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Summary: Catalytic steam reforming of ethanol is considered as a promising technology for producing H2 in the modern world. In this study, using a fixed‐bed reactor, steam reforming of ethanol was performed for production of carbon nanotubes (CNTs) and H2 simultaneously at 600°C on Ni/CaO catalysts. Commercial CaO and a synthetic CaO prepared using sol‐gel were scrutinized for ethanol's catalytic steam reforming. Analysis results of N2 isothermal adsorption indicate that the CaO synthesized by sol‐gel has more pore volume and surface area in comparison with the commercial CaO. When Ni was loaded, the Ni/CaO catalyst shows an encouraging catalytic property for H2 production, and an increase in Ni loading could improve H2 production. The Ni/CaO catalyst with sol‐gel CaO support has presented a higher hydrogen production and better catalytic stability than the catalysts with the commercial CaO support at low Ni loading. The highest hydrogen yield is 76.8% at Ni loading content of 10% for the Ni/sol‐gel CaO catalyst with WHSV of 3.32/h and S/C ratio of 3. The carbon formed after steam reforming primarily consists of filamentous carbons and amorphous carbons, and CNTs are the predominant type of carbon deposition. The deposited extent of carbon on the used Ni/CaO catalyst lessen upon more Ni loading, and the elongated CNTs are desired to be formed at the surface of the Ni/sol‐gel CaO catalyst. Thus, an efficient process and improved economic value is associated with prompt hydrogen production and CNTs from ethanol steam reforming. [ABSTRACT FROM AUTHOR]

Catalytic steam reforming for producing high quality syngas from biomass fuel gas was studied over monolithic NiO/porous ceramic catalysts in a fixed-bed reactor. Effects of reaction temperature, steam to carbon (S/C) ratio, and nickel loading content on catalyst performance were investigated. Results indicated that the NiO/porous ceramic monolith catalyst had a good ability to improve bio-fuel gas quality. H 2 yield, H 2 + CO content, and H 2 /CO ratio in produced gas were increased when reaction temperature was increased from 550 to 700 °C. H 2 yield was increased from 28.1% to 40.2% with S/C ratio increased from 1 to 2. And the yield of hydrogen was stabilized with the further increase of S/C ratio. Catalyst activity was not always enhanced with increased nickel content, when NiO loading content reaches 5.96%, serious aggregation and sintering of active composition on catalyst surface occur. The best performance, in terms of H 2 yield, is obtained with 2.50% NiO content at reaction temperature of 700 °C and S/C ratio of 2. [ABSTRACT FROM AUTHOR]

To explore the mechanism of the influence of Ni-Fe bimetallic catalyst for the producing high-value carbon nanotubes (CNTs) with clean hydrogen from waste plastic pyrolysis, the pyrolysis-catalysis of plastics were performed using a two stage fixed bed reaction system with Ni and Fe loading at variant molar ratios. The catalysts and produced carbon were analysed with various characterization method, including temperature-programed reduction/oxidation, X-ray diffraction, scanning electron microscopy or/and Raman spectroscopy. Both the H 2 concentration and H 2 yield reached maximum values of 73.93 vol.% and 84.72 mg g −1 plastic, respectively, as the ratio of Ni:Fe at 1:3. The amount and quality of CNTs were greatly influenced by the catalyst composition, and Ni and Fe display different roles to the overall reactivity of Ni-Fe catalyst for the pyrolysis-catalysis of waste plastics. Catalyst with more Fe loading produced more hydrogen and deposited carbon, due to higher cracking ability and the relatively lower interaction between active sites and support. The presence of Ni in Ni-Fe bimetallic catalyst enhanced the thermal stability and graphitization degree of produced carbons. The thermal quality of filamentous carbons might be associated with carbon defects. [ABSTRACT FROM AUTHOR]

Ni/SiO 2 catalysts prepared by a sol–gel method have been investigated for hydrogen production via steam reforming of ethanol using a continuous flow, fixed bed reactor system. Chemical equilibrium calculations were also performed to determine the effects of temperature and molar steam to carbon ratio on hydrogen production. The acidity of the preparation solution (modified by nitric acid and ammonia) and calcination atmosphere (air and N 2 ) were investigated in the preparation of the catalysts. BET surface area and porosity, temperature-programmed oxidation (TPO), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to characterise the prepared catalysts. The BET surface area was reduced when the solution acidity was lowered during the sol–gel preparation process. A pH value less than 2.0 was necessary to achieve high metal dispersion in the catalyst. Smaller NiO particles were obtained when the catalyst was calcined in N 2 . Material balances on ethanol steam reforming at 600 °C using the prepared Ni/SiO 2 catalysts were determined, and higher hydrogen production with lower coke deposition on the reacted catalysts were also obtained from the catalysts calcined in N 2 atmosphere. [ABSTRACT FROM AUTHOR]

Hydrogen production from the thermochemical conversion of biomass was carried out with nano-sized NiZnAlOx catalysts using a two-stage fixed bed reactor system. The gases derived from the pyrolysis of wood sawdust in the first stage were catalytically steam reformed in the second stage. The NiZnAlOx catalysts were synthesized by a co-precipitation method with different Ni molar fractions (5, 10, 15, 25 and 35%) and a constant Zn:Al molar ratio of 1:4. The catalysts were characterized by a wide range of techniques, including N 2 adsorption, SEM, XRD, TEM and temperature-programmed oxidation (TPO) and reduction (TPR). Fine metal particles of size around 10–11 nm were obtained and the catalysts had high stability characteristics, which improved the dispersion of active centers during the reaction and promoted the performance of the catalysts. The yield of gas was increased from 49.3 to 74.8 wt.%, and the volumetric concentration of hydrogen was increased from 34.7 to 48.1 vol.%, when the amount of Ni loading was increased from 5 to 35%. Meanwhile, the CH 4 fraction decreased from 10.2 to 0.2 vol.% and the C 2 –C 4 fraction was reduced from 2.4 vol.% to 0.0 vol.%. During the reaction, the crystal size of all catalysts was successfully maintained at around 10–11 nm with lowered catalyst coke formation, (particularly for the 35NiZn4Al catalyst where negligible coke was found) and additionally no obvious catalyst sintering was detected. The efficient production of hydrogen from the thermochemical conversion of renewable biomass indicates that it is a promising sustainable route to generate hydrogen from biomass using the NiZnAl metal oxide catalyst prepared in this work via a two-stage reaction system. [ABSTRACT FROM AUTHOR]

