Hydrogen-rich syngas production by chemical looping steam reforming of acetic acid as bio-oil model compound over Fe-doped LaNiO3 oxygen carriers

Ni-based perovskites are promising oxygen carriers for chemical looping steam reforming to produce H₂-rich gas from organics. In this study, a series of Fe-doped LaNiO₃ perovskites with various Ni/Fe ratios (LaNi_xFe_1-xO₃ (0 ≤ x ≤ 1)) were investigated for chemical looping steam reforming of acetic acid as a model compounds of bio-oil. Results illustrated that although LaNiO₃ showed higher activity for gas production, the Ni–Fe bimetallic perovskites were more stable during the steam reforming reactions. It was found that Fe doping can promote the content of lattice oxygen in the perovskite which could be released during the steam reforming reaction, thus coking resistant of the perovskite was effectively improved. Among the LaNi_xFe_1-xO₃ (0 ≤ x ≤ 1) perovskites, LaNi_0.8Fe_0.2O₃ exhibited the best synergistic effect between Ni and Fe to achieve the highest H₂/CO for H₂-rich gas production. Operational variables of the steam reforming reactions catalyzed by LaNi_0.8Fe_0.2O₃ for H₂ production were further optimized.     

Chemical looping gasification of biomass char for hydrogen-rich syngas production via Mn-doped Fe2O3 oxygen carrier

Because of its low cost, an iron-based oxygen carrier is a promising candidate for hydrogen-rich syngas production from the chemical looping gasification of biomass. However, it needs modification from a reactivity point of view. In this study effect of Mn doping on Fe₂O₃ has been investigated for hydrogen-rich syngas production from biomass char at different temperatures (700–900 °C) and steam flow rates (60–100 μL/min). Several techniques (XRD, XPS, BET, and TPR-H₂) have been utilized to characterize fresh and spent oxygen carriers. The result demonstrated Mn-doing boosted the redox activity and the amount of oxygen vacancies, which increased hydrogen gas generation. Hydrogen production displayed different behavior across temperatures due to detecting Fe₂O₃ and MnFeO₃ phases for spent oxygen carriers. For the Fe₂O₃ oxygen carrier hydrogen gas yield is 1.67 Nm³/kg which is due to reduction of Fe₂O₃ phase to Fe₃O₄. However, the MnFe₂O₄ spinel phase detected in the spent MnFeO₃ oxygen carrier is a reason for improving hydrogen gas yield to 1.84 Nm³/kg. Change reaction temperature from 900 °C to 850 °C reduced hydrogen gas yield from 1.84 Nm³/kg to 1.83 Nm³/kg for with MnFeO₃ oxygen carrier. Regarding different steam flows, the proper flow rates that can maintain the formed phases and obtained best hydrogen gas yield are 80 and 90 μL/min, respectively. Meanwhile, the best hydrogen gas yield (2.21Nm³/kg) are obtained with MnFeO₃ oxygen carrier at optimum conditions (850 °C and 90 μL/min).     

Hydrogen‐rich syngas production from chemical looping steam reforming of bio‐oil model compound: Effect of bimetal on LaNi0.8M0.2O3 (M = Fe,Co, Cu,and Mn)

Chemical looping steam reforming (CLSR) of acetic acid as bio‐oil model compound is a suitable way to produce hydrogen‐rich syngas. The LaNiO₃ and LaNi_0.8M_0.2O₃ (M = Fe, Co, Mn, and Cu) perovskites were prepared via the sol‐gel method. The perovskites were characterized by X‐ray diffraction (XRD), thermogravimetry (TG), and test activity of hydrogen‐rich syngas in a fixed bed. XRD and TG results showed that the coke generation on LaNi_0.8Fe_0.2O₃ needs a lower decomposition temperature, and a stable structure was appeared after reaction. The activity order of hydrogen‐rich syngas on five types of perovskite is LaNi_0.8Fe_0.2O₃ > LaNi_0.8Co_0.2O₃ > LaNiO₃ > LaNi_0.8Mn_0.2O₃ > LaNi_0.8Cu_0.2O₃ at 650°C, mole ratio of steam/carbon (2:1), and sample mixture flow (GHSV = 34 736 g of feed/(g catalyst h)). The CLSR of acetic acid with LaNi_0.8Fe_0.2O₃ at GHSV = 43 992 g of feed/(g catalyst h) showed good stability. Correlated to experimental results, the adsorption energy of steam and acetic acid on five types of perovskite were calculated using density functional theory (DFT). The adsorption energy of steam (?0.61 eV) and acetic acid (?0.93 eV) of LaNi_0.8Fe_0.2O₃ is maximum. This value of DFT calculation is well explained in the experimental results.     

