Route For Hydrogen Production Research Articles

Hydrogen Production as a Clean Energy Carrier through Heterojunction Semiconductors for Environmental Remediation

Today, as a result of the advancement of technology and increasing environmental problems, the need for clean energy has considerably increased. In this regard, hydrogen, which is a clean and sustainable energy carrier with high energy density, is among the well-regarded and effective means to deliver and store energy, and can also be used for environmental remediation purposes. Renewable hydrogen energy carriers can successfully substitute fossil fuels and decrease carbon dioxide (CO2) emissions and reduce the rate of global warming. Hydrogen generation from sustainable solar energy and water sources is an environmentally friendly resolution for growing global energy demands. Among various solar hydrogen production routes, semiconductor-based photocatalysis seems a promising scheme that is mainly performed using two kinds of homogeneous and heterogeneous methods, of which the latter is more advantageous. During semiconductor-based heterogeneous photocatalysis, a solid material is stimulated by exposure to light and generates an electron–hole pair that subsequently takes part in redox reactions leading to hydrogen production. This review paper tries to thoroughly introduce and discuss various semiconductor-based photocatalysis processes for environmental remediation with a specific focus on heterojunction semiconductors with the hope that it will pave the way for new designs with higher performance to protect the environment.

Preparation Strategy Using Pre-Nucleation Coupled with In Situ Reduction for a High-Performance Catalyst towards Selective Hydrogen Production from Formic Acid

Formic acid decomposition (FAD) is one of the most promising routes for rapid hydrogen (H2) production. Extensive efforts have been taken to develop efficient catalysts, which calls for the simultaneous regulation of the electronic structure and particle size of the catalyst. The former factor determines the intrinsic performance, while the latter corresponds to the active site utilization. Here, an effective preparation strategy, pre-nucleation coupled with in situ reduction, is developed to realize and well-tune both surface electronic states and particle size of the pallidum (Pd) catalyst. Benefiting from the structural merits, the as-prepared catalyst exhibits high mass-specific activity of 8.94 molH2/(gPd·h) with few carbon monoxide (CO) molecules, and the activation energy could reach a value as small as 33.1 kJ/mol. The work not only affords a highly competitive FAD catalyst but also paves a new avenue to the synthesis of ultra-fine metal nanoparticles with tailorable electronic structures.

Revealing the true origin of size-dependent Pd/C catalytic behavior towards formic acid decomposition

Formic acid decomposition (FAD) is considered a promising hydrogen production route to facilitate the ambient storage and on demand release of hydrogen energy. To optimize the catalysts for FAD, efforts have been paid to explore the underlying reason for the varied catalytic activity among catalysts with similar composition but differed structure. However, such endeavors are highly challenging due to the deeply intermingled effects of electronic structure, particle size, and facets, etc. Herein, to separately evaluate the respective effects of these factors, a series of catalysts with the same surface electronic structure and different particle size was prepared by cation dipole adjustment method. The performance and characterization results showed that the catalysts with different sizes and facets exhibited similar intrinsic activity with deviation of less than 5%. However, they showed 252% deviation of site stability, indicating that only the optimized electronic structure could enhance the intrinsic activity and a smaller particle size could extend the catalyst's life.

Hydrogen production from biogas: Process optimization using ASPEN Plus®

This work is part of the VABHYOGAZ (valorization of biogas into hydrogen) program, which targeted the industrial deployment of hydrogen production from biogas in France. To-date, different processes of methane reforming, such as steam reforming of methane (SRM), dry reforming of methane (DRM) and tri-reforming of methane (TRM), have been studied in the literature, but only SRM is applied at industrial scale. Since SRM is an energy-intensive process, a critical analysis of these routes for hydrogen production from biogas is indispensable for process optimization. This has been addressed in this work, by using ASPEN Plus® simulation. Different global processes of hydrogen production from biogas, via DRM, SRM, or TRM, with or without tail gas recycling, have been studied. Among them, hydrogen production using TRM technique (H2-TRM0.3C process) with a partial recycling of tail gas (30%) was found to be the best option, leading to the highest hydrogen production rate and the best energy yield. H2-TRM0.3C process was also found to be more efficient than the actual industrial process (H2-REF), which is based on SRM technique. Under the same conditions, H2-TRM0.3C process led to a higher H2 production (8.7% more), a lower total energy consumption (18.6% less), and a lower waste heat generation (15.4% less), in comparison with the actual industrial process (H2-REF).