Hydrogen production from the catalytic steam gasification of bio-char derived from the pyrolysis of sugar cane bagasse has been investigated in relation to gasification temperature up to 1050 °C, steam flow rate from 6 to 25 ml h −1 and type of Nickel catalyst. The catalysts used were Ni-dolomite, Ni–MgO and Ni–Al 2 O 3 , all with 10% nickel loading. The hydrogen yield in the absence of a catalyst at a gasification temperature of 950 °C was 100.97 mmol g −1 of bagasse char. However, the presence of the Ni–MgO and Ni–Al 2 O 3 catalysts produced significantly improved hydrogen yields of 178.75 and 187.25 mmol g −1 of bagasse char respectively at 950 °C. The hydrogen yield from the char with the Ni-dolomite only showed a modest increase in hydrogen yield. The influence of gasification temperature showed that the optimum temperature to obtain the highest hydrogen yield was 950 °C. Increase in gasification temperature from 750 to 950 °C significantly increased hydrogen yield from 45.30 to 187.25 mmol g −1 of bagasse char at 950 °C, but was followed by a decrease in yield at 1050 °C. The influence of steam flow rate showed that with the increase in steam flow rate from 6 to 15 ml h −1 hydrogen yield was increased from 187.25 to 208.41 mmol g −1 of bagasse char. Further increase in steam flow rate resulted in a decrease in hydrogen yield. [ABSTRACT FROM AUTHOR]

The production of hydrogen-enriched syngas from the thermo-chemical conversion of biomass was studied using Ni/CaAlO x catalysts prepared by co-precipitation method. The effect of Ca addition with different molar ratios of Ca:Al (1:3, 1:2, 1:1, 2:1, 3:1) on the properties and catalytic behavior in relation to syngas production and the coke formation on the surface of the catalysts were investigated. Catalysts were characterized by BET, XRD, TPR, SEM, and TEM. The SEM and TEM results showed that rod-shaped nano-particles were highly dispersed on the surface of the catalyst. The particle size of NiO was slightly affected with the increase of Ca content in the catalyst. It appeared that the selectivity of CO was increased and the selectivity of CO 2 was reduced with the increase of Ca addition to the catalyst. For example, CO 2 concentration was reduced from 20 to 12 vol.%, when the molar ratio of Ca/Al was increased from 1:3 to 3:1 for the Ni/CaAlO x catalyst; it is suggested that the water gas shift reaction was inhibited and CO 2 reforming reactions were promoted in the presence of the catalyst with higher Ca content. The CO/H 2 molar ratio could be manipulated by changing the Ca content in the catalyst, while the H 2 concentration remained almost constant (around 45 vol.%). Thus, using the Ni/CaAlO x catalyst developed in this work could provide a promising route to control the syngas composition, which is an important factor for syngas applications. [ABSTRACT FROM AUTHOR]

This paper investigates the co-production of hydrogen and carbon nanotubes from the pyrolysis–catalytic gasification of waste plastics (polypropylene). We report on the influence of a range of metal additions to a nickel based catalyst based on ternary mixed oxide types Ni–Metal–Al, where the metal was Zn, Mg, Ca, Ce or Mn. The results showed that of the different metal–nickel catalysts investigated, the Ni–Mn–Al catalyst was the most promising catalyst in relation to the co-production of hydrogen and CNT. For example, the Ni–Mn–Al catalyst produced 71.4 mmol hydrogen g − 1 plastic, while the hydrogen production using Ni–Ca–Al, Ni–Ce–Al and Ni–Zn–Al catalysts were 68.5 mmol g − 1 , 63.1 mmol g − 1 and 45.9 mmol hydrogen g − 1 plastic respectively. In addition, carbon deposition on the catalyst was highest in the order of: Ni–Mn–Al > Ni–Ca–Al > Ni–Zn–Al > Ni–Ce–Al > Ni–Mg–Al. The carbon deposition for the Ni–Mn–Al catalyst was found to consist of mostly carbon nanotubes. Further investigation of the Ni–Mn–Al catalyst demonstrated that the interaction between Ni and catalyst support plays a significant role in the gasification process; weak metal support interaction (for the Ni–Mn–Al catalyst calcined at 300 °C) resulted in a lower hydrogen production and much higher yield of carbon products. In addition, the influence of steam injection rate on hydrogen and carbon nanotube production was investigated for the Ni–Mn–Al catalyst. Increasing the steam injection rate significantly increased hydrogen production and decreased carbon deposition. However, at lower steam injection rates, the quality of the product carbon nanotubes was improved. [ABSTRACT FROM AUTHOR]

Hydrogen production from renewable resources has received extensive attention recently for a sustainable and renewable future. In this study, hydrogen was produced from catalytic steam reforming of the aqueous fraction of crude bio-oil, which was obtained from pyrolysis of biomass. Five Ni–Al catalysts modified with Ca, Ce, Mg, Mn and Zn were investigated using a fixed-bed reactor. Optimized process conditions were obtained with a steam reforming temperature of 800 °C and a steam to carbon ratio of 3.54. The life time of the catalysts in terms of stability of hydrogen production and prohibition of coke formation on the surface of the catalyst were carried out with continuous feeding of raw materials for 4 h. The results showed that the Ni–Mg–Al catalyst exhibited the highest stability of hydrogen production (56.46%) among the studied catalysts. In addition, the life-time test of catalytic experiments showed that all the catalysts suffered deactivation at the beginning of the experiment (reduction of hydrogen production), except for the Ni–Mg–Al catalyst; it is suggested that the observation of abundant amorphous carbon formed on the surface of reacted catalysts (temperature programmed oxidation results) may be responsible for the initial reduction of hydrogen production. In addition, the Ni–Ca–Al catalyst showed the lowest hydrogen production (46.58%) at both the early and stabilized stage of catalytic steam reforming of bio-oil. [ABSTRACT FROM AUTHOR]

