Effect of Nano‐support and Type of Active Metal on Reforming of CH4 with CO2

Two series of Co and Ni based catalysts supported over commercial (ZrO₂, CeO₂, and Al₂O₃) nano supports were investigated for dry reforming of methane. The catalytic activity of both Co and Ni based catalysts were assessed at different reaction temperatures ranging from 500—800 °C; however, for stability the time on stream experiments were conducted at 700 °C for 6 h. Various techniques such as N₂ adsorption‐desorption isotherm, temperature‐programmed reduction (H₂‐TPR), temperature‐programmed desorption (CO₂‐TPD), temperature‐programmed oxidation (TPO), X‐ray diffraction (XRD), thermogravimetric analysis (TGA) were applied for characterization of fresh and spent catalysts. The catalytic activity and stability tests clearly showed that the performance of catalyst is strongly dependent on type of active metal and support. Furthermore, active metal particle size and Lewis basicity are key factors which have significant influence on catalytic performance. The results indicated that Ni supported over nano ZrO₂ exhibited highest activity among all tested catalysts due to its unique properties including thermal stability and reducibility. The minimum carbon deposition and thus relatively stable performance was observed in case of Co‐Al catalyst, since this catalyst has shown highest Lewis basicity.     

Ni基催化剂催化燃油重整耦合选择性催化还原NOx反应

分别以La₂O₂CO₃, CeO₂, ZrO₂和Al₂O₃为载体, 采用浸渍法制备了Ni基重整催化剂, 并以正十二烷模拟车载燃油进行催化重整反应以同时制备小分子碳氢化合物(HCs)和H₂, 考察了其在4wt%Ag/Al₂O₃上选择性催化还原(HC-SCR)氮氧化物(NO_x)的性能. 采用N₂吸附-脱附、X射线粉末衍射、H₂程序升温还原和热重等手段对Ni基催化剂进行了表征. 结果表明, 随着重整催化剂氧化还原性能增强, 产物中H₂浓度增加, 可参与SCR反应的HCs含量减少, 从而导致重整-SCR耦合体系上NO_x净化活性温度窗口向低温移动, NO_x最高转化率降低. Ni/ZrO₂+Ag/Al₂O₃耦合体系中H₂/HCs符合SCR反应所需的最优比例, 在柴油车典型排气温度范围内表现出良好的NO_x净化能力. 同时, 在Ni/ZrO₂+Ag/Al₂O₃耦合体系上考察了其燃油重整-SCR的活性稳定性. 结果显示, 重整催化剂的耐久性有待进一步提高.     

High catalytic activity of V2O5-ZrO2 modified with H2SO4 for propene partial oxidation

For V₂O₅–ZrO₂ catalysts, up to 10 mol% the crystalline structure of V₂O₅ was not observed, indicating a good dispersity the surface of ZrO₂. V₂O₅–ZrO₂ catalyst modified with H₂SO₄ exhibited much on higher catalytic activity for propene partial oxidation than unmodified catalysts due to the increased acidity and acid strength of modified catalyst.     

CO2 methanation over nickel-based catalysts prepared by citric acid complexation method

Catalytic hydrogenation of carbon dioxide to methane can not only achieve the recycling of carbon resources, but also effectively meet the increasing demand for natural gas. In this paper, Ni-based catalysts on different supports including ZrO₂, CeO₂ and Al₂O₃ were synthesized using citric acid complexation method and their CO₂ methanation performances were tested. Among these catalysts, the Ni/ZrO₂ catalyst achieved the best CO₂ methanation activity. The catalysts were characterized by N₂-physisorption, XRD, H₂-TPR and H₂-TPD. The results indicate that the superiority of the Ni/ZrO₂ catalyst can be mainly ascribed to its not only high Ni dispersion but also high reduction degree. Since the reduction degree of Ni/Al₂O₃ is low, it exhibits poor activity. The preparation condition for the Ni/ZrO₂ catalyst was further optimized. The result shows that at molar ratio of citric acid to Ni ions of 3, the catalyst exhibits the best activity owing to the highest Ni dispersion, the largest Ni surface area, an appropriate metal-support interaction and the most moderate basic sites.     

