Ru catalysts for ammonia synthesis by selective site blocking.     

Anodic catalysts for polymer electrolyte fuel cells: the catalytic activity of Pt/C,Ru/C and Pt-Ru/C in oxidation of CO by O2

The catalytic activity for oxidation of CO by O₂ was investigated on commercial Pt/C, Pt-Ru/C (Pt/Ru atomic ratio = 20, 3, 1, 1/3) and Ru/C. All samples contained 20 wt.% metal. Assuming equal surface and bulk composition, the number of surface Pt and Ru atoms was calculated from the average size of the supported metal particle as determined by TEM. On Pt-Ru/C alloys, the turnover frequency per Ru atom, N_Ru/molecules s⁻¹ Ru-atom⁻¹, was independent of chemical composition. This finding suggests that the active site in these alloys is Ru. In the temperature range 300–400 K, the turnover frequency per active metal atom was 50–300 times higher on Pt-Ru/C than on Pt/C. The turnover frequency was 400 times higher on Ru/C than on Pt/C at 313 K and 90 times higher at 353 K. Addition of water vapor to the reactant mixture left the catalytic activity of Ru/C unchanged but slightly increased the activity of Pt/C. On both catalysts the activation energy and reaction orders were nearly the same as in dry atmosphere. Conversely, the addition of water markedly decreased the activation energy for Pt-Ru(1 : 1)/C alloy (from 19 to 11 kcal mol⁻¹). These findings suggest that fuel cells equipped with Pt-Ru/C anodes perform better than cells with Pt/C anodes. They do so because Ru effectively oxidizes the carbon monoxide present as an impurity in the H₂-reformed fuel.     

Effects of ethylene glycol addition on the properties of Ru/Al2O3 catalyst prepared by sol-gel method

Ru/Al₂O₃ catalysts were prepared by sol-gel method with an organic additive (ethylene glycol). The effect of the addition of ethylene glycol on the properties of Ru/Al₂O₃ was characterized by BET, XRD, EXAFS, and TGA/DTA. Ethylene glycol was effective to promote the phase transition of -Al₂O₃ even at 800°C calcination with high surface area. This finding is ascribed to the modified structure of aluminum alkoxide by ethylene glycol addition in the solution state. Ethylene glycol is also effective to get small particles of ruthenium after the reduction at 500°C. The EXAFS and UV-Vis spectra of Ru complex revealed that the coordination structure of Ru depended on the additive used. The ethylene glycol sol prefers to form octahedral Ru complex. This Ru complex in alumina matrix is stable up to 200°C and forms small Ru oxide particles even at 300°C calcination. This suggests that ethylene glycol coordinates to the Ru complex as well as to aluminum ion in the initial state, which is important to control the final properties of the Ru/Al₂O₃ catalyst.     

Carbon supported Ru–Se as methanol tolerant catalysts for DMFC cathodes. Part I: preparation and characterization of catalysts

Carbon supported Ru _x Se _y O _z catalysts were prepared from Ru₃(CO)₁₂ and RuCl₃ · xH₂O as ruthenium precursors and H₂SeO₃ and SeCl₄ as the selenium sources. Highly active catalysts for the oxygen reduction reaction (ORR) in direct methanol fuel cells (DMFC) were obtained via a multi-step preparation procedure consisting of a CO₂-activation of the carbon support prior to the preparation of a highly disperse Ru particles catalyst powder that is subsequently modified by Se. Ultimately, an excess of Se was removed during a final thermal annealing step at 800 °C under forming gas atmosphere. The morphology of the catalysts was analyzed by transmission electron microscopy (TEM) and X-ray diffraction (XRD), which shows that the catalysts consist of crystalline Ru-particles with sizes ranging from 2 to 4 nm exhibiting a good dispersion over the carbonaceous support. The corresponding catalytic activity in the process of oxygen reduction was analyzed by cyclic voltammetry (CV) and rotating disk electrode (RDE) measurements. The nature of the carbon support used for the preparation of RuSe cathode catalysts is of significant importance for the activity of the final materials. Catalysts supported on CO₂-activated Black Pearls 2000 gave the highest ORR-activity. Se stabilizes the Ru-particles against bulk oxidation and actively contributes to the catalytic activity. An exceptional property of the carbon supported Ru-particles modified with Se is their resistance to coalescence up to temperatures of 800 °C under inert or reducing conditions. Additional effects of Se-modification are the enhanced stability towards electrochemical oxidation of Ru and a lowering of the H₂O₂ formation in the ORR.     