Hydrogen production from the pyrolysis/reforming of refuse derived fuel (RDF) was investigated with a series of Ni/SiO2 catalysts. The catalysts were prepared by homogeneous precipitation derived from a sol–gel method (HPG) and compared to Ni/SiO2 catalysts prepared by adding a phase separation step to the HPG process (B-HPG). All the catalysts had a NiO loading of 10 wt.%, and three different calcination temperatures (500 °C, 700 °C and 900 °C) were used for each method. The prepared Ni/SiO2 catalysts were analysed to determine their surface area, and porosity characteristics; additionally scanning electron microscopy (SEM-EDX), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), and X-Ray diffraction (XRD) analyses were carried out. The results showed that the catalyst prepared by HPG and calcined at 700 °C (HPG700), presented a relatively high surface area (∼347 m2 g−1), large pore diameter (12.50 nm), and also resulted in the highest catalytic activity towards H2 production, attaining ∼60 vol.% hydrogen. The lowest hydrogen concentration of about 42 vol.% was obtained using the catalysts prepared by the combined HPG-phase separation method, and calcined at 900 °C (B-HPG900). It was also observed that at calcination temperatures higher than 700 °C the catalytic activity for hydrogen production was diminished for both preparation methods. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two-stage pyrolysis-gasification of plastics can produce H2 and carbon nanotubes. [•] Carbon nanotube quality or H2 yield can be optimised by control of steam content. [•] Therefore, wastes can be processed for environmental and economic benefit. [Copyright &y& Elsevier]

Abstract: Catalytic steam reforming of liquid hydrocarbons is one of the promising alternatives for hydrogen production. However, coke deposition on the reacted catalyst results in catalyst deactivation and also CO2 emission during reforming are among the main challenges in the process. In this work, the production of high-value carbon nanotubes (CNTs) during hydrogen production from catalytic reforming of toluene has been investigated. Thus, less carbon emission and higher product values can be expected from the process. A two-stage fixed bed pyrolysis-reforming reactor was used in this work. The results showed that the addition of a Ni–Mg–Al catalyst, with an additional downstream stainless steel mesh, increased hydrogen production from 24.8 to 54.8 (mmol H2 g−1 toluene), when water (steam) was injected at a rate of 0.01 g min−1. CNTs were also produced in the process in the presence of the Ni–Mg–Al catalyst and with a water injection rate of 0.01 g min−1 had the highest band ratio of G′/G when analyzed by Raman spectrometry, indicating the highest purity of CNTs. In addition, Raman spectra of the generated CNTs showed that the purity of CNTs was reduced with the addition of water for reforming without the Ni–Mg–Al catalyst. The presence of the Ni–Mg–Al catalyst significantly increased the yield of CNTs formed on the surface of the stainless steel mesh and also improved the quality of the CNTs in relation to the distribution of diameters and their length. [Copyright &y& Elsevier]

Abstract: A series of Ni/SiO2 catalysts have been prepared and investigated for their suitability for hydrogen production and tar reduction in a two-stage pyrolysis-reforming system, using refuse derived fuel (RDF) as the raw material. Experiments were conducted at a pyrolysis temperature of 600°C, and a reforming temperature of 800°C. The product gases were analysed by gas chromatography (GC) and the condensed fraction was collected and quantified using gas chromatography-mass spectrometry (GC–MS). The effects of the catalyst preparation method, nickel content and the addition of metal promoters (Ce, Mg, Al), were investigated. Catalysts were characterised using BET surface area analysis, temperature programmed oxidation (TPO), and scanning electron microscopy (SEM). The TPO and SEM analysis of the reacted catalysts showed that amorphous type carbons tended to be deposited over the Ni/SiO2 catalysts prepared by impregnation, while filamentous type carbons were favoured with the sol-gel prepared catalysts. The influence of catalyst promoters (Ce, Mg, Al) added to the Ni/SiO2 catalyst prepared by the sol-gel method was found not to be significant, as the H2 production was not increased and the tar formation was not reduced with the metal-added catalyst. The highest H2 concentration of 57.9vol.% and lower tar amount produced of 0.24mgtar/gRDF; were obtained using the 20wt.% Ni/SiO2 catalyst prepared by sol-gel. On the other hand a low catalytic activity for H2 production and higher tar produced were found for the impregnated series of catalysts, which might be due to the smaller surface area, pore size and due to the formation of amorphous carbons on the catalyst surface. Alkenes and alcohol functional groups were mainly found in the analysed tar samples, with major concentrations of styrene, phenol, indene, cresols, naphthalene, fluorene, and phenanthrene. [Copyright &y& Elsevier]

Abstract: Cellulose, hemicellulose and lignin are the main components of biomass. This work presents research into the pyrolysis/gasification of all three main components of biomass, in order to evaluate and compare their hydrogen production and also understand their gasification processes. A fixed bed, two-stage reaction system has been used employing various nickel-based catalysts. Gas concentration (CO, H2, CO, CO2 and CH4) was analysed for the produced non-condensed gases. Oil byproducts were analysed by gas chromatography/mass spectrometry (GC/MS). Various techniques such as X-Ray Diffraction (XRD), scanning electron microscopy (SEM) coupled to an energy dispersive X-ray spectroscopy (EDXS), temperature-programmed oxidation (TPO) were applied to characterize the fresh or reacted catalysts. The experimental results show that the lignin sample generates the highest residue fraction (52.0wt.%) among the three biomass components. When Niph name="sbnd" />Al (1:1) catalyst was used in the gasification process, gas yield was increased from 62.4 to 68.2wt.% for cellulose, and from 25.2 to 50.0wt.% for the pyrolysis/gasification of lignin. Hydrogen production was increased from 7.0 to 18.7 (mmolg−1 sample) when the Niph name="sbnd" />Al (1:1) catalyst was introduced in the pyrolysis/gasification of cellulose. Among the investigated catalysts, Niph name="sbnd" />Al (1:1) was found to be the most effective for hydrogen production from cellulose pyrolysis/gasification. [Copyright &y& Elsevier]

Abstract: Hydrogen and syngas production have been investigated from the pyrolysis/gasification of biomass components (cellulose, xylan and lignin) in the presence of Ni-based catalysts by using a two-stage fixed-bed reaction system. Biomass samples were pyrolysed at the first stage and the derived products were gasified at the second stage. The Ni–Mg–Al and Ni–Ca–Al catalysts, prepared by co-precipitation, were applied in the gasification process. The lignin sample pyrolysed with more difficulty (56.0wt.% of residue fraction) compared with cellulose and xylan at 500°C, and therefore resulted in the lowest gas yield (42.7wt.%) for the pyrolysis/gasification of lignin. However, the highest H2 concentration from the three types of feedstock (55.1vol.%) was collected for the lignin sample in the presence of steam and catalyst. Carbon deposition was very low as indicated from the TPO and SEM analyses of the reacted Ni–Mg–Al catalyst. The investigation of reaction conditions showed that water injection rate (0.02 and 0.05gmin−1) had little influence on the gas production from the pyrolysis/gasification of lignin in the presence of the Ni–Ca–Al catalyst; however, the increase of gasification temperature from 700 to 900°C resulted in a higher gas and hydrogen production due to the promotion of secondary reactions during the gasification process. Furthermore, coking was highest for the reacted Ni–Ca–Al catalyst at the gasification temperature of 800°C (7.27wt.%), when the temperature was increased from 700 to 900°C. This work shows that the components of biomass have a significant influence on the catalytic gasification process related to hydrogen and syngas production. [Copyright &y& Elsevier]

