Water hyacinth (Eichhornia crassipes) biochar as an alternative cathode electrocatalyst in an air-cathode single chamber microbial fuel cell

In the present work, Water Hyacinth Biochar (WHB) was produced by pyrolysis at 900 °C and then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDX-SEM, Fourier transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area and particle size analyses. The results indicate that WHB has Oxygen Reduction Reaction (ORR) catalytic activity, with an average of 2.58 electrons per oxygen molecule transferred from WHB for ORR. The ORR catalytic activity of WHB is attributed to its physical and chemical surface properties. The maximum power density produced from an air cathode single chamber microbial fuel cell (ACSC-MFC) with WHB as the ORR catalyst versus the Pt/C catalyst were 24.7 and 12.3 mWm⁻², respectively. This study demonstrates that Water Hyacinth Biochar can be used as an inexpensive catalyst for the ORR in microbial fuel cells.     

Hydrogen production from biomass and plastic mixtures by pyrolysis-gasification

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

Low carbon hydrogen production in Canada via natural gas pyrolysis

Large scale, low cost, and low carbon intensity hydrogen production is needed to reduce emissions in the energy and transportation sectors. We present a techno-economic analysis and life cycle assessment of natural gas pyrolysis technologies for hydrogen production, with carbon black (CB) as a co-product. Four designs were considered based on the source of heat to the pyrolysis system, the combustion medium, and use of carbon capture (CC) technology. The oxygen-fired-CB design with CC is the most attractive from financial and environmental perspectives, superior to a conventional steam methane reformer (SMR) process with CC. The estimated pre-tax minimum hydrogen selling prices for the pyrolysis technologies range between $1.08/kg and $2.43/kg when natural gas (NG) costs $3.76/GJ. Key advantages include near-zero onsite GHG emissions of the oxygen-fired-CB design with CC and up to 41% lower GHG emissions compared to the SMR + CC process. The results indicate that natural gas pyrolysis may be a feasible pathway for hydrogen production.     

Hydrogen production from catalytic reforming of the aqueous fraction of pyrolysis bio-oil with modified Ni–Al catalysts

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

Hydrogen production via catalytic pyrolysis of biomass in a two-stage fixed bed reactor system

This study introduces an innovative process of generating hydrogen-rich gas from biomass through the catalytic pyrolysis of biomass in a two-stage fixed bed reactor system. Water hyacinth was used as the biomass feedstock. The effects of various factors such as pyrolysis temperature, catalytic bed temperature, residence time, catalyst, and the nickel content of the catalyst on the pyrolysis productivity were investigated and the yields of H₂, CO, CH₄, and CO₂ were obtained. Results showed that the high productivity of hydrogen can be obtained particularly by increasing the catalytic bed temperature, residence time, and catalysts. The favorable reaction conditions are as follows: a first-stage pyrolysis temperature of 650 °C–700 °C, a second-stage catalytic bed temperature of 800 °C, a catalytic pyrolysis reaction time of 17 min, and a nickel content of 9% (wt %).     

Technoeconomic analysis for hydrogen and carbon Co-Production via catalytic pyrolysis of methane

Catalytic Methane Pyrolysis (CMP) is an innovative method to convert gaseous methane into valuable H₂ and carbon products. The catalytic approach to methane pyrolysis has the potential to decrease the required operating temperature for methane decomposition from >1000 °C to under 700 °C. In this work, a novel inexpensive catalyst is discussed that displays low operating temperatures, while still maintaining high reactivity and long proven lifetimes. The kinetics associated with the catalyst's performance are modeled and a correlation was developed for use with practical simulation tools. A techno-economic assessment was conducted applying experimentally determined kinetics for the CMP reaction with the specific catalyst. Two process concepts that utilize CMP using the novel catalyst are presented in this work. Optimizations were considered in these processes and the CO₂ emissions and cost of hydrogen production of the two optimized cases, CMP with H₂ combustion (CMP-H₂) and CMP with CH₄ Combustion (CMP-CH₄), are compared to that of the current industrial standard for hydrogen production, Steam Methane Reforming with carbon capture and sequestration (SMR-CCS). Both of the proposed concepts convert methane into gaseous hydrogen and valuable carbon products, graphitic carbon to carbon Nano fibers. The carbon price was treated as a variable to determine the sensitivity of hydrogen production cost to the carbon price. The analysis indicates that cost of hydrogen production is highly dependent on the recovery and sale of carbon byproducts. Based on Aspen modeling of these two concepts for large scale hydrogen production (216 tons/day), the cost of hydrogen production, without considering carbon sales, was estimated to be $<3.25/kg, assuming a natural gas price of $7/MMBTU and conservative catalyst cost of $8/kg. Assuming 100% recovery of carbon, the price can be reduced to $0/kg by selling the carbon at <$1/kg. A market assessment suggests that values of graphitic carbon and carbon fibers range from ~$10/kg and ~$25–113/kg, respectively. The cost of H₂ production via conventional SMR is ~$2.2/kg when accounting for the cost of CO₂ sequestration. The proposed processes produce a maximum of 0–2 kg CO₂/kg H₂ in contrast to the 10 kg CO₂/kg H₂ produced via conventional SMR-CCS. The process displays an enormous potential for competitive economics accompanied by reduced greenhouse gas emissions.     

