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Sorption-enhanced steam reforming (SESR) is a promising intensified strategy for producing highly pure hydrogen through in-situ CO 2 removal by a sorbent. This work experimentally explores the SESR of simulated bio-oil (mixture of acetic acid, acetone, ethanol, and phenol) over Ni/CaO-based bifunctional materials (BFMs) stabilized by industrial wastes (i.e., fly ash (FA) and UpGraded Slag Oxides (UGSO)) in a fixed bed reactor. The impact of CO 2 concentration and steam on the sorption efficiency of BFM-UGSO was investigated and the most likely carbonation route of BFM-UGSO in the presence of steam was proposed using N 2 physisorption isotherms (BET) and scanning electron microscopy (SEM). Moreover, a sorption kinetic model for BFM-UGSO was successfully developed. Whereas both developed materials (BFM-UGSO and BFM-FA) show exceptionally high H 2 purity (96.2 % and 98.4 %, respectively) at 550 °C, BFM-UGSO exhibited a much longer pre-breakthrough time (30 vs 21 min). Interestingly, BFM-UGSO showed remarkable cyclic stability with a CO 2 sorption capacity decay of less than 1 % along the 18 carbonation-regeneration cycles. It can be mainly attributed to the uniform distribution of mixed oxides generated by the interaction of Ni and CaO with metal oxides present in UGSO during material preparation. The inert phases, e.g., MgFe 2 O 4 , Fe 2 Al 2 O 4 , NiFe 2 O 4 , and Ca 2 Fe 2 O 5 (identified by X-ray diffraction patterns (XRD)) significantly hindered the sintering of CaO particles and limited pore structure failure. During the carbonation reaction, an increase in CO 2 concentration accelerated the kinetically controlled step of the carbonation reaction. Nevertheless, CaO conversion was found to be less affected for CO 2 concentrations exceeding 30 vol %. On the other hand, the morphological changes of the BFM-UGSO at wet conditions confirmed the ability of steam to promote solid-state diffusion in the product layer through the generation of abundant highly porous structure. The results of this work offer important insights into the SESR of bio-oil and open the door for further research in the exciting field of renewable hydrogen production. [Display omitted] • Intensified sorption-enhanced steam reforming of simulated bio-oil for renewable H 2 production. • UGSO-stabilized Ni/CaO bifunctional material (BFM-UGSO) offers remarkable efficiency. • The presence of steam highly improved the BFM-UGSO sorption capacity and cyclic stability. • A sorption kinetics model of UGSO-stabilized Ni/CaO bifunctional material was developed. [ABSTRACT FROM AUTHOR]

This work presents a multi-functional NiCoCe-based catalyst for crude oil steam reforming for hydrogen production. Arab Light (AL) and Arab Extra Light (AXL) were centrifuged to reduce the asphaltenes and sequentially steam reformed in a fixed bed reactor. Results showed that the NiCoCe catalyst was stable and highly selective under reaction conditions and in cyclic operation. The physicochemical properties of the catalyst were determined via inductively coupled plasma–optical emission spectrometry, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The high dispersion of the NiCo alloy on a Mg–Al support was crucial for ensuring the hydrocarbon reforming in the presence of heteroatomic species. • Multi-functional NiCoCe-based catalyst for crude oil to hydrogen. • Process based on steam reforming of different Arabian crudes. • Arabian light and Arabian extra light are centrifuged to reduce the asphaltenes. • The cyclic operation helped to sustain the catalyst activity and stability. • Continued hydrogen production for 14 h. [ABSTRACT FROM AUTHOR]

Ni–Al layered double hydroxide‐derived catalyst is modified with Ca and Co to improve their properties for ethanol steam reforming (ESR). The catalysts are prepared by coprecipitation and are characterized through N2 adsorption–desorption measurements, X‐Ray diffraction, temperature programmed reduction, temperature programmed oxidation, and NH3‐temperature programmed desorption. Catalyst activity tests are performed between 400 and 600 °C with the calcined catalysts and without reduction using ethanol and water in a 1:3 ratio in a fixed bed reactor with online gas chromatography analysis. The partial substitution of Ni by Co and Ca decreases the acidity of the catalyst. All samples remain stable after the reaction at 600 °C for 8 h and present a full ethanol conversion and high hydrogen selectivity, above 90%. The samples modified by Ca or Co are reduced to metallic phase during the reaction and reveal a smaller crystallite size than NiAl. The sample with Ca prepared with a different precipitant results in a catalyst with a more thermally stable active phase, low acidity, and higher specific surface area. This catalyst presents smaller crystallite size and low‐carbon formation after the reaction at 600 °C for 8 h, demonstrating higher potential for hydrogen production by ESR. [ABSTRACT FROM AUTHOR]

This research shows the effect of a catalyst supported on mordenite (natural and modified) impregnated with nickel, calcium, and potassium on palm kernel shell gasification for hydrogen production. The gasification process was carried out using a lab-scale fixed bed reactor at 900 °C with steam as gasifying agent. The use of the catalysts significantly improved the hydrogen production and the incorporation of metals in the mordenite increased hydrogen selectivity. The maximum H 2 content in the non-catalyzed gasification was approximately 34 mol%, while in the treatments with catalysts it ranged between 40 and 73 mol%. The T2-C5 catalyst impregnated with Ni, Ca, and K presented the highest H 2 content (72.9 mol%), which is associated with the synergistic interaction of nickel, calcium, and potassium. This catalyst presented the highest strong acidity (1.30 mmol NH 3 g−1) and the highest crystallinity (85.8%) compared to the other catalysts, properties that influenced the catalytic performance. • Synthesis of novel catalysts for H 2 production from biomass gasification. • Catalysts were supported on mordenite with different Ca/Ni, K/Ni and Ca/K/Ni ratios. • Catalysts were characterized with different techniques and used in gasification. • A synergistic effect of Ca, K and Ni favored hydrogen production. • Acidity and crystallinity influenced catalyst performance in the reaction. [ABSTRACT FROM AUTHOR]

The catalytic properties of supported Pt-containing catalysts for dimethoxymethane partial oxidation (DMM PO) into syngas was studied in a tubular fixed bed reactor at atmospheric pressure and relatively low temperatures (∼300–500 °C). Comparative studies of granular 0.5–1.9 wt % Pt/Ce 0.75 Zr 0.25 O 2–δ and structured 0.08 wt% Pt/8 wt% Ce 0.75 Zr 0.25 O 2–δ /6 wt% η-Al 2 O 3 /FeCrAl catalysts in DMM PO were performed. The SEM and STEM HAADF techniques were used for catalyst characterization. The structured catalyst was proved promising for producing syngas by the DMM PO reaction for SOFC feeding applications. In particular, at atmospheric pressure, temperature 400 °C, and the reaction mixture (28.6 vol% DMM, 14.3 vol% O 2 , 57.1 vol% N 2) feed rate of 5 L/(g·h), this catalyst provided complete conversion of DMM and O 2 to syngas with a total H 2 and CO content of 69 vol% and syngas productivity of ∼8 L/(g · h). • Structured Pt/CZ/Al 2 О 3 /FeCrAl catalyst was studied in DMM PO for the first time. • Pt/CZ in the structured catalyst works more efficiently than in the granular catalyst. • The catalyst provides 100% DMM conversion to syngas with H 2 +CO content of 69 vol%. • The catalyst with 80 mg Pt is sufficient for 1 kW SOFC integrated DMM PO reformer. [ABSTRACT FROM AUTHOR]

Pyrolytic reforming of toluene over Ni-based catalysts loaded on nano-sized and micro-sized γ-Al 2 O 3 is investigated in a fixed bed reactor under the temperature from 500 °C to 800 °C. The physicochemical properties of γ-Al 2 O 3 and Ni/Al 2 O 3 catalysts were characterized by HRTEM, XPS, XRD and H 2 -pulse chemisorption. The metal Ni loaded on micro-sized γ-Al 2 O 3 gave the steady toluene conversion of more than 80% and graphite yield of 87.3% after 1 h of reforming reaction. The rapid decrease of H 2 yield from 5.2 mmol/g-toluene to 0.4 mmol/g-toluene over Ni/nano-Al 2 O 3 was obtained during the 1 h of reforming reaction at 500 °C. The particle size of metal Ni over nano-sized and micro-sized γ-Al 2 O 3 were centered at 7.8 nm and 28.8 nm, respectively. The metastable NiC x crystallites were observed over the spent Ni/nano-Al 2 O 3 catalyst, while only metal Ni were obtained over the spent Ni/micro-Al 2 O 3 catalyst. Ni0+ particle size-dependent crystalline phase was evidenced by MD simulations, where incorporation of more carbon atoms was achieved on small Ni particles. The energy barrier for –CH 2 dehydrogenation over Ni 32 C, Ni 4 C and Ni 3 C were estimated to be 90.2, 105.1 and 116.0 kJ/mol through the DFT simulation, respectively. It can be concluded that the crystalline Ni phase was maintained over Ni/micro-Al 2 O 3 with large Ni particle size, prolonging the catalytic endurance and promoting the CNTs (Carbon Nanotubes) growth without the deposition of unexpected amorphous carbon. • The influence of γ-Al 2 O 3 on Ni/Al 2 O 3 catalytic reforming performance was investigated. • Ni0+ particle size-dependent pyrolytic reforming for co-production of H 2 and CNTs was revealed. • The carbon solubility on Ni particles with different sizes was simulated. [ABSTRACT FROM AUTHOR]

