Can fool's gold “pyrite” become real gold as a catalyst for clean-energy H2 production?

The natural, most abundant sulfide mineral of pyrite was modified using polyethyleneimine (PEI) for use as a catalyst in H₂ release reactions from NaBH₄ in methanol. The catalytic performances of pyrite, pyrite-PEI, and protonated pyrite-PEI (pyrite-PEI+) were compared and the hydrogen generation rate (HGR) values of 795 ± 26, 2883 ± 190, and 4320 ± 188 mL H₂/(g of catalyst x min)⁻¹ were measured for H₂ production from NaBH₄ methanolysis. The effect of methanol:water mixture at various ratios, the amount of catalyst, the concentration of NaBH₄, and temperature on H₂ production from NaBH₄ in methanol catalyzed by pyrite-PEI⁺ were investigated. The activation energies for pyrite-PEI, and pyrite-PEI⁺ catalyzed H₂ release reactions were calculated as 47.2 and 36.8 kJ/mol, respectively. It was found that the activity % for the pyrite-PEI⁺ catalyst decreased to 76.2 ± 2.7% after five consecutive uses with 100% conversion for each re-use study. Furthermore, the re-generation of pyrite-PEI⁺ catalyst after the 5th usage was readily ensured by HCl treatment to completely recover and further increase the activity% of the catalyst. Therefore, pyrite was shown to be a useful re-generable and economic green catalyst for H₂ production in many potential applications.     

Modifying the structure of red mud by simple treatments for high and stable performance in COx-free hydrogen production from ammonia

Red mud (RM) modified by various treatments was used as a catalyst for ammonia decomposition. Catalytic activity measurements performed at 500 °C and differential conversions illustrated that the rate increases with a decrease in the size of Fe₃N_y nanoparticles formed during activation in NH₃ flow. Measurements at 700 °C showed that a catalyst prepared by digesting RM in 6 M HCl followed by calcination at 900 °C provides a stable ammonia conversion of 98.8 ± 0.5% for more than 70 h at a space velocity of 120 000 cm³ NH₃ h^?1 g_cat^?1. This rate is premier among all iron-based catalysts in terms of both activity and stability and even on par with the performance of other non-noble metal catalysts. Detailed characterization indicated Fe₃N_y species readily available on the surface as the active species. Results provided here enable the utilization of RM as an environmentally-friendly, highly efficient, and almost cost-free catalyst for CO_x-free hydrogen production.     

Hydrogen‐rich gas production from catalytic gasification of pine sawdust over Fe‐Ce/olivine catalyst

In order to improve hydrogen production and reduce tar generation during the biomass gasification, a catalyst loaded Fe‐Ce using calcined olivine as the support (Fe‐Ce/olivine catalysts) was prepared through deposition‐precipitation method. The characteristics of catalysts were determined by XRF, BET, XRD, and FTIR. Syngas yield, hydrogen yield, and tar yield were used to evaluate the catalyst activity. Meanwhile, the stability of catalysts was also studied. The results showed that the specific surface area and pore volume of olivine after calcined at high temperature were improved which was beneficial for the load of metals. α‐Fe₂O₃ and CeO₂ were the main active component of Fe‐Ce/olivine catalyst. The Fe‐Ce/olivine catalyst displayed a good performance on the catalytic gasification of pine sawdust with a syngas yield of 0.93 Nm³/kg, H₂ yield of 21.37 mol/kg, and carbon conversion rate of 55.14% at a catalytic temperature and gasification temperature of 800°C. Meanwhile, the Fe‐Ce/olivine catalyst could maintain a good stability after 150 minutes used.     

Carbon spheres from lactose as green catalyst for fast hydrogen production via methanolysis

Micrometer sized carbon spheres (CSs) are prepared in a single step using lactose precursor via hydrothermal method. These CSs are chemically modified with 3-chloro-2-hydroxypropyl ammonium chloride (CHPACl) and triethylenetetramine (TETA) to generate amine groups on the particle surface. Modified CSs with TETA was protonated with HCl as CSs-TETA-HCl that the zeta potential is increased to +40.3 ± 0.70 from ?51.4 ± 4.66 mV. The catalytic performance of CSs are tested as catalysts in the methanolysis of NaBH₄, and the best catalytic performance as 2586 mL min^?1 g^?1 hydrogen generation rate (HGR) was obtained by CSs-TETA-HCl catalyst at 298 K as metal free catalyst. Furthermore, various parameters such as the amount of NaBH₄, the reaction temperature, and the reusability of CSs-TETA-HCl particles are investigated. More importantly, relatively low activation energy, 23.82 kJ mol^?1 for CSs-TETA-HCl catalyzed NaBH₄ methanolysis reaction is obtained in comparison to metal nanoparticle and metal free catalysts reported for the same purpose in the literature.     