Synthesis of novel CoBiTi LDH and fabrication of LDH-LDO 3D-Heterojunction for enhanced infrared induced water splitting to hydrogen

The climate changes due to the long dependence on fossil fuel as the main energy source needs to discover alternative technologies for production of green fuels. Photocatalytic water splitting to hydrogen is a potential technology to achieve this challenge goal, but the process is still far from industrial application due to the weak activities of the fabricated catalysts of wide bandgap energies. Here, novel 1D CoBiTi layered double hydroxide (CBT-LDH) with a bandgap of 2.4 eV has been synthesized by a facile route and achieved hydrogen evolution rate (HER) of 272.8 μmolg−1h−1 without scavengers. Due to doping with highly active Bi, 2D CoBiTi layered double oxide (CBTO) with high infrared (IR)-responsivity (bandgap = 1.27 eV) has been made by drying 1D CBT-LDH at 150 °C, which can achieve 113 μmolg−1h−1 in the presence of a scavenger. However, in-situ compositing CBT-LDH and CBTO can fabricate novel 3D-heterojunction and duplicate the HER by 5 folds (∼1255 μmolg−1h−1) under Xenon light irradiation. The novel 3D-heterojunction can effectively quench the recombination of the photoexcited species by the functional groups from CBT-LDH and cause a strong synergy between the visible and IR irradiation as a promising route for industrial hydrogen production.

Correction: Levelized cost of CO2 mitigation from hydrogen production routes

Correction for ‘Levelized cost of CO2 mitigation from hydrogen production routes’ by B. Parkinson et al., Energy Environ. Sci., 2019, 12, 19–40, https://doi.org/10.1039/C8EE02079E.

Decreasing the Coking and Deactivation of a Reforming Ni-Ce/Al2o3 Catalyst with Intraparticle Sic in Hydrogen Production Routes

Decreasing the Coking and Deactivation of a Reforming Ni-Ce/Al2o3 Catalyst with Intraparticle Sic in Hydrogen Production Routes

Fabrication of TiVO4 photoelectrode for photoelectrochemical application.

Photoelectrochemical (PEC) water splitting is one of the promising, environmentally friendly, carbon emission-free strategies for the cost-effective production of hydrogen. The interest in developing effective approaches for solar-to-hydrogen production with stable and visible light active semiconductors directed many researchers to develop stable and efficient materials. For the first time, a nanostructured TiVO4 photoanode was fabricated at a substrate temperature of 250 °C and further annealed at 600 °C using the spray pyrolysis technique and it obtained an optical band gap of ∼2.18 eV. The photoanode underwent photoelectrochemical testing, where it exhibited a high photocurrent density of 0.080 mA cm-2 at 1.23 V (vs. reversible hydrogen electrode), which can be stable up to 110 min. Further, various physicochemical characterizations were employed to understand the phase purity and thin film growth mechanism. A systematic substrate and annealed temperatures were monitored during the fabrication process. The transmission electron microscopy (TEM) studies revealed agglomeration of TiVO4 nanoparticles with an average size of ∼100 nm accompanying dendritic orientation at the outer edge. This study envisages the design and development of a novel photocatalyst for water splitting under visible light irradiation, an ideal route to a cost-effective, large-scale, sustainable route for hydrogen production.

Techno-Economic Evaluation of Hydrogen Production via Gasification of Vacuum Residue Integrated with Dry Methane Reforming

The continuous rise of global carbon emissions demands the utilization of fossil fuels in a sustainable way. Owing to various forms of emissions, our environment conditions might be affected, necessitating more focus of scientists and researchers to upgrade oil processing to more efficient manner. Gasification is a potential technology that can convert fossil fuels to produce clean and environmentally friendly hydrogen fuel in an economical manner. Therefore, this study analyzed and examined it critically. In this study, two different routes for the produc-tion of high-purity hydrogen from vacuum residue while minimizing the carbon emissions were proposed. The first route (Case I) studied the gasification of heavy vacuum residue (VR) in series with dry methane reforming (DMR). The second route studied the gasification of VR in parallel integration with DMR (Case II). After investigating both processes, a brief comparison was made between the two routes of hydrogen production in terms of their CO2 emissions, en-ergy efficiency, energy consumption, and environmental and economic impacts. In this study, the two vacuum-residue-to-hydrogen (VRTH) processes were simulated using Aspen Plus for a hydrogen production capacity of 50 t/h with 99.9 wt.% purity. The results showed that Case II offered a process energy efficiency of 57.8%, which was slightly higher than that of Case I. The unit cost of the hydrogen product for Case II was USD 15.95 per metric ton of hydrogen, which was almost 9% lower than that of Case I. In terms of the environmental analysis, both cases had comparably low carbon emissions of around 8.3 kg of CO2/kg of hydrogen produced; with such high purity, the hydrogen could be used for production of other products further downstream or for industrial applications.