Catalytic Hydroprocessing of p-Cresol: Metal, Solvent and Mass-Transfer Effects

A systematic study of the comparative performances of supported Pt, Pd, Ru and conventional CoMo/Al₂O₃, NiMo/Al₂O₃, NiW/Al₂O₃ catalysts as well as the effects of solvent, H₂ pressure and temperature on the hydroprocessing activity of a representative model bio-oil compound (e.g., p-cresol) is presented. With water as solvent, Pt/C catalyst shows the highest activity and selectivity towards hydrocarbons (toluene and methylcyclohexane), followed by Pt/Al₂O₃, Pd and Ru catalysts. Calculations indicate that the reactions in aqueous phase are hindered by mass-transfer limitations at the investigated conditions. In contrast, with supercritical n-heptane as solvent at identical pressure and temperature, the reactant and H₂ are completely miscible and calculations indicate that mass-transfer limitations are eliminated. All the noble metal catalysts (Pt, Pd and Ru) show nearly total conversion but low selectivity to toluene in supercritical n-heptane. Further, conventional CoMo/Al₂O₃, NiMo/Al₂O₃ and NiW/Al₂O₃ catalysts do not show any hydrodeoxygenation activity in water, but in supercritical n-heptane, CoMo/Al₂O₃ shows the highest activity among the tested conventional catalysts with 97?% selectivity to toluene. Systematic parametric investigations with Pt/C and Pt/Al₂O₃ catalysts indicate that with water as the solvent, the reaction occurs in a liquid phase with low H₂ availability (i.e., low H₂ surface coverage) and toluene formation is favored. In supercritical n-heptane with high H₂ availability (i.e., high H₂ surface coverage), the ring hydrogenation pathway is favored leading to the high selectivity to 4-methylcyclohexanol. In addition to differences in H₂ surface coverage, the starkly different selectivities between the two solvents may also be due to the influence of solvent polarity on p-cresol adsorption characteristics.     

Reaction performance and characterization of Co/Al2O3 Fischer–Tropsch catalysts promoted with Pt, Pd and Ru

A series of noble metal (Pt, Ru or Pd) promoted Co/Al₂O₃ catalysts were prepared by sequential impregnation method. The catalysts were characterized by XRD, TPR, H₂-TPD and TPSR techniques, and their catalytic performance in Fischer–Tropsch synthesis was investigated in a fixed-bed reactor. The results of activity measurements show that the addition of small amounts of noble metal greatly improved the activity of the Co/Al₂O₃ catalyst. TPR experimental results demonstrate that hydrogen spillover from the noble metal to cobalt oxide clusters facilitated the reduction of cobalt oxide and, thus significantly increased the reducibility of Co/Al₂O₃ catalyst. The presence of noble metal increased the amount of chemisorbed hydrogen and weakened the bond strength of Co–H. TPSR results indicate that CO was adsorbed in a more reactive state on the promoted catalysts.     

Aqueous-phase reforming of ethylene glycol over supported Pt and Pd bimetallic catalysts

More than 130 Pt and Pd bimetallic catalysts were screened for hydrogen production by aqueous-phase reforming (APR) of ethylene glycol solutions using a high-throughput reactor. Promising catalysts were characterized by CO chemisorption and tested further in a fixed bed reactor. Bimetallic PtNi, PtCo, PtFe and PdFe catalysts were significantly more active per gram of catalyst and had higher turnover frequencies for hydrogen production (TOF_H2) than monometallic Pt and Pd catalysts. The PtNi/Al₂O₃ and PtCo/Al₂O₃ catalysts, with Pt to Co or Ni atomic ratios ranging from 1:1 to 1:9, had TOF_H2 values (based on CO chemisorption uptake) equal to 2.8–5.2 min⁻¹ at 483 K for APR of ethylene glycol solutions, compared to 1.9 min⁻¹ for Pt/Al₂O₃ under similar reaction conditions. A Pt₁Fe₉/Al₂O₃ catalyst showed TOF_H2 values of 0.3–4.3 min⁻¹ at 453–483 K, about three times higher than Pt/Al₂O₃ under identical reaction conditions. A Pd₁Fe₉/Al₂O₃ catalyst had values of TOF_H2 equal to 1.4 and 4.3 min⁻¹ at temperatures of 453 and 483 K, respectively, and these values are 39–46 times higher than Pd/Al₂O₃ at the same reaction conditions. Catalysts consisting of Pd supported on high surface area Fe₂O₃ (Nanocat) showed the highest turnover frequencies for H₂ production among those catalysts tested, with values of TOF_H2 equal to 14.6, 39.1 and 60.1 min⁻¹ at temperatures of 453, 483 and 498 K, respectively. These results suggest that the activity of Pt-based catalysts for APR can be increased by alloying Pt with a metal (Ni or Co) that decreases the strengths with which CO and hydrogen interact with the surface (because these species inhibit the reaction), thereby increasing the fraction of catalytic sites available for reaction with ethylene glycol. The activity of Pd-based catalysts for APR can be increased by adding a water-gas shift promoter (e.g. Fe₂O₃).     