Biomass to hydrogen-rich syngas via catalytic steam reforming of bio-oil

Hydrogen-rich syngas production from the catalytic steam reforming of bio-oil from fast pyrolysis of pinewood sawdust was investigated by using La_1−xK_xMnO₃ perovskite-type catalysts. The effects of the K substitution, temperature, water to carbon molar ratio (WCMR) and bio-oil weight hourly space velocity (W_bHSV) on H₂ yield, carbon conversion and the product distribution were studied in a fixed-bed reactor. The results showed that La_1−xK_xMnO₃ perovskite-type catalysts with a K substitution of 0.2 gave the best performance and had a higher catalytic activity than the commercial Ni/ZrO₂. Both high temperature and low W_bHSV led to higher H₂ yield. However, excessive steam reduced hydrogen yield. For the La_0.8K_0.2MnO₃ catalyst, a hydrogen yield of 72.5% was obtained under the optimum operating condition (T = 800 °C, WCMR = 3 and W_bHSV = 12 h⁻¹). The deactivation of the catalysts mainly was caused by coke deposition.     

Hydrogen production from bio-oil: A thermodynamic analysis of sorption-enhanced chemical looping steam reforming

The steam reforming of pyrolysis bio-oil is one proposed route to low carbon hydrogen production, which may be enhanced by combination with advanced steam reforming techniques. The advanced reforming of bio-oil is investigated via a thermodynamic analysis based on the minimisation of Gibbs Energy. Conventional steam reforming (C-SR) is assessed alongside sorption-enhanced steam reforming (SE-SR), chemical looping steam reforming (CLSR) and sorption-enhanced chemical looping steam reforming (SE-CLSR). The selected CO₂ sorbent is CaO(s) and oxygen transfer material (OTM) is Ni/NiO. PEFB bio-oil is modelled as a surrogate mixture and two common model compounds, acetic acid and furfural, are also considered. A process comparison highlights the advantages of sorption-enhancement and chemical looping, including improved purity and yield, and reductions in carbon deposition and process net energy balance.The operating regime of SE-CLSR is evaluated in order to assess the impact of S/C ratio, NiO/C ratio, CaO/C ratio and temperature. Autothermal operation can be achieved for S/C ratios between 1 and 3. In autothermal operation at 30 bar, S/C ratio of 2 gives a yield of 11.8 wt%, and hydrogen purity of 96.9 mol%. Alternatively, if autothermal operation is not a priority, the yield can be improved by reducing the quantity of OTM. The thermodynamic analysis highlights the role of advanced reforming techniques in enhancing the potential of bio-oil as a source of hydrogen.     

Enhanced hydrogen-rich syngas generation in chemical looping methane reforming using an interstitial doped La1.6Sr0.4FeCoO6

Chemical looping methane reforming (CLMR) is a promising technology for syngas generation by designing an oxygen carrier to partially oxidize methane into mixed gases with expected H₂/CO ratio. The major challenge is the development of oxygen carriers with high reactivity, good selectivity, and excellent recyclability. We investigated a novel interstitial doped perovskite as an oxygen carrier to regulate the oxidation activity and demonstrated that Mg ions that interstitial entering into the crystal lattice of perovskite can improve the activation of methane greatly without any change of the crystal structure. According to the results of XPS and H₂-TPR, Mg ions also reduced the electron binding energy of oxygen on the sample surface and increased the migration rate of lattice oxygen. Compared with LSFC and Li-LSFC, the interstitial doping Mg-LSFC exhibited higher average methane conversion up to 98.66%, accompanying with 78.15% hydrogen content. Furthermore, the average yield of hydrogen of Mg-LSFC increased from 1.60 ml to 2.25 ml per 1 ml of methane when 0.02 g/min water participated in the reaction. Besides, the stability of Mg-LSFC was also proved by thermogravimetric experiments and fixed bed pulse experiments. Based on the experiment results, the reaction mechanism for methane activation was discussed to further providing a pathway to effectively enhance the hydrogen-rich syngas generation.     