Nature of active sites in the cobalt-zirconium oxide catalyst

The temperature-programmed reduction, powder X-ray diffraction, and oxygen adsorption methods were applied to study the phase composition and the nature of the active surface of the catalyst Co(10%)/ZrO₂. The results of the physicochemical studies were compared with the data on the activity and selectivity of the catalysts in the synthesis of hydrocarbons from CO and H₂. The mechanism for the reduction of the cobalt phases in the Co(10%)/ZrO₂ system was proposed. The main features governing the formation of active sites of the synthesis of high-molecular-weight hydrocarbons were considered.     

Bestimmung kleiner Gehalte an Zink, Nickel nnd Eisen in Titan-, Zirkonium- und Thoriumdioxid, sowie an Uran in Thoriumdioxid mittels R?ntgenfluorescenzanalyse

Zusammenfassung Die Untersuchungen zur Bestimmung kleiner Gehalte an Zink, Nickel und Eisen in den Dioxiden von Titan, Zirkonium und Thorium mittels Röntgenfluorescenzanalyse haben gezeigt, daß die Eichkurven für Zn, Ni und Fe in TiO₂ in dem untersuchten Bereich (bis 0,1%) geradlinig verlaufen. Beim ZrO₂ wurde Geradinigkeit für Zn und Fe bis etwa 0,4% für Ni nur bis etwa 0,1% gefunden. Beim ThO₂ war die Nettoimpulszahl D der Konzentration c proportional für Zn, Fe und U bis zur untersuchten Konzentration von 1,288%, für Ni nur bis etwa 0,4%. Die Nachweisgrenzen der Elemente für eine Zählzeit von 5 min und eine statistische Sicherheit von 99,7% ergaben sich wie folgt: TiO₂ Zn 0,001, Ni 0,001, Fe 0,003; ZrO₂ Zn 0,002, Ni 0,002, Fe 0,007; ThO₂ Zn 0,006, Ni 0,005, Fe 0,015, U 0,02 Gew.-%.

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Summary Investigations on the determination of low concentrations of zinc nickel and iron in TiO₂, ZrO₂, and ThO₂ and of uranium in ThO₂ by means of X-ray fluorescence analysis have shown that the calibration curves are linear for Zn, Ni, and Fe in TiO₂ in the investigated range of 0.1%, for Zn and Fe in ZrO₂ of 0.4%, for Ni in ZrO₂ of 0.1%, for Zn, Fe, and U in ThO₂ in the investigated range of 1.288% and for Ni in ThO₂ of 0.4%. The calculated limits of detections for a counting time of 5 min and 99.7% confidence are: TiO₂: Zn 0.001, Ni 0.001, Fe 0.003; ZrO₂: Zn 0.002, M 0.002, Fe 0.007; ThO₂: Zn 0.006, Ni 0.005, Fe 0.015, U 0.02 w.-%.

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Herrn Prof. Dr. F. Strassmann zum 65. Geburtstag gewidmet.

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Herrn Prof. Dr. Ing. F. Strassmann, dem Bundesministerium für Wissenschaftliche Forschung und der Deutschen Forschungsgemeinschaft danken wir für die Überlassung von Instituts- bzw. Forschungsmitteln.     

Cu/Mn/ZrO2 catalyst for alcohol synthesis by Fischer-Tropsch modified elements

A Cu/Mn/ZrO₂ methanol synthesis catalyst modified by Fischer-Tropsch (F-T) element (Ni,Co,Fe) was prepared by an coprecipatation method. The addition of F-T elements had a great effect on the catalyst performance. The higher alcohol selectivity increased greatly compared with that of the Cu/Mn/ZrO₂ catalyst when nickel and cobalt were added, while the addition of iron improved the selectivity tohydrocarbon due to the interaction of the F-T element and the Cu/Mn/ZrO₂ catalyst.     

Catalytic performance of a Ni catalyst supported on CeO2, ZrO2 and CeO2–ZrO2 in the upgrading of cellulose fast pyrolysis vapors

This work was devoted to the investigation of the catalytic performance of a Ni catalyst supported on CeO₂, ZrO₂ and CeO₂–ZrO₂ in the upgrading of cellulose fast-pyrolysis vapors. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and temperature-programmed reduction (TPR) were used for the surface characterization of the prepared materials. The activity of the catalysts was evaluated by analytical pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). It was demonstrated that the use of 20%Ni/15%CeO₂–ZrO₂ allowed one to obtain the highest olefin and paraffin contents, while owing to the application of 20%Ni/ZrO₂ catalyst the largest amount of aromatics was produced and a considerable decrease in the amount of carboxylic acid fraction was noticed.     