The impact of ZrO2 as a catalytic promoter for nickel-based alumina supported catalysts has been studied for the hydrogen synthesis via glycerol steam reforming. Hydrogen is a promising contender of clean fuel and has a key significance in the quest of an environment-preservation, low emission and more sustainable energy approach. Glycerol is a by-product produced during production of biodiesel by trans-esterification of vegetable oils. The higher hydrogen content in glycerol makes it the potential renewable feedstock for hydrogen production. Steam reforming process is the best method available which is highest in energy efficiency and most importantly most economical. The production of catalysts was based on the wet impregnation and co-precipitation methods. The majority of the bulk and surface properties of different synthesized catalysts were considered and determined by several characterization techniques like X-ray diffraction technique, BET surface area and scanning electron microscopy. The performance of catalyst is based on glycerol conversion and hydrogen yield obtained from the steam reforming process taking place in the fixed bed catalytic reactor. The effect of different operating conditions like contact time, temperature, metal loading, and steam to glycerol ratio were investigated to produce maximum hydrogen and glycerol conversion. The results show that the incorporation of promoter 2 % ZrO2 improved the activity of Ni/Al2O3 catalysts significantly resulting 96 % glycerol conversion, 84 % hydrogen production and greater stability at contact time = 15 kg cat s/mol, temperature = 800 °C, steam to glycerol ratio = 9:1 mol/mol, and pressure = 1 atm. [ABSTRACT FROM AUTHOR]

Renewable hydrogen production by aqueous phase reforming (APR) over Ni/Al-Ca catalysts was studied using pure or refined crude glycerol as feedstock. The APR was carried out in a fixed bed reactor at 238 °C, 37 absolute bar for 3 h, using a solution of 5 wt.% of glycerol, obtaining gas and liquid products. The catalysts were prepared by the co-precipitation method, calcined at different temperatures, and characterized before and after their use by several techniques (XRD, ICP-OES, H2-TPR, NH3-TPD, CO2-TPD, FESEM, and N2-physisorption). Increasing the calcination temperature and adding Ca decreased the surface area from 256 to 188 m2/g, and its value after the APR changed depending on the feedstock used. The properties of the acid and basic sites of the catalysts influenced the H2 yield also depending on the feed used. The Ni crystallite was between 6 and 20 nm. In general, the incorporation of Ca into Ni-based catalysts and the increase of the calcination temperature improved H2 production, obtaining 188 mg H2/mol C fed during the APR of refined crude glycerol over Ni/AlCa-675 catalyst, which was calcined at 675 °C. This is a promising result from the point of view of enhancing the economic viability of biodiesel. [ABSTRACT FROM AUTHOR]

Experimental methods and thermodynamic simulations were employed in this study to assess the H 2 production potential of a CaFe 2 O 4 based blue H 2 production process from natural gas (NG, >90 vol%CH 4). Fixed bed reactor testing was used to verify the product outcomes. Syngas production from methane using CaFe 2 O 4 was demonstrated. Stable H 2 production with high steam conversion was demonstrated with the CaFe 2 O 4 when reduced with methane. The thermodynamic integrated process simulation enabled simulation of the process in two and three reactor configurations to understand the feasibility of a heat integrated system. The 2-reactor process used the generation of syngas as the prevailing mode for H 2 generation while the 3-reactor system utilized steam water splitting in a dedicated reactor as the prevailing mode to generate H 2. Simulation of the 2-reactor process's FR showed syngas generation similar to the products from fixed bed demonstrations, establishing a connection between thermodynamic simulation and experimental data. The H 2 yield potentials of the various configurations were determined and compared to steam methane reforming with capture (SMR-CCS) and a Fe 2 O 3 based system from the literature. The 2-reactor process has the potential to generate 1.6–2.1 mol of H 2 /mole of NG fed to the system. Three reactor configurations showed the highest potential for H 2 yield with a range of 2.2–2.56 mol of H 2 /mole NG but with the need for additional CCS at the highest yield. A thermal management approach was introduced that combined the chemistries of CaFe 2 O 4 and CuFeAlO 4 which enabled increasing the potential yield to 2.66 mol H 2 /mol NG and enabling a system without the need for addition carbon capture to meet 90% threshold targets. The three reactor cases showed the most competitive performance in comparison to SMR-CCS with up to a 14.6% improvement in H 2 yield. [Display omitted] • Bench scale fixed bed reactor demonstrations for H 2 productions with CaFe 2 O 4. • Thermally integrated H 2 production process screening analysis of 2 and 3 reactor concepts. • 2 reactor concept H 2 yield range: 1.6–1.9 mol H 2 /mol CH 4. • 3 reactor concept H 2 yield range: 2.51–2.66 mol H 2 /mol CH 4. • Novel thermal management strategy using exothermic oxygen carrier (CuFeAlO 4) co-mixing with CaFe 2 O 4. [ABSTRACT FROM AUTHOR]

The present work reports the techno-economic analysis of hydrogen generation using Dimethyl Ether Steam Reforming (DMESR) and Methanol Steam Reforming (MSR) processes. For both processes, steady-state simulation models were developed using Aspen Plus. The two processes are analysed by taking into account the kinetics of the Cu/ZnO/Al2O3 catalyst for MSR and Cu–Ni/γ-Al2O3 catalyst for DMESR in an RPLUG model simulated as a Fixed Bed Reactor (FBR) at a temperature of 250°C and pressure 20 bar. The work dives into heat integration opportunities to reduce the operating cost of the two processes. The article also provides a gist of the approximate cost to produce hydrogen by the two processes by taking into consideration the cost of equipment and utilities involved. It is found that the TAC for DMESR is marginally higher than MSR mainly because of the higher cost of utilities involved. It was also found that NPV for MSR is comparatively higher than DMESR. The article also provides TAC for Selective Methanation of Carbon Monoxide (SMC) for both processes with the purpose of minimising CO. [ABSTRACT FROM AUTHOR]

Ni/red mud (RM) catalysts were prepared by wet impregnation and used in the catalytic steam gasification of bamboo sawdust (BS) to produce hydrogen-rich syngas. The system was optimized in terms of the amount of added nickel (10%), reaction temperature (800 °C), and catalyst placement (separately behind the BS). The maximum H 2 yield was 17.3% higher than that using pure RM catalyst and 43.8% higher than that of BS gasification alone, and the H 2 /CO ratio in the syngas reached 7.82. This Ni/RM catalyst also retained good activity after six cycles in a double-stage fixed bed reactor. Analysis using X-ray fluorescence, X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, and other methods revealed that the interaction of Ni, Fe, and Mg in Ni/RM produced bimetallic compounds containing active sites, such as NiFe 2 O 4 , MgNiO 2 , and NiO. This explains the good catalytic performance in the tar conversion during the gasification process. [Display omitted] • Nickel catalyst was loaded onto red mud (RM) support by wet impregnation. • Ni/RM enhanced syngas yield and H 2 ratio in steam gasification of bamboo sawdust. • The higher H 2 generation was mainly due to conversion of gaseous products and tar. • Ni formed bimetallic compounds with Fe, Mg, and Ti in RM as active sites. [ABSTRACT FROM AUTHOR]

Ni-Co loaded hemp-derived activated carbon (AC) catalyst is synthesized by the wet impregnation method for steam methane reforming (SMR) for hydrogen production. The monometallic and bimetallic metal (Co, Ni) catalysts were synthesized over activated AC with 5 wt% by the wet impregnation method and characterized by using various techniques. XRD and SEM results suggested that the catalysts with small metal crystallites promote a better dispersion of highly porous AC.The catalytic assessment of all synthesized catalysts for SMR was carried out in a thermal fixed bed reactor at 750 °C, WHSV 2000 mL CH4 g−1 h−1, and S/C of 2.0. The catalytic results showed that among all the investigated samples, monometallic cobalt catalyst (5% Co@AC) exhibited the best results in terms of CH4 conversion (97.17%) and H2 production (66.08%). While the 5% Ni@AC and 5% NiCo@AC show a CH4 conversion of 90.28% and 92.52%, respectively, whereas the H2 production was 61.02% and 65.89%. [ABSTRACT FROM AUTHOR]