A novel Microcystis aeruginosa supported manganese catalyst for hydrogen generation through methanolysis of sodium borohydride

In this study, Microcystis Aeruginosa (MA)- microalgae species was used for the first time as a support material with metal ions loading to fabricate a highly efficient catalyst for the hydrogen generation through methanolysis of sodium borohydride (NaBH₄). Microalgae was pre-treated with hydrochloric acid (3 M HCl) for 24 h at 80 °C. Subsequently, different metal ions (Mn, Co, and Mo) were loaded to the pre-treated samples. Finally, metal-loaded samples were subjected to burning in oven to fabricate the catalyst. Primarily, manganese metal was selected based on the best metal performance. Afterwards, different metal loading ratios, burning temperatures and burning times were evaluated to synthesize the optimal MA-HCl-Mn catalyst. Results showed the optimal conditions as Mn ratio, burning temperature and time as 50%, 500 °C and 45 min, respectively. To characterize the catalyst, FTIR, SEM-EDX, XRD, XPS and TEM analyses were performed. Hydrogen generation via methanolysis was performed at various NaBH4 ratio of 1–7.5% while changing concentrations from 0.05 to 0.25 g catalysts with diverge temperatures of (30, 40, 50 and 60 °C). The maximum hydrogen generation rate (HGR) by this novel catalyst was found as 4335.3, 5949.9, 7649.4 and 8758.9 mLmin⁻¹gcat⁻¹, respectively. Furthermore, the activation energy was determined to be 8.46 kJ mol⁻¹.     

Catalytic activity of metal-free amine-modified dextran microgels in hydrogen release through methanolysis of NaBH4

Polymeric microgels were prepared from dextran (Dex) by crosslinking linear natural polymer dextran with divinyl sulfone (DVS) with a surfactant-free emulsion technique resulting in high gravimetric yield of 78.5 ± 5.3% with wide size distribution. Dex microgels were chemically modified, and then used as catalyst in the methanolysis of NaBH₄ to produce H₂. The chemical modification of Dex microgel was done on epichlorohydrin (ECH)-reacted Dex microgels with ethylenediamine (EDA), diethylenetriamine (DETA), and triethylenetetraamine (TETA) in dimethylformamide (DMF) at 90°C for 12 hours. The modified dextran-TETA microgels were protonated using treatment with hydrochloric acid (HCl) and m-Dex microgels-TETA-HCl was found to be a very efficient catalyst for methanolysis of NaBH₄ to produce H₂. The effects of reaction temperature and NaBH₄ concentration on H₂ generation rates were investigated and m-Dex microgels-TETA-HCl catalyst possessed excellent catalytic performances with 100% conversion and 80% activity at end of 10 consecutive uses and was highly re-generatable with simple HCl treatment. Interestingly, m-Dex microgels-TETA-HCl catalyst can catalyze NaBH₄ methanolysis reaction in a mild temperature range 0 to 35°C with E_a value of 30.72 kJ/mol and in subzero temperature range, −20 to 0°C with E_a value of 32.87 kJ/mol, which is comparable with many catalysts reported in the literature.     

Hydrogen production from ethanol steam reforming over Ni/SiO2 catalysts: A comparative study of traditional preparation and microwave modification methods

Four silica‐supported nickel catalysts with Ni content of 10 wt% were prepared by impregnation and coprecipitation methods with or without microwave‐assisted calcination. The prepared catalysts were characterized by some techniques (BET, XRD, TEM, XPS, H₂‐TPR, etc.) and evaluated with respect to steam reforming of ethanol (SRE) for hydrogen production. The results show that the prepared Ni/SiO₂ catalysts are all very active and selective for SRE. The high activity of the four catalysts may benefit from their high specific areas and the good dispersion of active components on the carrier. The rate of carbon deposition decreases with reaction temperature especially below 450 °C. The maximum hydrogen yield of 4.54 mol H₂/mol EtOH‐reacted can be obtained over the Ni/SiO₂ catalyst by the microwave‐assisted coprecipitation method at a reaction temperature of 600 °C, EtOH/H₂O molar ratio of 1:12, liquid hourly space velocity of 11.54 h^?1 and time on stream within 600 min. The Ni/SiO₂ catalysts with microwave modification exhibits better performances of hydrogen production, stability and resistance to carbon deposition than that without microwave modification preparation, which is mainly attributed to that the microwave‐assisted treatment can decrease the catalyst acidity and enhance the interaction between metal support. Copyright © 2013 John Wiley & Sons, Ltd.     