Smart Solution Chemistry to Sn‐Containing Intermetallic Compounds through a Self‐Disproportionation Process

Developing new methods to synthesize intermetallics is one of the most critical issues for the discovery and application of multifunctional metal materials; however, the synthesis of Sn‐containing intermetallics is challenging. In this work, we demonstrated for the first time that a self‐disproportionation‐induced in situ process produces cavernous Sn?Cu intermetallics (Cu₃Sn and Cu₆Sn₅). The successful synthesis is realized by introducing inorganic metal salts (SnCl₂ ? 2 H₂O) to NaOH aqueous solution to form an intermediate product of reductant (Na₂SnO₂) and by employing steam pressures that enhance the reduction ability. Distinct from the traditional in situ reduction, the current reduction process avoided the uncontrolled phase composition and excessive use of organic regents. An insight into the mechanism was revealed for the Sn?Cu case. Moreover, this method could be extended to other Sn‐containing materials (Sn?Co, Sn?Ni). All these intermetallics were attempted in the catalytic effect on thermal decompositions of ammonium perchlorate. It is demonstrated that Cu₃Sn showed an outstanding catalytic performance. The superior property might be primarily originated from the intrinsic chemical compositions and cavernous morphology as well. We supposed that this smart solution reduction methodology reported here would provide a new recognition for the reduction reaction, and its modified strategy may be applied to the synthesis of other metals, intermetallics as well as some unknown materials.     

Chitosan–sodium alginate encapsulated Co-doped ZrO<Subscript>2</Subscript>–MWCNTs nanocomposites for photocatalytic decolorization of organic dyes

Photocatalytic decolorization properties of cobalt doped-ZrO₂-multiwalled carbon nanotubes (Co–ZrO₂–MWCNTs) and chitosan–sodium alginate encapsulated Co–ZrO₂–MWCNTs (CS/Alg–Co–ZrO₂–MWCNTs) with varying weight percentage of Co–ZrO₂–MWCNTs are presented in this research paper. The Co–ZrO₂–MWCNTs was first synthesized through homogenous co-precipitation method and introduced into the chitosan–sodium sodium alginate (CS/Alg) biopolymer matrix. The bio-nanocomposites were characterized using X-ray powder diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, (UV–Vis)-spectroscopy and energy dispersive spectroscopy to obtain information on their structure, formation, morphology, size and elemental analysis. The photodecolorization efficiency of the samples was determined through their decolorization of trypan blue dye aqueous solution in 180 min. Recyclability of the catalysts was also assessed. The bio-nanocomposites experienced reduced band gap values with subsequent improvement in visible light activity compared to the uncapped Co–ZrO₂–MWCNTs. All the CS/Alg–Co–ZrO₂–MWCNTs exhibited higher photodecolorization activities than the uncapped Co–ZrO₂–MWCNTs. The most efficient catalyst (CS/Alg–40 % Co–ZrO₂–MWCNTs) with a band gap of 2.56 eV displayed 94 % decolorization efficiency of the dye. Though reusability of the catalyst is significant, its efficiency diminished consistently after each cycle.     

Dry reforming of greenhouse gases CH4/CO2 over MgO-promoted Ni–Co/Al2O3–ZrO2 nanocatalyst: effect of MgO addition via sol–gel method on catalytic properties and hydrogen yield