The development of efficient and compact reactors is an urgent need in the field of distributed hydrogen production. Steam reforming of methane is the main method to produce hydrogen. Aiming at the problems of high heat and mass transfer resistance of the existing fixed bed reactors, and the difficulty of replacing the wall-coated catalyst in the microreactors, a composite packed bed was proposed to meet the demand of small-scale hydrogen production. The structure consists of a multi-channel framework with high thermal conductivity, which is filled with Ni/Al2O3 catalyst particles in each channel. A three-dimensional numerical model of the steam methane reforming process in the novel reactor was established using ANSYS FLUENT software. The heat transfer and reaction characteristics in the reactor were studied. Firstly, the advantages of the multi-channel skeleton in enhancing the radial heat transfer performance were verified by comparing it with the traditional randomly packed bed without the channel skeleton. Secondly, the influences of inlet velocity, inlet temperature, and heating wall temperature on the heat transfer and reaction performances in the reactor were studied, and a sensitivity factor was adopted to do the sensitivity analysis. The results show that the methane conversion rate is most sensitive to the wall temperature, while the inlet velocity and inlet temperature have less effect. Finally, the effects of two skeleton materials were studied. The results show that when the wall temperature is higher than 1200 K, there is no significant difference between these two reactors, which indicates that the use of cordierite with a lower price, but also with a lower thermal conductivity can significantly reduce the reactor's cost. The conclusions can be used as a reference for the design of small-scale hydrogen production reactors. [ABSTRACT FROM AUTHOR]

This work proposes the production of high-purity hydrogen by an intensified non-isothermal sorption-enhanced bio-oil steam reforming (SEBOSR) process, by combining the bio-oil steam reforming over a Ni/La 2 O 3 -αAl 2 O 3 catalyst and in-situ CO 2 adsorption over Li 2 CuO 2. The kinetics of CO 2 adsorption on Li 2 CuO 2 was studied experimentally and applied to assess the performance of SEBOSR in a fixed bed reactor via a non-isothermal mathematical model. Model simulations show that the prebreakthrough stage of the SEBOSR process, which corresponds to high purity H 2 production, can be extended by increasing the adsorbent loading and the S/C ratio, as well as by decreasing the inlet gas velocity. Increasing inlet temperature generates longer prebreakthrough step times but leads to a reduction in hydrogen purity. This intensified process allows to diminish the catalyst deactivation, which ultimately only occurs in the inlet region of the packed bed to some extent. In addition, SEBOSR indirectly uses sustainable CO 2 -neutral biomass as a source of hydrogen; highly pure and renewable H 2 can be produced in one step (without the need of additional gas purification), via a process with enhanced thermal efficiency. • Simulation of sorption-enhanced bio-oil steam reforming (SE-BOSR) for H 2 production. • Bio-oil reforming on Ni/La 2 O 3 -αAl 2 O 3 catalyst linked with CO 2 adsorption on Li 2 CuO 2. • H 2 production via a thermal efficiency process using indirectly CO 2 -neutral biomass. • High purity H 2 run time is extended adding sorbent & steam and reducing gas flowrate. • Simulations highlight the reduction of catalyst deactivation in SE-BOSR process. [ABSTRACT FROM AUTHOR]

In this study, the performance of thin film Ni/ZrO2 and NiCu/ZrO2 catalysts in a microchannel reactor in the dry methane reforming reaction (DRM) is investigated. Thin film nanocatalysts are prepared by the physical vapor deposition (PVD) method. GIXRD, FESEM‐Cross, FESEM‐Surface, and EDX analyzes are used to evaluate the properties of thin film nanostructures. The results show that in addition to the addition of copper as a promoter, a change in the coating time causes a change in the formation of the thin layer and the growth mechanism of the layers. Reactor tests are evaluated at temperatures ranging from 700°C to 800°C, at P = 1 atm, with a CH4:CO2 ratio of 1. Results of this study are compared with two other studies in fixed bed reactors that show the microchannel reactor has better performance. The presence of copper on Ni/ZrO2 could have significant effects on the stability of hydrogen production and the reduction of carbon deposition. Thin film Ni/ZrO2 catalyst with 2 min coating time and NiCu/ZrO2 catalyst with NiCu weight ratio of 4: 1 with 1 min coating time at 800°C show the best performance in terms of hydrogen production and H2/CO ratio (1.43 for a sample of Ni/ZrO2 and 1.68 for a sample of NiCu/ZrO2). [ABSTRACT FROM AUTHOR]

The CO2 utilization is a significant issue due to the rigorous greenhouse effect, and the major bottleneck of methane dry reforming reaction is carbon deposition. Nd2O3 promoted Ni-based catalysts have ample oxygen vacancies, which could promote the decomposition of carbon dioxide into CO and O* species and thus may perform a favorable anti-coking ability to overcome this difficulty, and Ni/Al2O3–Y2O3–x%Nd2O3 (x = 0, 2, 2.5, 3, 3.5, 4) catalysts were synthesized by sol–gel method and employed in DRM. The XRD, BET, TEM, TG, CO2-TPD and XPS were used to characterize the morphology and physicochemical properties of the prepared samples, confirming the Nd2O3 addition in Ni/Al2O3–Y2O3 catalysts behaved abundant oxygen vacancies, increased basicity of the support, mesoporous structures with small metallic Ni particle size, and high dispersion of Ni. Moreover, the catalytic performances were evaluated in a fixed bed tubular reactor, and the experimental results indicated Ni/Al2O3–Y2O3–3%Nd2O3 demonstrated an outstanding activity and stability at 800 °C owing to both inhibition of carbon deposition and Ni agglomeration, which was largely due to the sufficient oxygen vacancies. [ABSTRACT FROM AUTHOR]

The operation of reforming catalysts in a fixed bed reactor undergoes a high level of interaction between the operating parameters and the reaction mechanism. Understanding such an interaction reduces the catalyst deactivation rate. In the present work, three kinds of nanocatalysts (i.e., Pt/HY, Pt-Zn/HY, and Pt-Rh/HY) were synthesized. The catalysts' performances were evaluated for n-heptane reactions in the fixed bed reactor. The operating conditions applied were the following: 1 bar pressure, WHSV of 4, hydrogen/n-heptane ratio of 4, and the reaction temperatures of 425, 450, 475, 500, and 525 °C. The optimal reaction temperature for all three types of nanocatalysts to produce high-quality isomers and aromatic hydrocarbons was 500 °C. Accordingly, the nanocatalyst Pt-Zn/HY provided the highest catalytic selectivity for the desired hydrocarbons. Moreover, the Pt-Zn/HY-nanocatalyst showed more resistance against catalyst deactivation in comparison with the other two types of nanocatalysts (Pt/HY and Pt-Rh/HY). This work offers more understanding for the application of nanocatalysts in the reforming process in petroleum refineries with high performance and economic feasibility. [ABSTRACT FROM AUTHOR]

The production of hydrogen and syngas (H 2 /CO) from waste tires by pyrolysis catalytic steam reforming was investigated in a two-stage fixed bed reactor. In this study, tire char served as a sacrificial catalyst, facilitating the combination of catalytic steam reforming and char steam gasification reactions. The tire char acted as both a catalyst and a gasification reactant, enhancing the gas product yield. The process parameters investigated were, a reforming temperature range of 700–1000 °C, steam space velocity between 2 and 12 g h−1 g−1 char and reaction times of 0.5–2 h. The influence of the parameters on the yield and composition of the product gases and the characteristics of the used catalyst were analyzed in detail. The results indicated that higher temperature and steam space velocity increased H 2 and CO yields in the presence of a tire char catalyst. Elemental analysis of the used tire char, surface morphology and pore structure provided insights into the extent of tire char consumption in the reaction. Prolonged reaction time allowed for more thorough reactions between the pyrolysis volatiles and tire char, promoting the production of H 2. At a reaction time of 2 h, the H 2 yield reached 223 mmol g−1, representing 74 wt% of the maximum hydrogen yield. [Display omitted] • Pyrolysis-catalytic steam reforming of waste tires produces high H 2 and syngas yield. • Tire char catalyst is gasified (sacrificed) to enhance H 2 and syngas yield. • Higher temperature and steam inputs increased H 2 and CO yields. • H 2 yield of 223 mmol g−1, representing 74 wt% of the theoretical maximum H 2 yield. [ABSTRACT FROM AUTHOR]