Abstract: A two-stage continuous screw-kiln reactor was investigated for the production of synthesis gas (syngas) from the pyrolysis of biomass in the form of waste wood and subsequent catalytic steam reforming of the pyrolysis oils and gases. Four nickel based catalysts; NiO/Al2O3, NiO/CeO2/Al2O3, NiO/SiO2 (prepared by an incipient wetness method) and another NiO/SiO2 (prepared by a sol–gel method), were synthesized and used in the catalytic steam reforming process. Pyrolysis of the biomass at a rapid heating rate of approximately 40°C/s, was carried out at a pyrolysis temperature of 500°C and the second stage reforming of the evolved pyrolysis gases was carried out with a catalytic bed kept at a temperature of 760°C. Gases were analysed using gas chromatography while the fresh and reacted catalyst was analysed by scanning electron microscopy, thermogravimetric analysis, transmission electron microscopy with energy dispersive X-ray and X-ray photoelectron spectroscopy. The reactor design was shown to be effective for the pyrolysis and catalytic steam reforming of biomass with a maximum syngas yield of 54.0wt.% produced when the sol–gel prepared NiO/SiO2 catalyst was used, which had the highest surface area of 765m2 g−1. The maximum H2 production of 44.4vol.% was obtained when the NiO/Al2O3 catalyst was used. [Copyright &y& Elsevier]

Abstract: The steam pyrolysis-gasification of biomass, wood sawdust, was carried out with a Ni/MCM-41 catalyst for hydrogen production in a two-stage fixed bed reaction system. The wood sawdust was pyrolysed in the first reactor and the derived products were gasified in the second reactor. The synthesised MCM-41 mesoporous catalyst supports were impregnated with different Ni loadings (5, 10, 20 and 40wt.%), which were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed reduction (TPR), transmission electron microscopy (TEM) and temperature-programmed oxidation (TPO). NiO particles were homogeneously dispersed inside the pores of 5, 10, and 20wt.% Ni/MCM-41 catalysts; however, more bulkly NiO particles (up to 200nm particle size) were detected outside the pores with an increase of the Ni loading up to 40wt.%. Gas production was increased from 40.7 to 62.8wt.%, hydrogen production was increased from 30.1 to 50.6vol.% of total gas composition when the Ni loading was increased from 5 to 40wt.% during the pyrolysis-gasification of wood sawdust. This work showed low coke deposition (from 0.5 to 4.0wt.%) with valuable bio-oil by-products using the Ni/MCM-41 catalyst. The highly efficient conversion of renewable biomass resource to hydrogen and bio-oil with very low coke deposition indicates that biomass gasification on Ni/MCM-41 catalysts via two-stage reaction is a promising method for the development of the biorefinery concept. [Copyright &y& Elsevier]

Abstract: Hydrogen production from the pyrolysis–gasification of waste tyres has been investigated with a Ni/CeO2/Al2O3 catalyst using a two-stage fixed bed reaction system. The conditions of catalyst preparation such as Ni and CeO2 content and calcination temperature were investigated in relation to product yield and composition. The fresh and reacted catalysts were analysed using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results showed that there were small changes in the gas and hydrogen yield by adding 5 wt.% of CeO2 into the Ni/CeO2/Al2O3 catalyst. The gas yield related to the mass of waste tyre and the amount of reacted water were increased with the increase of CeO2 content from 5 to 15 wt.%. However, with the further increase of CeO2 content to 30 wt.%, the gas yield related to the mass of tyre and the amount of reacted water was reduced. Increasing the Ni content of the catalyst showed a positive influence on the gas yield and hydrogen production. The investigation of the calcination temperature of the Ni/CeO2/Al2O3 catalyst showed that the oil yield related to the mass of tyre and reacted water decreased from 28.4 to 23.4 wt.% for the catalyst calcined at 500 °C, and decreased from 24.2 to 17.7 wt.% for the catalyst calcined at 750 °C. When the Ni content of the catalyst was increased from 5 to 20 wt.%. there were only small changes in total gas and hydrogen production from the pyrolysis–gasification of waste tyre. Lower coke deposition on the reacted catalyst was obtained for the Ni/CeO2/Al2O3 catalyst prepared at the calcination temperature of 750 °C compared with the 500 °C calcination temperature. [Copyright &y& Elsevier]

Abstract: Steam reforming of ethanol to produce hydrogen was carried out using a two-stage reaction system with several nano-Ni/SiO2 catalysts prepared at different citric acid (CA) contents using the sol–gel process. The fresh (non-calcined and calcined) catalysts and the reacted catalysts were analysed using surface area and pore size analysis, Fourier-transform infrared (FTIR) spectroscopy, thermo-gravimetry analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that a meso-structured material was produced at Ni:CA ratios lower than 1:0.5; and the pore volume of the catalyst was increased when more citric acid was used during the sol–gel preparation. Gas and hydrogen yield were observed to be increased when the Ni:CA ratio was reduced from 1:0.5 to 1:3.0; however, gas concentration was slightly changed for the catalysts prepared at different Ni:CA ratios. In addition, coke formation was increased from 0.7 to 7.5wt.% when the Ni:CA ratio decreased from 1:0.5 to 1:3.0. It was also found that the Ni/SiO2 catalyst prepared at the low CA content (Ni:CA=0.5) was non-stable during the ethanol steam reforming process; since sintering was obtained as observed using TEM analysis of the used catalyst. [ABSTRACT FROM AUTHOR]