Effect of in-situ and ex-situ injection of steam on staged-gasification for hydrogen production

K modified Ni-based catalysts are used to investigate the effect of in-situ and ex-situ injection of steam (ISI and ESI) on biomass pyrolysis and in-line catalytic steam reforming in a two-stage fixed bed reactor. The results show that 0.5 wt% K is appropriate to modify the Ni-based catalysts for steam reforming of biomass pyrolysis vapor. Compared to the catalytic cracking without steam addition, both ISI and ESI increase the gas yield and the carbon conversion efficiency (X_c) of the pyrolysis vapors. And the ESI is more beneficial to the conversion of pyrolysis vapors to small molecular gases. The maximum hydrogen concentration, hydrogen yield and carbon conversion efficiency (X_c) of staged-gasification can reach 53.8%, 31 mmol/g-bio, and 94.6%, respectively, when both stages are at 700 °C with ex-situ steam injection (S/C = 1.2) and 3 g catalyst loaded in the second stage. Also, the steam is beneficial to removing the depositions of graphitized coke and small molecular polycyclic aromatic hydrocarbon on the catalysts. However, it is yet difficult for steam to react with the highly ordered carbonaceous.     

Degradation of rubber waste into hydrogen enriched syngas via microwave-induced catalytic pyrolysis

Microwave-induced catalytic pyrolysis of end-of-life tires was conducted for the purpose of producing hydrogen-enriched syngas. Tire derived char (TDC) was employed as the catalyst due to its superiorities of excellent microwave-absorbing ability, remarkable catalytic effect, and cost-effectiveness. The effects of the carbon structure, microwave power, and tire-to-catalysts ratio on the hydrogen yield and conversion rate were investigated. TDC had two functions in promoting the production of hydrogen in microwave-induced pyrolysis (MP). One was facilitating the degradation of tar into gas, and the other was initiating the catalytic reforming of light hydrocarbons into hydrogen. The highest hydrogen yield (27.81 mmol/g) and conversion rate (85.57%) were obtained under optimal experimental conditions. The as-generated TDC in MP could be reused as a catalyst for MP, thus improving the economics of this method significantly. This research provides an efficient and economical strategy for the microwave-induced pyrolysis of end-of-life tires to produce hydrogen-rich syngas.     

Low-carbon hydrogen production via electron beam plasma methane pyrolysis: Techno-economic analysis and carbon footprint assessment

Electron beam plasma methane pyrolysis is a hydrogen production pathway from natural gas without direct CO₂ emissions. In this work, two concepts for a technical implementation of the electron beam plasma pyrolysis in a large-scale hydrogen production plant are presented and evaluated in regards of efficiency, economics and carbon footprint. The potential of this technology is identified by an assessment of the results with the benchmark technologies steam methane reforming, steam methane reforming with carbon capture and storage as well as water electrolysis. The techno-economic analysis shows levelized costs of hydrogen for the plasma pyrolysis between 2.55 €/kg H₂ and 5.00 €/kg H₂ under the current economic framework. Projections for future price developments reveal a significant reduction potential for the hydrogen production costs, which support the profitability of plasma pyrolysis under certain scenarios. In particular, water electrolysis as direct competitor with renewable electricity as energy supply shows a considerably higher specific energy consumption leading to economic advantages of plasma pyrolysis for cost-intensive energy sources and a high degree of utilization. Finally, the carbon footprint assessment indicates the high potential for a reduction of life cycle emissions by electron beam plasma methane pyrolysis (1.9 kg CO₂ eq./kg H₂ – 6.4 kg CO₂ eq./kg H₂, depending on the electricity source) compared to state-of-the-art hydrogen production technology (10.8 kg CO₂ eq./kg H₂).     

