Nano composite composed of MoOx-La2O3Ni on SiO2 for storing hydrogen into CH4 via CO2 methanation

The crucial problems for the catalysts of CO₂ methanation are the low activity at low temperature and deactivation caused by metal sintering. In order to overcome the problems or to improve the shortages, a new scheme has been put forward by loading LaNi_1-xMo_xO₃ with perovskite-type structure on SiO₂. After reduction, Ni nanoparticles, MoO_x and La₂O₃ would be all stay together and highly dispersed on SiO₂ (Ni/MoO_x-La₂O₃/SiO₂). The techniques of BET, XRD, H₂-TPR, HRTEM, ICP, H₂ chemisorption and XPS were used to characterize the prepared samples. Through effectively combining MoO_x which is active for the reaction of reverse water gas shift and Ni which can catalyze CO methanation, the resultant Ni/MoO_x-La₂O₃/SiO₂ catalyst exhibited pretty good performance for CO₂ methanation, especially showing very good resistance to metal sintering. NiLa₂O₃/SiO₂ catalyst without adding Mo was investigated for comparison. Since many metallic ions can enter into the lattice of a perovskite-type oxide, therefore, many combined catalysts for sequential reactions may be designed via this scheme.     

Steam reforming of toluene as model compound of biomass tar over Ni–Co/La2O3 nano-catalysts: Synergy of Ni and Co

A series of LaNi_1-xCo_xO₃ (x = 0, 0.2, 0.5, 0.8 and 1) perovskite catalysts were prepared successfully and applied for toluene steam reforming as a model tar molecule. The Ni–Co alloy formation in reduced LaNi_1-xCo_xO₃ was confirmed by TPR, XRD and XPS. The strong interaction in LaNi_0.8Co_0.2O₃ between Ni and Co produced highly dispersed and smaller metal (8–9 nm), higher reducibility and larger amounts of active sites as well as more abundant oxygen defects and higher surface/lattice oxygen mobility, confirmed by XRD, TEM, TPR, XPS and O₂-TPD. Also, a higher electron density prevented Ni from oxidation and sintering; a more oxidized Co (Co³⁺) facilitated the dissociation of water and activation of CO₂, thus removing the coke. At 600 °C, S/C = 3.4 and WHSV = 16.56 ml h⁻¹ g_cat⁻¹, an equilibrium conversion was achieved initially and over 80% conversion after 24 h were obtained for LaNi_0.8Co_0.2O₃ with a high H₂ yield (81.8% at maximum) and 8.0 of H₂/CO ratio. The graphitic/filamentous coke formation was alleviated and no metal sintering was presented after the reaction.     

Promotional effect of Fe on perovskite LaNixFe1−xO3 catalyst for hydrogen production via steam reforming of toluene

The effect of Fe addition on catalytic activity and stability of LaNi_xFe_1−xO₃ perovskite catalyst was investigated for hydrogen production via steam reforming of tar using toluene as a model compound. The addition of Fe to LaNiO₃ catalyst at the optimum amount enhanced the catalytic performance in steam reforming of toluene. LaNi_0.8Fe_0.2O₃ catalyst shows the best performance in terms of catalytic activity and stability for 8 h of reaction time. The catalyst characterization indicates the presence of Ni-rich Ni–Fe smaller bimetallic particles, strong metal support interaction, and lower carbon deposition rate on LaNi_0.8Fe_0.2O₃ catalyst. The synergy between Ni and Fe atoms on the small Ni–Fe bimetallic particles is crucial for high activity of the LaNi_0.8Fe_0.2O₃ catalyst. In addition, the strong interaction between metal and support on the LaNi_0.8Fe_0.2O₃ catalyst can prevent metal sintering, thus, achieving high catalytic stability.     

Metallic Ni nanocatalyst in situ formed from LaNi5H5 toward efficient CO2 methanation

LaNi₅ alloy can be utilized to directly store and release hydrogen in mild condition, thus it is considered as a long-term safe and stable solid-state hydrogen storage material. In this work, LaNi₅H₅ was used as the solid-state hydrogen source in the CO₂ methanation reaction. Impressively, the carbon dioxide conversion can be achieved to nearly 100% under 3 MPa mixed gas at 200 °C. The microstructure and composition analysis results reveal that the high catalytic activity may originate from the promoted elementary steps over in situ formed metallic Ni nanoparticles during the CO₂ methanation process. More importantly, as the lowered reaction temperature prevented the agglomeration of Ni nanoparticles, this catalyst exhibited durable stability with 99% conversion rate of CO₂ retained after 400 h cycling test.     