Abstract: A novel Ni–Mg–Al–CaO catalyst/sorbent has been prepared by integration of the catalytic and CO2 absorbing properties of the material to maximise the production of hydrogen. The prepared catalyst was tested for hydrogen production from the pyrolysis–gasification of polypropylene by using a two-stage fixed-bed reaction system. X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM)-energy dispersive X-ray spectrometry (EDXS) were used to characterize the prepared Ni–Mg–Al–CaO catalyst/sorbent. Ni–Mg–Al–CaO and calcined dolomite showed a stable carbonation conversion after several cycles of carbonation/calcination, while CaO showed a certain degree of decay. The calcined dolomite showed low efficiency for hydrogen production from pyrolysis–gasification of polypropylene. Increasing the gasification temperature resulted in a decrease of H2/CO ratio for the Ni–Mg–Al catalyst mixed with sand; however, a stable H2/CO ratio (around 3.0) was obtained for the Ni–Mg–Al–CaO catalyst. An increased Ni–Mg–Al–CaO catalyst/polypropylene ratio promoted the production of hydrogen from the pyrolysis–gasification of polypropylene. Approximately 70wt.% of the potential H2 production was obtained, when the Ni–Mg–Al–CaO catalyst/polypropylene ratio and gasification temperature were 5 and 800°C, respectively. [Copyright &y& Elsevier]

Abstract: Co-precipitated Ni-Mg-Al catalyst was prepared and investigated in relation to the production of hydrogen from the catalytic steam pyrolysis-gasification of polypropylene using a two-stage reaction system. Coke formation on the Ni-Mg-Al catalyst was investigated by using temperature-programmed oxidation (TPO), X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM) and focused ion beam (FIB)/scanning electron microscopy (SEM). The coke formation mechanism on the Ni-Mg-Al catalyst is proposed. It is suggested that the Ni-Mg-Al catalyst is initially reduced during the gasification process, the reactions of decomposition/reforming of hydrocarbons gases occur on the surface and inside the catalyst; this resulted in partial fragmentation of the catalyst into small particles. Layered carbons, perhaps containing monoatomic carbon, metal carbides, etc., are suggested to be a transition layer for the formation of filamentous carbons. The addition of Mg into the Ni-Al catalyst was found to increase the catalytic activity and the physical stability of catalyst. In addition, increasing the calcination temperature from 750 to 850°C reduced the surface area of the fresh Ni-Mg-Al catalyst, increased the NiO crystal size, and resulted in a decrease of catalytic activity in the pyrolysis-gasification of polypropylene; however, a more stable catalyst was obtained with higher calcination temperature. [Copyright &y& Elsevier]

Abstract: Post-consumer plastic waste derived from municipal solid waste was investigated using a two-stage, catalytic steam pyrolysis–gasification process for the production of hydrogen. The three important process parameters of catalyst:plastic ratio, gasification temperature and water injection rate were investigated. Temperature-programmed oxidation (TPO) and scanning electron microscopy (SEM) methods were used to analyse the reacted catalysts. The results showed that there was little influence of catalyst:plastic ratio between the range 0.5 and 2.0(g/g) on the mass balance and gas composition for the pyrolysis–gasification of waste plastics; this might be due to the effective catalytic activity of the Ni–Mg–Al catalyst. However, increasing the gasification temperature and the water injection rate resulted in an increase of total gas yield and hydrogen production. The coke formation on the catalyst was reduced with increasing use of catalyst; however, a maximum coke formation (9.6wt.%) was obtained at the gasification temperature of 700°C when the influence of gasification temperature was investigated. The maximum coke formation was obtained at the water injection rate of 4.74gh−1, and a more reactive form of coke seemed to be formed on the catalyst with an increase of the water injection rate, according to the TPO experiments. [Copyright &y& Elsevier]

Abstract: The production of hydrogen from the two-stage pyrolysis–gasification of polypropylene using a Ni/CeO2/ZSM-5 catalyst has been investigated. Experiments were conducted on CeO2 loading, calcination temperature and Ni loading of the Ni/CeO2/ZSM-5 catalyst in relation to hydrogen production. The results indicated that with increasing CeO2 loading from 5 to 30wt.% for the 10wt.% Ni/CeO2/ZSM-5 catalyst calcined at 750°C, hydrogen concentration in the gas product and the theoretical potential hydrogen production were decreased from 63.0 to 49.8vol.% and 50.4 to 21.6wt.%, respectively. In addition, the amount of coke deposited on the catalyst was reduced from 9.5 to 6.2wt.%. The calcination temperature had little influence on hydrogen production for the catalyst containing 5wt.% of CeO2. However, for the 10wt.% Ni/CeO2/ZSM-5 catalyst with a CeO2 content of 10 or 30wt.%, the catalytic activities reduced when the calcination temperature was increased from 500 to 750°C. The SEM results showed that large amounts of filamentous carbons were formed on the surface of the catalysts. The investigation of different Ni content indicates that the Ni/CeO2/ZSM-5 ((2-10)-5-500) catalyst containing 2wt.% Ni showed poor catalytic activity in relation to the pyrolysis–gasification of polypropylene according to the theoretical potential H2 production (7.2wt.%). Increasing the Ni loading to 5 or 10wt.% in the Ni/CeO2/ZSM-5 ((2-10)-5-500) catalyst, high potential hydrogen production was obtained. [Copyright &y& Elsevier]

Abstract: Co-precipitated nickel-based catalysts with different metallic molar ratios and calcination temperature were investigated for the production of hydrogen from the pyrolysis–gasification of polypropylene. The experiments were carried out at a pyrolysis temperature of 500°C and gasification temperature of 800°C in the presence of steam using a two-stage reaction system. The results suggest that with increasing Ni content in the Ni-Al or Ni-Mg-Al catalyst, the catalytic activity of the catalyst increased, in relation to hydrogen production. For example, the potential hydrogen production increased from 48.8 to 57.7wt.%, and the amount of water reacted increased from 1.2 to 1.3 (g water/g polypropylene), when the Ni-Al molar ratio was increased from 1:4 to 1:1. After reaction in the pyrolysis–gasification process, the non-reduced Ni-Al catalyst was reduced into metallic Ni, as observed from XRD and TGA analysis. The introduction of Mg into the Ni-Al catalyst significantly increased the amount of reacted water and improved the performance of the catalyst in relation to coke formation, although the hydrogen production was not significantly improved. For the Ni-Al or Ni-Mg-Al catalyst, a 850°C calcination temperature resulted in a lower catalytic activity compared to the lower calcination temperature of 750°C. The substitution of Cu for Mg in the Ni-Mg-Al catalyst significantly reduced the catalytic ability for hydrogen production. [Copyright &y& Elsevier]