Hydrogen production by partial oxidation of ethanol over Pt/CNT catalysts

The platinum‐supported catalysts have been prepared by ethylene glycol reduction method, and the catalysts were applied to the partial oxidation of ethanol (POE) for hydrogen production. Four types of support, including CNTs, Al₂O₃, ZrO₂, and CeO₂, were used on POE catalytic performance test. Prior to catalyst preparation, the influence of acidic pretreatment on CNTs purity, surface morphology, and pore structure were investigated. The acid‐treated CNTs and prepared catalysts were characterized with N₂ physisorption, Raman, thermogravimetric, and transmission electron microscopy analysis. The experimental results show that the particle size and metal dispersion of platinum on CNTs, as well as POE activity, depend on pH value of reducing agent and reduction temperature in the stage of catalyst preparation. In the condition pH value of 10 and temperature at 120 °C for catalyst 5 wt% Pt/CNTs preparation, 2 nm platinum clusters were obtained. Using the as‐prepared catalyst to study the effects of POE reaction conditions on the ethanol conversion, hydrogen selectivity, and hydrogen production rate under constant gas hourly space velocity, the corresponding values at the optimum reaction temperature 400 °C and O₂/C₂H₅OH molar ratio of 0.5 were 98.2%, 97.5%, and 202.3 mmol s^?1 kg^?1, respectively. Copyright © 2013 John Wiley & Sons, Ltd.     

La2O3-modified highly dispersed AuPd alloy nanoparticles and their superior catalysis on the dehydrogenation of formic acid

Formic acid (FA, HCOOH), a convenient and safe hydrogen storage material, has the great potential for fuel cell applications. However, hydrogen generation of FA is inefficient in the presence of heterogeneous catalysts at relatively low temperatures, which remains a big challenge. Herein, La₂O₃-modified highly dispersed AuPd alloy nanoparticles (AuPdLa₂O₃) with small particle size have been successfully anchored on carbon nanotubes (CNTs) by a facile co-reduction route. Moreover, the catalyst exhibits excellent catalytic activity and 100% hydrogen selectivity for hydrogen generation in the formic acid/sodium formate (FA/SF) system with the initial turnover frequency (TOF) value of 589 mol H₂ mol^?1 catalyst h^?1 at 50 °C and 280 mol H₂ mol^?1 catalyst h^?1 even at room temperature (25 °C). The present Au_0.3Pd_0.7-(La₂O₃)_0.6/CNTs with superior catalysis on FA dehydrogenation without any CO generation at room temperature can not only pave the way for practical application of hydrogen storage system, but also can be extended to other catalysis system.     

Very fast H2 production from the methanolysis of NaBH4 by metal‐free poly(ethylene imine) microgel catalysts

The polyethyleneimine (PEI) microgels prepared via microemulsion polymerization are protonated by hydrochloric acid treatment (p‐PEI) and quaternized (q‐PEI) via modification reaction with methyl iodide and with bromo alkanes of different alkyl chain lengths such as 1‐bromoethane, 1‐bromobutane, 1‐bromohexane, and 1‐bromooctane. The bare p‐PEI and q‐PEI microgels are used as catalysts directly without any metal nanoparticles for the methanolysis reaction of sodium borohydride (NaBH₄). Various parameters such as the protonation/quaternization reaction on PEI microgels, the amount of catalyst, the amount of NaBH₄, and temperature are investigated for their effects on the hydrogen (H₂) production rate. The reaction of self‐methanolysis of NaBH₄ finishes in about 32.5 min, whereas the bare PEI microgel as catalyst finishes the methanolysis of NaBH₄ in 22 min. Surprisingly, it is found that when the protonated PEI microgels are used as catalyst, the same methanolysis of NaBH₄ is finished in 1.5 min. The highest H₂ generation rate value is observed for protonated PEI microgels (10 mg) with 8013 mL of H₂/(g of catalyst.min) for the methanolysis of NaBH₄. Moreover, activation parameters are also calculated with activation energy value of 23.7 kJ/mol, enthalpy 20.9 kJ/mol, and entropy ?158 J/K.mol. Copyright © 2016 John Wiley & Sons, Ltd.     