Chemical looping steam reforming of ethanol without and with in-situ CO2 capture

Chemical looping steam reforming (CLSR) of ethanol using oxygen carriers (OCs) for hydrogen production has been considered a highly efficient technology. In this study, NiO/MgAl₂O₄ oxygen carriers (OCs) were employed for hydrogen production via CLSR with and without CaO sorbent for in-situ CO₂ removal (sorption enhanced chemical looping steam reforming, SE-CLSR). To find optimal reaction conditions of the CLSR process, including reforming temperatures, the catalyst mass, and the NiO loadings on hydrogen production performances were studied. The results reveal that the optimal temperature of OCs for hydrogen production is 650 °C. In addition, 96% hydrogen selectivity and a 'dead time' (the reduced time of OCs) less than 1 minute is obtained with the 1 g 20NiO/MgAl₂O₄ catalysts. The superior catalytic activity of 20NiO/MgAl₂O₄ is due to the maximal quantity of NiO loadings providing the most Ni active surface centers. High purity hydrogen is successfully produced via CLSR coupling with CaO sorbent in-situ CO₂ removal (SE-CLSR), and the breakthrough time of CaO is about 20 minutes under the condition that space velocity was 1.908 h^?1. Stability CLSR experiments found that the hydrogen production and hydrogen selectivity decreased obviously from 207 mmol to 174 mmol and 95%–85% due to the inevitable OCs sintering and carbon deposition. Finally, stable hydrogen production with the purity of 89%～87% and selectivity of 96%～93% was obtained in the modified stability SE-CLSR experiments.     

Chemical looping reforming of ethanol for syngas generation: A theoretical investigation

Chemical looping reforming (CLR) is a novel technology that can be used for reforming of cheaply available abundant biofuel like ethanol for the production of hydrogen/syngas for fuel cells. A systematic thermodynamic study for the CLR process using selected oxygen carriers was done to analyze the products and energy requirements of the CLR process in the temperature range of 500–1200 °C at 1 bar pressure for ethanol. The results showed favorable conditions for syngas manufacture from this process. Fe₂O₃ was found to be the best performing oxygen carrier followed by calcium and sodium sulfates, while Mn oxides were the least preferred oxygen carriers for CLR of ethanol process. The optimum process temperature was found to be 1000 °C. The actual CLR‐ethanol process shows exothermicity against the theoretical endothermic partial oxidation of ethanol. The results obtained in this theoretical study can pave the way for experimental programs for syngas generation for SOFC‐type fuel cells. Similar studies can be undertaken for other fuels for fuel processor development by CLR process. Copyright © 2012 John Wiley & Sons, Ltd.     

Modeling chemical looping syngas production in a microreactor using perovskite oxygen carriers

Synthesis gas, a mixture of hydrogen and carbon monoxide, could be produced in a chemical looping process. The objective of this work is the modeling of syngas production in a fixed bed microreactor by chemical looping reforming. A perovskite oxygen carrier was used for the reduction of methane to syngas. Twenty one gas-solid kinetic models were applied to the experimental data in which their parameters were estimated using an optimization code. The results show that among all models, reaction order model is the most preferable choice with satisfactory fitting criteria. The gas-solid model was coupled with a catalytic scheme to predict not only the conversion of perovskite oxygen carrier, but also the catalytic performance of the solid particles for syngas production. The kinetic parameters of the unified model were evaluated based on the experimental data of a fixed bed reactor. Analysis of both perovskite and nickel oxide, oxygen carriers shows that perovskite particles could convert 50 times slower than those of nickel oxide. A H₂/CO ratio of below 10 was obtained in a period of time. A large amount of hydrogen was produced after completing gas-solid reactions which was due to cracking of methane to carbon and hydrogen. Although hydrogen was the main outlet product afterwards, corresponding carbon formation is a problem which should be avoided. The reduction of methane was proposed before 500 s with a carbon formation of below 0.04 kg carbon per one kg of perovskite carrier. Solid reduction conversion, methane consumption and product distribution were analyzed inside the microreactor.     