Sol–gel method was employed to prepare Ni–Co/Al₂O₃–MgO–ZrO₂ nanocatalyst with various loadings of MgO (5, 10 and 25 wt%) for dry reforming of methane. The physiochemical properties of nanocatalysts were characterized by XRD, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), BET and fourier transform infrared spectroscopy (FTIR) analysis. Evaluation of catalytic performance was conducted in atmospheric pressure, stoichiometric feed ratio, GHSV of 24 l/g_cat h and temperature range from 550 to 850 °C. XRD patterns represented that as MgO content increases, the amorphous behavior slightly intensifies and also dispersion of active phase improves which probably caused by strong metal–support interaction. Furthermore, FESEM analysis confirmed that all of prepared samples are nano scale. EDX results besides verifying the declared claim about the dispersion of samples proved the presence and detected the position of the various elements. In addition, based on the FESEM analysis, narrow particle size distribution, uniform morphology and dispersion without agglomeration were found for Ni–Co/Al₂O₃–MgO–ZrO₂ with 25 wt% MgO. Moreover, smallest average particle size 11.6 nm (close to the critical size for Ni–Co catalyst to avoid carbon formation) was obtained for this nanocatalyst. Also, according to the BET analysis, MgO rich nanocatalyst represented the higher surface area than the other ones. Based on the excellent characterizations, Ni–Co/Al₂O₃–MgO–ZrO₂ with 25 wt% MgO exhibited the best products yield through all of the investigated temperature e.g. H₂ = 96.9 % and CO = 97.1 % at 850 °C. Furthermore, this nanocatalyst demonstrated the stable yield with H₂/CO close to unit during 1,440 min stability test.     

Spectral and biological investigation of 5-hydroxyl-3-oxopyrazoline 1-carbothiohydrazide and its transition metal complexes

Mononuclear complexes of 5-hydroxyl-3-oxopyrazoline-1-carbothiohydrazide, H₃HOC, with VO²⁺, Co(II), Ni(II), Cu(II) and Cd(II) have been isolated. The elemental analyses, magnetic, spectral [u.v.–vis., i.r., e.s.r. ¹H n.m.r. and mass] with thermal analysis have been used to characterize the isolated complexes. The ligand behaves as a mononegative tridentate with Ni(II) and Co(II) ions and neutral bidentate in [Cu(H₃HOC)(NO₃)₂]0.5 H₂O, [VO(H₃HOC)SO₄] and [Cd(H₃HOC)Cl₂C₂H₅OH]C₂H₅OH complexes. The octahedral structure was suggested for all the isolated complexes except VO²⁺. The TG analyses recorded different decomposition steps started at a temperature, indicating thermally unstable complexes. Screening showed antimicrobial activity for Cd(II) and Ni(II) complexes against the investigated bacteria as well as a significant adverse effects on DNA but a moderate effect is displayed with the other complexes.     

串联双釜连续反应装置中Ru-Co-B/ZrO2上苯选择加氢制环己烯

采用化学还原法制备了苯选择加氢制环己烯催化剂Ru-B/ZrO₂,考察了Cr,Mn,Fe,Co,Ni,Cu和Zn等过渡金属的添加对Ru-B/ZrO₂催化剂性能的影响.结果表明,这些过渡金属的添加均可提高Ru-B/ZrO₂催化剂中的B含量.B的修饰及第二种金属或金属氧化物的集团效应和配位效应导致Ru-B/ZrO₂催化剂活性降低和环己烯选择性升高.当Co/Ru原子比为0.06时,Ru-Co-B/ZrO₂催化剂上反应25min苯转化率为75.8%时,环己烯选择性和收率分别为82.8%和62.8%.在双釜串联连续反应器中和优化反应条件下,Ru-Co-B/ZrO₂催化剂使用419h内苯转化率稳定在40%左右,环己烯选择性和收率分别稳定在73%和30%左右.     

SIMS and AES measurements on the LaNi5-hydrogen system

Summary SIMS (Secondary Ion Mass Spectrometry) and AES (Auger Electron Spectroscopy) investigations were carried out on polycrystalline LaNi₅ samples and on LaNi₅ samples, which have been loaded with hydrogen electrochemically. AES measurements show an enrichment of obviously oxidized La at the surface, while in the SIMS spectra the emission of negative ions attracts special attention. In contrast to the V-H- and Nb-H-system negative Me_xH_y-ions turned out to be the most sensitive species for hydrogen detection in SIMS experiments on LaNi₅. The emission of negative ions of type Ni_x and Ni_yH_x, which are not observed on pure Ni are due to the electropositive character of La in this special matrix and the presence of hydrogen. The results point to a higher affinity of hydrogen to Ni than to La.     