Abstract: Several nickel-based catalysts (Ni/Al2O3, Ni/MgO, Ni/CeO2, Ni/ZSM-5, Ni-Al, Ni-Mg-Al and Ni/CeO2/Al2O3) have been prepared and investigated for their suitability for the production of hydrogen from the two-stage pyrolysis–gasification of polypropylene. Experiments were conducted at a pyrolysis temperature of 500°C and gasification temperature was kept constant at 800°C with a catalyst/polypropylene ratio of 0.5. Fresh and reacted catalysts were characterized using a variety of methods, including, thermogravimetric analysis, scanning electron microscopy with energy dispersive X-ray spectrometry and transmission electron microscopy. The results showed that Ni/Al2O3 was deactivated by two types of carbons (monoatomic carbons and filamentous carbons) with a total coke deposition of 11.2wt.% after reaction, although it showed to be an effective catalyst for the production of hydrogen with a production of 26.7wt.% of the theoretical yield of hydrogen from that available in the polypropylene. The Ni/MgO catalyst showed low catalytic activity for H2 production, which might be due to the formation of monoatomic carbons on the surface of the catalyst, blocking the access of gaseous products to the catalyst. Ni-Al (1:2) and Ni-Mg-Al (1:1:2) catalysts prepared by co-precipitation showed good catalytic abilities in terms of both H2 production and prevention of coke formation. The ZSM-5 zeolite with higher surface area was also shown to be a good support for the nickel-based catalyst, since, the Ni/ZSM-5 catalyst showed a high rate of hydrogen production (44.3wt.% of theoretical) from the pyrolysis–gasification of polypropylene. [Copyright &y& Elsevier]

In order to cope with the global energy crisis and environmental pollution problems, there are urgent needs for clean energy such as biomass-derived hydrogen. CaO is effective to promote hydrogen production from biomass gasification due to its high capacity of in-situ CO 2 capture. In this work, a two-stage fixed bed reactor was used to produce hydrogen by catalytic conversion of biomass with and without in-situ CO 2 capture. In addition, three Ni loadings (5 wt%, 10 wt%, and 20 wt%) supported by Al 2 O 3 and sol-gel CaO have been prepared and tested. The BET analysis shows the surface area of the catalysts increases first and then decreases with the increase of Ni loading. Results from high-resolution transmission electron microscopy (HRTEM) images reveals that NiO particles are well distributed over the porous CaO. The X-ray diffraction (XRD) analysis indicates the NiO nanocrystalline size is increased with increasing Ni loading on Ni/Al 2 O 3 , and the most homogeneous dispersion was shown by 10 wt% Ni/CaO. Around 666 mgCO 2 /gCaO of CO 2 adsorption capacity and 850 min stability were obtained using the sol-gel CaO sorbent. Compared to the reference Ni/Al 2 O 3 catalysts, the resistance of carbon deposition on the Ni/CaO results in a lower coke deposition, which is attributed to the basicity of the catalysts. In addition, the increase of loading promotes the decomposition of biomass-derived oxygenated compounds. Much more hydrogen is obtained using the Ni/CaO catalysts compared with Ni/Al 2 O 3 due to in-situ CO 2 capture. However, the sintering and particle agglomeration using the 20 wt% Ni-catalyst might be responsible for the reduction of hydrogen production. The highest H 2 concentration of 19.32 vol% at 424 °C was obtained when the 10 wt% Ni/CaO catalyst was used. Image 1 • Bifunctional Ni/CaO and Ni/Al 2 O 3 catalysts were studied for biomass gasification. • CNTs are main carbons on the surface of the used Ni/CaO catalyst. • Amorphous carbons are largely found on the used Ni/Al 2 O 3. • 10 wt% Ni/CaO produced the highest hydrogen yield. [ABSTRACT FROM AUTHOR]

Biomass gasification is a promising technology to produce renewable syngas used for energy and chemical applications. However, biomass gasification has challenges of low process energy efficiency, low syngas production with low H 2 /CO ratio and the sintering of biomass ash which limit the deployment of the technology. This work investigated the influence of in-situ generated heat from CaO–CO 2 on cellulose CO 2 gasification using a fixed bed reactor, thermogravimetric analysis-Fourier transform infrared spectroscopy (TGA-FTIR) and differential scanning calorimetry (DSC). Experimental results indicate an approximate 20 °C temperature difference in the fix-bed reactor between cellulose CO 2 gasification with the energy compensation of CaO carbonation (denoted auto-thermal biomass gasification) and conventional CO 2 gasification of cellulose after the power of external furnaces were turned off. Around 5 times H 2 /CO molar ratio is obtained after switching off the power in the auto-thermal biomass gasification compared with conventional gasification. The gas yield enhances significantly from 0.29 g g−1 cellulose to 0.56 g g−1 cellulose when CaO/cellulose mass ratio increases from 0 to 5. Furthermore, the TGA-FTIR results demonstrate the feasibility of adopting energy compensation of CaO carbonation to reduce the gasification temperature. DSC analysis also proves that the released heat from the CaO–CO 2 reaction reduces the required energy for cellulose degradation. • Autothermal and conventional gasification are compared. • Higher H 2 /CO molar ratio was obtained at 650 °C in the autothermal gasification. • The gas yield increases with the increase of CaO/cellulose mass ratio. • The CaO–CO 2 reaction reduces the required energy for cellulose degradation. [ABSTRACT FROM AUTHOR]

There is great interest in producing hydrogen from renewable sources such as biomass rather than from fossil fuels. This paper presents new experimental results at different pyrolysis temperature and development of a dynamic model for a biomass pyrolysis/steam reforming process in a two stage fixed bed reactor. The model considers the hydrodynamics of the fixed bed reactor, the interfacial mass and energy transfer between the fluid–solid systems and the porous catalyst, and the energy transfer on a kinetic model. The 2D dynamic model resulted in a system of partial differential equations which was solved numerically in gPROMS®. The model was validated with the experimental results. The model predictions show good agreement with the experimental results. The model can be used as a useful tool for design, operation, optimisation and control of the biomass steam gasification process. [ABSTRACT FROM AUTHOR]