Ruthenium(0) nanoparticles supported on silica coated Fe3O4 as magnetically separable catalysts for hydrolytic dehydrogenation of ammonia borane

Ruthenium(0) nanoparticles supported on bare or silica-coated magnetite are prepared by impregnation of ruthenium(III) ions followed by their reduction with aqueous solution of sodium borohydride on the surface of support. These magnetically isolable catalysts are used in hydrogen generation from the hydrolysis of ammonia borane at room temperature. They conserve their initial catalytic activity even after the fifth reuse in the hydrolysis reaction. Ruthenium(0) nanoparticles supported on bare magnetite and silica-coated magnetite provide turnover frequency values of 29 min^?1 and 127 min^?1 and in hydrolytic dehydrogenation of ammonia borane at 25.0 ± 0.1 °C. Thus, coating of the surface of magnetite with silica results in a significant enhancement in catalytic activity of ruthenium(0) nanoparticles in hydrogen generation from the hydrolysis of ammonia borane.     

H2 production from methane decomposition by fullerene at low temperature

Carbon materials have previously been reported to work as catalysts for hydrogen (H₂) production from hydrocarbons. Mechanisms of the catalytic behavior of graphite and carbon black (CB) have often been discussed in literature. Graphite and CB is constructed from mainly 6-membered rings with sp² bonds. To understand the catalytic behavior of carbon materials for H₂ production by methane (CH₄) decomposition, the catalytic behavior of fullerenes with 6-membered rings and also those comprising 5- and 7-membered rings with sp² bonds and their associated mechanisms should be investigated. In this study, the fullerene catalyst activity has been investigated using gas chromatography and the electronic states and nanoscale structures have been analyzed.H₂ production started at 400 °C and the H₂ production rate gradually increased with time, and the activation energy of the fullerene for H₂ production by CH₄ decomposition was found to be 166 kJ/mol. Moreover, in situ heating X-ray photon spectroscopy (XPS) measurements showed that the π-π1 transition signal becomes stronger with increasing temperature above the threshold of 300 °C. The transition of the π electrons to π1 orbitals upon heating is expected to decompose CH₄ absorbed on fullerene. Moreover, transmission electron microscopy (TEM) analysis revealed that the generated carbon atoms from the CH₄ decomposition were deposited onto the surfaces of the fullerenes, forming amorphous and layered concentric sphere carbon. Amorphous carbon is reported to not work as a catalyst for CH₄ decomposition at around 400 °C. From XPS analysis and TEM observations of these two structures, it is anticipated that the ring structures without 6-membered rings in carbon materials with sp² bonding contribute to this catalytic behavior for CH₄ decomposition at a low temperature of 400 °C.     

Hydrogen‐rich gas production from ethanol steam‐reforming reaction using NiZr‐loaded MCM‐48 catalysts at mild temperature

The rich‐hydrogen generation from ethanol steam reforming over NiZr, which is used as an anode material in solid oxide fuel cells, ‐loaded MCM‐48 (NiZr/MCM‐48) catalyst was investigated in this study. We used an impregnation approach to synthesize an MCM‐48 (70.0 wt‐%) support loaded with bimetallic NiZr (30.0‐wt%, Ni:Zr atomic ratio = 4:6, 5:5, and 6:4), and the prepared catalysts were applied to the steam‐reforming reactions of ethanol. These three bimetallic NiZr/MCM‐48 catalysts exhibited significantly higher reforming reactivity than the mono‐metal, Ni‐loaded MCM‐48 (Ni/MCM‐48) catalyst. The hydrogen production was started from 350°C over the three NiZr/MCM‐48 catalysts, compared to above 550°C over the Ni/MCM‐48 catalyst. The catalytic performance was affected by the Zr content. The H₂ production and ethanol conversion were maximized at 85% and 95%, respectively, over Ni₄Zr₆/MCM‐48 at 750°C for 1 h at CH₃CH₂OH:H₂O = 1:1 and a gas hourly space velocity of 4000 h^‐1. This high performance was maintained for up to 60 h. Copyright © 2013 John Wiley & Sons, Ltd.     