Application of high-surface-area ZrO2 in preconcentration and determination of 18 elements by on-line flow injection with inductively coupled plasma atomic emission spectrometry

A flow-injection analysis (FIA) system incorporating a micro-column of ZrO₂ has been used for the development of an on-line multi-element method for the simultaneous preconcentration and determination of Al, Bi, Cd, Co, Cr, Cu, Fe, Ga, In, Mn, Mo, Ni, Pb, Tl, V, Sb, Sn, and Zn by inductively coupled plasma atomic emission spectrometry (ICP–AES). The conditions for quantitative and reproducible preconcentration, elution, and subsequent on-line ICP–AES determination were established. A sample (pH 8) is pumped through the column at 3 mL min^–1 and sequentially eluted directly into the ICP–AES with 3 mol L^–1 HNO₃. With a sample volume of 100 mL and an elution volume of 1 mL signal enhancement 100 times better than for conventional continuous aspirating systems was obtained for the elements studied. The reproducibility (RSD %) of the method at the 10 ng mL^–1 level in the eluate is acceptable – less than 8% for five replicates. Recoveries between 95.4% and 99.9% were obtained for the elements analysed. ZrO₂, with a specific surface area of 57 m² g^–1 and a capacity of approximately 5 mg g^–1 for the elements studied, was synthesized by hydrolysis of ZrCl₄. The preconcentration system was evaluated for several simple synthetic matrices, standard water samples and synthetic seawater. The effect of foreign ions on the efficiency of preconcentration of the elements studied was investigated. The application of a micro-column filled with high-surface-area ZrO₂ and flow injection inductively coupled plasma atomic emission spectrometry enables preconcentration and simultaneous determination of 18 elements at low concentrations (ng L^–1) in different water samples.     

Autothermal reforming of methane to syngas using co-precipitated Ni−(La2O3) x −(ZrO2)1−x catalyst

Two different catalysts, Ni?(ZrO₂) and Ni?(La₂O₃)_0.1?(ZrO₂)_0.9, were synthesized to use as catalysts in the autothermal reforming of methane. Ni?(ZrO₂) catalyst without lanthanum prepared in this study has a good initial performance, but as the reactions keep progressing, the activities gradually decrease. In contrast, the activities of Ni?(La₂O₃)_0.1?(ZrO₂)_0.9 catalyst have high thermal stability and coke resistance due to the presence of La. Both methane conversion and hydrogen yield of Ni?(La₂O₃)_0.1?(ZrO₂)_0.9 in non-reduced form are better than reduced form and as good as commercial Ni-based catalyst (ICI 57-4).     

Aspects of the inorganic chemistry of rubber vulcanisation. Part 5(1) complexes of zinc,nickel and cobalt derived from 2-mercaptobenzothiazole and its 5-ethoxy- and ethyl-derivatives

Summary Metal complexes of 2-mercaptobenzothiazole (5-RC₇H₃-NS₂H) (R=H) and its 5-ethoxy (R=EtO) and 5-ethyl (R=Et) derivatives which are reasonably soluble in common organic solvents are described. The species prepared include M(5-RC₇H₃NS₂)₂(pyr)₂ (pyr=pyridine; M=Zn, Ni or Co; R=Et or EtO) and [M(5-RC₇H₃NS₂)₂]_n (M=Zn or Ni; R= Et or EtO; M=Co, R=EtO). Addition of [Me₄N]-[5-RC₇ H₃NS₂] to [Ni(5-RC₇H₃NS₂)₂]_n afforded green, paramagnetic [Me₄N][Ni(5-RC₇H₃NS₂)₃] (R=H or EtO). Attempts to oxidise [Ni(5-EtOC₇H₃NS₂)₂] to nickel(IV) species are described. The formation of Co(5-EtC₇H₃NS₂)₃-(pyr)₂ and Co(C₇H₄NS₂)₃I₂, which may contain cobalt(III), is reported.     

Hydrodeoxygenation of Anisole over Ni/α-Al2O3 Catalyst

Ni-based catalysts supported on di erent supports (α-Al₂O₃,γ-Al₂O₃, SiO2, TiO₂, and ZrO₂) were prepared by impregnation. Effects of supports on catalytic performance were tested using hydrodeoxygenation reaction (HDO) of anisole as model reaction. Ni/α-Al₂O₃ was found to be the highest active catalyst for HDO of anisole. Under the optimal conditions, the anisole conversion is 93.25% and the hydrocarbon yield is 90.47%. Catalyst characteriza-tion using H₂-TPD method demonstrates that Ni/α-Al₂O₃ catalyst possesses more amount of active metal Ni than those of other investigated catalysts, which can enhance the cat-alytic activity for hydrogenation. Furthermore, it is found that the Ni/α-Al₂O₃ catalyst has excellent repeatability, and the carbon deposited on the surface of catalyst is negligible.     