Hydrogen-rich syngas production by the three-dimensional structure of LaNiO3 catalyst from a blend of acetic acid and acetone as a bio-oil model compound

Converting biomass bio-oil to hydrogen is valuable strategy. In this study, a blend of acetic acid and acetone has been utilized as a bio-oil model compound, where perovskite in a three-dimensional structure (3D-LaNiO₃) synthesized by a silica template method used as a catalyst. The result shows that the main phase of perovskite at 3D-LaNiO₃ catalyst has lower crystal size, resulting in decrease possibility of agglomeration. The amount of oxygen vacancies and higher ratio of Ni³⁺/Ni²⁺ are produced, enhancing the redox of catalyst. The stronger basic site and lager surface indicated the ability of improving coke deposition resistance. These results explained great activity of 3D-LaNiO₃ catalyst in producing hydrogen-rich syngas. The different steam/carbon mole ratios (S/C) have been discussed at 1 to 4, and the gas yield of H₂ (93.5%) shows highest at 600 °C and S/C = 3. Meanwhile, under this condition, the H₂ gas yield was stable and over 90% throughout 15 h of reaction. By analysis of spent 3D-LaNiO₃ catalyst, the result indicated that it has ability to resist the production of graphite coke deposition which is one of reasons for keeping catalyst activity. On the other hand, the stable of perovskite structure help in produce lattice oxygen for oxidizing coke deposited.     

Optimization of two bio-oil steam reforming processes for hydrogen production based on thermodynamic analysis

Thermodynamics of hydrogen production from conventional steam reforming (C-SR) and sorption-enhanced steam reforming (SE-SR) of bio-oil was performed under different conditions including reforming temperature, S/C ratio (the mole ratio of steam to carbon in the bio-oil), operating pressure and CaO/C ratio (the mole ratio of CaO to carbon in the bio-oil). Increasing temperature and S/C ratio, and decreasing the operating pressure were favorable to improve the hydrogen yield. Compared to C-SR, SE-SR had the significant advantage of higher hydrogen yield at lower desirable temperature, and showed a significant suppression for carbon formation. However excess CaO (CaO/C > 1) almost had no additional contribution to hydrogen production. Aimed to achieve the maximum utilization of bio-oil with as little energy consumption as possible, the influences of temperature and S/C ratio on the reforming performance (energy requirements and bio-oil consumption per unit volume of hydrogen produced, Q_D/H2 (kJ/Nm³) and Y_Bio-oil/H2 (kg/Nm³)) were comprehensively evaluated using matrix analysis while ensuring the highest hydrogen yield as possible. The optimal operating parameters were confirmed at 650 °C, S/C = 2 for C-SR; and 550 °C, S/C = 2 for SE-SR. Under their respective optimal conditions, the Y_Bio-oil/H2 of SE-SR is significant decreased, by 18.50% compared to that of C-SR, although the Q_D/H2 was slightly increased, just by 7.55%.     

Hydrogen production via chemical looping steam reforming of ethanol by Ni-based oxygen carriers supported on CeO2 and La2O3 promoted Al2O3

This work studies the effects of Ce⁴⁺ and/or La³⁺ on NiO/Al₂O₃ oxygen carrier (OC) on chemical looping steam reforming of ethanol for hydrogen production - alternating between fuel feed step (FFS) and air feed step (AFS). Suitable amount of Ce- and La-doping increases OC carbon tolerance. The solubility limit is found at 50 mol% La in solid solution. At higher La-doping, La₂O₃ disperses on the surface and adsorbs CO₂ forming La₂O₂CO₃ during FFS. From the 1st cycle, 12.5 wt%Ni/7 wt%La₂O₃-3wt%CeO₂–Al₂O₃ (N/7LCA) displays the highest averaged H₂ yield (3.2 mol/mol ethanol) with 87% ethanol conversion. However, after the 5th cycle, 12.5 wt%Ni/3 wt%La₂O₃-7wt%CeO₂–Al₂O₃ (N/3LCA) exhibits more stability and presents the highest ethanol conversion (88%) and H₂ yield (2.7 mol/mol ethanol). Amorphous coke on the OCs decreases with increasing La³⁺ content and can be removed at 500 °C during AFS; nevertheless, fibrous coke and La₂O₂CO₃ cannot be eliminated. Therefore, after multiple redox cycles, highly La-doped OCs exhibits rather low stability.     

Thermodynamic analysis of syngas production from biodiesel via chemical looping reforming

In this study, thermodynamic analysis of the syngas production using biodiesel derived from waste cooking oil is studied based on the chemical looping reforming (CLR) process. The NiO is used as the oxygen carrier to carry out the thermodynamic analysis. Syngas with various H₂/CO ratios can be obtained by chemical looping dry reforming (CL-DR) or steam reforming (CL-SR). It is found that the syngas obtained from CL-DR is suitable for long-chain carbon fuel synthesis while syngas obtained from CL-SR is suitable for methanol synthesis. The carbon-free syngas production can be obtained when reforming temperature is higher than 700 °C for all processes. To convert the carbon resulted from biodiesel coking and operate the CLR with a lower oxygen carrier flow rate, a carbon reactor is introduced between the air and fuel reactors for removing the carbon using H₂O or CO₂ as the oxidizing agent. Because of the endothermic nature of both Boudouard and water-gas reactions, the carbon conversion in the carbon reactor increases with increased reaction temperature. High purity H₂ or CO yield can be obtained when the carbon reactor is operated with high reaction temperature and oxidizing agent flow.     