Ammonia decomposition over SiO2-supported Ni–Co bimetallic catalyst for COx-free hydrogen generation

NH₃ decomposition over non-noble catalyst to generate CO_x-free H₂ has attracted great attention in recent years. In this work, fumed SiO₂-supported Ni, Co and Ni–Co bimetallic catalysts are synthesized by using a co-impregnation method and evaluated for NH₃ decomposition, which shows that the bimetallic catalysts exhibit better catalytic activity than the monometallic ones. This enhanced activity observed on bimetallic catalyst can be largely attributed to the more appropriate catalyst metal-N binding energy resulting from the synergistic effect between Ni and Co in the formed Ni–Co alloy. Among the synthesized catalysts, Ni₅Co₅/SiO₂ synthesized with the Ni/Co molar ratio of 5:5 achieves 76.8% NH₃ conversion under a GHSV of 30,000 mL h⁻¹ g⁻¹_cat at 550 °C and shows the best catalytic activity, which can be further improved by doping with K (78.1% NH₃ conversion at 30,000 mL h⁻¹ g⁻¹_cat), and the obtained Ni₅Co₅/SiO₂–K also shows excellent catalytic stability.     

Highly coke resistant Ni–Co/KCC-1 catalysts for dry reforming of methane

Nanofibrous KCC-1 supported Ni–Co bimetallic catalysts were investigated for dry reforming of methane for syngas generation. Monometallic catalysts such as Ni/KCC-1 and Co/KCC-1, and a series of bimetallic Ni–Co/KCC-1 catalysts were prepared by impregnation and co-impregnation method, respectively. All the catalysts were characterized by XRD, FT-IR, HR-SEM, FE-SEM, XPS, FT-Raman, BET, UV–Visible DRS and AAS techniques. Monometallic nickel supported catalyst contains NiO as an active phase, whereas bimetallic nickel catalysts contain Ni₂O₃, and NiCo₂O₄ on the surface. In the case of cobalt loaded catalysts, spinel Co₃O₄ is the dominant active species, apart from NiCo₂O₄. The addition of cobalt in Ni/KCC-1 has a pronounced effect on the crystallite size, surface area and active species. The hydrogen pretreatment of the catalyst produces bimetallic Ni–Co alloy on the surface. The catalytic activities of the bimetallic catalysts towards dry reforming of methane are better than monometallic catalysts. Mesoporous silica-based KCC-1 offers easy accessibility to the entire surface moieties due to its fibrous nature and the presence of channels, instead of pores. The 2.5%Ni-7.5%Co/KCC-1 showed the maximum CH₄ and CO₂ conversion along with a remarkably low H₂/CO ratio. The life-time test confirms the high thermal stability of the catalysts at 700 °C for 8 h, with less deactivation due to coke formation. The spent catalysts were characterized by XRD, TGA, FT-Raman, and FE-SEM to understand the structural and chemical changes during the reaction. The insignificant D band and G band of graphitic carbon in FT-Raman spectra for the highly active 2.5%Ni-7.5%Co/KCC-1 and 5%Ni–5%Co/KCC-1 catalysts along with TGA results containing 12% weight loss confirms the minimum coke deposition, formation of amorphous carbon and highest coke resistance. The fibrous support restricts the sintering and aggregation of nickel particles as well the deposition of coke. The addition of amphoteric cobalt increases the activity and stability of the catalysts. Ni–Co/KCC-1 with high coke resistance seems to be a promising catalyst for dry reforming of methane.     

Self-optimized and renewable Ni–Co alloy@Co–Co2C catalyst for higher alcohols synthesis from syngas

Higher alcohols synthesis (HAS) from syngas (CO/H₂) has attracted widespread attention, while the low selectivity and poor stability of the catalysts mainly stumbled its industrial application. In the work, Ni–Co alloy nanoparticles (NPs) derived from Co_1-xNi_xAl₂O₄ loaded on the SiO₂ with large specific surface area were prepared; and during reaction, the highly dispersed Ni–Co alloys were self-optimized to Ni–Co alloy@Co–Co₂C. Importantly, Ni–Co alloy@Co–Co₂C can be regenerated through oxidation - reduction - self-optimization process. Characteristic results indicated that the structural liberalization during the reaction process inhibited the loss of Ni, regulated and balanced the dual active sites of the catalyst and the Ni–Co alloys were regenerated after the re-oxidation and re-reduction process. The optimized catalyst exhibited excellent catalytic performance, including a high total selectivity to alcohols of 39.3% and an excellent catalytic stability at 250 °C, 3.5 MPa (H₂/CO = 2) and a space velocity of 6000 mL (g_cat h)^?1. In addition, the Ni–Co alloy@Co–Co₂C catalyst after stability test could recover its original catalytic performance after re-oxidation and re-reduction. The renewable characteristics and superior catalytic performance of Ni–Co alloy@Co–Co₂C made the catalyst to be one of the potential industrial catalysts for HAS.     