[Display omitted] • A rapid and feasible approach to calculate reaction rate was approved for a complex reaction system. • A kinetic model was established to describe the reaction behaviours of SMR using structured catalysts. • Same SMR reaction kinetics were found when biogas was used as a sustainable source of methane. The intrinsic kinetics of steam methane reforming were experimentally investigated using a monolithic nickel-based catalyst in a specially designed fixed bed system. All kinetic tests were performed under various operating conditions: steam to carbon ratio of 2 to 5, methane volumetric concentration in feed gas of 3 % to 9 %, temperature of 500 to 650 °C, and typical biogas compositions with N 2 dilution (carbon dioxide 35.7–55.6 %, methane 44.4–64.3 %, with 86–91 % nitrogen dilution). A deconvolution process was applied during the rate calculation and the reaction orders with respect to different gases were determined, coupled with thermodynamic system analysis. The reaction mechanism was then proposed and a Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model was established, followed by kinetic parameter estimations for the model and a further model validation with experimental data. Based on the model, the intrinsic kinetic of SMR reaction using monolithic catalysts was described. The validity and feasibility of applying the faster approach for kinetic parameter estimation were demonstrated, and this work is the first demonstration of a complex reaction system. Also, the reaction mechanism appeared to show a suitably high correlation with alternative and more sustainable methane sources (i.e. biogas). [ABSTRACT FROM AUTHOR]

Catalytic hydrolysis of carbonyl sulfur (COS) from blast furnace gas is one of the keys to achieving ultra-low emission in the iron–steel industry. To improve the COS hydrolysis activity on γ-Al2O3 catalyst at low temperature, catalysts with Fe or La as the active component were prepared by the impregnation method, the physical and chemical properties of the catalyst were characterized by ICP, XRF, XRD, BET, and TPD. The hydrolysis activity of COS and sulfur resistance ability on various catalysts were investigated in a fixed bed reactor combined with gas chromatography. The results show that the addition of Fe or La improves the COS hydrolysis activity due to the increase in alkaline sites on the catalyst surface. The roles of various alkaline sites on catalysts have been recognized. The weak alkaline center is the reaction site of COS hydrolysis, the middle and strong alkaline centers are the adsorption and oxidation sites of H2S. The Fe/Al2O3 catalyst has higher hydrolytic activity and oxidative capacity for H2S removal due to forming more sulfate species on Fe. The La/Al2O3 catalyst has higher hydrolysis efficiency in that H2S rapidly desorbs from the catalyst surface to the gas phase, and then, the activity of reaction sites is recovered. This provides an idea for the preparation of sulfur-resistant catalysts. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) is an important way to produce synthesis gas, requiring the use of catalysts stable at high temperatures and capable of resisting coke formation. In this work, Ni/Al2O3 and Ni/Mg‐Al2O3 catalysts were synthesized with calcined aluminas at different temperatures (623, 773, 923, and 1073 K) to evaluate the effect of calcination temperature on catalyst properties and performance. The synthesis of catalysts was performed by wet impregnation with predicted levels of Ni (10% w/w) and Mg (5% w/w) in the treated supports. The DRM assays were conducted in an experimental laboratory unit (continuous fixed bed reactor with in‐situ catalyst activation) using a 1:1 (v/v) CH4:CO2 mixture, a weight basis gas hourly space velocity (WGHSV) of 15 L h−1 gcat−1, and operation at 973 K. The reaction product was evaluated by gas chromatography. Variations in CH4 and CO2 conversions and H2/CO ratio were observed, indicating that these catalysts have different physical and chemical characteristics attributed to different effects caused by calcinating the supports (Al2O3 and Mg‐Al2O3) at different temperatures. [ABSTRACT FROM AUTHOR]

Selecting a suitable catalyst for implementing the simultaneous production of hydrogen-rich syngas and multi-walled carbon nanotubes through the integration of dry reforming and methane decomposition reactions has recently gained great interests. In this study, a series of bimetallic (NiMo/MgO) and trimetallic (CoNiMo/MgO, FeNiMo/MgO, CoFeMo/MgO) catalysts was prepared and evaluated for a catalytic activity of CH4 and CO2 conversions of biogas in a fixed bed reactor at 800 °C and atmospheric pressure. Among the investigated catalysts, the bimetallic NiMo/MgO catalyst showed the outstanding catalytic performance with 86.4% CH4 conversion and 95.6% CO2 conversion as well as producing the highest syngas purity of 90.0% with H2/CO ratio = 1.1. Moreover, the characterization of the synthesized solid products proved that the well-aligned structured morphology, high purity, and excellent textural properties of CNTs were obtained by using NiMo/MgO catalyst. On the other hand, using trimetallic catalysts which have the composition of Co and Fe leads to the severe deactivation. This could be attributed the catalyst oxidation with CO2 in biogas, resulting in the transformation of metals into large metal oxides. The integrative process with NiMo/MgO catalyst is regarded as a promising pathway, which has a high potential for directly converting biogas into the high value-added products and providing a green approach for managing the enormous amounts of wastes. [ABSTRACT FROM AUTHOR]

Catalytic steam reforming of tar model compounds (toluene, xylene, ethylbenzene, cumene, quinoline, naphthalene and phenol) was carried out over different catalysts and in a fixed bed reactor. Tried catalysts were nickel/molybdenum over alumina, Fe supported on activated carbon, natural dolomite and a char obtained from pyrolysis of plastics. The effects of temperature, reaction time, space velocity and water:tar molar ratio on conversion, H2:CO ratio and catalyst deactivation were studied. The carbonaceous deposits were quantified by TPO and the results were related to activity and deactivation. Increasing the temperature favors the performance of the nickel-molybdenum catalyst, which shows 100% conversion up to 240 min time-on-stream, though the H2:CO ratio is the lowest, 2. At 873 K the char has a similar activity as the other catalysts, with about 50% conversion. The H2:CO ratio is however improved to 4. On a cost and environmental basis this catalyst seems the best option. It is a residue of other process (low cost), it has good activity and produces a good quality gas. [ABSTRACT FROM AUTHOR]

Olivine, a natural mineral consisting of different metal oxides (mainly Mg, Si and Fe oxides) was used as a support for nickel catalyst used in steam reforming of ethanol. Catalyst containing different wt% of Ni on olivine were prepared by conventional wet-impregnation method and characterized by BET, XRD, SEM (coupled with EDS) and H 2 -TPR. The reaction was carried out in a tubular fixed bed reactor. Among all the catalysts, 5% Ni on olivine catalyst gave highest hydrogen yield as well as ethanol conversion through ethanol steam reforming reaction. The catalyst activity was analyzed by varying three important process parameters (temperature, ethanol to water molar ratio and space-time). The reaction was performed in the temperature range of 450 °C to 550 °C with 1:6 to 1:12 M feed ratio of ethanol to water at a space-time range 7.21–15.87 kg cat h/kmol ethanol. A maximum yield of 4.62 mol of hydrogen per mole of ethanol reacted was obtained at 550 °C with ethanol to steam molar ratio of 1:10 and space-time of 7.94 kg cat h/kmol ethanol with the ethanol conversion level of 97%. CHNS analysis of the spent catalyst was performed to find the coke deposited over the catalyst surface during the reaction. The power law and LHHW type kinetic models were developed. The power law model predicts the activation energy as 29.07 kJ/mol, whereas the LHHW type model gives the activation energy as 27.4 kJ/mol. [Display omitted] • Ni/Olivine catalysts of varying Ni content were synthesized for ethanol steam reforming. • 5% Ni on Olivine catalyst exhibited best performance. • The effects of different process parameters on catalyst performance were investigated. • An optimum ethanol conversion of 97% and a hydrogen yield of 4.62 mol H 2 /mol ethanol converted were obtained. • Kinetic models were developed. [ABSTRACT FROM AUTHOR]