Renewable Hydrogen Production from Butanol Steam Reforming over Nickel Catalysts Promoted by Lanthanides

Hydrogen is mainly produced by steam reforming of natural gas, a nonrenewable resource. Alternative and renewable routes for hydrogen production play an important role in reducing dependence on oil and minimizing the emission of greenhouse gases. In this work, butanol, a model compound of bio-oil, was employed for hydrogen production by steam reforming. The reaction was evaluated for 30 h in a tubular quartz reactor at 500 °C, atmospheric pressure, GHSV of 500,000 h−1, and an aqueous solution feed of 10% v/v butanol. For this reaction, catalysts with 20 wt.% NiO were prepared by wet impregnation using three supports: γ-alumina and alumina modified with 10 wt.% of cerium and lanthanum oxides. Both promoters increased the reduction degree of the catalysts and decreased catalyst acidity, which is closely related to coke formation and deactivation. Ni/La2O3–Al2O3 presented a higher nickel dispersion (14.6%) which, combined with other properties, led to a higher stability, higher mean hydrogen yield (71%), and lower coke formation per mass (56%). On the other hand, the nonpromoted catalyst suffered a significant deactivation associated with coke formation favored by its highest acidity (3.1 µmol m−²).

An efficient process for sustainable and scalable hydrogen production from green ammonia

This study comprehensively investigates hydrogen production from green ammonia reforming, including synthesis of catalysts, reactor development, process integration, and techno-economic analysis. In-house developed Ru/La–Al2O3 pellet catalyst having perovskite structure showed high catalytic activity of 2827 h−1 at 450 °C and stability over 6700 h at 550 °C, exceeding the performance of the majority of powder catalysts reported in the literature. A scalable 12-faceted reactor adopting the as-produced catalyst was designed to enhance heat transfer, producing over 66 L min−1 of hydrogen with state-of-the-art ammonia reforming efficiency of 83.6 %. Near-zero CO2 emission of hydrogen extraction from green ammonia was demonstrated by-product gas recirculation as a combustion heat source. A techno-economic assessment was conducted for system scales from 10 kW to 10 MW, demonstrating the effect of reduced minimum hydrogen selling prices from 7.03 USD kg−1 at small modular scales to 3.98 USD kg−1 at larger industrial scales. Sensitivity analyses indicate that hydrogen selling prices may reduce even further (up to 50 %). The suggested hydrogen production route from green NH3 demonstrates superior CO2 reduction ranging from 78 % to 95 % in kg CO2 (kg H2)−1 compared to biomass gasification and steam methane reforming. These findings can be used as a basis for following economic and policy studies to further validate the effectiveness of the suggested system and process for H2 production from NH3.

SrxTi1–xCoO3±δ Perovskite‐like Catalysts with Enhanced Activity for Hydrogen Production

AbstractAutothermal reforming (ATR) of acetic acid (HOAc) is a promising and alternative route for hydrogen production from renewable resources, but catalyst deactivation caused by cobalt metal sintering and coking is a major concern in ATR. In this work, perovskite‐like catalysts of the formula SrxTi1–xCoO3±δ (x = 0, 0.2, 0.5, and 0.8) were prepared by evaporation‐induced self‐assembly and then evaluated in ATR for hydrogen production. The SrxTi1–xCoO3±δ catalysts exhibited high activity and stability as well as 100 % conversion of HOAc. Additionally, the Co particles with strong metal‐support interaction of SrTi(Co)O3 inhibited coking and agglomeration, and showed potential for hydrogen production by the ATR process.

Synthesis of an efficient, and recyclable mesoporous BiVO4/TiO2 direct Z-scheme heterojunction by sonochemical route for photocatalytic hydrogen production and photodegradation of rhodamine B dye in the visible region

Sonicated mesoporous BiVO 4 /TiO 2 heterojunctions were recorded for highly efficient photodegradation of rhodamine B dye and production of hydrogen gas. The heterojunction structures were characterized by XRD, DRS, FTIR, BET, FESEM, HRTEM and PL. The efficiency of the radiation power of ultrasound waves [50–300 Watt/cm 2 ] on dye degradation and efficiency of hydrogen production was established. BiVO 4 shifts the photocatalytic response of titania toward visible region. The photocatalytic efficiency of RhB removal on the nanocomposites surface containing 10 wt% BiVO 4 is 0.021 min −1 tenfold higher than that of bare TiO 2 (0.0023 min −1 ). The optimum concentration of BiVO 4 was found to be 10 wt% that generate hydrogen gas with rate equal to 14.3 mmolg −1 h −1 . Ultrasound radiation is a prime key in reducing the population of particle aggregates and reflects a strong interaction between BiVO 4 and TiO 2 nanoparticles that results in lowering the electron-hole pairs recombination rate and increase the concentration of active sites and amount hydrogen evolved. The production of hydroxyl and superoxide radicals suggest a direct Z-scheme mechanism for explaining the high photocatalytic reactivity of sample. • Novel BiVO 4 /TiO 2 nanocomposites were synthesized by sonochemical route. • A strong chemical interaction between BiVO 4 and TiO 2 nanoparticles. • Z-electron transfer scheme is purposed. • A stable photocatalyst for five consecutive cycles.