CO2 methanation over CoNi bimetal-doped ordered mesoporous Al2O3 catalysts with enhanced low-temperature activities

The Ni based catalysts have been considered as potential candidates for the CO₂ methanation owing to the low cost. However, the poor low-temperature catalytic activities limit their large-scale industrial application. In order to address this challenge, a series of CoNi bimetal doped ordered mesoporous Al₂O₃ materials have been designed and fabricated via the one-pot evaporation induced self-assembly strategy and employed as the catalysts for CO₂ methanation. It is found that the large specific surface areas (up to 260.0 m^2/g), big pore volumes (up to 0.59 cm³/g), and narrow pore size distributions of these catalysts have been successfully retained after 700 °C calcination. The Co and Ni species are homogenously distributed among the Al₂O₃ matrix due to the unique advantage of the one-pot synthesis strategy. The strong interaction between metal and mesoporous framework have been formed and the severely thermal sintering of the metallic CoNi active centers can be successfully inhibited during the processes of catalyst reduction and 50 h CO₂ methanation reaction. More importantly, the synergistic effect between Co and Ni can greatly enhance the low-temperature catalytic activity by coordinating the activation of H₂ and CO₂, prominently decreasing the activation energy toward CO₂ methanation. As a result, their low-temperature activities are evidently promoted. Furthermore, the effect of the Co/(Co + Ni) molar percentage ratio on the catalytic property has been also systematically investigated over these catalysts. It is found that only the catalyst with appropriate ratio (20.0%) behaves the optimum catalytic performances. Therefore, the current CoNi based ordered mesoporous materials promise potential catalysts for CO₂ methanation.     

PVP-stabilized Co–Ni nanoparticles as magnetically recyclable catalysts for hydrogen production from methanolysis of ammonia borane

Hydrogen production by hydrolysis of ammonia borane has been studied extensively, but the methanolysis has been progressing slowly, especially with non-noble metals as low cost catalyst, which is limited by complicated preparation methods or not conducive to actual application. Herein, a series of magnetically recyclable bimetallic Co–Ni nanoparticles were produced by a facile solution-phase reduction technique, using polyvinylpyrrolidone (PVP) as the stabilizing agent. The as-prepared Co–Ni alloys were amorphous and highly dispersed. Among six different PVP-stabilized Co_1-xNi_x nanoparticles (x = 0, 0.1, 0.3, 0.5, 0.7, 1) studied, the PVP-stabilized Co_0.7Ni_0.3 nanoparticles show the best catalytic performance with a TOF value of 35.3 mol_H2/(mol_catalyst·min) for hydrogen production from methanolysis of ammonia borane at 298 K, showing good synergistic effect between Co and Ni. Moreover, the catalyst can remain 91.2% initial catalytic activity after eight cycles, showing excellent stability and magnetic recyclability.     

The study of bimetallic Ni–Co/cordierite catalyst for cracking of tar from biomass pyrolysis

In order to crack the tar from biomass pyrolysis, five cordierite-supported monolithic catalysts with different Ni/Co ratio were prepared by vacuum wetness impregnation. All catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), Brunauer–Emmett–Teller (BET), and scanning electron microscope (SEM). XRD and XPS characterization results show the inexistence of spinel structure such as NiAl₂O₄ and CoAl₂O₄. TPR characterization results suggest the possible formation of Ni–Co alloy. BET characterization results show that the effect of Ni/Co ratio on catalyst specific surface area is obvious. The catalytic test results show that the performance of bimetallic catalyst is better than that of monometallic catalyst. The Ni₃Co₁/cordierite catalyst exhibits the best catalytic performance among all bimetallic catalysts, its tar conversion and gas yield reach 96.4% and 1.21 Nm³/kg, respectively, at a weight hourly space velocity (WHSV) of 1.4 h⁻¹.     