Abstract: The addition of plastics to the steam pyrolysis/gasification of wood sawdust with and without a Ni/Al2O3 catalyst was investigated in order to increase the production of hydrogen in the gaseous stream. To study the influence of the biomass/plastic ratio in the initial feedstock, 5, 10 and 20 wt.% of polypropylene was introduced with the wood in the pyrolysis reactor. To investigate the effect of plastic type, a blend of 80 wt.% of biomass and 20 wt.% of either polypropylene, high density polyethylene, polystyrene or a mixture of real world plastics was fed into the reactor. The results showed that a higher gas yield (56.9 wt.%) and a higher hydrogen concentration and production (36.1 vol.% and 10.98 mmol H2 g−1 sample, respectively) were obtained in the gaseous fraction when 20 wt.% of polypropylene was mixed with the biomass. This significant improvement in gas and hydrogen yield was attributed to synergetic effects between intermediate species generated via co-pyrolysis. The Ni/Al2O3 catalyst dramatically improved the gas yield as well as the hydrogen concentration and production due to the enhancement of water gas shift and steam reforming reactions. Very low amounts of coke (less than 1 wt.% in all cases) were formed on the catalyst during reaction, with the deposited carbonaceous material being of the filamentous type. The Ni/Al2O3 catalyst was shown to be effective for hydrogen production in the co-pyrolysis/gasification process of wood sawdust and plastics. [Copyright &y& Elsevier]

Catalytic steam gasification of biomass can produce clean and renewable hydrogen. In this study, Ce/Fe bimetallic catalysts were used to promote hydrogen production from cellulose steam catalytic reforming at 500–900 °C. The effect of different Ce/Fe ratios on the catalytic performance of hydrogen production was studied. The distribution of products, gas composition, carbon deposition and the stability of the catalyst were analyzed with variant approaches. The results show that the catalytic performance of the CeO 2 /Fe 2 O 3 catalyst in relation to hydrogen production was much better than pure CeO 2 or Fe 2 O 3 . When the ratio of Ce:Fe was 3:7, the maximum yield of the H 2 was 28.58 mmol at 800 °C. CeFeO 3 could be generated at 800 °C or higher temperature after redox reactions without forming CeO 2 /Fe 2 O 3 clathrate. And the existence of CeFeO 3 enhanced the thermal stability of Ce/Fe catalyst. The presence of CeO 2 not only improved the oxidative ability of the iron catalysts, but also was in favour of the oxidation of possible deposited carbon on the surface of the used catalysts. [ABSTRACT FROM AUTHOR]

Mesoporous silica supported Ni nanoparticles have been investigated for hydrogen production from ethanol steam reforming. Ethanol reforming is structure-sensitive over Ni, and also dependent on support mesostructure; three-dimensional KIT-6 possessing interconnected mesopores offers superior metal dispersion, steam reforming activity, and on-stream stability against deactivation compared with a two-dimensional SBA-15 support. [ABSTRACT FROM AUTHOR]

Biochar is a promising catalyst/support for biomass gasification. Hydrogen production from biomass steam gasification with biochar or Ni-based biochar has been investigated using a two stage fixed bed reactor. Commercial activated carbon was also studied as a comparison. Catalyst was prepared with an impregnation method and characterized by X-ray diffraction, specific surface and porosity analysis, X-ray fluorescence and scanning electron micrograph. The effects of gasification temperature, steam to biomass ratio, Ni loading and bio-char properties on catalyst activity in terms of hydrogen production were explored. The Ni/AC catalyst showed the best performance at gasification temperature of 800 °C, S/B = 4, Ni loading of 15 wt.%. Texture and composition characterization of the catalysts suggested the interaction between volatiles and biochar promoted the reforming of pyrolysis volatiles. Cotton-char supported Ni exhibited the highest activity of H 2 production (64.02 vol.%, 92.08 mg g −1 biomass) from biomass gasification, while rice-char showed the lowest H 2 production. [ABSTRACT FROM AUTHOR]

The inherent alkaline metals in biomass material are known to be volatile during biomass pyrolysis. However, there are very limited works about the investigation of the influence of alkaline metal on hydrogen production from downstream catalytic reforming of pyrolysis vapors. In this study, the influence of volatile K inside the cellulose sample was investigated in terms of hydrogen production and catalyst stability using a two-stage fixed-bed reaction system in the presence of a Ni/Al 2 O 3 catalyst. When the content of K in the cellulose sample was increased from 0 to 15%, the deposition of K on the surface of the reacted catalyst was kept constant at around 0.5 wt.% in terms of the weight of the catalyst. The life time test shows that hydrogen production was around 28 (mmol g −1 cellulose) for each experiment, when the catalyst was reused 5 times using the pure cellulose sample. However, the hydrogen production was significantly reduced to 22 (mmol g −1 cellulose) after the catalyst was reused 5 times with the 2.5% K/cellulose sample. X-Ray Fluorescence analysis shows that the reduce hydrogen production might be ascribed to the increase of the K deposition on the surface of the reused catalyst. [ABSTRACT FROM AUTHOR]

Tar reduction is an important issue for the development of biomass gasification process. In this work, a NiO/ceramic foam catalyst was developed and studied for catalytic steam reforming of tar model compound (benzene) using a fixed-bed reactor. Different reaction temperatures, equivalent ratios (ER), and steam/carbon (S/C) molar ratios were investigated with a space velocity of 5.6 h − 1 . The introduction of the NiO/ceramic foam catalyst showed excellent production of hydrogen and carbon conversion. With the increase of reaction temperature from 700 to 900 °C, the yield of hydrogen increased from 140.67 to 182.06 (g H 2 kg − 1 benzene). The increase of ER resulted in the decrease of the H 2 yield. A stability test (including regeneration of reacted catalyst) showed that the catalyst was deactivated by the deposition of carbons (confirmed from scanning electron microscopy), which could be removed using air oxidation at 750 °C. The catalytic activity of the catalyst in relation to the hydrogen production could be regained after the regeneration process. A kinetic model study of the process showed that the apparent activation energy and the pre-exponential factor were 73.38 kJ/mol and 1.18 × 10 5 (m 3 kg − 1 catalyst h − 1 ), respectively. [ABSTRACT FROM AUTHOR]

A Ni–Mg–Al–Ca catalyst was prepared by a co-precipitation method for hydrogen production from polymeric materials. The prepared catalyst was designed for both the steam cracking of hydrocarbons and for the in situ absorption of CO 2 via enhancement of the water–gas shift reaction. The influence of Ca content in the catalyst and catalyst calcination temperature in relation to the pyrolysis–gasification of a wood sawdust/polypropylene mixture was investigated. The highest hydrogen yield of 39.6 mol H 2 /g Ni with H 2 /CO ratio of 1.90 was obtained in the presence of the Ca containing catalyst of molar ratio Ni:Mg:Al:Ca = 1:1:1:4, calcined at 500 °C. In addition, thermogravimetric and morphology analyses of the reacted catalysts revealed that Ca introduction into the Ni–Mg–Al catalyst prevented the deposition of filamentous carbon on the catalyst surface. Furthermore, all metals were well dispersed in the catalyst after the pyrolysis–gasification process with 20–30 nm of NiO sized particles observed after the gasification without significant aggregation. [ABSTRACT FROM AUTHOR]