A series of nine different mono and bimetallic catalysts based on Ni, Rh and Pd supported on γ-Al 2 O 3 or CeO 2 -Al 2 O 3 was screened and compared in terms of activity and stability for the dry reforming of methane (DRM) reaction. All catalysts were prepared by the incipient wetness impregnation (IWI) method and characterized by XRD, XRF, TPR, H 2 chemisorption and N 2 physisorption. The used techniques aimed at determining crystalline phases, metal loading and dispersion and textural properties, which are properties that will affect the catalytic performance. The reactions were carried out in a fixed bed quartz reactor with temperatures ranging from 700° to 800 °C, WHSV 30 L g cat −1 h−1 and CH 4 :CO 2 = 1 for periods of at least 48 h. All monometallic Ni based catalyst suffered from deactivation by coke deposition in the first hours of reaction at 700 °C. However, the original catalytic performance of these catalysts was restored after a regeneration treatment. At higher temperatures (800 °C), the 15%Ni/CeO 2 -Al 2 O 3 catalyst presented no obvious signs of deactivation over the course of 48 h. Monometallic Pd/CeO 2 -Al 2 O 3 catalysts, despite presenting higher turnover frequencies (TOF) when compared to monometallic and bimetallic Ni based catalysts, lost activity due to coke deposition. Both monometallic Rh based catalysts (0.5%Rh/CeO 2 -Al 2 O 3 and 1%Rh/CeO 2 -Al 2 O 3) presented a remarkable activity and stability with no signs of deactivation for 96 h TOS. The 0.5%Rh/CeO 2 -Al 2 O 3 catalyst presented the highest TOF values among all screened catalyst with TOF CH4 of 9.9 s−1 and TOF CO2 of 12 s−1. [Display omitted] • Ni, Rh and Pd based mono and bimetallic catalysts were tested for the DRM reaction. • High temperatures (800 °C) enhances Ni/CeO 2 -Al 2 O 3 catalyst stability. • Monometallic Rh catalysts showed remarkable activity and stability. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) has important and positive environmental and industrial impacts, as it consumes two of the top greenhouse gases in order to produce syngas (H2 and CO) and thus hydrogen (H2). The performance of DRM of conversions of CH4 and CO2 was investigated over Ni/ZrO2 catalysts. The catalytic performance of all prepared catalysts for DRM was assessed in a micro-tubular fixed bed reactor under similar reaction conditions (i.e., activation and reaction temperatures at 700 °C, a feed flow rate of 70 mL/min, reaction temperature, and a 440 min reaction time). Various characterization techniques, such as BET, CO2-TPD, TGA, XRD, EDX, and TEM, were employed. The zirconia support was modified with MgO or Y2O3. The yttria-stabilized zirconia catalyst (5Ni15YZr) provided the optimum activity performance of CH4 and CO2 conversions of 56.1 and 64.3%, respectively, at 700 °C and a 70 mL/min flow rate; this catalyst also had the highest basicity. The Ni-based catalyst was promoted with Cs, Ga, and Sr. The Sr-promoted catalyst produced the highest enhancement of activity. The influence of the reaction temperature and the feed flow rate on 5Ni15YZr and 5NiSr15YZr indicated that the activity increased with the increase in the reaction temperature and lower feed flow rate. For 5Ni3Sr15YZr, at a reaction temperature of 800 °C, the CH4 and CO2 conversions were 76.3 and 79.9%, respectively, whereas at 700 °C, the conversions of CH4 and CO2 were 66.6 and 79.6% respectively. [ABSTRACT FROM AUTHOR]

To derive the kinetic model for steam reforming of ethanol, the experiment tests were accomplished at vast working conditions (i.e., temperature: 300–900°C, pressure: 1–11 bar, and H2O/C2H5OH ratio (S/E) of 3–21) on the Ni‐Pt/CeO2 catalyst in a fixed bed reactor. The physicochemical properties of the prepared catalyst were investigated by x‐ray fluorescence, thermal gravimetric analysis x‐ray diffractometer, and N2 adsorption/desorption Brunauer‐Emmett‐Teller (BET) tests. The kinetic model was developed based on the Langmuir–Freundlich approach, and the proposed mechanism included four reversible reactions on two types of the active site. The values of estimated activation energy for four reactions were in the range of reported values by various workers. The kinetic model error to anticipate the responses was 11.96% and a well forecasted H2 yield compared to other responses. The complete ethanol conversion reached above 700°C at 1 bar pressure irrespective of the S/E value. The variation of CO yield in terms of temperature was very low up to 700°C. An augmentation in S/E, enhanced ethanol conversion and H2 yield, while these trends were reversed for CO yield and CH4 selectivity. [ABSTRACT FROM AUTHOR]

Summary: Ni/γ‐Al2O3, Ni/HZSM5, Co/HZSM5, Mo/HZSM5, and NiMo/γ‐Al2O3 catalysts were synthesized by the wetness impregnation technique. Field emission scanning electron microscopy, X‐ray diffraction, and nitrogen physisorption methods were used for characterizing the prepared catalysts. The activity of the synthesized catalysts was studied by passing the mixed naphtha and H2 over a fixed bed reactor with sulfiding process prior to HDS reactions at ambient pressure, 285°C, LHSV of 5.8 h−1, and H2/HC volumetric ratio of 94. Ni, Co, and Mo with mass percent of 3.5 wt% were loaded on laboratory‐synthesized γ‐Al2O3 and purchased HZSM5 supports. For promoted NiMo/γ‐Al2O3 catalyst, 3.5 wt% Ni and 17 wt% Mo were impregnated on laboratory synthesized γ‐alumina support, similar to the commercial industrial catalyst. Ultimately, the HDS reactions over the synthesized NiMo/γ‐Al2O3 decreased the total sulfur content of mixed naphtha from 430 to 25 ppm wt, as a synthesized catalyst with the best reactor performance and acceptable long‐term stability. [ABSTRACT FROM AUTHOR]

The steam reforming of methanol (SRM) provides an efficient approach for the H2 production, but current SRM catalysts suffer from low activity, selectivity and stability. Herein, we report that ZnO nanoparticles (NPs) supported on ZnZrOx solid solution have excellent catalytic properties for SRM. The systematic studies suggest that ZnO/ZnZrOx catalysts with smaller ZnO domain (1–2 nm) are more selective and active than those with larger ZnO NPs. The existence of cooperative effect between the ZnO NPs (for methanol activation) and ZnZrOx solid solution (for water activation) was verified by the control experiment with ZnO/Al2O3 and ZnZrOx as catalysts. In situ DRIFTS of SRM and TPSR/MS studies suggest that the reaction undergoes through formates pathway over ZnO/ZnZrOx, where ZnO NPs and ZnZrOx work in a cooperative mode to favor the SRM reaction and suppress the side reactions. The optimized ZnO/ZnZrOx catalyst affords 99.7 % methanol conversion with CO selectivity as low as 2.4 % for single‐pass in a fixed bed reactor. [ABSTRACT FROM AUTHOR]

Mg and Al dual-metal functionalized nanoscale porous carbon materials (MgAl@NC) with highly ordered mesoporous structures and mixed active sites were successfully prepared using a simple one-pot synthesis method. The catalytic properties of the resultant MgAl@NC catalysts were investigated for the synthesis of ethyl methyl carbonate (EMC) in a fixed bed reactor. The catalysts exhibited remarkably high activity, selectivity and stability for the transesterification of diethyl carbonates (DEC) with dimethyl carbonates (DMC) even under high LHSV conditions. A 50.0% DEC conversion and a 99.2% EMC selectivity could be obtained at 103 °C and an LHSV = 7.8 h−1. The catalyst maintained a high product yield with almost no decrease in catalytic performance after 360 h. The well-dispersed magnesium aluminate spinel and α-cristobalite formed neighboring acid–base sites, while the synergistic catalytic effects of the mixed active sites should be critical for activation of the reactants. It may also be the reason for the efficient production of EMC under very high LHSV conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Acidity of the samples was in the opposite order of cation size: NiLi > NiNa > NiK. • NiLi presents the higher reduction temperature of mixed oxides. • NiLi presents the smaller Ni0 crystallite size after reduction. • The NiLi catalyst shows the highest resistance to sintering in biogas dry reforming. In this work, Ni-M-Al (M = K, Na, and Li) LDH-derived catalysts were evaluated for the biogas dry reforming. The catalysts were prepared by co-precipitation and characterized by S BET , XRD, TPR, NH 3 -TPD, CO 2 -TPD, SEM and TPO. Reactions were carried out in a fixed bed reactor with online GC analysis in step-wise mode in the range of 500–750 °C and the stability tests were performed at 700 °C. All prepared samples exhibited hydrotalcite-type structure. Differences in reducibility and in the acidity of oxides were observed. The acidity of the catalyst was in the order: NiLi > NiNa > NiK, which is in the opposite order of monovalent cation size. The NiLi catalyst showed the highest resistance to sintering during the reactions due to the higher reduction temperature of mixed oxides (Ni 2 AlO 4 and NiAl 2 O 4) which results in smaller Ni° crystallite size after reduction. The results at 700 °C showed that NiLi catalyst deactivation occurs mainly by carbon deposition, whereas the deactivation of NiK and NiNa catalyst occurs mainly by sintering. TPO results indicated different carbon species produced depending on how the reaction is performed. All the catalysts produced carbon nanotubes at 700 °C. [ABSTRACT FROM AUTHOR]