The effects of bimetallic Co–Ru nanoparticles on Co/RuO2/Al2O3 catalysts for the water gas shift and methanation

The effects of Co on RuO₂/Al₂O₃'s activities for water gas shift (WGS) and methanation were studied. Catalysts were characterized with BET, XRD, SEM/EDS, H₂-TPR and CO-TPR. The effects of various parameters, such as calcination temperature, Ru–Co loading, Ru/Co ratio, inlet CO concentration and H₂O/CO ratio on the activities of catalysts were investigated. There existed Co_I (strongly interact with RuO₂) and Co_II (weakly interact with RuO₂). For Co/RuO₂/Al₂O₃ (Ru/Co = 1, AT = 350), only Co_I existed as bimetallic Co–Ru nanoparticles. This unique structure led this catalyst to achieve the highest CO conversion of 98.6% exceeding WGS's theoretical thermodynamic equilibrium limit due to the co-occurrence of methanation. Co/RuO₂/Al₂O₃ was more favorable to catalyze CO methanation than CO₂ methanation. The apparent activation energies of forward and reverse WGS catalyzed by Co/RuO₂/Al₂O₃ were 37.8 and 74.6 kJ mol⁻¹, respectively. The difference was corresponding well to the enthalpy change (−41.1 kJ mol⁻¹) of WGS.     

Green synthesis of MCM-41 derived from renewable biomass and construction of VOx-Modified nickel phyllosilicate catalyst for CO2 methanation

In order to achieve green synthesis of MCM-41 and address the sintering problem of Ni-based catalyst supported on silica material, MCM-41 with regular spherical morphology was prepared using sodium silicate extracted from renewable equisetum fluviatile as silicon source, and then a group of nickel phyllosilicates were synthesized via the reaction of MCM-41 sphere and nickel nitrate under hydrothermal condition. Much denser nanosheets corresponding to lamellar nickel phyllosilicate were formed on the surface of MCM-41 sphere with the raise of hydrothermal temperature in the range of 180–220 °C, resulting in the nickel content varying from 17.2 to 41.8 wt%. Fine Ni particles with size smaller than 6 nm could be obtained on the 750^oC-reduced catalyst owing to the strong nickel-silica interaction derived from Ni-phyllosilicate. After the addition of V₂O₅ promoter, Ni particle size was further reduced to around 4.5 nm at high Ni loading above 30 wt%. Vanadium species was in the mixed valence state of V(III), V(IV) and V(V) after reduction, which increased the electron cloud density of Ni⁰, resulting in high catalytic activity of the VO_x-modified Ni-phyllosilicate catalyst for CO₂ methanation. In a 100 h-400^oC-lifetime test and 600 °C-steam hydrothermal treatment, the VO_x-modified Ni-phyllosilicate catalyst also showed high long-term stability, excellent sintering resistance of metallic nickel particles and high hydrothermal stability due to the strong surface confinement effect of nickel phyllosilicate and promotion of VO_x species. In all, this work provided a green synthesis of MCM-41 as well as an efficient Ni/SiO₂ catalyst derived from nickel phyllosilicate for CO₂ methanation.     

Solid-state synthesis method for the preparation of cobalt doped Ni–Al2O3 mesoporous catalysts for CO2 methanation

In this study, a simple solid-state synthesis method was employed for the preparation of the Ni–Co–Al₂O₃ catalysts with various Co loadings, and the prepared catalysts were used in CO₂ methanation reaction. The results demonstrated that the incorporation of cobalt in nickel-based catalysts enhanced the activity of the catalyst. The results showed that the 15 wt%Ni-12.5 wt%Co–Al₂O₃ sample with a specific surface area of 129.96 m²/g possessed the highest catalytic performance in CO₂ methanation (76.2% CO₂ conversion and 96.39% CH₄ selectivity at 400 °C) and this catalyst presented high stability over 10 h time-on-stream. Also, CO methanation was investigated and the results showed a complete CO conversion at 300 °C.     