Investigation on hydrogen production by catalytic steam reforming of maize stalk fast pyrolysis bio-oil

Hydrogen production via catalytic steam reforming of maize stalk fast pyrolysis bio-oil over the nickel/alumina supported catalysts promoted with cerium was studied using a laboratory scale fixed bed coupled with Fourier transform infrared spectroscopy/thermal conductivity detection analysis (FTIR/TCD). The effects of nickel loading, reaction temperature, water to carbon molar ratio (WCMR) and bio-oil weight hourly space velocity (W_bHSV) on hydrogen production were investigated. The highest hydrogen yield of 71.4% was obtained over the 14.9%Ni-2.0%Ce/A1₂O₃ catalyst under the reforming conditions of temperature = 900 °C, WCMR = 6 and W_bHSV = 12 h⁻¹. Increasing reaction temperature from 600 to 900 °C resulted in the significant increase of hydrogen yield. The hydrogen yield was significantly enhanced by increasing the WCMR from 1 to 3, whereas it increased slightly by further increasing WCMR. The hydrogen yield decreased with the increase of W_bHSV. Meanwhile, the coke deposition percentage changed little with increasing W_bHSV up to 12 h⁻¹ and then it increased by 4.5% with the further increase of W_bHSV from 12 to 24 h⁻¹.     

Mechanistic study of bio-oil catalytic steam reforming for hydrogen production: Acetic acid decomposition

To clarify the understanding of the mechanism of bio-oil catalytic steam reforming, we selected acetic acid as a typical bio-oil model compound to study its detailed behavior in decomposition over an active stepped Ni surface by density functional theory calculations. The adsorption geometries and energies of various intermediates were reported. Linear correlations between the adsorption energy and the number of hydrogen atoms removed for CH_xCOOH, CH_xCOO, and CH_x species (x = 1–3) were found, with increments of ?1.56, ?0.81, and ?1.80 eV, respectively. Thirty-seven possible elementary reactions of acetic acid decomposition were proposed, and their activation energies, reaction energies, rate constants, and equilibrium constants were calculated. Acetic acid dissociation likely started via α-carbon dehydrogenation, OH dehydrogenation, and dehydroxylation. Combined with microkinetic modeling, the most preferable decomposition pathway was suggested as CH₃COOH → CH₃CO → CO + CH₃. The rate-determining step was CH₃COOH dehydroxylation to CH₃CO with an activation energy of 0.68 eV and a rate constant of 3.82 × 10⁸ s^?1. The formation of CH₃COO was dominant at high temperatures, whereas its decomposition occurred with difficulty.     

Carbon deposition behavior in steam reforming of bio-oil model compound for hydrogen production

Catalyst deactivation caused by coke formation is a bottleneck in steam reforming of bio-oil for hydrogen production. The investigation of carbon deposition behavior can make a contribution to the improvement of catalyst and the knowledge of reaction mechanism. In this paper, m-cresol (C₇H₈O, one of the organic compounds present in bio-oil) was chosen as model compound. The experiment was carried out on a commercial Ni/MgO catalyst. As a comparative test, m-cresol decomposition showed carbon deposition can be formed more easily under higher temperature. In steam reforming process, for the competition of carbon deposition and carbon elimination, a peak value of coking formation rate was obtained in a broad range of temperature (575–900 °C). The increase of steam to carbon ratio can favor the carbon elimination. Final coking formation rate curve was determined under optimal reaction conditions and the results showed the severity of carbon deposition maintained a very low level during the entire reaction time. Based on the distribution of reforming products, high temperature and sufficient water feeding can favor the carbon conversion from solid and liquid phase to gaseous phase. Unreacted m-cresol is the main organic compound detected in liquid condensate. Some secondary reactions can be deduced through the other compounds detected. The carbon deposition state on catalyst surface can be in the form of nanofiber, but their concrete shapes can be different due to different reaction conditions.     