Hydrogen production via in-line pyrolysis-reforming of organic solid waste enhanced by steel slags

Steel slag derivates prepared from waste steel slag using acid leach method, are employed to promote hydrogen production from organic solid waste by in-line pyrolysis-steam reforming of Chinese medicine residues (CMR). The optimum pyrolysis conditions are determined during the fast pyrolysis experiment of CMR (T_prolysis = 800 °C, F_N2 = 200 mL_STP/min). During in-line pyrolysis-reforming of CMR with steel slag derivates, for example CaO(SS)-50 wt%LR compounds, as reforming catalyst, the hydrogen yield is profoundly increased from 7.57 mmol/g_CMR (pyrolysis operation) to 11.49 mmol/g_CMR, while tar yield has been reduced 30.50%. FeO_x in LR remarkably increases lattice oxygen and adsorption oxygen in NCA-LR or NCA-LR-CaO(SS) compounds, so tar and CO conversion are efficiently improved while coke deposition on catalyst surface is significantly reduced. LR is demonstrated to be able to act as or partially alternate nickel-based catalyst during steam reforming of pyrolysis gas, which would greatly reduce the cost of hydrogen production from OSWs.     

Preparation of nanocrystalline metal (Cr,Al, Mn,Ce, Ni,Co and Cu) modified ferrite catalysts for the high temperature water gas shift reaction

Water gas shift reaction is an essential process of hydrogen production and carbon monoxide removal from syngas. Fe–Cr–Cu catalysts are typical industrial catalysts for high temperature water gas shift reaction but have environmental and safety concerns related to chromium content. In this work nanocrystalline metal (M)-modified ferrite catalysts (M = Cr, Al, Mn, Ce, Ni, Co and Cu) for replacement of chromium were prepared by coprecipitation method and the effects of promoters on the structural and catalytic properties of the iron based catalysts were studied. Prepared catalysts were characterized using X-ray diffraction (XRD), N₂ adsorption (BET), temperature-programmed reduction (TPR) and transmission electron microscopies (TEM) techniques. Temperature-programmed reduction measurements inferred that copper favors the active phase formation and significantly decreased the reduction temperature of hematite to magnetite. In addition, water gas shift activity results revealed that Fe–Al–Cu catalyst with Fe/Al = 10 and Fe/Cu = 5 weight ratios showed the highest catalytic activity among the prepared catalysts. Moreover, the effect of calcination temperature, GHSV and steam/gas ratio on the catalytic performance of this catalyst was investigated.     

Distributed production of hydrogen by auto-thermal reforming of fast pyrolysis bio-oil

We demonstrated an auto-thermal reforming process for producing hydrogen from biomass pyrolysis liquids. Using a noble metal catalyst (0.5% Pt/Al₂O₃ from BASF) at a methane-equivalent space velocity of around 2000 h⁻¹, a reformer temperature of 800 °C–850 °C, a steam-to-carbon ratio of 2.8–4.0, and an oxygen-to-carbon ratio of 0.9–1.1, we produced 9–11 g of hydrogen per 100 g of fast pyrolysis bio-oil, which corresponds to 70%–83% of the stoichiometric potential. The elemental composition of bio-oil and the bio-oil carbon-to-gas conversion, which ranged from 70% to 89%, had the most significant impact on the yield of hydrogen. Because of incomplete volatility the remaining 11%–30% of bio-oil carbon formed deposits in the evaporator. Assuming the same process efficiency as that in the laboratory unit, the cost of hydrogen production in a 1500 kg/day plant was estimated at $4.26/kg with the feedstock, fast pyrolysis bio-oil, contributing 56.3% of the production cost.     

Optimizing Ni–Ce/HZSM-5 catalysts for ex-situ conversion of pine wood pyrolytic vapours into light aromatics and phenolic compounds

The main objective of the present work is to investigate the influence of nickel to cerium ratio on hydrogen exchanged Zeolite Socony Mobil-5 (HZSM-5) towards the catalytic upgrading of pine derived oxygenated pyrolysis vapours into aromatic hydrocarbon and phenol in pyrolysis oil via ex-situ fixed bed reactor. The presence of CeO₂ could change electron density of Ni, promote the reduction of Ni species, accelerate the transfer of carbon species, and suppress the production of carbon deposits (17.53%–25.11%) compared with the parent HZSM-5 catalyst (28.95%); it also improved the hydrodeoxygenation ability of all xNiyCe/HZSM-5(nickel and cerium bimetal modified HZSM-5) catalysts, resulting increases in noncondensable gas content (from 31.46% to 52.99%–65.53%). Ni to Ce ratio of 1:1 and 1:2 produced highest aromatic hydrocarbon (32.14%) and phenols (55.51%) relative peak areas. The acid center of HZSM-5 and the metal acid center of the Ni:Ce = 1:1 catalyst obviously fine-tuned the formation of coke; and promoted hydrocarbon production. Moreover, high Ni content promoted alkylation of benzene at C6–C9 and increased C10⁺ PAHs relative peak area; high Ce content promoted the formation of olefin and Increasing the cleavage of C–O bonds and promoted hydrogenation or dehydrogenation, reduced polycyclic aromatic hydrocarbons and coke yield, and increased phenols and alkylphenols selectivity.     