Catalytic transformation of light alkanes to aromatic compounds which are feedstocks to petrochemical industries is an important process. Here, a simple method of co-impregnation was employed to synthesize Zn-Cu/ZSM-5 for propane aromatization. Copper of varying loading 1–3 wt% was co-impregnated with zinc to improve zinc stability at the reaction condition. Catalyst physicochemical properties were analyzed using XRD, BET, N 2 -adsorption, FTIR, FTIR-Pyridine, SEM, TEM, H 2 -TPR and XPS. The XRD and FTIR characterization showed that the modified catalysts retained their crystallinity after metal impregnation with the XPS confirming the metal species having oxidation state of 2+. Hydrogen-TPR and XPS change in reduction temperature and binding energy spectra showed stronger intermetallic interaction respectively. Incorporation of Cu with Zn on ZSM-5 reduced Bronsted acidity from the FTIR-Pyridine while N 2 -adsorption isotherms verified the catalyst are microporous. The performance tests for propane aromatization over synthesized catalysts were carried out in a fixed bed reactor using GHSV of 1200 ml/g-h at 540 °C and atmospheric pressure. Co-impregnation of Zn with Cu improved the catalytic activity and sustained aromatic selectivity at an average of 85% for 12 h' time on stream as compared to HZSM-5 (10%) and Zn/ZSM-5 (50%). Product distribution showed reduced light hydrocarbon formation and increased aromatic compounds with high selectivity towards toluene, m and o-xylene among the aromatic product distribution. The best aromatic selectivity product distribution was recorded for 2 wt% Cu with Zn, thus a more stable catalyst developed. XPS and H 2 -TPR analysis showed that the synergistic interaction between the two metals (Cu and Zn) improved the performance of bimetallic Zn-Cu/ZSM-5 catalyst by promoting zinc dispersion and stability during reaction. [ABSTRACT FROM AUTHOR]

Steam iron process represents a technology for H 2 production based on iron redox cycles. Fe x O y are reduced by syngas/carbon to iron, which is subsequently oxidized by steam to produce pure H 2. However, the system shows low stability. In this work, the effect of promoters (Al 2 O 3 , MgO and CeO 2) on Fe x O y stability is investigated (10 consecutive redox cycles). Bioethanol is used as a reducing agent. The particles are synthesized by coprecipitation method, analysed by BET, XRD, SEM and tested in a fixed bed reactor (675 °C, 1 bar). Pure H 2 is obtained controlling the Fe x O y reduction degree feeding different amounts of ethanol (4.56–1.14 mmol) until no CO is detected in oxidation. The results show that the promoters not only improve the thermal stability of Fe x O y but also affect its redox activity and react with iron forming spinel structures. MgO led to the highest activity and cyclability (H 2 = 0.15 NL; E = 35%). • Steam iron process is a promising alternative to obtain pure H 2 ideal for PEMFC. • Pure and renewable H 2 is achieved using bioethanol in the reduction step. • The promoters Al 2 O 3 , CeO 2 and MgO aim to improve the Fe redox cyclability. • Al 2 O 3 and MgO play an active role reacting with Fe and forming spinel structures. • MgO gives the highest pure H 2 yields (H2(NL)/EtOH(g) = 3.422) stable for 10 cycles. [ABSTRACT FROM AUTHOR]

Summary: In this study, cobalt (Co) loaded Sr2TiFeO6‐δ (STF) double perovskite was synthesized using a modified nitrate combustion method for the application in catalytic decomposition of methane (CH4) for hydrogen (H2) production in a fixed bed reactor. The physicochemical properties of the catalyst were analyzed using X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy, N2 adsorption‐desorption, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy. The catalyst showed a stable crystalline behavior with a uniform dispersion of Co over STF. The different compositions with varying Co loading were tested for methane decomposition at 850°C and constant flow rate. The 5% Co/STF achieving a maximum CH4 conversion of ~95% with an H2 yield of ~49%. Five percentage Co/STF showed excellent catalytic activity and stability for 46.5 hours time on stream without any indication of performance degradation. The spent catalyst was also analyzed using XRD, SEM, and TGA. The carbon deposited is shaped as carbon nanotubes that are a byproduct and also assist in metal exsolution in high‐temperature processes. The use of STF shows the excellent potential showed by perovskites, which are stable in reducing environments, as support materials for methane decomposition. [ABSTRACT FROM AUTHOR]

Methane steam reforming is the most widely used pathway for hydrogen production. In this context, the use of a fixed bed catalytic reactor with a hydrogen-selective membrane is one of the most promising technologies to produce high purity hydrogen gas. In this work, the membrane reactor three-dimensional computational fluid dynamic (CFD) model was developed to investigate the performance. In this model, methane steam reforming global kinetic model has been coupled with the CFD model using User-Defined Function (UDF). Whereas, hydrogen permeation across the membrane is implemented by introducing source and sink formulation. The CFD simulation results were compared to the experimental data, where the developed model successfully captured the experimentally observed trends. We studied the influence of the various operating parameters, as temperature, steam to carbon ratio, sweep gas flow configuration and space velocity on the overall performance. The main observation and attained optimal operation windows from the study was discussed to provide insight into the factors affecting the overall performance. [Display omitted] • 3D CFD analysis of methane steam reforming in a membrane reactor. • Xu forment based kinetic model and Sieverts' law-based permeation model were coupled. • The CFD model evaluates the temperature, GHSV, S/C ratio and sweep gas flow pattern. • Key performance phenomena were identified, and optimum conditions were suggested. [ABSTRACT FROM AUTHOR]

Summary: Combined steam and dry reforming of methanol (CSDRM) experiments were applied to measure the responses of CH3OH conversion, H2/CO ratio, H2 and CO yield at a temperature range of 300°C to 900°C, CO2/H2O ratio of 0.5 to 2.5 and (CO2 + H2O)/CH3OH ratio of 1 to 3 on Fe‐Mn‐Cu/ZrO2 catalyst in a fixed bed reactor. Fe‐Mn‐Cu/ZrO2 catalyst was synthesized via the co‐precipitation approach, and its physicochemical properties were examined through X‐ray diffractometer, X‐ray fluorescence, temperature‐programmed reduction, N2 adsorption/desorption and thermal gravimetric analysis tests. A kinetic model for CSDRM reaction was derived via the Langmuir‐Freundlich method and the proposed mechanism included three reversible reactions on three types of active sites. A Mamdani‐type fuzzy model was also developed for comparison purposes, as there was no need for detailed knowledge of the process. The error of the kinetic and Mamdani‐type fuzzy model approaches obtained 12.69% and 16.42%, respectively. H2 yield obtained from kinetic model values was closer to the experimental data compared to other responses. However, for the fuzzy model approach, the difference between experimental and calculated methanol conversion was lower. [ABSTRACT FROM AUTHOR]

• Cu-Ni-Al-LDH catalysts were successfully prepared by coprecipitation. • The presence of Cu-Ni alloy influences the S BET , acidity and reducibility of catalysts. • Cu-containing catalyst presented a high thermal stability due to Cu-Ni alloy. • Catalyst with Ni/Cu = 5 and activated with CH 4 presented the best activity results. Hydrogen from the decomposition of CH 4 is an essential source of clean energy and contributes to a decarbonization process. In this work, Cu-Ni-Al-LDH were prepared by coprecipitation, evaluating the Ni/Cu ratio and the catalyst activation. The samples were characterized through N 2 -adsorption-desorption, XRD, H 2 -TPR, NH 3 -TPD, TPO and SEM. The catalytic activity was evaluated between 500 and 700 °C in a fixed bed reactor with online GC analysis. Reactions at 600 °C during 6 h were also carried, with samples previously reduced with H 2 or activated with CH 4. The characterization results show that the increase of copper caused a decrease in the specific area, enhanced the acidity, and decrease the reduction temperature of catalysts, due to the presence of Cu-Ni alloy phase. Activity results at variable temperature showed a strong deactivation by sintering for NiAl catalyst at 600 °C, differently of Cu-containing catalyst which presented a high thermal stability, independently of activation with H 2 or with CH 4. For reactions with a constant temperature of 600 °C and activated with CH 4 , the order of activity of the catalysts was Cu11 ≫ Cu22 > Cu33 ≫ NiAl, while deactivation was in the reverse order. The catalyst with the lowest Cu content (Ni/Cu = 5) activated with CH 4 was the one that presented the best activity results. Deactivation of the catalyst without Cu occurs through sintering, whereas the Cu-Ni alloy was essential to increase the resistance to sintering in Cu-containing catalysts. Activation with methane proved to be a beneficial substitute to H 2 -reduction. [ABSTRACT FROM AUTHOR]