Improved low-temperature activity of Ni–Ce/γ-Al2O3 catalyst with layer structural precursor prepared by cold plasma for CO2 methanation

Ni–Ce/γ-Al₂O₃ catalyst (Ni–Ce-LDH-P) derived from LDHs was synthesized on γ-Al₂O₃. Plasma technology was employed to its preparation process. Impregnation method and thermal calcination and reduction technology were used to prepare reference catalysts (Ni–Ce-LDH-C, Ni–Ce-P and Ni–Ce-C). CO₂ methanation was chosen as the probe reaction. XRD, BET, SEM, TEM and CO₂-TPD were used to characterize the microstructure and properties of catalyst. Experimental results showed that Ni–Ce-LDH-P catalyst with smaller Ni size, better Ni dispersion and higher alkalinity exhibited outstanding low-temperature activity at range of 200–350 °C. Characterization results showed that the precursor of Ni–Ce-LDH-P catalyst presented in lamellar shape, inferring the formation of chemical bonds among Ni, Ce and Al (from γ-Al₂O₃). It is the chemical bonds that improved the dispersion of Ni crystal and the interaction between Ni and γ-Al₂O₃. Meanwhile, the plasma technology with relatively low temperature prevented the sintering and agglomeration of Ni during the preparation process. Therefore, the excellent performance of Ni–Ce-LDH-P catalyst should be ascribed to the synergy of the unique lamellar structure and the special characteristics of “high energy at relatively low temperature” of plasma technology.     

Methanation of CO2 over alumina supported nickel or cobalt catalysts: Effects of the coordination between metal and support on formation of the reaction intermediates

This study focused on the potential coordination between nickel or cobalt and alumina in Ni/Al₂O₃ and Co/Al₂O₃ catalysts and the impacts on their catalytic performances in methanation of CO₂. The results exhibited that Co/Al₂O₃ catalyst was far more active than Ni/Al₂O₃ catalyst, due to the varied reaction intermediates formed in methanation. The DRIFTS results of methanation of CO₂ exhibited that, over bare alumina, bicarbonate, formate and carbonate were the main intermediate species, which could be formed at even 80 °C. Over unsupported Ni catalyst, the formaldehyde species (H₂CO*) and CO* species were dominated. Over the Ni/Al₂O₃ catalyst, however, the reaction intermediates formed were determined by alumina and accumulated on surface of the catalysts. The coordination effects between nickel and alumina in Ni/Al₂O₃ were thus not remarkable in terms of enhancing catalytic activity when compared to that in Co/Al₂O₃ catalyst. Over unsupported Co catalyst and the bare alumina, the reaction intermediates formed were roughly similar. Nevertheless, the combination of Co and alumina in Co/Al₂O₃ catalyst could effectively facilitate the conversion of bicarbonate, formate and carbonate species. CO₂ could be activated over metallic cobalt sites, which could migrate and integrate with the hydroxyl group in alumina to form bicarbonate and further to formate and CO* species, and be further hydrogenated over cobalt sites to CH₄. Such a coordination between alumina and cobalt species promoted the catalytic performances.     

Production of hydrogen via steam reforming of acetic acid over Ni and Co supported on La2O3 catalyst

Nickel (Ni)-cobalt (Co) supported on lanthanum (III) oxide (La₂O₃) catalyst was prepared via impregnation technique to study the steam reformation of acetic acid for hydrogen generation by using one-step fixed bed reactor. Moreover, in order to specify the physical and the chemical attributes of the catalyst, X-ray diffraction (XRD), nitrogen physisorption, temperature-programmed reduction (TPR), temperature-programmed desorption of ammonia and carbon dioxide (TPD-NH₃ and CO₂), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) methods were employed. The nitrogen physisorption analysis showed that the presence of Co on Ni/La₂O₃ improved the textural properties of the catalyst by increasing the surface area, the pore diameter and the pore volume of the catalyst. This improved the dispersion of metal particle and caused a reduction in the size of metal particle, and consequently, increased the catalytic activity, as well as the resistance to coke formation. On top of that, the condensation and the dehydration reactions during acetic acid steam reforming created carbon deposition on acidic site of the catalyst, which resulted in the deactivation of catalyst and the formation of coke. Besides, in this study, Ni/La₂O₃ contributed to a high acetic acid conversion (100%) at 700 °C, but it produced more coking compared to Ni–Co/La₂O₃ and Co/La₂O₃ catalysts.     

Oxygen evolution reaction on Ni-substituted Co3O4 nanowire array electrodes

Nanowire arrays of mixed oxides of Co and Ni freely standing on Ni foam are prepared by a template-free growth method. The effects of Ni content on the morphology, structure and catalyst performance for oxygen evolution reaction are investigated by scanning electron microscopy, X-ray diffraction spectroscopy and electrochemical techniques including cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. A transformation from nanowire arrays to nanoplate arrays is found with the increase of the atomic ratio of Ni to Co in the preparation solution. The Ni_xCo_3−xO₄ electrode obtained at 1:1 of Ni:Co in the preparation solution exhibits nanowire array structure and has better catalytic performance for oxygen evolution reaction than other Ni_xCo_3−xO₄ and Co₃O₄ electrodes. The catalytic activities of the Ni_xCo_3−xO₄ and Co₃O₄ electrodes are correlated with their surface roughness. Superior stability of the Ni_xCo_3−xO₄ nanowire array electrode is demonstrated by a chronopotentiometric test. The reaction orders with respect to OH⁻ on the Ni_xCo_3−xO₄ electrode are close to 2 and 1 at low and high overpotentials, respectively.     