Bio-Hydrogen Production from Wastewater: A Comparative Study of Low Energy Intensive Production Processes

Billions of litres of wastewater are produced daily from domestic and industrial areas, and whilst wastewater is often perceived as a problem, it has the potential to be viewed as a rich source for resources and energy. Wastewater contains between four and five times more energy than is required to treat it, and is a potential source of bio-hydrogen—a clean energy vector, a feedstock chemical and a fuel, widely recognised to have a role in the decarbonisation of the future energy system. This paper investigates sustainable, low-energy intensive routes for hydrogen production from wastewater, critically analysing five technologies, namely photo-fermentation, dark fermentation, photocatalysis, microbial photo electrochemical processes and microbial electrolysis cells (MECs). The paper compares key parameters influencing H2 production yield, such as pH, temperature and reactor design, summarises the state of the art in each area, and highlights the scale-up technical challenges. In addition to H2 production, these processes can be used for partial wastewater remediation, providing at least 45% reduction in chemical oxygen demand (COD), and are suitable for integration into existing wastewater treatment plants. Key advancements in lab-based research are included, highlighting the potential for each technology to contribute to the development of clean energy. Whilst there have been efforts to scale dark fermentation, electro and photo chemical technologies are still at the early stages of development (Technology Readiness Levels below 4); therefore, pilot plants and demonstrators sited at wastewater treatment facilities are needed to assess commercial viability. As such, a multidisciplinary approach is needed to overcome the current barriers to implementation, integrating expertise in engineering, chemistry and microbiology with the commercial experience of both water and energy sectors. The review concludes by highlighting MECs as a promising technology, due to excellent system modularity, good hydrogen yield (3.6–7.9 L/L/d from synthetic wastewater) and the potential to remove up to 80% COD from influent streams.

Insights on biological hydrogen production routes and potential microorganisms for high hydrogen yield

Considering the present energy demand and industrial growth, finding a potential sustainable energy source is crucial. Among renewable fuels, hydrogen is considered to be the primary choice as it offers substantial benefits over other conventional fuels. Hydrogen can be generated from waste substrates, is cleaner, and has the highest energy density when compared to conventional fuels. Hydrogen production, particularly biological hydrogen production, is believed to be cost-efficient as it can be successfully performed in ambient conditions with easy operational techniques in an environmental-friendly manner. This review summarizes the different routes of biological hydrogen production including biophotolysis, indirect photolysis, dark fermentation, photofermentation, and microbial electrolysis. Further, leading microorganisms involved in biohydrogen production, such as Clostridium spp., Enterobacter spp., Bacillus spp., Escherichia coli, thermophilic lactic acid bacteria, and Klebsiella spp., along with the molecular approaches employed for the enhancement of biohydrogen production are discussed. In addition, a thorough techno-economic analysis of factors involved in the scale-up of hydrogen production is carried out.

Thermochemical conversion routes of hydrogen production from organic biomass: processes, challenges and limitations

Hydrogen production from various organic biomass via thermochemical process is considered as a promising and economical viable technique. The advantages of this process are higher product yield and flexibility with current available facilities than other hydrogen production methods. Nowadays, large-scale hydrogen production from various biomass is the challenging process. Still, few thermochemical conversion process are yet in developing stage and there are several issues need to be solved for its successful pilot-scale operation, for example fluctuation equipment cost, availability of feedstocks, practical barriers, and public reception. Most of the researchers have strongly recommend that organic biomass is a suitable and predominant source of feedstock for hydrogen production. But, an extensive energy is required for the thermochemical conversion technologies to produce hydrogen rich syngas, due to extremely endothermic effect. In future, more research is required to reduce the emission of greenhouse gas and hydrogen production cost. In addition to this, certain mathematical modeling is required to reduce process energy demand. Detailed techno economic investigations are required to prior implementation of large-scale reactor. This review focuses on various thermochemical conversion technologies and their potential ways of hydrogen production using various organic biomass as a feedstock, challenges, and limitations associated with the process.