As a perspective catalyst composition for methane non-oxidative decomposition/methane pyrolysis (CH 4 ⇌C+2 H 2) yielding clean hydrogen and only solid carbon, the combination of nickel and molybdenum on MgO support was investigated. With deliberately low Ni content and strong metal-support interaction, 7%Ni4%Mo/MgO and 7%Ni12%Mo/MgO catalysts and the monometallic references were prepared. Structural analysis was performed using TPR, XRD, TEM, XPS and Raman spectroscopy in reduced state and after methane decomposition test. Catalytic performance was investigated i) in a highly diluted CH 4 flow in a fixed bed reactor under temperature ramp and ii) in 50% CH 4 /Ar using a horizontal reactor at 800 °C. Synergetic interaction of Mo and Ni was observed under both conditions. The results revealed that the deactivation was coupled with alloy segregation for the low Mo loading, while the more stable, non-segregating Mo/Ni∼1 composition of the individual metal particles in 7%Ni12%Mo/MgO sample resulted in good activity and high carbon nanotube yield. [Display omitted] • NiMo/MgO samples with Mo/Ni=1.2 and 0.4 were prepared by adsorption-precipitation. • Reduction resulted in alloyed NiMo particles in strong interaction with MgO. • In methane pyrolysis synergetic effect was observed, larger for Mo/Ni= 1.2. • During CNT formation alloyed NiMo particles segregated in samples with Mo/Ni=0.4. • The higher alloy stability in Mo/Ni=1.2 sample increased catalyst lifetime. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sorption enhanced chemical looping H 2 production with reduced energy demands. • NiO/CaO–based solids with oxygen transfer, adsorptive & catalytic functionalities. • Up to 25 % reduction of solid inventory compared to sorbent/oxygen carrier mixtures. • Improved coupling of exothermic/endothermic reactions compared to individual solids. In this work, we report the development and performance evaluation of hybrid, multifunctional catalytic materials based on NiO and CaO for the Sorption Enhanced Chemical Looping Steam Methane Reforming process (SE–CL–SMR). The multifunctional materials with various NiO/CaO/inert ratios were prepared via the sol–gel auto–combustion method. Testing under SE–CL–SMR conditions was conducted in a fixed bed reactor unit. High CH 4 conversion is achieved over all developed materials, resulting in the production of high–purity hydrogen (> 95 %) at 650 °C and steam/carbon ratio of 3. Compared to a mixed bed of sorbent and oxygen transfer material (OTM), operation with the multifunctional material allows for more efficient use of the heat generated by Ni reoxidation during regeneration due to the direct heat transfer between the OTM and sorbent phases. Although higher NiO and CaO content in the hybrid material translates to greater loss of autothermicity during regeneration with increasing number of cycles, the decrease of the inert fraction reduces up to ∼25 % the volume of the bed compared to the respective sorbent/OTM mixture. Such an outcome clearly demonstrates the benefit of using a multifunctional material for the intensified SE–CL–SMR process. [ABSTRACT FROM AUTHOR]

Several bimetallic Ni Co catalysts supported on θ-Al2O3 together with 10 wt% Ni and 10 wt% Co on θ-Al2O3 were prepared via the incipient wetness method, characterized by X-ray diffraction (XRD), nitrogen adsorption, transmission electron microscopy, temperature programmed reduction, temperature programmed CO2 desorption, Fourier Transformed Infrared Spectroscopy (FTIR) with pyridine adsorption-desorption and tested in dry methane reforming at 700°C in a fixed bed reactor. According to XRD the metal oxide crystallite sizes decreased from 20 nm for 10 wt% Co/θ-Al2O3 to 13 nm for 5 wt% Ni-5 wt% Co/θ-Al2O3, which also showed formation of a mixed oxide alloy. The unit cell parameters for spinel in the fresh catalyst and fcc metal formed during the reaction followed the Vegard’s rule. Although monometallic 10 wt% Co/ θ-Al2O3 exhibited high hydrogen consumption, desorption temperature was also high resulting in a rather low activity of 10 wt% Co/θ-Al2O3 in comparison to bimetallic 5 wt% Ni5 wt% Co/θ-Al2O3. The latter exhibited the highest initial activity for hydrogen formation due to its relatively small metal particle size. This catalyst suffered, however, from extensive coking. The most stable catalyst was 10 wt% Ni/θ-Al2O3 for which the hydrogen yield decreased form 56% to 45% during 100 h time-on-stream. For this s catalyst no sintering occurred, opposite to 10 wt% Co/θ-Al2O3. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two nickel based catalysts (Ni-UGSO and Ni-Olivine) are tested and compared in toluene steam reforming. • Calcination leads to the formation of NiO/MgO solid solution in the case of Ni-UGSO. • Ni does not integrate the olivine matrix in the case of Ni-Olivine. • Ni-UGSO shows 98 % of conversion of toluene with excellent resistance to carbon deposition. Two nickel-based catalysts are used for toluene steam reforming: Ni-Olivine and Ni-UGSO (Nickel-UpGraded Slug Oxides). Both catalysts are made from mining residues and prepared by incipient wetness impregnation (IWI). The activity and stability of the two catalysts in toluene steam reforming are investigated and compared, at atmospheric pressure and 800 °C in a fixed bed reactor. Reaction temperature and Ni Loading effects are evaluated for the Ni-UGSO catalyst. The physicochemical properties of the catalysts were analyzed using the following characterization techniques: X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX), X-ray absorption near edge spectroscopy (XANES), Temperature Programmed Reduction (TPR) and Brunauer-Emmett-Teller (BET) specific surface area. Results showed that toluene conversion, mainly into CO and H 2 , reached up to (98 w%). The catalyst activity was tested in multiple 24 h time-on-stream continuous isothermal runs and no signs of deactivation were observed. Ni in Ni-UGSO has a strong metal-support interaction, which, according to characterization results, is due to the formation of a NiO/MgO solid solution. This catalyst exhibited an elevated catalytic activity along with a high resistance to carbon formation. Ni in Ni-Olivine has shown a weak metal-support interaction leading to the formation of filamentous carbon at the catalyst's surface. [ABSTRACT FROM AUTHOR]

Cracking and isomerization of n-alkanes, employing bifunctional catalysts, are vital reactions in various refinery processes for producing different high-quality fuels. These catalysts consist of a specific metal component and a specific acid function. The metal component is used for dehydrogenation and hydrogenation constituted from a specific noble metal such as palladium and platinum. The acid function, on the other hand, is used for cracking and isomerization aims. In this work, a number of mesoporous catalysts with different ratios of Si/Ti based on MSU containing Platinum were synthesized and characterized with XRF, XRD, NH3–TPD, and BET tests. These catalysts were applied in n-heptane hydroconversion process in a fixed bed microreactor to see their performance in an actual process. In the microreactor, the pressure was constant (atmospheric), and the temperature varies in the range of 250–600°C. The performance of each of the catalysts was investigated in different ratios of hydrogen to hydrocarbon (5, 10, 15, 20, and 25) and in two values of Weight Hour Space Velocity (WHSV) (1.5 and 2.5 h–1). Products analysis carried out to check out the activity and selectivity of each of the catalysts. The result showed that all samples have a high surface area, favorable pore distribution, and high acidity. The outcome of the study showed that the CAT-D catalyst has the highest activity for normal heptane conversion. This catalyst also has the highest selectivity for isomerization products at moderate temperatures (350°C) and WHSV = 1.5 h–1. [ABSTRACT FROM AUTHOR]

The analysis of this study focuses on the production of H2 based on the methanol steam reforming in an isothermal, steady state and one-dimensional model. Two reactors namely, fixed bed reactor (FBR) and H2 selective membrane reactor (MR) are being evaluated by simulation. FBR consists of a cylindrical column packed with Cu/ZnO/Al2O3 catalyst particle bed, whereas MR is a cylindrical reactor with one reaction tube consisting of an inert nature membrane (Pd/Ag) are considered. At the complete conversion of methanol, the yield of H2 is significantly affected by H2 selective membrane, temperature and pressure conditions. H2 yield of 2.72 has been achieved after the almost complete conversion of methanol at 593 K temperature, the pressure of 1 atm and steam/methanol ratio of 1.5 in FBR. H2 yield, molar flow rate of CO2 has also been increased, and CO concentration has been reduced by using MR. Similarly, H2 yield has increased to 2.76 with decreasing CO concentration using MR at the same operating conditions with an increase in pressure in the reaction zone to 2 atm. Hence, the results indicate that the H2 yield with a small amount of CO has been achieved in MR at optimum operating conditions. Abbreviations: FBR: Fixed Bed Reactor; MR: Membrane Reactor; SRM: Methanol Steam Reforming; MD: Methanol Decomposition; WGS: Water Gas Shift; PROX: Preferential Oxidation; S/M: Steam to Methanol Molar Ratio in Feed; O/C: Oxygen to Carbon Ratio; L/D: Length to Diameter Ratio; POX: Partial Oxidation; ATR: Auto-Thermal Reforming; SR: Sweep Ratio (sweep gas/methanol molar ratio) [ABSTRACT FROM AUTHOR]