Electrochemical evaluation of mixed ionic electronic perovskite cathode LaNi1-xCoxO3-δ for IT-SOFC synthesized by high temperature decomposition

The cobalt doped perovskite cathode material LaNi_1-xCo_xO_3-δ (x = 0.4, 0.6, 0.8) synthesized by cost effective high temperature decomposition is investigated as mixed ionic electronic conductor (MIEC) for intermediate temperature solid oxide fuel cell (IT-SOFC). LaNiO₃ is known for its high electronic conductivity and to introduce more oxygen vacancies for enhancing its ionic conductivity, Ni at B site is substituted by Co. XRD analysis showed perovskite structure for all samples with no additional phases, which was also confirmed by FTIR results. Microstructure analysis revealed well connected and porous structure for LaNi_1-xCo_xO_3-δ (x = 0.6) compared to other compositions. The elemental analysis using EDX confirmed presence of lanthanum, nickel, and cobalt within all samples. No prominent weight loss was observed during TGA analysis. The highest value of conductivity was obtained for LaNi_1-xCo_xO_3-δ (x = 0.6) due to its porous and networked structure of sub micrometric grains. The superior performance is attained for the cell based on LaNi_1-xCo_xO_3-δ (x = 0.6) cathode with maximum power density of 0.45 Wcm^?2 compared to other composition which can be attributed to its well connected and porous structure that caused enhanced electrochemical reaction at triple phase boundary (TPB). It was therefore deduced that LaNi_1-xCo_xO_3-δ (x = 0.6) is promising composition to be used as MIEC cathode for IT-SOFC.     

Investigation of Ba doping in A-site deficient perovskite Ni-exsolved catalysts for biogas dry reforming

This work presents the development of an A-site deficient La_0.9−xBa_xAl_0.85Ni_0.15O₃ (x = 0, 0.02, 0.04, and 0.06) perovskite oxide catalyst for dry reforming of model biogas. The catalysts are prepared using a citrate sol-gel method and used for biogas dry reforming at 800 °C for feed ratios (CH₄/CO₂) of 1.5 and 2.0. The fresh and spent catalysts are analyzed using XRD, FTIR, TPD, XPS, FESEM, TEM, TPR, TGA-DTA, and Raman analysis. The XRD analysis exhibits the host perovskite oxide structure and the exsolved Ni phase for all prepared catalysts. The partial doping of Ba improves the metal support interaction and oxygen vacancies that enhance catalytic activity and stability, as revealed by the TPR and XPS analysis. The stability experiment on La_0.9−xBa_xAl_0.85Ni_0.15O₃, for x = 0 catalyst resulted in reduced activity due to the catalyst deactivation by sintering, as confirmed by XRD and FE-SEM. Among all the catalysts studied, La_0.84Ba_0.06Al_0.85Ni_0.15O₃ (LB6AN-15) exhibited the highest catalytic stability with CH₄, and CO₂ conversions are 60% and 93%, respectively, for 40 h time-on-stream due to the strong metal support interactions, high oxygen vacancies, and anti-sintering of exsolved Ni nanoparticles in biogas dry reforming.     

Effect of Zn substitution to a LaNiO3−δ perovskite structured catalyst in ethanol steam reforming

A LaNi_1?xZn_xO_3?δ perovskite structured oxide catalyst is prepared with a one-step citrate complex method and applied as the precursor of the catalyst in ethanol steam reforming (ESR) reaction. The Zn substitution makes the perovskite-oxide difficult to be reduced due to the strong bond of La–O–Zn, which favors the formation of small Ni particle size thus moderates the sintering of nickel. The doping of Zn also effectively suppresses coking in the reaction. The spillover of oxygen and the electron donation effect of Zn species to the surface of metallic nickel is confirmed with an XPS technique. The doping amount shows an optimum value and a LaNi_0.85Zn_0.15O_3?δ sample exhibits the highest H₂ product yield and best stability at 700 °C.