Hydrogen production enhancement using hot gas cleaning system combined with prepared Ni-based catalyst in biomass gasification

This paper investigates the hot gas temperature effect on enhancing hydrogen generation and minimizing tar yield using zeolite and prepared Ni-based catalysts in rice straw gasification. Results obtained from this work have shown that increasing hot gas temperature and applying catalysts can enhance energy yield efficiency. When zeolite catalyst and hot gas temperature were adjusted from 250 °C to 400 °C, H₂ and CO increased slightly from 7.31% to 14.57%–8.03% and 17.34%, respectively. The tar removal efficiency varies in the 70%–90% range. When the zeolite was replaced with prepared Ni-based catalysts and hot gas cleaning (HGC) operated at 250 °C, H₂ contents were significantly increased from 6.63% to 12.24% resulting in decreasing the hydrocarbon (tar), and methane content. This implied that NiO could promote the water-gas shift reaction and CH₄ reforming reaction. Under other conditions in which the hot gas temperature was 400 °C, deactivated effects on prepared Ni-based catalyst were observed for inhibiting syngas and tar reduction in the HGC system. The prepared Ni-based catalyst worked at 250 °C demonstrate higher stability, catalyst activity, and less coke decomposition in dry reforming. In summary, the optimum catalytic performance in syngas production and tar elimination was achieved when the catalytic temperature was 250 °C in the presence of prepared Ni-based catalysts, producing 5.92 MJ/kg of lower heating value (LHV) and 73.9% tar removal efficiency.     

Highly efficient CoB catalyst using a support material based on Spirulina microalgal strain treated with ZnCl2 for hydrogen generation via sodium borohydride methanolysis

In the study, a different support material based on ZnCl₂‐treated Spirulina microalgal strain (SSMS‐ZnCl₂) was prepared. Then, the SSMS‐ZnCl₂‐CoB catalysts were used as a very efficient catalyst to produce hydrogen via the SB methanolysis. The SB concentration, Co metal percentage in the supported‐catalyst, ZnCl₂ concentration, ZnCl₂ impregnation time, temperature, and reusability experiments were performed. The maximum hydrogen generation rates (HGR) for the SSMS‐ZnCl₂‐CoB at 30°C and 60°C were found to be 9266 and 36 366 mL min^?1 g_cat^?1, respectively. In addition, TOF values for 30°C and 60°C were calculated 33 and 110 L·mol_H2·mol_Co^?1·min^?1 for the methanolysis of SB with SSMS‐ZnCl₂‐CoB catalyst. The activation energy was 31.13 kJ mol^?1. The reusability experiments were repeated five times under the same conditions. The almost 100% conversion was obtained at each use. XRD, FTIR, TEM, SEM‐EDX, and ICP‐MS analysis were performed for SSMS‐ZnCl₂‐CoB characterization.     

Magnetic dendritic KCC-1 nanosphere-supported cobalt composite as a separable catalyst for hydrogen generation from NaBH4 hydrolysis

The introduction of magnetism into a catalyst can greatly optimize its separation performance. In the present work, a kind of magnetically separable catalysts for promoting NaBH₄ hydrolysis have been fabricated by anchoring cobalt nanoparticles on magnetic dendritic KCC-1 nanospheres composed of magnetic Fe₃O₄ core and fibrous shell. The fabricated catalysts were characterized with various characterization methods, including absorption spectroscopy (AAS), scanning electron microscopy (SEM), high-resolution transmission electronic microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM), and Fourier transform infrared (FT-IR), etc. This kind of catalysts exhibit high catalytic activity for promoting the hydrolysis of NaBH₄ under alkaline conditions, giving a hydrogen generation rate and activation energy of 3.83 L min⁻¹ g_Co⁻¹ (30 °C) and 53.63 kJ mol⁻¹, respectively. After used for 5 cycles, the catalyst showed 36.5% catalytic activity reserved. Most importantly, the magnetism of the catalyst made it easily separated and recycled from the solution after the reaction completed. The development of this kind of catalysts could provide a promising option for catalyzing NaBH₄ hydrolysis for portable hydrogen production from.     