• Toluene steam reforming to H 2 with in-situ CO 2 capture by Ni/Perovskite and CaO. • Understanding the key roles of S/C ratio and temperature during SESR of toluene. • Achievement of 90% hydrogen yield with a fraction of maximum 95% under 650 °C. • Good compatibility of Ni/Perovskite catalyst and CaO sorbent in SESR of toluene. It is known that a considerable amount of tar is usually generated in the biomass gasification process, and catalytic steam reforming is an effective method to remove this by-product. The coupling of in-situ CO 2 capture in the process can further shift the forward reforming reaction and produce hydrogen with a high purity. In this work, sorption enhanced steam reforming (SESR) of toluene (as a model compound of biomass tar) was investigated thermodynamically and experimentally using the mechanically mixed Ni/perovskite catalyst and CaO sorbent. It is verified that the appropriate temperature is 650 °C under stoichiometric reaction (S/C = 2), and around 75% average H 2 yield with a maximum H 2 purity over 95% could be obtained. Moreover, the cyclic SESR-regeneration and characterization including XRD, SEM/EDS, TEM and XPS were carried out, and it shows a stable catalytic performance and compatibility of the Ni/perovskite catalyst in the SESR process for high-purity hydrogen production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biomass derived carbon material is a potential electrocatalyst for hydrogen evolution. • Metal-involved modification significantly enhanced the electrocatalytic activity of biomass-based carbon. • The challenges and future development of biomass-derived carbon applicated in hydrogen evolution are addressed. Hydrogen evolution reaction (HER) involving electrocatalytic process is established as a promising and non-pollution method for hydrogen production. The cheap alternatives of precious-metal electrocatalysts with high activity and robust stability is essential for the high-scale application of electrocatalytic hydrogen evolution. Recently, carbon-based electrocatalysts derived from biomass have attracted more and more attentions with thanks to their characteristics as low-cost, renewable, abundantly distributed and environmentally friendly. In this work, the original carbon material derived from biomass and the one doped with N and/or S as HER electrocatalysts are intensively overviewed regarding to the electrochemical performance and hydrogen yield. The overpotential at 10 mA cm−2 (η 10) is generally greater than 100 mV, which is far inferior to Pt-based catalysts. Consequently, biomass-based carbon materials decorated by transition metal and/or trace amount precious metal were introduced for improving the HER performance. The synergistic effect between metals and heteroatoms can significantly enhance the electrocatalytic activity, and the smallest value of η 10 is 10 mV. The limitations and challenges in this area were also addressed as (1) the in-depth investigation of conversion and electrocatalytic mechanism, (2) metal modification via in-situ growth, (3) the reproducibility for biomass transformation, and (4) the catalyst assembly with renewable energy equipment. [ABSTRACT FROM AUTHOR]

• Non-isothermal pyrolysis of bituminous coal were studied by coupling TG-MS/DSC. • Improved Coats-Redfern kinetics method to improve kinetics accuracy was developed. • Catalytic steam-assisted pyrolysis of bituminous coal by CaO was enhanced. • The addition of CaO and water feeding rates significantly promoted the H 2 production. The non-isothermal characteristics and pyrolysis kinetics of bituminous coal at different heating rates of 10, 20, and 30 ℃/min were studied by coupling TG-MS/DSC techniques. A fixed-bed reactor was used to investigate the coal-CaO-H 2 O reactions to understand hydrogen production and the effects of CaO under different water feeding rates. The pyrolysis phase, the maximum mass loss rate, the characteristic peak temperature, and the release of the main volatile gases were studied. Based on the improved Coats-Redfern method by introducing the function of Q (E/RT), the activation energies and pre-exponential factors of non-isothermal pyrolysis of bituminous coal were estimated iteratively by regression to enhance their accuracy. The values of E were calculated as 22, 22, 19 kJ/mol in the first stage, 67, 75, 78 kJ/mol in the second stage, 114, 96, 133 kJ/mol in the third stage at the heating rates of 10, 20, and 30 ℃/min. Finally, the concentration and selectivity of gaseous products from the pyrolysis of bituminous coal were studied. The concentrations of H 2 , CO, and CO 2 in the gas products increased with the addition of CaO and the increase of water feeding rate. Besides, the concentration of CH 4 increases with the increase of water feeding rate but decreases significantly with the addition of CaO. It is also worth noting that the pyrolysis process was enhanced by CaO addition to in-situ CO 2 captured and catalytic cracking reactions at the initial stage of the pyrolysis process. [ABSTRACT FROM AUTHOR]

• Alkali/alkaline earth metals promote catalytic performance of Ni/LSAO. • Coking resistance is improved by the increased surface-absorbed oxygen. • Superior anti-coking performance of K-loading catalysts below 600 °C. • 0.3 wt% loading of K/Ca/Mg has the best promotion in toluene steam reforming. Biomass steam gasification has a large potential to produce high-purity hydrogen, and perovskites are good candidates to act as catalyst supports in eliminating the biomass tar produced during reforming. However, various alkali and alkaline earth metals are contained in actual biomass, which would be released during reactions and could affect the catalytic performance of perovskite-supported catalysts. To explore potential roles of alkali and alkaline earth metals in the catalysis process, in this work, typical K, Ca and Mg were added into Ni/La 0.7 Sr 0.3 AlO 3−x catalysts, and their performance in steam reforming of toluene as a model of biomass tar for hydrogen production were investigated comprehensively. Catalytic performance shows that the presence of K, Ca, and Mg leads to a better resistance to coking (a reduction of over 60%) and sintering of the Ni/perovskite catalysts utilized, and this trend becomes more pronounced as the decrease of reaction temperature. Furthermore, a series of catalyst characterizations, including XRF, XRD, SEM, TPR, TPD, and XPS were conducted to understand the action mechanism. And results reveal that the presence of K, Ca, and Mg in catalysts promotes the absorption ability of surface oxygen, which could oxidize reaction intermediates or the carbon deposited, thus enabling good reforming properties of the perovskite-supported Ni catalysts in the reforming of biomass tar. [ABSTRACT FROM AUTHOR]