Structure and Catalytic Properties of Ceria-based Nickel Catalysts for CO<Subscript>2</Subscript> Reforming of Methane

Carbon dioxide reforming (CDR) of methane to synthesis gas over supported nickel catalysts has been reviewed. The present review mainly focuses on the advantage of ceria based nickel catalysts for the CDR of methane. Nickel catalysts supported on ceria–zirconia showed the highest activity for CDR than nickel supported on other oxides such as zirconia, ceria and alumina. The addition of zirconia to ceria enhances the catalytic activity as well as the catalyst stability. The catalytic performance also depends on the crystal structure of Ni–Ce–ZrO₂. For example, nickel catalysts co-precipitated with Ce_0.8Zr_0.2O₂ having cubic phase gave synthesis gas with CH₄ conversion more than 97% at 800 °C and the activity was maintained for 100 h during the reaction. On the contrary, Ni–Ce–ZrO₂ having tetragonal phase (Ce_0.8Zr_0.2O₂) or mixed oxide phase (Ce_0.5Zr_0.5O₂) deactivated during the reaction due to carbon formation. The enhanced catalytic performance of co-precipitated catalyst is attributed to a combination effect of nano-crystalline nature of cubic Ce_0.8Zr_0.2O₂ support and the finely dispersed nano size NiO _x crystallites, resulting in the intimate contact between Ni and Ce_0.8Zr_0.2O₂ particles. The Ni/Ce–ZrO₂/θ–Al₂O₃ also exhibited high catalytic activity during CDR with a synthesis gas conversion more than 97% at 800 °C without significant deactivation for more than 40 h. The high stability of the catalyst is mainly ascribed to the beneficial pre-coating of Ce–ZrO₂ resulting in the existence of stable NiO _x species, a strong interaction between Ni and the support, and an abundance of mobile oxygen species in itself. TPR results further confirmed that NiO _x formation was more favorable than NiO or NiAl₂O₄ formation and further results suggested the existence of strong metal-support interaction (SMSI) between Ni and the support. Some of the important factors to optimize the CDR of methane such as reaction temperature, space velocity, feed CO₂/CH₄ ratio and H₂O and/or O₂ addition were also examined.     

Hydrogen Production by Steam Reforming of Ethanol Over Mesoporous Ni–Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–ZrO<Subscript>2</Subscript> Catalysts

This review paper reports the recent progress concerning the application of nickel–alumina–zirconia based catalysts to the ethanol steam reforming for hydrogen production. Several series of mesoporous nickel–alumina–zirconia based catalysts were prepared by an epoxide-initiated sol–gel method. The first series comprised Ni–Al₂O₃–ZrO₂ xerogel catalysts with diverse Zr/Al molar ratios. Chemical species maintained a well-dispersed state, while catalyst acidity decreased with increasing Zr/Al molar ratio. An optimal amount of Zr (Zr/Al molar ratio of 0.2) was required to achieve the highest hydrogen yield. In the second series, Ni–Al₂O₃–ZrO₂ xerogel catalysts with different Ni content were examined. Reducibility and nickel surface area of the catalysts could be modulated by changing nickel content. Ni–Al₂O₃–ZrO₂ catalyst with 15 wt% of nickel content showed the highest nickel surface area and the best catalytic performance. In the catalysts where copper was introduced as an additive (Cu–Ni–Al₂O₃–ZrO₂), it was found that nickel dispersion, nickel surface area, and ethanol adsorption capacity were enhanced at an appropriate amount of copper introduction, leading to a promising catalytic activity. Ni–Sr–Al₂O₃–ZrO₂ catalysts prepared by changing drying method were tested as well. Textural properties of Ni–Sr–Al₂O₃–ZrO₂ aerogel catalyst produced from supercritical drying were enhanced when compared to those of xerogel catalyst produced from conventional drying. Nickel dispersion and nickel surface area were higher on Ni–Sr–Al₂O₃–ZrO₂ aerogel catalyst, which led to higher hydrogen yield and catalyst stability over Ni–Sr–Al₂O₃–ZrO₂ aerogel catalyst.