A detailed exergy analysis was performed for the steam reforming process of glycerol by means of a series of experiments in a bench scale apparatus. The reforming was conducted in a fixed bed reactor, which operated in heat recovery mode by extracting the demanded energy from hot exhaust gases provided by a diesel engine. In order to determine the role of the main operational parameters into the exergy efficiency of the studied process, the experiments were carried out with glycerol feed concentrations in water ranging from 10% up to 90% weight, whereas the outlet reactor temperature was varied from 600 °C up to 800 °C. Detailed exergy balances revealed a compromise between the exergy destruction within the reforming reactor and liquid separator versus the exergy losses associated to the tar and char outputs. This trade-off was favourable to the 50% and 70% glycerol feed concentration regimes and plateaus of about 74% exergy efficiency and 24 MJ/kg dry syngas exergy content were verified from 650 to 800 °C reactor temperatures. • Detailed exergy analysis of glycerol steam reforming. • Syngas maximum exergy value and efficiency coincided with maximum hydrogen yield. • Experiments indicate a maximum reforming exergy efficiency of 75.8%. • Trade-off between irreversibilities and tar exergy losses was evidenced. [ABSTRACT FROM AUTHOR]

This study presents detailed experimental and theoretical investigation of manganese-based metal oxides, MnMO x (M: Fe, Ni, Cu) as potential catalysts for the low-temperature toluene oxidation. The first part of the paper deals with the detailed characterization of the prepared catalysts and testing of their catalytic activity and stability in the fixed-bed reactor. The MnFeO x exhibited superior and stable catalytic activity for toluene oxidation (T 90 = 419–446 K), comparable with the activity of the commercial Pt–Al 2 O 3 catalyst (T 90 = 393–423 K). Among the studied catalysts the following order of catalytic activity was determined: MnFeO x > MnNiO x ≈ MnCuO x > MnO x. The one-dimensional (1D) pseudo-homogeneous model was applied to describe behavior of the fixed bed reactor for the low temperature toluene oxidation over prepared MnFeO x catalysts. The second part of the paper is focused on theoretical investigation of toluene interaction on the surface of the single metal oxides (Mn 2 O 3 , MnO 2 , Fe 2 O 3 , NiO and CuO) in the oxygen atmosphere using the ReaxFF method, since they were individual dominant phases in the prepared catalysts. A good correlation between the predicted binding energy of toluene adsorption on the surface of studied metal oxide phases and experimentally determined catalytic activities was observed. [ABSTRACT FROM AUTHOR]

The effect of ceria dopant aiming at stability in Ni/doped-ceria anodic layers for direct ethanol solid oxide fuel cells (SOFC) was studied. Solid solutions of ceria doped with Y, Gd, Zr, or Nb (10 mol%) impregnated with NiO were tested in a fixed bed reactor for ethanol conversion reactions and for direct (dry) ethanol SOFC. The ceria dopant showed a marked effect on both the catalytic and the electrical transport properties of the ceramic support. Catalytic activity data revealed that the studied materials deactivate in ethanol decomposition reaction but are stable for ethanol steam reforming. Thus, feeding dry ethanol to the SOFC with a Ni/doped-ceria anodic catalytic layer evidenced that water produced from the electrochemical hydrogen oxidation provides steam for the internal reforming resulting in great stability of the fuel cells tested during ~100 h. The combined catalysis and SOFC results demonstrate Ni/doped-ceria is as candidate anode layer for stable SOFC running on bioethanol. Image 1 • Direct bioethanol solid oxide fuel cells stable for 100 h without water. • The ceria dopant affects the transport and catalytic properties for ethanol SOFC. • Ni/doped-ceria catalytic layer ensures ethanol conversion and avoids carbon deposit. [ABSTRACT FROM AUTHOR]

The performance of fixed and fluidized bed reactors in the steam reforming of biomass fast pyrolysis volatiles was compared, with especial attention paying to the differences observed in catalysts deactivation. The experiments were carried out in continuous regime in a bench scale unit provided with a conical spouted bed for the pyrolysis step. They were carried out on a Ni-Ca/Al 2 O 3 commercial catalyst and under optimum conditions determined in previous studies, i.e., pyrolysis temperature 500 °C, reforming temperature 600 °C and a steam/biomass ratio of 4. Moreover, the influence of space time was analysed in both reforming reactors. The fixed bed reactor showed higher initial conversion and H 2 yield, as it allowed attaining a H 2 yield higher than 90 % with a space time of 10 g cat min g volatiles −1. However, a space time of 15 g cat min g volatiles −1 was required in the fluidized bed to obtain a similar H 2 yield. Moreover, the fixed bed also led to lower catalyst deactivation. Catalyst deactivation was mainly related to coke deposition, and higher coke contents were observed in the catalysts used in the fluidized bed reactor (1.2 mg coke g cat −1 g biomass −1) than those in the fixed bed one (0.6 mg coke g cat −1 g biomass −1). Therefore, the differences in the performance of the two reactors were analysed and their practical interest was discussed. [ABSTRACT FROM AUTHOR]

Gold particle with an average size of d Au ~ 4 nm was dispersed on ZnO by the deposition precipitation method. The fabricated Au/ZnO catalyst was used to produce hydrogen from reforming of methanol. Four reforming reactions, i.e., decomposition of methanol (DM), steam reforming of methanol (SRM), partial oxidation of methanol (POM) and oxidative steam reforming of methanol (OSRM), were evaluated in a fixed bed reactor. A reaction temperature of T R > 623 K was required for catalyzing reactions of DM and SRM. Interestingly, high methanol conversion (C MeOH > 90%) was found from reforming reactions of POM and OSRM at an amazing low temperature of T R < 473 K. Besides, a presentable hydrogen yield (R H2 ~ 2.4) and a low selectivity of CO (S CO ~ 1%) were simultaneously attained from the reaction of OSRM. Therefore, the low temperature OSRM reaction over the Au/ZnO catalyst is suggested as a friendly reforming process for on-board production of hydrogen. • The fabricated Au/ZnO is used to produce hydrogen from the reforming of methanol. • R H2 ~ 2.4 and S CO ~ 1% are attained from the OSRM over Au/ZnO at 470 K. • Highly dispersed Au/ZnO catalyst is outstanding to produce HRG via the OSRM reaction. [ABSTRACT FROM AUTHOR]

La/Mg ratio was evaluated in Ni–Mg–La–Al catalysts for the biogas dry reforming. The reactions were carried out in a fixed bed tubular reactor using synthetic biogas (70% CH4 and 30% CO2). The catalyst characterization showed that the increase of La/Mg ratio decreased the specific surface area of the catalyst and the average crystallite size of Ni0, but increased the acid strength of sites identified by NH3-TPD analysis. These properties contributed to improving the activity and catalytic stability for CH4 conversion at 700 °C. The Mg presence increased the strength of basic sites of the catalysts and plays an important role in CO2 conversion. The catalyst with La/Mg = 4 presented the best activity and stability for the reaction at 700 °C, due to the greater resistance to sintering associated with de small size of Ni0, and a proper combination of acid and basic sites. H2/CO ratios higher than 1 were obtained due to the contribution of the CH4 decomposition reaction. [ABSTRACT FROM AUTHOR]

Dry (CO2) reforming of methane is conducted over two newly synthesized Ni20/Ce‐γAl2O3 and Ni20/Ce‐meso‐Al2O3 catalysts. The x‐ray diffraction (XRD) patterns indicated that Ni20/Ce‐meso‐Al2O3 exhibits a better dispersion of nickel, while Ni20/Ce‐γAl2O3 has larger amounts of nickel crystallites. The temperature programmed desorption (TPD) kinetics analysis indicated that Ni20/Ce‐meso‐Al2O3 had a lesser metal‐support interaction than the Ni20/Ce‐γAl2O3. The thermal gravimetric analysis (TGA) indicated that the incorporation of ceria into the Al2O3 matrix helps to stabilize Ni20/Ce‐meso‐Al2O3 during dry reforming of methane. The temperature programmed reduction (TPR) indicated that the synthesized catalysts were sufficiently reducible below 750 °C. A fixed bed reactor evaluation (at 750 °C) showed that both catalysts can facilitate methane reforming to syngas with minimal coking throughout the 30 hours time‐on‐stream (TOS). However, Ni20/Ce‐meso‐Al2O3 is more promising in terms of prolonged stability for dry reforming applications. Moreover, the syngas yield for Ni20/Ce‐γAl2O3 is close to equilibrium prediction during the first 1 hour of reaction time. [ABSTRACT FROM AUTHOR]