Efficient production of hydrogen and multi-walled carbon nanotubes from ethanol over Fe/Al2O3 catalysts

Fe/Al₂O₃ catalysts with different Fe loadings (10-90 mol%) were prepared by hydrothermal method. Ethanol decomposition was studied over these Fe/Al₂O₃ catalysts at temperatures between 500 and 800 °C to produce hydrogen and multi-walled carbon nanotubes (MWCNTs) at the same time. The results showed that the catalytic activity and stability of Fe/Al₂O₃ depended strongly on the Fe loading and reaction temperature. The Fe(30 mol%)/Al₂O₃ and Fe(40 mol%)/Al₂O₃ were both the effective catalyst for ethanol decomposition into hydrogen and MWCNTs at 600 °C. Several reaction pathways were proposed to explain ethanol decomposition to produce hydrogen and carbon (including nanotube) at the same time.     

Influence of preparation method on performance of Cu(Zn)(Zr)-alumina catalysts for the hydrogen production via steam reforming of methanol

The selective production of hydrogen via steam reforming of methanol (SRM) was performed using prepared catalysts at atmospheric pressure over a temperature range 200–260^∘C. Reverse water gas shift reaction and methanol decomposition reactions also take place simultaneously with the steam reforming reaction producing carbon monoxide which is highly poisonous to the platinum anode of PEM fuel cell, therefore the detailed study of effect of catalyst preparation method and of different promoters on SRM has been carried out for the minimization of carbon monoxide formation and maximization of hydrogen production. Wet impregnation and co-precipitation methods have been comparatively examined for the preparation of precursors to Cu(Zn)(Al₂O₃) and Cu(Zn)(Zr)(Al₂O₃). The catalyst preparation method affected the methanol conversion, hydrogen yield and carbon monoxide formation significantly. Incorporation of zirconia in Cu(Zn)(Al₂O₃) catalyst enhanced the catalytic activity, hydrogen selectivity and also lower the CO formation. Catalyst Cu(Zn)(Zr)(Al₂O₃) with composition Cu/Zn/Zr/Al:12/4/4/80 prepared by co-precipitation method was the most active catalyst giving methanol conversion up to 97% and CO concentration up to 400 ppm. Catalysts were characterized by atomic absorption spectroscopy (AAS), Brunauer-Emett-Teller (BET) surface area, pore volume, pore size and X-ray powder diffraction (XRPD). The XRPD patterns revealed that the addition of zirconia improves the dispersion of copper which resulted in the better catalytic performance of Cu(Zn)(Zr)(Al₂O₃). The time-on-stream (TOS) catalysts stability test was also conducted for which the Cu(Zn)(Zr)(Al₂O₃) catalyst gave the consistent performance for a long time compared to other catalysts.     

Steam reforming of kerosene over a metal-monolithic alumina-supported Ru catalyst: Effect of preparation conditions and electrical-heating test

A plate-type anodic alumina support (γ-Al₂O₃/Fe–Cr–Ni alloy/γ-Al₂O₃) was used to prepare a series of Ru catalysts. The performance of these catalysts was investigated in the steam reforming of kerosene (SRK). Ethanol solution impregnation was used to enhance metal dispersion on the catalyst surface. The catalyst prepared by ethanol solution impregnation and dried at 120 °C (Ru/Al₂O₃-ED) gave a higher metal dispersion and more favorable activity and durability than that prepared in aqueous solution. However, owing to shrinking caused by the oxidation of ruthenium species, high temperature calcination in air after impregnation greatly decreased the metal dispersion on the catalyst surface, regardless of the impregnation solution type. In contrast to calcination in air, high temperature N₂ treatment could decompose the reducible ruthenium species on the Ru/Al₂O₃-ED completely. This indicates that H₂ pre-reduction is not an essential procedure for the SRK reactions over this catalyst. The experimental results also confirm this hypothesis. The effect of Ce addition was also investigated and was found to enhance significantly the catalyst tolerance to carbon deposition thereby improving the SRK durability of Ru/Al₂O₃-ED under a high space velocity. In addition, owing to the high electrical resistance of the Fe–Cr–Ni alloy, the anodic alumina catalyst itself can be used as a heater, when an electrical current is applied along the alloy layer. Under an electrical-heating pattern, the SRK reaction system reached stability within 15 min, offering a strong possibility for shortening the start-up time of conventional reformers from 1 to 2 h to a few minutes.