Synergistic effect of curcumin and activated carbon catalyst enhancing hydrogen production from biomass pyrolysis

This study observes the synergistic effect of low cost and environmentally friendly catalysts, Activated Carbon and curcumin on the production of hydrogen gas in the biomass pyrolysis process. The Study used turmeric containing curcumin as an anti-oxidant agent added to the activated carbon (AC) catalyst. Biomass from coconut wood was pyrolyzed up to 550 °C using a fixed bed reactor. Both AC and curcumin were combined with a ratio of 1:0, 1:1, 1: 3, 0:1, and 3:1. The addition of AC and curcumin was able to increase the production of hydrogen and methane gas. The combination of AC and curcumin with 1:1 ratio was able to increase hydrogen gas by 25.6%. In addition, this combination was also increase methane gas by 71.8%.Curcumin as an anti-oxidant is able to prevents recombination reactions between radical molecules. Activated carbon surface is more protected from free radicals attacking and sticking to the surface. The phi-phi interaction between the two aromatic rings and the surface of activated carbon produces electrostatic forces on the surface of activated carbon to become stronger therefore it is more reactive in cracking hydrocarbon molecules and producing hydrogen gas. Software simulation, SEM, XRD, and FTIR tests were performed to support the analysis of experimental results.     

Electrochemically active biofilm mediated bio-hydrogen production catalyzed by positively charged gold nanoparticles

An electrochemically active biofilm (EAB) was used for the synthesis of positively charged gold nanoparticles [(+)AuNPs] and in-situ hydrogen production without any external energy input. The EAB generate electrons and protons by decomposing sodium acetate (carbon source) in water at 30 °C. These electrons were used initially to reduce Au³⁺ to Au⁰, and later in-situ, these generated electrons and protons were used for hydrogen production. The as-synthesized (+)AuNPs acted as catalyst by providing a charged surface to reduce the protons, leading to the formation of molecular hydrogen according to the Volmer-Heyrovsky mechanism. The hydrogen produced was confirmed and estimated by gas chromatography and a fuel cell test, respectively. The maximum rate of hydrogen production reached ∼105 ± 2 mL/L day. This suggests that hydrogen production is possible in a single chamber reactor using an EAB in the presence of sodium acetate as a substrate and (+)AuNPs as a catalyst.     

Hydrogen production via catalytic steam reforming of the aqueous fraction of bio-oil using nickel-based coprecipitated catalysts

Hydrogen production was studied in the catalytic steam reforming of a synthetic and a real aqueous fraction of bio-oil. Ni/Al coprecipitated catalysts with varying nickel content (23, 28 and 33 relative atomic %) were prepared by an increasing pH technique and tested during 2 h under different experimental conditions in a small bench scale fixed bed setup. The 28% Ni catalyst yielded a more stable performance over time (steam-to-carbon molar ratio, S/C = 5.58) at 650 °C and a catalyst weight/organic flow rate (W/m_org) ratio of 1.7 g catalyst min/g organic. Using the synthetic aqueous fraction as feed, almost complete overall carbon conversion to gas and hydrogen yields close to equilibrium could be obtained with the 28% Ni catalyst throughout. Up to 63% of overall carbon conversion to gas and an overall hydrogen yield of 0.09 g/g organic could be achieved when using the real aqueous fraction of bio-oil, but the catalyst performance showed a decay with time after 20 min of reaction due to severe coke deposition. Increasing the W/m_org ratio up to 5 g catalyst min/g organic yielded a more stable catalyst performance throughout, but overall carbon conversion to gas did not surpass 83% and the overall hydrogen yield was only ca. 77% of the thermodynamic equilibrium. Increasing reaction temperatures (600–800 °C) up to 750 °C enhanced the overall carbon conversion to gas and the overall yield to hydrogen. However, at 800 °C the catalyst performance was slightly worse, as a result of an increase in thermal cracking reactions leading to an increased formation of carbon deposits.     