One-pot synthesis of supported Ni@Al2O3 catalysts with uniform small-sized Ni for hydrogen generation via ammonia decomposition

Nickel based materials are the most potential catalysts for CO_x-free hydrogen production from ammonia decomposition. However, the facile synthesis of supported Ni-based catalysts with small size Ni particles, high porosity and good structural stability is still of great demand. In this work, uniform small-sized Ni particles supported into porous alumina matrix (Ni@Al₂O₃) are synthesized by a simple one-pot method and used for ammonia decomposition. The Ni content is controlled from 5 at.% to 25 at.%. Especailly, the 25Ni@Al₂O₃ catalyst shows the best catalytic performance. With a GHSV of 24,000 cm³g_cat^?1h^?1, 93.9% NH₃ conversion is achieved at 600 °C and nearly full conversion of NH₃ is realized at 650 °C. The hydrogen formation rate of 25NiAl catalyst reaches 3.6 mmol g_cat^?1min^?1 at 400 °C and 7.8 mmol g_cat^?1min^?1 at 450 °C. The enhanced activity observed on 25Ni@Al₂O₃ catalyst can be attributed to the structural characteristic that large amounts of uniform-sized small (7.2 ± 0.9 nm) Ni particles are highly dispersed into porous alumina matrix. The aggregation of active metallic Ni particles during the high temperature reaction can be effectively prevented by the porous alumina matrix due to the strong interaction between them, thus ensuring a good catalytic performance.     

Copper oxide hollow spheres: Synthesis and catalytic application in hydrolytic dehydrogenation of ammonia borane

In this paper, CuO hollow microspheres with different shell thickness and porosity have been synthesized using carbonaceous saccharide microspheres as templates according to a modified literature method. These CuO hollow microspheres were characterized and their catalytic properties in the hydrolytic dehydrogenation of ammonia borane (NH₃BH₃, AB) were examined. A kinetic study indicated that a maximum hydrogen generation rate of 294 mL H₂ min^?1 (g catalyst)^?1 can be achieved at 45 ± 0.2 °C in the present system, which is comparable with that for other reported Cu based catalysts.     

Hydrogen generation via supercritical water gasification of lignin using Ni‐Co/Mg‐Al catalysts

In this study, a group of Ni‐Co/Mg‐Al catalysts was prepared for hydrogen production via supercritical water gasification of lignin. The effects of different supports and preparation methods were examined. All catalysts were evaluated under the operation conditions of 650 °C, 26 MPa, and water to biomass mass ratio of 5 in a batch reactor. The Cop.2.6Ni‐5.2Co/2.6Mg‐Al catalyst showed the best performance with highest gas yield (12.9 wt%) and hydrogen yield (2.36 mmol·g^?1). The results from catalyst characterization suggest that the properties of this type of catalyst are dependent on multiple factors including support Mg‐Al molar ratio and preparation method, and better coke resistance of the catalyst could be obtained by the preparation method of coprecipitation. Therefore, coprecipitation method should be applied for the preparation of Ni‐Co/Mg‐Al catalysts for hydrogen production via supercritical water gasification of lignin. Copyright © 2017 John Wiley & Sons, Ltd.     

Hydrogen production from wood gasification promoted by waste eggshell catalyst

Bio‐hydrogen renowned as a future potential hydrogen source and studies were devoted in developing the efficient way to obtain the hydrogen. Biomass gasification of Azadirachta excelsa wood was carried out with addition of naturally derived CaO catalyst using temperature‐programmed gasification (TPG) technique. The reaction (TPG) was performed at 50–1000°C in 5% O₂/He with flow rate 10 ml/min, and the product gas evolution (H₂, CH₄, CO and CO₂) was detected by online mass spectrometer. The waste eggshell was chosen as a natural source of CaO, and the effect of catalyst loading was investigated in this study. All the fresh and used catalysts were characterized, and the physicochemical changes of the eggshell were observed through scanning electron microscopy, X‐ray fluorescence and X‐ray diffraction techniques. Hydrogen yield were increased along with the catalyst loading (20%, 40% and 60%) from 57 to 73%, respectively, compared to the reaction without catalyst. The additions of waste eggshell enhanced the catalytic activity and suppressed CO₂ production through CaO absorption property which induced the water gas shift reaction that promotes H₂ production at lower temperature. Copyright © 2013 John Wiley & Sons, Ltd.