Nickel-iron modified natural ore oxygen carriers for chemical looping steam methane reforming to produce hydrogen

Chemical looping steam methane reforming (CL-SMR) is a promising and efficient method to produce hydrogen and syngas. However, oxygen carrier (OC) prepared by synthesis are complex, expensive and poor mechanical performance, while natural ore OCs are low activity and poor selectivity. In order to avoid these problems, Ni/Fe modification of natural ores were proposed to improve the reactivity and stability of OC to CL-SMR. The results indicated that the modified calcite recombined and improved the structural phase during the reaction, enhancing performance and inhibiting agglomeration. Moreover, high ratio of iron to nickel was easy to sinter and decline the OC performance. In addition, with the increase of steam flow, both CH₄ conversion and carbon deposition decreased. Thereinto, the highest H₂ concentration, CH₄ conversion efficiency and H₂ yield were obtained when the ratio of steam to OC was 0.05. Furthermore, CH₄ flow rate had a great impact on CL-SMR performance. When the ratio of CH₄ to OC was 0.04, it achieved the highest CH₄ conversion efficiency of 98.96%, the highest H₂ concentration of 98.83% and the lowest carbon deposition of 3.23%. However, the carbon deposition increased with the increase of CH₄ flow rate. After a long-time chemical looping process, the Ni/Fe modified calcite showed a consistently stable performance with average H₂ concentration of 93.08%, CH₄ conversion efficiency of 88.03%, and carbon deposition of 2.15%.     

Chemical looping reforming of ethanol-containing organic wastewater for high ratio H2/CO syngas with iron-based oxygen carrier

This work focused on chemical looping reforming (CLR) of ethanol-containing wastewater using iron-based oxygen carrier for high ratio H₂/CO syngas. Effects of various operating parameters on CLR experiments have been investigated. High temperature promotes the reactivity of oxygen carrier and release more lattice oxygen for CLR of ethanol-containing wastewater to realize maximum carbon conversion. 5% ethanol-containing wastewater, closed to the actual concentration of alcohol distillery wastewater, favors syngas yield. Ethanol-containing wastewater CLR processes could be divided into three stages, including the catalytic cracking, combination of catalytic cracking and reforming, and mainly catalytic reforming of ethanol, corresponding to three reduction periods Fe₂O₃ → Fe₃O₄, Fe₃O₄ → Fe₂O_2.45, and Fe₂O_2.45 → FeO, respectively. The whole process of ethanol-containing organic wastewater CLR is exothermic. Reaction heat released from the oxidation process of the reduced oxygen carrier can meet heat demand for CLR process. Ethanol-containing organic wastewater CLR opens up a new direction for hydrogen generation and waste treatment.     

Effect of steam reforming on methane-fueled chemical looping combustion with Cu-based oxygen carrier

The reduction characteristics of Cu-based oxygen carrier with H₂, CO and CH₄ were investigated using a fixed bed reactor, TPR and TGA. Results showed that temperatures for the complete reduction of Cu-based oxygen carrier with H₂ and CO are 300 °C and 225 °C, respectively, while the corresponding temperature with CH₄ is 650 °C. The carbon deposition from CH₄ occurred at over 550 °C. CO-chemisorption experiments were also conducted on the oxygen carrier, and it was indicated that Cu-based oxygen carrier sinter seriously at 700 °C. In order to lower the required reduction temperature of oxygen carriers, a new chemical looping combustion (CLC) process with CH₄ steam reforming has been presented in this paper. The basic feasibility of the process was illustrated using CuO–SiO₂. The new CLC process has the potential to replace the conventional gas-fired middle- and low-pressure steam and hot water boilers.     

Hydrogen production from catalytic steam reforming of biomass pyrolysis oil or bio-oil derivatives: A review

Steam reforming of biomass pyrolysis oil or bio-oil derivatives is one of the attractive approaches for hydrogen production. The current research focused on the development of promising catalysts with favorable catalytic activity and high coke resistance. Noble metal such as Rh has been proven to achieve promising reforming reaction efficiencies. However, Ni has attracted considerable attention owing to its stability, cost effectiveness, and good activity in breaking C–C and C–H bonds. Nevertheless, Ni-based catalysts have serious carbon deposition problems arising from chemical poisoning, metal sintering, and poor metal dispersion. This paper attempted to review the current trends in catalyst development considering the aspects of supports, metals, and promoters as an effort to find possible solutions for the limitations of Ni-based catalysts. The present review also covered the current understanding on the reaction mechanisms as well as the future prospects in the field of steam reforming catalysts.