Highly Efficient Al-Doped Ni–Mn–O Catalysts for Auto-Thermal Reforming of Acetic Acid: Role of MnAl2O4 for Stability of Ni Species

Auto-thermal reforming (ATR) of acetic acid (HAc) from renewable bio-oil is an alternative route for hydrogen production, and a series of Ni/Mn(II)Al(III)Ox±δ catalysts were prepared via co-precipi...

Numerical study of sorption-enhanced methane steam reforming over Ni/Al2O3 catalyst in a fixed-bed reactor

The present work deals with the Sorption-Enhanced Methane Steam Reforming (SE-MSR), an interesting and energy-efficient hydrogen production route with in situ CO2 capture. A computational fluid dynamics (CFD) model for an industrial-scale fixed-bed reactor, with Ni/Al2O3 as catalyst and CaO as an adsorbent for CO2 capture, is developed taken into consideration also the coke deposition. Temperature is shown to be the key parameter of the SE-MSR chemical process at large scales. H2 production is constant and maximum until the saturation of CaO sorbent occurs, after which the concentrations of all the other compounds start to vary, and the efficiency of the process begins to drop. When the exothermic carbonation reaction stops, an alteration of the thermal regimes is observed. The absence of the contribution of the exothermic carbonation reaction results in a decrease of the temperature, which in turn determines a lower conversion of CH4 and H2O, according to the endothermic reforming reactions.The maximum H2 outlet mole fraction (dry basis) is 0.8, and it occurs in the presence of CO2 sorption; the value drops to 0.42 once the adsorbent reaches its maximum conversion degree. The molar selectivity in hydrogen relative to the quantity of CH4 fed to the reactor is of the order of 1.75 (with CO2-capture) and 0.8 (without CO2 capture).The molar fluxes obtained and the kinetics of the system model show the excellent choice of the operating conditions of the catalyst to produce a large quantity of hydrogen as well as of the adsorbent, which eliminates the CO2 responsible of coke deposition.

In-situ microwave-assisted catalytic upgrading of heavy oil: Experimental validation and effect of catalyst pore structure on activity

In-situ combustion alone may not provide sufficient heating for downhole, catalytic upgrading of heavy oil in the Toe-to-Heel Air Injection (THAI) process. In this study, a new microwave heating technique has been proposed as a strategy to provide the requisite heating. Microwave technology is alone able to provide rapid heating which can be targeted at the catalyst packing and/or the incoming oil in its immediate vicinity. It was demonstrated, contrary to previous assertions, that heavy oil can be heated directly with microwaves to 425 °C, which is the temperature needed for successful catalytic upgrading, without the need for an additional microwave susceptor. Upgrading of >3.2° API points, a reduction in viscosity to less than 100 cP, and >12% reduction in sulfur content was achieved using commercially available hydrodesulfurization (HDS) catalyst. The HDS catalyst induced dehydrogenation, with nearly 20% hydrogen detected in the gas product. Hence, in THAI field settings, part of the oil-in-place could be sacrificed for dehydrogenation, with the produced hydrogen directed to aid hydrodesulfurization and improve upgrading. Further, this could provide a route for downhole hydrogen production, which can contribute to the efforts towards the hydrogen economy. A single, unified model of evolving catalyst structure was developed. The model incorporated the unusual gas sorption data, computerized x-ray tomography and electron microprobe characterization, as well as the reaction behavior. The proposed model also highlighted the significant impact of the particular catalyst fabrication process on the catalytic activity.

Conversion of ethane to ethylene and hydrogen by utilizing carbon dioxide: Screening catalysts

Owing to the necessity of carbon dioxide conversion and exploring new routes for ethylene and hydrogen production, carbon-dioxide-assisted dehydrogenation over alumina-supported catalysts is evaluated in the present contribution. In this regard, the experimental results of a wide range of catalysts at 700 °C and the GHSV of 3600 Lreactants/kgcatalyst.hr are presented and compared. The utilized catalysts showed activity toward the conversion of ethane. However, a few of them showed good selectivity for the production of either ethylene or hydrogen. The catalysts made up of the oxides of cobalt and molybdenum showed very good conversion, selectivity, and yield for ethylene production. Investigating the effect of time on steam on the catalyst performance indicated that these catalysts would be suitable choices in the course of ethylene production. 58% conversion of ethane and 21.9% ethylene yield are the achievements of utilizing the molybdenum-cobalt oxide catalyst. By utilizing rhenium-platinum nickel-potassium catalysts, 100% ethane conversion in tandem with more than 260.0% hydrogen yield was also obtained.