Ruthenium quantum dots supported on carbon nanofibers as an efficient electrocatalyst for hydrogen evolution reaction

The hydrogen evolution reaction (HER) is a key step for producing hydrogen by water electrolysis, and an economical, facile and environment friendly method of fabricating catalysts for HER is urgent and essential. In this work, we design a high efficient and stable HER catalyst though a simple adsorption and pyrolysis method. The fabricated catalyst presents ruthenium (Ru) quantum dots (QDs) uniformly distributes on the carbon nanofibers (CNF) with a three dimensional (3D) networks structure (Ru@CNF). By means of quantum size effect of Ru QDs and the 3D networks structure of the carbon nanofibers, the former is beneficial to provide more catalytic active sites and the latter is in favour of electron transport. The sample Ru@CNF exhibits a low overpotential of 20 mV at a current density of 10 mA cm⁻² and Tafel slope of 31 mV dec⁻¹ in 1 M KOH, which is better than that of Pt/C (28 mV and 36 mV dec⁻¹), and most of reported Ru-based and transition metal catalysts. Furthermore, it exhibits robust stability when testing at an overpotential of 75 mV for 24 h. Therefore, this work provides a low-cost, simple and feasible method for fabricating HER catalyst, which possesses commercial application prospect in the field of producing hydrogen by water electrolysis.     

Influence of catalyst and temperature on gasification performance of pig compost for hydrogen-rich gas production

The catalytic steam gasification of pig compost (PC) for hydrogen-rich gas production was conducted in a fixed-bed reactor. The influence of the catalyst and reactor temperature on yield and product composition was studied at the temperature range of 700–850 °C, for weight hourly space velocity (WHSV) in the range of 0.30–0.60 h⁻¹. The results indicate that the developed NiO on modified dolomite (NiO/MD) catalyst reveals better catalytic performance on the tar elimination and hydrogen yield than calcined MD or NiO/γ-Al₂O₃ catalyst. Meanwhile, the lower WHSV and higher reactor temperature can contribute to more hydrogen production and gas yield. Moreover, the char from catalytic steam gasification of PC has a highest ash content of 75.84% at 850 °C. In conclusion, pig compost is a potential candidate for hydrogen gas production through catalytic steam gasification technology.     

Hydrogen production from a solution plasma process of bio-oil

This study examined the possibility of hydrogen production using a solution plasma process (SPP). The reactants were lignin model compounds and actual lignin oil. The highest amount of hydrogen was generated in SPP using m-cresol. The total amount of gas generated by the plasma reaction for 20 min using 23 g of m-cresol was 1.69 L, which comprised of 65.51% hydrogen and 29.85% CO. Furthermore, a maximum of 1.91 L of hydrogen was generated by a reaction between pyrolysis oil and ethanol with a weight ratio of 1:1. The presence of carbon black, a reaction byproduct, was measured by Fourier transform infrared spectroscopy, which revealed molybdenum trioxide peaks. It was confirmed that molybdenum used as an electrode was doped on carbon.     

Nano P zeolite modified with Au/Cu bimetallic nanoparticles for enhanced hydrogen evolution reaction

In the present study, the excellent catalytic performance of Au/Cu bimetallic nanoparticles based on nano P zeolite modified carbon paste electrode (Au/Cu-NPZ-CPE) as one of the most promising electrocatalyst toward hydrogen production is introduced. Herein, nano P zeolite is synthesized by using agriculture residues, stem sweep ash with purity approximately 80.205 wt% of SiO₂ which provides attractive economically silica source for the preparation of inexpensive zeolite. For the preparation of Au/Cu-NPZ-CPE, ion exchange protocol followed by galvanic replacement reaction was employed to result Au/Cu embedded zeolite framework. By evaluating the electrocatalytic activity of proposed catalyst with linear sweep voltammetry and Tafel polarization, a low overpotential of 100 mV and high exchange current density (2.51 mA cm⁻²) are demonstrated which compares favorably to most previously reported electrocatalysts for hydrogen evolution reaction. Owing to the inherent porosity of synthesized nano P zeolite, it successfully prevents the aggregation of bimetallic nanoparticles which promotes the hydrogen evolution reaction. Particularly, low Tafel slope for offered catalyst (33 mV dec⁻¹) demonstrates the acceleration of hydrogen evolution reaction kinetics owing to the increase in the number of accessible active sites. Tafel slope of Au/Cu-NPZ-CPE is 3, 5, 6, 6.5 and 7 times lower than that for Au-NPZ-CPE, Cu-NPZ-CPE, Au/Cu-CPE, NPZ-CPE and CPE, respectively, which shows the best electrocatalytic activity among other modified carbon paste electrodes. Furthermore, the corresponding long term stability test by chronoamperometry method indicates that the current density reaches to nearly 91% of its primary value (after 5500 s) which provides the favorable practical demands of the catalyst in hydrogen production.